ABB motors and drives Driving energy efficiency worldwide. Sustainability guide No. 1

Transcription

1 ABB motors and drives Driving energy efficiency worldwide Sustainability guide No. 1

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3 ABB motors and drives Driving energy efficiency worldwide Sustainability guide No. 1 3AFE REV B EN EFFECTIVE: Copyright 2009 ABB. All rights reserved.

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5 Contents Chapter 1 Introduction... 7 Chapter 2 - The energy dilemma... 8 Growing needs, diminishing resources, increasing environmental concerns 8 Europe could cut energy consumption by 20 percent... 9 Climate consensus: something has to be done... 9 Atmospheric warming reaches new levels Industry uses over 40 percent of total world electricity Chapter 3 - Europe takes action The EU s bold advance Momentum is building up Raising awareness among decision makers Most productive employees Management must be proactive ESCO: an efficient financing model Monitoring systems essential Chapter 4 - Sustainable and efficient energy use Quick, effective and low cost Energy efficiency needs to become fashionable Global demand for drives Two-thirds of industrial electricity used by electric motors Better control and higher efficiency Chapter 5 - ABB motors and drives for efficient control Potential for major energy savings Half speed for only a quarter of the energy Subsidies for high efficiency motors New standards pave the way for international harmonization Developing an effective motor management policy AC drives are the ideal solution for speed control Looking at the entire life cycle Chapter 6 - Energy audits identify potential savings Evaluating how energy is used Recommendations based on actual data Additional savings from unexpected sources Payback within months Tools help with financing calculations... 34

6 Chapter 7 - Case studies: big savings with modest investments China: Plastics plant cuts energy consumption by 30 percent China: Substantial energy savings and reduced emissions Finland: Drives help to cut water utility s energy bill Germany: Drives keep natural gas supplies flowing smoothly Honduras: Sugar plant boosts annual revenues by $1 million India: Improved fan control increases efficiency at cement plant Netherlands / international: High efficiency motors cut running costs Sweden: Mining company acquires only high efficiency motors UK: Salt producer saves over 1,600 MWh per year US: Drives play key role in helping to preserve vegetable crops US: University of Texas saves millions through boiler retrofit... 50

7 Chapter 1 Introduction Fossil fuels are non-renewable. Significant untapped reserves are still available, but their extraction is becoming increasingly more difficult and expensive. It is clear that if the world continues to use its fossil fuel resources at present consumption rates they will be exhausted in a relatively short time. In a situation where energy needs are rising and supplies are diminishing, one obvious course of action is to use energy more efficiently. This guide examines how readily available, tried and tested technologies variable speed drives and high efficiency motors - can help to save energy and reduce greenhouse gas emissions. Motor-driven pumps and fans, for example, provide significant scope for energy saving. Many such applications are operated in a very inefficient manner: the motor drives the pump or fan at full speed, and the desired rate of flow of liquid or gas is achieved by throttling the output by means of valves, vanes or other mechanical devices. Operating this way - running the motor at full speed and then restricting the output - can be compared to driving a car with one foot on the accelerator and the other on the brake. Pump and fan systems can generally be run more efficiently be adding a variable speed drive (VSD). A VSD will regulate the motor speed to match the precise needs of the process and thereby boost the efficiency of the entire system. In 2008 the worldwide installed base of ABB drives saved about 160 terawatt-hours (TWh), which is equivalent to the annual consumption of more than 39 million families. The drives also reduced carbon dioxide emissions by around 135 million tonnes in the same year. AC drives and high efficiency motors are being installed in all kinds of applications all over the world. This guide gives a number of real-life examples where drives and high efficiency motors have not only reduced energy consumption but also provided other benefits such as better quality products, reduced greenhouse gas emissions, and less wear and tear on process equipment.

8 Chapter 2 - The energy dilemma Growing needs, diminishing resources, increasing environmental concerns Fossil fuels are non-renewable and at present consumption rates the world will exhaust its fossil fuel resources in a relatively short time. New ways of providing energy such as atomic fusion and hydrogen fuel cells will not become properly viable for some considerable time. Renewable sources can make up part of the shortfall, but are also subject to limitations. Proposals for wind turbines invariably meet strong resistance from people living in the affected locality, for example, and biofuels still need a great deal of development work before they can be used in place of existing fuels. Meanwhile, world energy consumption is steadily rising. World consumption almost doubled from 1973 to 2004 and continues to rise, albeit at a slower rate. By 2030 it is estimated that some 25 percent more energy will be used than in Figure 2.1. Although renewables and atomic energy have increased their relative shares of world energy supplies, fossil fuels still provide the major part of world energy.

9 The energy dilemma Figure 2.2. World energy needs appear insatiable. It is expected that energy use will rise by some 25 percent from 2010 to Europe could cut energy consumption by 20 percent Using the available energy more efficiently is an ideal way to meet ever-rising energy needs and secure energy supplies. According to the EU s Green Paper on Energy Efficiency, the EU could save at least 20 percent of its current energy consumption. This is equivalent to the present combined energy consumption of Germany and Finland, or 60 billion euros per year. By 2030, on the basis of present trends, the EU will be 90 percent dependent on imports for its oil; the corresponding figure for gas will be 80 percent. Making a real effort to cap EU energy demand at present levels and subsequently reduce it would represent a big step towards securing EU energy supplies. The application of energy efficiency measures would also help to create many new, high quality employment opportunities. Furthermore, with a successful energy efficiency scheme, some of the 60 billion euros saved on energy would go towards increasing the EU s competitiveness and promoting better living conditions for its citizens. In this way an average household could save up to 1,000 euros per year, depending on its energy consumption. Climate consensus: something has to be done The world is living it up. Western countries seem to be consuming ever more energy, and as living standards in the developing countries improve, the rest of the world is catching up.

10 The energy dilemma A consensus among politicians, scientists and industry leaders has been building: something has to be done. This is underlined by the results of a study conducted by the Intergovernmental Panel on Climate Change (IPCC), which was presented in early 2007 in Paris. The IPCC study investigates the natural and human drivers of climate change, examines climate processes, and presents estimates of future climate change. Analysis of ice cores spanning many thousands of years shows that global atmospheric concentrations of carbon dioxide, methane and nitrous oxide have increased markedly as a result of human activities since the mid 1700s and now far exceed pre-industrial values. Global increases in carbon dioxide concentrations are primarily due to fossil fuel use and land-use change, while increases in methane and nitrous oxide concentrations are primarily due to agriculture. The global atmospheric concentration of carbon dioxide has increased from a pre-industrial value of about 280 parts per million (ppm) to a level of 379 parts per million (ppm) in The annual rate of increase in the carbon dioxide concentration was higher during the 10 year period from 1995 to 2005 than at any time since the beginning of continuous direct atmospheric measurements. Figure 2.3. Carbon dioxide emissions have grown in all parts of the world. The level is now over one and a half times greater than 30 years ago. 10

11 The energy dilemma Atmospheric warming reaches new levels Increasing levels of carbon dioxide are leading to atmospheric warming. There is no longer any ambiguity about the warming of the climate system. It is evident from the many changes that can be observed: increasing global average air and ocean temperatures, rising sea levels, and widespread melting of snow and ice covers. Of the twelve years between 1995 and 2006, eleven rank among the 12 warmest years since 1850, when instrumental records of global surface temperatures started to be kept. Numerous long-term climate changes have been observed on the continental, regional, and ocean basin scales. These include changes in Arctic temperatures and ice behavior, widespread changes in amounts of precipitation, ocean salinity, and wind patterns, and changes in extreme weather conditions including droughts, heavy precipitation, heat waves, and tropical cyclones. Projections indicate that warming of about 0.2 C per decade can be expected during the next two decades. Even if concentrations of all greenhouse gases and aerosols were kept constant at year 2000 levels, a further warming of about 0.1 C per decade would be expected. Continued greenhouse gas emissions at or above current rates would cause further warming. They would also induce many changes in the global climate system during the present century that would very likely be greater than those observed during the previous one hundred years. Even if greenhouse gas concentrations were to be stabilized, anthropogenic warming and sea level rise would continue for centuries due to the timescales associated with climate processes and feedback systems. If all the ice in Greenland melted, the sea level would rise by seven meters. Even with less dramatic changes the world faces a rise in sea level of between 20 centimeters and one meter, depending on the estimate, during this century. Industry uses over 40 percent of total world electricity The world is demanding more and more electricity. From 1973 to 2004 world electricity consumption almost tripled. Industry accounts for just over 40 percent of total consumption. 11

12 The energy dilemma Energy saving is without doubt the quickest, most effective and most cost-efficient way of reducing greenhouse gas emissions, as well as improving air quality, particularly in densely populated areas. The IPCC s Mitigation of Climate Change report finds that in order to satisfy demand for energy it is often more costeffective to invest in improving end-use energy efficiency than in increasing energy supply. Improving efficiency has a positive impact on energy security, local and regional air pollution abatement, and employment. The report also concludes that economic potential in the industrial sector is predominantly found in the energy intensive industries. The available mitigation options are not being fully used either in the industrialized or developing nations. Many industrial facilities in developing countries are new and incorporate the latest technology with the lowest specific emissions. However, many older, inefficient facilities remain in both industrialized and developing countries. Upgrading these facilities can deliver significant emission reductions. The slow rate at which capital goods are turned over, lack of financial and technical resources, and limitations in the ability of firms, particularly small and medium-sized enterprises, to access and absorb technological information are key barriers to the full application of the available mitigation options. Figure 2.4. World consumption of electricity has almost tripled in thirty years. 12

13 The energy dilemma The Motor Challenge Programme - a voluntary scheme promoted by the European Commission to help companies improve the energy efficiency of their electric motor driven systems - estimates that such systems account for approximately 65 percent of the electricity consumed by industry in the EU. Switching to energy efficient motor driven systems throughout Europe could produce savings amounting to 202 billion kwh in electricity consumption, which is equivalent to a reduction of 10 billion euros in annual operating costs for industry. Potential electricity savings (billion kwh/year) EU-15 EU-25 France Germany Italy UK High efficiency motors Variable speed drives Applications (pumps, fans, compressors) Total Table 2.1. Switching to energy efficient motor driven systems in the EU could save over 200 billion kwh annually. Rising energy prices have forced companies to seek ways of limiting their energy consumption. In the UK it has been estimated that the chemical industry uses 22 percent of all the energy used by UK manufacturing. This industry accounts for 2 percent of the country s gross domestic product (GDP) and employs some 230,000 people. It is facing average price increases of 70 percent for gas and 60 percent for electricity, prompting companies within the industry to look for ways of further improving their energy efficiency before their competitiveness is eroded by cheaper imports. Energy price rises are affecting companies across the board, from large multinationals to small, local businesses, and not only in the chemical industry but in printing, food production and other energy intensive sectors, too. Sources: EU Green Paper on Energy Efficiency Intergovernmental Panel on Climate Change: Climate Change 2007 International Energy Agency: Key World Energy Statistics Energy Efficient Motor Driven Systems, The Motor Challenge Programme 13

14 Chapter 3 - Europe takes action The EU s bold advance November 2006 saw agreement on a new energy efficiency action plan by European energy ministers. The measures proposed in the plan will lead to an estimated 20 percent improvement in energy efficiency by In March 2007 the Council of Europe adopted a significant energy and climate package, which is based on three main elements: building a true internal energy market, shifting to low carbon energy, and promoting energy efficiency. The EU is now committed to reducing greenhouse gas emissions by at least 20 percent by Furthermore, the Heads of State and Government have endorsed a binding target of 20 percent for the share of overall EU energy consumption to come from renewable supplies. Climate change is definitely the headline issue, but security of energy supply is also a critical topic, says Ms. Sirkka Vilkamo, Deputy Director General and Head of the Renewables and Energy Efficiency Division at Finland s Ministry of Trade and Industry. At present there are around 20 EU Directives which relate to energy. The Energy Performance of Buildings Directive, for instance, stipulates certain measures but does not specify numerical objectives. There is certainly good potential for savings in this area, as around 40 percent of the energy consumed in the EU is used for heating and cooling buildings. The Energy Services Directive passed in May 2006, by contrast, does lay down numerical objectives. This Directive applies to all energy using sectors, with the exception of businesses involved in emissions trading, and aviation and maritime bunker fuels. It provides an indicative 9 percent objective for energy saving over the period In 2016 we have to be able to show that we have achieved savings of 9 percent. This does not mean, however, that in 2016 we should be consuming 9 percent less energy than in The obligation is to implement measures that generate savings so the idea is that if we had not done anything we would be consuming 9 percent more in 2016, explains Heikki Väisänen, Senior Adviser at the Energy Department of the Finnish Ministry of Trade and Industry. 14

15 Europe takes action Momentum is building up It is difficult to show that savings have really taken place when energy consumption is steadily on the rise. The challenge for member states is to prove that something that no longer exists the kilowatt-hours of energy consumption taken out of use did in fact once exist. In all fields and sectors there is a lot that can be done. The goal of increasing energy efficiency by 20 percent implies a reduction in energy consumption of 13 percent from today s levels. The underlying objective of increased energy efficiency is to reduce climate change. Ideally, this is something that the whole world should be involved in, but the EU is prepared to act alone if other parties are not yet prepared to participate. The two key drivers are the need to avoid compromising current operations and the desire to cut emissions. While renewable energy has been more of an issue in the public debate, recent studies show that improving energy efficiency has been seen as a more efficient tool at the EU level and even at the world level. The EU has played an active role with new energy efficiency initiatives, and will now also be active on the global scale. Looking back over the last ten years, there has been a lot of talk about energy efficiency. Now there is real momentum to do something. The objectives set by the EU clearly show its current ambitions, Väisänen says. Now we have actual numerical objectives the pressure is really on. This makes the whole thing much more serious. Emissions trading has been one way of steering developments in the right direction, says Sirkka Vilkamo. Raising awareness among decision makers Heikki Väisänen acknowledges that improving energy efficiency is not in itself part of the basic business of companies. However, companies and government can work together because better energy efficiency also makes businesses more competitive. Energy costs may be small relative to a company s turnover, meaning that the financial advantages of energy efficiency are not particularly visible. However, better energy efficiency can significantly lower production costs and provide the best return on investment. Therefore, it is important to raise awareness of energy efficiency among decision makers. In Väisänen s experience, the main issue is often not that of finding the necessary funding but simply of making the decision to use it. 15

16 Europe takes action We have been running an energy efficiency agreement scheme for the last ten years. Its greatest value has been in getting companies interested in the benefits energy efficiency can provide. In addition, those companies that were already interested have received extra support for their work. One of the benefits of the energy efficiency agreements is that they provide a network through which knowledge can be shared, he says. When a company decides to enter into an agreement, it makes a commitment to analyze its existing situation and improve its energy efficiency - by boosting the efficiency of its production process, for instance. In return the company can be granted subsidies for energy audits and energy efficiency investments. Energy efficiency agreements now cover more than 60 percent of the total energy consumption in Finland. Väisänen believes that a voluntary agreement-based system provides the optimum cost-efficiency because it leaves room for individual thinking and flexibility in the measures taken. Most productive employees The energy efficiency improvements achieved have to be measurable for feedback purposes. Heikki Väisänen compares the feedback loop to the real-time fuel consumption displays found in many cars. Drivers remain strongly motivated to drive economically when they see how it reduces their fuel consumption and benefits them financially. The employees involved in company energy programs may well be the most productive members of the workforce. There are not very many people who can directly contribute, say, half a million euros per year to their company s bottom line, he says. He stresses that companies should not limit their energy efficiency activities to standalone projects: best practices can and should be duplicated in other plants. Companies should also ensure that energy efficiency is established as part of their purchasing guidelines. Class A equipment may be slightly more expensive than less efficient products, but the difference in price is rapidly recovered when operating costs are taken into consideration. Management must be proactive Sirkka Vilkamo points out that the signing of an agreement is only the first step: it has to be adopted by the company s management. She says that energy audits, one of the obligations contained in the agreements, can be compared to periodic health checks. 16

17 Europe takes action Heikki Väisänen explains that the audit approach provides a solid basis for subsequent action: All the companies that have joined the scheme have started by doing an energy audit. Based on the audit findings, the company then decides when and how it will take the next step. In industry, investment payback times of two to three years are usually feasible, while in other sectors, such as local authorities, the payback time can be between five and ten years. The agreements have prompted a wide range of measures aiming to increase energy efficiency. These include acquisition of new production equipment, VSDs, compressed air and heatrecovery systems. ESCO: an efficient financing model There is also an alternative way of financing the investments. It is known as energy performance contracting - the investments are paid back over time by the energy savings that are realized, says Väisänen. These Energy Service Company (ESCO) operations can achieve even better efficiencies by implementing entire projects - from energy audits to financing and investments. In many companies in Finland this concept has established itself as an everyday way of implementing investments to boost energy efficiency. Previously the ESCOs had to take out a loan to cover the investment, but now the usual practice is for the ESCO contract to be sold to a commercial finance provider once the investment has been commissioned and the level of realized savings verified. Further work needs to be done to gain broader acceptance for ESCO agreements, but as Heikki Väisänen confirms once a company has tried the system it is then easier to put together a second agreement to implement improvements elsewhere at the same site. Energy efficiencies are often built on a step-bystep basis. Monitoring systems essential Heikki Väisänen believes that energy efficiency agreements will play a decisive role in ensuring that the EU s energy efficiency goals are reached, especially because it is necessary to collect information on the amount of savings realized. 17

18 Europe takes action There are differences between the member states in respect of the amount of information on energy efficiency that is collected, and the methods used to calculate energy savings. The Energy Services Directive seeks to harmonize the methodologies used for calculating savings. While this is a necessity for certain types of measures, it may however prove quite problematic with others. Climate conditions pose quite different challenges between Northern and Southern Europe, for instance. Guidelines on the methodologies for calculating energy savings are now being developed but it remains to be seen how much harmonization can finally be achieved. 18

19 Chapter 4 - Sustainable and efficient energy use Quick, effective and low cost Many solutions have been put forward to combat climate change. Renewable energy, carbon capture and biofuels stand out among the main ones. All three approaches are valid and must be pursued, but at present most of the required technologies are either not yet ready to be applied in practice, still too expensive, or involve undesirable side effects. By contrast, ABB supplies technologies that can help to reduce carbon dioxide emissions immediately and they can be deployed quickly and at low cost. The idea is to use energy more efficiently. ABB has been developing energy efficient technologies for many years, and solutions incorporating these technologies can produce big savings in energy and emissions. ABB supplies technologies that can help to reduce carbon dioxide emissions immediately. In industry the biggest reductions in emissions in the short term will come from measures to run processes more efficiently. Of total electricity consumption, industry accounts for about 40 percent, of which two-thirds is used by electric motors. VSDs can reduce the energy consumption of motors by 50 percent in many applications, and yet less than 10 percent of motors are operated by drives. This represents a fantastic opportunity to bring about a dramatic reduction in emissions using readily available, low cost and proven technology. 19

20 Sustainable and efficient energy use Energy efficiency needs to become fashionable Global demand for drives ABB s mission is to pursue power and productivity for a better world. Panu Virolainen,, Vice President, Technology, of ABB s Low Voltage AC Drives business feels that the idea behind the mission is nowadays so self-evident that it does not require any explanation. After a moment s thought he adds that in practice it means that ABB helps customers to use electrical power effectively and increase industrial productivity in a sustainable way. For large corporations energy efficiency may also have become a self-evident way to increase productivity and curb rising energy costs. It is among small and medium sized enterprises that the savings and benefits are less obvious. Virolainen says somewhat jokingly - that energy efficiency needs to become fashionable to become more widely adopted. In fact, market statistics indicate that energy efficiency is on the way to becoming a fashion. Sales of AC drives have been growing steadily at an annual rate of 6 10 percent. We are now seeing the same kind of urgency as there was in the 1970 s when the oil crisis caused energy prices to sky-rocket. ABB came up with a solution to save energy by controlling the frequency of the power supply. Since then the technology has evolved into a highly reliable and cost-effective means of controlling industrial processes, Virolainen says. In the 21st century energy saving is still a hot topic, but there is also another major concern: greenhouse gas emissions have to be cut. AC drives are much smaller and cost a lot less than 30 years ago. Prices of electronic equipment have been heading downwards for a number of years and, coupled with rising energy costs, this means that payback times for energy saving equipment have become much shorter. As a result, installing AC drives on even small machines has become an attractive option. Pumps, fans, compressors and extruders account for a large proportion of industrial drive applications. Virolainen states that the actual operation point of these originally designed to be. In many cases energy is wasted because the flow of liquid or gas is regulated by means of a brake or throttle mechanism. The idea behind an AC drive is to adjust the speed to match the point of operation. 20

21 Sustainable and efficient energy use The worldwide installed base of ABB drives saved about 160 TWh in 2008, which is equivalent to the annual consumption of more than 39 million families. The drives also reduced carbon dioxide emissions by around 135 million tonnes in the same year. With high powered machinery even incremental changes in energy efficiency can bring about big savings relative to the purchase price but, as Virolainen points out, the trend is to equip smaller and smaller machines with AC drives. In Japan, for instance, many rooms have individual ventilation equipment consisting of a small motor, a ventilator and an AC drive. These low-cost integrated packages are used to control the airflow in all rooms individually. This equipment is widely used in Japan, where energy prices have generally been very high. Europe has not yet caught up in this respect, says Virolainen. Two-thirds of industrial electricity used by electric motors In industry, 65 percent of total electricity consumption is used for driving electric motors. Using AC drives, motor speeds can be controlled according to demand, making possible savings of up to 70 percent in energy consumption. In Europe, demand for AC drives has been significantly boosted by emissions trading and other measures to cut back carbon dioxide emissions. Demand has also been increased by the fact that there are now only limited oil resources available at affordable prices. For its part, the US has also started to look for ways to reduce its dependence on oil. Utilizing the available energy more efficiently is one of the most obvious solutions. China, by contrast, has different problems. Production volumes are growing so rapidly that it is not possible to build sufficient power plants to meet the demand. In order to keep its growth on track, China will have to save energy. India faces the same kinds of challenges. Better control and higher efficiency ABB has a well-established procedure to help customers save energy. This begins with an energy audit, which usually produces clear suggestions for areas that can be improved. Large companies have tended to lead the way, because energy is usually a major cost for them. 21

22 Sustainable and efficient energy use The main argument for acquiring AC drives is to save energy but, as Panu Virolainen explains, drives also provide better control over the entire process. Using drives could mean that a production machine can be used for different kinds of materials or manufacturing recipes, for instance. When fixed-speed motors without drives were used, speed changes required the use of infinitely-variable speed drives, belts or gear boxes. Hydraulics were also often needed, which could mean oil leakages. Speed control mechanisms often led to losses in power transmission. Today s AC drives eliminate these kinds of problem. A further factor in favor of drives is that the prices for mechanical solutions are not decreasing and in some cases are even increasing gradually - while the prices of AC drives have declined steadily with advances in control electronics. The scientific principles underlying the operation of AC drives have remained the same for a number of years. They have become the foundation for a proven technology that has been enhanced with software based solutions for controlling properties such as pressure, temperature, or flow rates. 22

23 Chapter 5 - ABB motors and drives for efficient control Potential for major energy savings With electric motors accounting for an estimated 65 percent of industrial energy use, any increases in efficiency clearly provide the potential for major savings. The energy consumption of electric motors can be reduced in two main ways by implementing efficient speed control and by increasing the efficiency of the motors themselves. VSDs are by far the most effective method of controlling motor speeds. In practice, however, control is often still implemented with throttling valves in pump systems, vanes in fan applications, or gears or belt drives in rotating machinery. Belt drives, gearboxes and hydraulic couplings all add to the inefficiency of the system, and require the motor to run at full speed all of the time. In addition, mechanical drives can be noisy as well as difficult to service, as they are situated between the motor and the driven machinery. Mechanical drives often seem cost-effective at first sight, but they waste energy. Running a motor at full speed while throttling the output is rather like trying to control the speed of a car by keeping one foot on the accelerator and the other one on the brake part of the output produced is immediately wasted. Taken over industry as a whole, the total amount of energy wasted in this way is huge: of the estimated 65 percent of industrial energy that is used by electric motors, some 20 percent is lost by throttling mechanisms. Half speed for only a quarter of the energy In pump and fan applications, VSDs can cut energy bills by as much as 60 percent. A pump or fan running at half speed consumes only one quarter as much energy as a unit running at full speed. As a small reduction in speed can make a big difference in energy consumption, and because many pump and fan systems run at less than full capacity for much of the time, VSDs can produce huge savings. This is particularly so when compared to motors that are continuously running at full speed, even though motors have improved in efficiency by an average of 3 percent over the last decade. It has been estimated that AC drives supplied by ABB over the past ten years for the speed control of pumps and fans have reduced electricity consumption by around 160 TWh per year worldwide. 23

24 ABB motors and drives for efficient control Regulating motor speeds has the added benefit that production increases can easily be accommodated without the need for extra investment, as AC drives can easily manage speed increases of 5 20 percent. By matching the performance of the motor to the needs of the process, drives can produce major savings when compared to the wasteful practice of running the motor at full speed against a restriction to modulate output. In an ideal world, energy would be applied with pinpoint accuracy when and where it was needed, and no energy would be wasted. Despite the obvious energy saving advantages, 97 percent of all motors in applications under 2.2 kw have no form of speed control at all. This corresponds to some 37 million industrial motors sold annually worldwide. This might have been understandable in the past, as a small drive cost in the region of $500 (400 euros) per kw. Drives across the range have become smaller and cheaper over the past few years, however, and now start at around $150 (100 euros) per kw. This can make investment in a VSD a viable proposition on energy grounds alone. In addition, the new generation of drives is smaller and so installation might be possible in places where space constraints were an issue in the past. The latest drives are also more energy efficient than their predecessors. ABB is leading the way in developing drive technology, with state-of-the-art control techniques such as direct torque control (DTC). A feature of DTC which contributes directly to energy efficiency is motor flux optimization, which greatly improves the efficiency of the total drive (the controller and the motor), especially in pump and fan applications. The drives themselves are becoming leaner too, not only smaller in size but more energy efficient to manufacture, with smaller circuit boards and enclosures made of recyclable plastic. Subsidies for high efficiency motors In many countries financial incentives are now available to encourage investment in high efficiency motors. The Danish Energy Agency is one of the leading organizations in the field. It has published a list of high efficiency motors and offers a subsidy of $10 (7.70 euros) per kilowatt for both new and replacement units purchased from the list. This scheme is promoted direct to the 4,000 largest motor users. The USA and Canada have introduced the Energy Policy and Conservation Act (EPAct). Among other legislation to improve the environment, this specifically targets motors from 0.75 to 150 kw as prime candidates for improvement. A scheme similar to the Danish one has been adopted, with a published list of high efficiency motors and reduced electricity tariffs for users of the listed products. 24

25 ABB motors and drives for efficient control The US Department of Energy also requires the efficiency rating to be indicated on the motor nameplate, the energy efficiency to be displayed prominently in all literature and marketing material, and the inclusion of other markings to facilitate the enforcement of energy efficiency standards. Failure to comply with these requirements results in severe penalties. New standards pave the way for international harmonization The IEC has introduced two new standards relating to energy efficient motors. IEC/EN specifies new rules concerning efficiency testing methods and IEC defines new efficiency classes for motors. ABB welcomes the new IEC standards, as their effect will be to level the playing field for motor manufacturers. The new standard will tighten up procedures and enable manufacturers to publish more accurate efficiency values. The new classification standard harmonizes the currently differing requirements around the world regarding efficiency levels of induction motors. It will hopefully put an end to the difficulties experienced by manufacturers when producing motors for a global market. Emissions will be reduced significantly if a majority of motor manufacturers take steps to improve the efficiency of their products. Motor users will benefit by having access to more transparent and easier to understand information, and will be encouraged to install high efficiency motors exclusively. IEC/EN , which came into force in September 2007, introduces new rules concerning the testing methods to be used for determining losses and efficiency. The documentation supplied with the motor must state which method is used. Of the methods available under the new standard, ABB uses the indirect method with stray load losses determined by measurement. The resulting efficiency values differ from those obtained under the previous IEC testing standard, IEC : It must be noted that efficiency values are only comparable if they are obtained using the same method. 25

26 ABB motors and drives for efficient control Figure 5.1. The EU has published energy efficiency categories for motors. There are three class levels: Eff1, Eff2, and Eff3, applying to low voltage two- and four-pole motors rated from 1.1 to 90 kw. The aim is to phase out production of less energy efficient machines. IEC was introduced in October 2008 and defines three IE (International Efficiency) efficiency classes for single-speed, three phase, cage induction motors. IE1 = Standard efficiency (efficiency levels roughly equivalent to EFF2 under the European efficiency scheme) IE2 = High efficiency (efficiency levels roughly equivalent to EFF1 under the European scheme and identical to EPAct in the USA for 60 Hz) IE3 = Premium efficiency (new efficiency class in Europe and identical to NEMA Premium in the USA for 60Hz) Efficiency levels defined in IEC are based on tests methods specified in IEC : Compared to the old CEMEP efficiency classes (EFF1, EFF2 & EFF3) in Europe, the scope been expanded to include 2-, 4- and 6-pole motors and rated outputs from 0.75 to 375 kw. The new efficiency classes therefore cover almost all motors. Two drawbacks of the old European system were that there was no mandatory minimum efficiency and the system was not congruent with classification systems applied in other parts of the world. IEC :2008 does not include rules on implementation of the new efficiency classes. In EU countries implementation is subject to a decision by the European Commission, while elsewhere it is subject to national legislation. ABB is closely monitoring the drafting of this legislation and is taking steps to ensure its products will comply with the new requirements when they enter into force. 26

27 ABB motors and drives for efficient control Developing an effective motor management policy Motors can be designed to minimize losses and thus increase efficiency by improving those aspects of design and construction that give rise to the main losses. The greatest losses are the iron losses that occur in the rotor and stator, accounting for 50 percent of the total loss. These losses can be reduced by using low loss steel and thinner laminations. Copper losses account for 20 percent, and can be decreased by using an optimum slot fill design and larger conductors. Bearing friction and windage losses total 23 percent and can be reduced by using a smaller cooling fan. Stray losses, which account for 7 percent of the total, can be reduced by improving the slot geometry. Users can also do a great deal to ensure they are getting the highest efficiency from their motors. A motor management policy is a very useful tool in this respect and should be put in place. One policy decision should be to select high efficiency motors when purchasing new equipment, and minimum acceptable efficiency values should be specified. The policy should also include criteria for deciding whether to replace or rewind a failed motor. This ensures that the decision can be made long before actual failure occurs. The table below shows an example life cycle cost assessment, in this case a comparison between two standard 15 kw electric motors of different designs running at 12 kw. Motor A is manufactured by ABB, motor B by a competitor. Although motor A requires more copper and iron to manufacture than motor B, this makes motor A more efficient in operation, meaning that it uses less electricity than motor B over its lifetime. The example assumes that both motors operate for 8,000 hours per year for 15 years. 27

28 ABB motors and drives for efficient control Environmental impact over life cycle Use of resources Motor A: 12 kw 91.1% efficiency Coal (kg) 16,370 20,690 Gas (kg) 2,070 2,620 Oil (kg) 3,240 4,090 Steel (kg) Copper (kg) Aluminum (kg) 4 4 Silicon (kg) Motor B: 12 kw 91.1% efficiency Emissions Carbon dioxide (kg) Sulfur dioxide (kg) Nitrogen dioxide (kg) Hydrochloric acid Metals (g) Heavy metals (g) Solid waste (kg) Particles (kg) Other (kg) Total EPS indices ELU of which of which 99.4% 99.5% from operation from operation (EPS = Environmental Priority Strategies in Product Design; ELU = Environmental Load Units) Table 5.2. Environmental impact of two standard 12 kw motors of different designs. Motor A is from ABB. AC drives are the ideal solution for speed control VSDs can save a lot of energy and money in applications where demand varies. They enable users to minimize their equipment life cycle cost and improve performance. Electric motors are behind virtually everything that moves, and are by far the biggest users of electricity in industry and building systems. The energy efficiency of many motor installations can be dramatically improved with VSDs which ensure that motors only run at the speeds and times required. Drives are inexpensive and easy to install, but most motors are nevertheless left running at a single speed for long periods of time, often without any working load. The potential savings are significant a pump or a fan running at 80 percent speed only uses 64 percent of the energy and slightly more than 50 percent of the power used by one running at full speed. The problem is exacerbated by the fact that many 28

29 ABB motors and drives for efficient control motors are oversized, using more energy than the application actually needs. This is because motors are only available with a certain number of fixed speeds. Users tend to get the next bigger sized motor relative to the requirement and then throttle the output, for instance by using a valve to reduce the water flow in a pumping application. By reducing the speed of the motor, a drive can help to ensure that a pump, for instance, uses no more energy than necessary to achieve the required flow. In addition to the energy savings, other benefits include accurate control and less mechanical wear, reducing maintenance and extending the lifetime expectancy of the system. While payback times of two to three years are normal, payback times as short as six months can sometimes be achieved on the basis of energy savings alone. Looking at the entire life cycle Motors are often overlooked when energy efficiency measures are under consideration because the large numbers of motors in use mean that each individual unit may seem insignificant in isolation. However, it is precisely their great number that makes motors so important. To minimize running costs, users should look at the whole life cycle, starting with the acquisition of new equipment and new plant design. How much less would the equipment cost over its life cycle if a VSD were fitted from the outset? Getting an oversized motor means paying for output that is not needed, and it also translates into inefficiency because the motor is not fully used. Taking a proactive approach to energy efficiency can help companies of all sizes to achieve substantial savings. Many pump and fan applications run at constant speeds, even though variable speed operation would often give far better performance at much lower cost. If a 100 kw fan is throttled by 50 percent, for instance, the investment in a VSD would probably have a payback time of less than two to three years. Drives operate by switching the fixed mains supply voltage to a variable voltage and frequency in response to an electrical control signal. When coupled to a fan or pump motor, the change in frequency will result in a corresponding change in motor speed. This means that the motor speed can be set on the basis of external parameters such as water flow or air temperature. 29

30 Chapter 6 - Energy audits identify potential savings Evaluating how energy is used Few industrial systems are, in practice, optimally dimensioned from the point of view of energy efficiency. It is an extremely challenging task to design an optimized plant with hundreds of actuators, valves, pumps, fans, etc. for a complex process while taking into account a range of parameters from varying demand to ageing equipment. The investment cost for both the (re)design and selection of control technology still remains a major decision criterion, even if it only represents less than 5 percent of the plant s life cycle costs. In order for a company to reduce its energy costs, it needs to evaluate how it uses energy. An energy audit is a systematic examination of key pump and fan applications that includes the monitoring of energy consumed both before and after the change to VSDs. The audit defines where and how much energy can be saved by installing VSDs. These figures are then translated into a potential monthly saving indicating how much energy costs could be reduced by installing the recommended equipment. Users sometimes find it hard to believe that a 20 percent reduction in speed can produce a 50 percent saving in energy. The savings can be verified, however, and the best way to start is with an energy audit. ABB s Energy Audit Scheme produces recommendations backed up by careful analysis of collected data. Figure 6.1. At 50 percent airflow, the commonly used guide vane system uses over three times the energy of a VSD and motor combination. 30

31 Energy audits identify potential savings Recommendations based on actual data The audit process begins with a briefing where the customer describes the process and its operation to ABB s audit staff. The audit team explains in detail how the audit is performed and also outlines the costs. The investments that are recommended as a result of the audit will be paid for by the energy savings realized. The payback time can be as short as six months, and in most cases the investments are fully covered in 2-3 years, says Jukka Tolvanen, Energy Efficiency Market Manager at ABB LV drives. The first meeting prepares the ground for further analysis, which is preceded by a walk-through of the production facilities. This gives the audit team the opportunity to gather more detailed information about equipment such as pumps, fans, and extruders that are operating in the process. The exact output values of all the motors are not always known, but the plate values can be noted. During the walk-through the auditors also collect other relevant information about how the machines are used. Information on whether or not machines are driven at full power, operated continuously, and whether or not they are throttled, is important for the audit process. Data loggers are installed and left on-site in some cases for a few weeks - to record data on parameters such as power, current, and flow. In some cases a compact, transportable AC drive unit is brought in to provide real usage data to justify the investments, Jukka Tolvanen explains. The audit is usually restricted to the motors or parts of the production process that provide the biggest potential for savings. Based on the data collected during the audit, ABB computes how much energy and carbon dioxide emissions could be saved by installing VSDs. After the first audit is completed and any recommended investments have been implemented, further audits are often commissioned. Additional savings from unexpected sources Jukka Tolvanen says that in many cases installing drives not only saves energy but also leads to savings in other areas that are more difficult to evaluate beforehand: Calculating the power 31

32 Energy audits identify potential savings Payback within months savings is relatively easy, but once the new equipment is in place we often realize that the temperature and noise levels in the plant have decreased dramatically. When machines are operated at the required speed and only when necessary, they need less cooling. This usually means that they do not need servicing as often, which, in turn, provides further cost savings. Sometimes there has even been a decrease in the consumption of raw materials in one plant there was a fan that was always run at full power, and it turned out that lightweight particles of the raw material were simply being blown away. In another instance an audit recommended that the plant s compressors should be fitted with AC drives. When this was done it not only reduced the overall energy consumption but also resolved an overheating problem. Previously, when the compressor in question reached a certain temperature it was automatically turned off to protect the machine. Once drives had been fitted the compressors could be operated without interruption, Jukka Tolvanen recalls. In the longer term there will be an increasing diversity of motors and drives, meaning that customers are likely to need even more help to get the most out of their equipment. While customers focus on their own businesses, we can use the audit process as a stepping stone towards achieving greater efficiencies for them. An energy audit is often very revealing for customers, as it shows them how they can cut their energy bills and let the savings pay for the new equipment. In many countries there are Energy Saving Companies (ESCOs) that offer lease-back arrangements to finance the investment in new equipment. The payback time for VSDs is often a matter of months on the basis of energy savings alone. In addition, by optimizing the speed to match the requirements of the process, users often find they get better product quality and reduced maintenance costs. To take an actual example from manufacturing industry, a UK company installed an ABB drive to operate a fan. By reducing the speed by 20 percent the drive produced a 56 percent reduction in power (from 118 to 51 kw), saving over 440,000 kwh a year. The cost of the drive was GBP5,600 (8,000 euros) and the energy savings amounted to GBP17,000 (24,300 euros) per year or GBP1,400 (2,025 euros) per month. The straight payback was therefore just four months. The drive has naturally continued to save money for the company every month, and will do so 32

33 Energy audits identify potential savings for the rest of its life. There are few other investments that can offer this type of payback boosting the company s profits by GBP17,000 (24,300 euros) per year would require a significant increase in sales. The rewards for investing in energy efficient motors are less dramatic but still worth pursuing, as direct-on-line installations are so common. The electricity consumed by the motor represents the overwhelming part of its lifetime cost. The purchase cost is very small in comparison and is overtaken by the electricity cost after three months of continuous operation. A 90 kw energy efficient motor can cost GBP1,500 (2,140 euros) more to buy than a standard efficiency model, but can save over GBP10,000 (14,290 euros) over the course of a ten-year service life compared to the standard efficiency unit. In addition, because the high efficiency motor has lower energy losses it will have a lower running temperature giving improved reliability. This makes high efficiency motors a better choice in critical applications, for instance in the paper industry where downtime costs are high. Figure 6.2. Savings begin to accumulate after a relatively short period of time: in this example the payback period is just four months. In the UK small and medium sized companies may be eligible for favorable loans to help purchase energy saving equipment. Many other countries have their own systems for financing energy efficient investments. 33

34 Energy audits identify potential savings Tools help with financing calculations ABB offers two different tools to help make financing and investment decisions easier: PumpSave for comparisons between variable speed AC drives and other pump control methods. FanSave for comparisons between variable speed AC drives and other fan control methods. These tools help users to calculate the payback period for investments in ABB drives. The Net Present Value (NPV) of the investment can also be calculated, taking the actual cost of capital and equipment service life into consideration. Customers can download these tools from or ask for assistance from their local ABB office or ABB drives channel partner. Companies seeking to cut their energy costs do not even need to use their own cash resources or bank borrowing facilities. Other ways of financing AC drive and motor packages include (availability may vary depending on country or region) hire purchase arrangements, finance leases, operating leases, and Energy Service Company (ESCO) agreements. 34

35 Chapter 7 - Case studies: big savings with modest investments China: Plastics plant cuts energy consumption by 30 percent Issue Solution Benefits The Petrochemical Plastic Factory in Daqing, northern China, manufactures a range of petroleum-based plastics and synthetic materials. Annual output is some 8,000 9,000 tons. Productivity at the Daqing plant was below expectation because the motor used to drive the continuous mixer was limited to two speeds. The 1,300 kw motor, which was acquired 20 years ago, is a 6- and 8-pole, 6.0 kv machine with two fixed operating speeds of 750 and 1,000 rpm. Fixed speeds meant that the mixer could not run at its optimal operating point, and could not react to the sudden load changes that occur during the polyethylene mixing process. This led to poor product quality and frequent breakdowns, which reduced output. ABB was asked to investigate how the mixer s performance could be improved in order to boost productivity without any loss of consistency to the plastics being mixed. The answer was an ABB drive, together with a locally supplied input isolation transformer. An important aspect of this solution is the use of a sine filter, which eliminates harmonics to the motor, allowing the existing motor to continue in use without derating. The ABB drive enables the motor speed to be varied from 500 to 1,000 rpm. As a result the mixer works at its optimal operating point with the added advantages of smooth starting and rapid reaction to sudden load changes. Both product quality and process efficiency have improved substantially. Power requirements are reduced as the motor speed can now be varied to precisely match the demands of varying mixer loads. Loads can range from less than six to around ten tons of mix materials. With a load of approx. 9.5 tons, the motor previously used 1,215 kw. Following installation of the ABB drive, the same mixer load requires only 1,150 kw of motor power. 35

36 Case studies: big savings with modest investments The plant estimates that the drive has reduced energy consumption by 30 percent. The payback period for the complete system has been calculated at around two years. The drive is of standard design and can therefore be easily retrofitted to existing motors. In the case of the Daqing plant, connecting the drive to the existing motor simply meant changing the motor connection from star to delta. Location Segment and application Savings and benefits Petrochemical Plastic Factory, Daqing, China Plastics - Mixer ABB drive enables variable speed operation instead of previous fixed speeds - 30 percent reduction in energy consumption - improvements in process efficiency and product quality China: Substantial energy savings and reduced emissions China s energy needs are growing as its economy expands. Many Chinese companies have embraced VSD control technology, with the dual aims of saving energy and cutting back greenhouse gas emissions. The three examples below, representing three different industries, show the kinds of savings that are being achieved. Cement: A cement factory in Jiangsu Province has installed a number of ABB drives to operate kiln fans. The drives replace hydraulic couplings on a production line. The resulting energy savings amount to 2.8 kwh/t, which totals 4,200 MWh annually. In addition to producing savings of RMB1.68 million (163,110 euros), the drives have also reduced carbon dioxide emissions by 2.1 million kg annually. Estimated payback time for the system is 1-2 years. The introduction of drives has also reduced reactive power issues. 36

37 Case studies: big savings with modest investments Water: A Beijing water utility designed a new booster pump station with ABB drive control instead of throttling. The station handles the water supply for around 200,000 inhabitants, and the energy savings through the use of drives have been calculated at approximately 30 percent. This represents an annual energy saving of about 1,000 MWh. Greenhouse gas emissions are also reduced: the drives based pumping station releases 500,000 kg less carbon dioxide into the atmosphere than it would if throttling were used. The system s payback time has been estimated at 18 months. Aluminum: The Qinghai branch of Aluminium Corporation of China acquired seven 315 kw drives to control fans in an exhaust gas cleaning system. The fans, with a combined rating of 1,820 kw, were previously run at a fixed speed. The drives have brought about annual energy savings of around 8,000 MWh. In addition greenhouse gas emissions have been cut by 4 million kg yearly. The drives have not only increased the efficiency of the plant, they have also enhanced system stability. The payback time for the investment is one year. Location Segment and application Savings and benefits Cement factory, Jiangsu Province Water utility, Beijing Aluminium Corporation of China, Qinghai Cement Fans Water Pumping Metal - Fans ABB drives operate kiln fans - annual energy savings of 4,200 MWh million kg annual reduction in CO 2 emissions ABB drive control at booster pump station - annual energy saving approx. 1,000 MWh - 500,000 kg less CO 2 emissions ABB drives control fans in exhaust gas cleaning system - annual energy savings of approx. 8,000 MWh - 4 million kg annual reduction in CO 2 emissions 37

38 Case studies: big savings with modest investments Finland: Drives help to cut water utility s energy bill Issue Pietarsaaren Vesi, the water utility which serves the town of Pietarsaari in Finland, states that ABB drives and new pumps have reduced energy consumption by 30 percent and helped to maintain more stable pressure in the distribution system. Pietarsaari s water supply is taken from a local river. Following treatment, the water is pumped to a 1,500 cubic meter aboveground storage tank and pressure boosting station. The pressure boosting station feeds water directly into the distribution system and seeks to maintain constant pressure in the pipes. The station is equipped with two 75 kw and one 37 kw electric pumps, with a diesel-powered pump as back-up. The drives at the pressure boosting station feature intelligent pump control (IPC), an optional software package for ABB drives which incorporates all the functions generally required by pump users. The Pietarsaari installation uses IPC s multipump control, pump priority, and flow measurement functions. Multipump control is used to operate several pumps together. Each pump is controlled by its own drive, with one being speed adjusted and the rest run at constant speed. This results in smooth control with no pressure peaks. Fail-safe operation is achieved by implementing the control connections in a star configuration, which also provides instant system recovery capability. 38

39 Case studies: big savings with modest investments Pump priority control balances the operating time of all the pumps in the system over the long term. This facilitates maintenance planning, and can boost energy efficiency by operating pumps closer to their best efficiency point. In water supply systems the consumption rate is generally greater during the day, so the drives are programmed to operate the higher capacity pumps during daytime and the smaller unit at night. Benefits Pressure control is crucial in this application, as the pressure boosting station supplies water directly to the distribution system. The industrial drives with IPC maintain stable pressure without any hammer effect. This reduces pipeline stress, resulting in fewer leaks and reduced maintenance requirements. At the same time the use of drives avoids the disturbance to the electrical network that is often caused by direct-on-line starting. According to Pietarsaaren Vesi, the upgrade has resulted in significant energy savings over the previous direct-on-line configuration: Together with our new pumps, the drives have enabled us to reduce our energy consumption by about 30 percent. The pressure in the system is much more stable, which has reduced leaks, reduced maintenance needs, and increased end-user satisfaction, says Jan Snellman, Automation Engineer. Location Segment and application Savings and benefits Water distribution system in Pietarsaari, Finland Water - Pumps ABB drives with intelligent pump control operate pumps at a pressure boosting station - 30 percent reduction in energy consumption - more stable pressure reduces pipeline stress Germany: Drives keep natural gas supplies flowing smoothly WINGAS GmbH is one of Germany s major gas suppliers, with pipelines bringing gas from northern Russia and the North Sea to the nation s most important industrial centers. The company is a joint venture between Wintershall AG of Germany and OAO Gazprom of Russia. WINGAS uses ABB drives to operate compressors at its compressor station at Weisweiler and gas storage facility at Rehden. 39

40 Case studies: big savings with modest investments Issue To transport natural gas efficiently over large distances the gas has to be compressed. To build up and maintain the required pressure, compressor stations are located at intervals along the pipelines. Solution The WINGAS compressor station on the WEDAL (Western German Link) pipeline at Weisweiler uses an ABB drive to power a 12.5 MW compressor. This drive unit has been in operation since the beginning of ABB has also supplied two 12.5 MW drive units to power compressors at the natural gas storage facility at Rehden. The compressors boost the gas pressure to 300 bar to enable it to be injected into rock, which provides a natural storage medium. The Rehden facility has a capacity of 4.2 billion cubic meters of natural gas, making it the largest of its kind in Western Europe. Benefits The use of ABB drives provides considerable savings in energy and maintenance costs and thus high productivity. Further benefits include minimum noise levels and zero carbon dioxide emissions. When compared with gas turbines, ABB drives have lower initial investment costs and operating expenses and, therefore, shorter amortization times. The drive system used by WINGAS has demonstrated its reliability and proven technology in numerous installations. Standardization has positively impacted the costs, availability and reliability of this type of large drive. 40

41 Case studies: big savings with modest investments ABB has so far supplied and installed more than 120 medium voltage VSDs for chemical, oil and gas applications. More than 1,950 MV drives, with a total power of 8,100 MW, are in use worldwide and represent the entire range from 300 kw to 100 MW. Customers can choose from various drive systems such as voltage-source converters, thyristor-controlled motors and sub-synchronous converter cascades for motors with speeds up to 7,000 rpm. Location Segment and application Savings and benefits WINGAS compressor station at Weisweiler and storage facility at Rehden, Germany Oil and Gas - Compressors ABB drives control compressors that compress gas for transportation and storage - low energy consumption - savings in maintenance costs, higher productivity - zero carbon dioxide emissions Honduras: Sugar plant boosts annual revenues by $1 million Issue Solution Compania Azucarera Hondurena S.A. is one of the largest sugar companies in Honduras. The company s Santa Matilde sugar plant operates 155 days per year and has a capacity of 10,200 tons of cane per day, with an increase to 12,000 tons per day expected. To optimize energy use at the plant, the company replaced five steam turbines, which were used to drive the cane mill, with ABB drives and induction motors. Sugar plants produce steam by combustion of bagasse, which is the principal waste product from sugar production. Part of the steam is used to power turbines, which in turn drive the canecrushing mills. The rest of the steam is used to generate electricity for use in the plant. Under normal operating conditions, sugar plants generate enough electricity to satisfy their own energy requirements and can at times sell energy to the grid. The cost of electricity in Honduras is relatively high because it is mainly generated with fuel oil. It therefore makes sound business sense to minimize energy use at the plant so that more energy can be delivered to the grid. By using VSDs and electric motors instead of steam turbines to operate the cane mill, the steam can now be used exclusively 41

42 Case studies: big savings with modest investments Benefits to generate electricity, which will feed the whole plant and can be sold to the grid. According to Jorge Arriaga, Engineer at the plant, The people at Santa Matilde are very pleased with the performance of the ABB drives. Our plant s overall energy efficiency has increased tremendously since we replaced the steam turbines with drives. Today, we are not only energy self-sufficient, but we have also increased our annual revenues by around $1 million by selling excess energy to the grid. Furthermore, the process runs much more smoothly than before. In the past, the cane mill was driven by five 750 kw steam turbines for a total of 3,750 kw. Given that the turbines require 35 pounds of steam per kilowatt, about 131,000 pounds of steam were required to drive the cane mill. After replacing the steam turbines with electrical drives, the 131,000 pounds of steam could be used to generate electricity at a rate of 12.7 pounds/kw. This results in additional generation of 10,300 kw/h, which is used to feed the drives. Furthermore, excess energy totaling around 6,550 kw can be sold to the grid. This creates about $1 million (769,200 euros) per year in additional revenue for the company. As a result the payback time for the MV drive investment was about one year. Location Segment and application Savings and benefits Compania Azucarera Hondureana sugar mill at Santa Matilde, Honduras Food and beverage Sugar cane mill ABB drives and induction motors used to drive cane mill - increased energy efficiency, with excess energy worth approx. $1 million sold annually - smoother process operation 42

43 Case studies: big savings with modest investments India: Improved fan control increases efficiency at cement plant Issue The Chettinad Cement Corporation Ltd (CCCL) plant in Karikkali, India, has an annual capacity of approx. 1.2 million tons. It was India s first cement plant to install ABB drives for speed and torque control of the bag house, raw mill, cement mill and preheater fans. Electrical energy costs represent about percent of the total production cost of cement, putting cement plants among the largest industrial energy consumers. Large fans account for the majority of the electricity consumed. In the past, Indian cement producers have used Cascade converters - also known as Slip Power Recovery Systems (SPRSs) - to control the speed of the process fans. However, due to inherent problems with SPRSs such as poor operation in weak networks and increased harmonics, producers are now considering the use of VSDs. Solution VSDs can reduce energy consumption from around 90 to 70 kwh/ton of cement produced. The method used to control the flow rate not only has a major impact on costs, but will also affect productivity. ABB drives feature flux optimization to reduce total energy consumption when operating below the nominal load. Total efficiency can be improved by up to 10 percent. 43

44 Case studies: big savings with modest investments Benefits According to CCCL s Deputy General Manager, K. Narayanan, Medium voltage VSDs represent a new concept for the Indian cement industry. Compared to the SPRSs used in the past, ABB s MV AC drives offer much more operating flexibility with speed variation from 0 to 100 percent, while considerably reducing maintenance costs. Another advantage of drives is that the high starting currents - quite normal with any of the conventional starting circuits now belong to the past. VSDs bring down the ratings of the various starting circuit components and reduce stresses. We are very pleased with the performance of the ABB drives we ve installed. Compared with the operating speed range of Cascade converters ( percent), VSDs offer much higher flexibility over the entire speed range (0 100 percent). The use of an IGCT (Integrated Gate Commutated Thyristor) power semiconductor as an integrated protection device reduces the ABB drive s parts count, providing outstanding reliability and availability. In addition, the ride-through function enables the drive system to withstand power supply disturbances. Location Segment and application Savings and benefits Chettinad Cement Corporation, Karikkali, India Cement - Fans ABB drives for speed and torque control of bag house, raw mill, cement mill and preheater fans - total efficiency improvement of up to 10 percent - enhanced flexibility - reduced maintenance costs Netherlands / international: High efficiency motors cut running costs DSM is a highly integrated group of companies that supplies the life sciences and material sciences sectors with a range of products including high performance materials, polymers and industrial chemicals. It has annual sales of 6.3 billion euros and 22,000 employees in over 200 locations worldwide. 44

45 Case studies: big savings with modest investments Issue We have found that repaired motors are less energy efficient than new ones. If we compare a new high efficiency motor with an old motor, we see a considerable difference: the energy efficiency of the old motor decreases after it is repaired, says Maintenance Engineer Peter Pieters. Solution When deciding whether to purchase a new motor or repair an old one, we consider the price of the new motor and how it will depreciate over the following four years, says Pieters. Benefits Even the most expensive new high efficiency motor will cost less over the long term taking into consideration the initial investment, the life expectancy of the bearings and energy losses. We use around 20,000 motors at DSM, so choosing new high efficiency motors will lead to a very significant annual reduction in running costs. DSM is committed to reducing energy consumption. By improving the energy efficiency of our motors and equipment as well as of our energy resources such as electricity and steam, we are making our own contribution to a better world, adds Ben Odman, Director of Electrical Engineering and Consultancy at DSM. Location Segment Savings and benefits Facilities in the Netherlands and worldwide Chemicals - significant reduction in running costs - supports commitment to reduce energy consumption 45

46 Case studies: big savings with modest investments Sweden: Mining company acquires only high efficiency motors Issue LKAB is an international high technology minerals group based in Sweden. It supplies upgraded iron ore products and industrial minerals, and employs over 3,500 people. Electric motor efficiency is extremely important to LKAB. The company uses almost 15,000 electric motors at its mines and other facilities, accounting for 90 percent of LKAB s annual electricity consumption of around 1.7 TWh. This figure represents 1 percent of Sweden s total electricity consumption. Solution Nearly ten years ago, LKAB placed itself firmly in the forefront of industrial energy efficiency when it announced that it would only acquire energy efficient motors in the future. They are slightly more expensive to purchase, but you save money in the long run the purchase price represents only about 1 percent of the total costs associated with running the motor over its service life, says LKAB s Lennart Mukka. For LKAB and other industrial customers, ABB s process performance high efficiency motors are now the obvious choice. Benefits By replacing its existing motors with high efficiency motors, LKAB has achieved significant savings. At the same time, energy efficient motors provide LKAB with the operating capacity it needs without additional maintenance load. 46

47 Case studies: big savings with modest investments A further benefit of ABB process performance motors is that ABB can on request guarantee their efficiency. The advantages of this became clear to LKAB during the 1990s, when electric motors were audited at one of its plants. The audit revealed that motors supplied by other manufacturers were often less efficient than specified by the vendor. In contrast, when ABB markets its high efficiency motors as the most energy efficient motors in the world, it can back its claims with an efficiency guarantee. Location Segment Savings and benefits Mines and other facilities in Sweden Mining - significant savings in energy costs - capacity needs met without additional maintenance load UK: Salt producer saves over 1,600 MWh per year Issue Solution UK salt producer Salt Union has the capacity to produce around one million tons of salt every year at its Runcorn site. The company says that ABB equipment costing just GBP20,000 (28,570 euros) has cut energy consumption by over 60 percent, resulting in savings exceeding GBP100,000 (142,850 euros) per year. As part of the production process, salt is passed through dryers which use fans to suck air in. As well as food-grade, pure dried vacuum salt, the plant also produces a courser granular product used in applications such as dishwashers. The dryer for this product previously used a fan to suck air through at a rate controlled by a damper. The damper was 95 percent closed during normal operation, so most of the energy consumed was being used to suck air through the narrow constriction. An energy audit was performed by Central Electrical, an ABB Drives Alliance member, to determine the potential for energy savings. The original fan motor was rated at 337 kw, but Central Electrical s calculations showed that 132 kw should be sufficient to create the draft needed by the dryer. That s a huge energy saving when you think we run the unit for about 8,000 hours a year, says Dave Mullin, Electrical Plant Improvement Engineer. In fact, it s equivalent to over 1,600 MWh per year. 47

48 Case studies: big savings with modest investments Benefits The reason why the original fan was significantly oversized can be traced back to a previous process. The dryer was formerly used to process vacuum salt crystals, which are much smaller than the spherical, 2-3 mm diameter particles in granular salt. These fine crystals created a far bigger pressure drop across the dryer than the coarse product that is processed today. The old fan was replaced by a smaller version, operated by a 132 kw four-pole motor coupled to an ABB drive. The resulting energy savings now average GBP9,000 (12,860 euros) a month, or GBP100,000 (142,850 euros) per year. The fan was probably on the generous side to start with. Years ago it was common for engineers to add a safety margin, Dave Mullin explains. But once the duty changed it became grossly oversized. Ken Tym of Central Electrical says that this type of problem is common: Industries and processes change, but there are a lot of areas that manufacturers don t seem to consider. Sometimes the main task is to inform end users about the energy savings that are achievable. At Salt Union, energy-saving initiatives are not confined to the process. Even the small amount of waste heat produced by the ABB drive is being put to work warming up the switch room in winter. Location Segment and application Savings and benefits Salt Union, Runcorn, UK Food and beverage - Fans Oversized fan replaced and fitted with an ABB drive - energy consumption reduced by over 60 percent - savings exceeding GBP100,000 (142,850 euros) per year 48

49 Case studies: big savings with modest investments US: Drives play key role in helping to preserve vegetable crops Issue Solution Onions and potatoes are big business in certain parts of the US. In Oregon, Washington and Idaho, for example, onions contribute over $125 million (96 million euros) to the economy annually. The impact of potato production for the same three states is even more significant upwards of $1 billion (769.2 million euros) annually. To ensure high quality, onions and potatoes must be stored at optimal temperatures and humidity levels. JMC Ventilation Refrigeration, LLC, specializes in custom ventilation and refrigeration systems for potato and onion storage. The Kennewick, Washington-based company applies new and existing technologies to provide precise, on-site and remote environmental control that helps ensure vegetable quality and reduce mass loss (shrinkage), while saving energy. A crucial component in JMC s systems, ABB VSDs with Ethernet communications, are used to control fan motor speed and airflow, which directly affects temperature and humidity. Part of what our system has to do, JMC founder Joel Micka explains, is to deliver a certain amount of air typically, about 20 cfm (cubic feet per minute) per ton for potato storage units. In the state of Washington, our average-size storage is 10,000 tons. So we would be supplying 200,000 cfm of air. 49

50 Case studies: big savings with modest investments Benefits The University of Idaho recently studied the impact of VSDs on potato storage facilities and reported that the average annual saving in fan energy is 40 percent, and the average mass-loss saving is 0.81 percent. The researchers also found that color, sugars and other quality characteristics are not impacted by VSD use. Controlling the air supply helps reduce mass loss (shrinkage) for potatoes. Typically farmers get paid by the weight of their potatoes, and the potato is about 80 percent water, explains Micka. To maintain high humidity, we use the drive to slow down the fan at certain times of the year so that it supplies less air to the potatoes and, in turn, reduces shrink loss. He goes on to say that the safety and efficiency the new systems provide through remote control and monitoring are even more important than the energy savings. This is because storage facilities are often located many miles from the main offices. Location Segment and application Savings and benefits Potato and onion storage facilities in Idaho, Oregon and Washington State, US Food and beverage - Fans ABB drives control fans that keep temperature and humidity at constant levels - annual saving in fan energy 40 percent - reduction in shrink loss of the produce US: University of Texas saves millions through boiler retrofit Issue The University of Texas at Austin is the flagship institution of the University of Texas system. Heating and energy for the 200 buildings on the University s campus are supplied by boilers and gas turbines at the Hal C. Weaver Power Plant. An emissions-control project is providing substantial savings for the University. With annual electricity savings of 746,000 kwh and fuel savings of hundreds of millions of BTUs, the project payback time is less than one year. Our objective as we began the boiler retrofit was to reduce NOx emissions, but improved combustion efficiency meant that we ended up increasing our energy output while cutting the amount of gas used. This allowed us to bank our standby boilers, saving us hundreds of thousands of dollars per year, says Juan M. Ontiveros, Director of Utility and Energy Management at the University. 50

51 Case studies: big savings with modest investments Solution The upgrade incorporates the Benz Air Compu-NOx control platform, which uses AC drives and fans, instead of dampers, for precise metering of airflow. Prior to installation of the ABB drives, the fans always ran at the same speed and the quantity of air was controlled through inlet dampers. This was inefficient under partial-load conditions, and wasted both power and money. By removing the dampers in favor of AC drives to control the fan speed, less horsepower is used to drive the fans. Benefits Initial projections targeted savings of $500,000 (384,600 euros) annually for the first boiler retrofit, but due to fuel price increases, the University stands to save an additional $1 million (769,200 euros) from the retrofit of Boiler 3. When Boiler 7 is brought online, the University may save up to $6,000 (4,615 euros) per day from that unit s boiler banking capabilities, says Robert Benz, President of Benz Air Engineering Co., Inc., which handled installation of the new technology. Nitrogen oxide emissions have been cut dramatically by the project. Before the upgrade, Boiler 3 alone emitted tons of nitrogen oxide per year, which has been reduced to 21.0 tons per year. With energy and fuel costs soaring, the payback on the Compu- NOx system will be less than 12 months. The system will then continue to produce savings for years to come through its fuel gas recirculation and VSD fan control systems. Location Segment and application Savings and benefits Power Plant at University of Texas, Austin, US Power plant - Fans ABB drives control fans for precise airflow to the boiler - annual energy savings of some USD 1.5 million - major reduction in nitrogen oxide emissions 51

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