Systematic implementation of CHP plants in Frankfurt am Main

Transcription

1 Systematic implementation of CHP plants am Main Wendelin Friedel City of Frankfurt am Main Energiereferat Municipal energy agency Galvanistraße 28 DE-6086 Frankfurt am Main Dr. Werner Neumann City of Frankfurt am Main Energiereferat Municipal energy agency Galvanistraße 28 DE-6086 Frankfurt am Main Keywords Co-generation, Tri-generation, CHP, Absorption cooling, Decentralized heat and power production, Reduction of CO 2 -emissions, Climate protection Abstract The aim of the Cities policy as member of the Climate Alliance and Energie Cites is to reduce the CO 2 - emissions significantly. To organize the process of CO 2 reduction and to develop an energy concept for Frankfurt, the Energiereferat was founded as a local energy agency in The activities concentrate on improving energy efficiency and reduce energy consumption in all areas. In 1990 the Energiereferat started to perform systematic studies on potential sites for decentralized cogeneration systems. For the project a consistent method for evaluating the technical feasibility and economic viability was developed. The studies also covered the environmental impact of co-generation and, in some cases, tri-generation. From 1990 to 2002 the decentralized CHP was raised from 100 kwel to kwel (office buildings, swimming pools, hospitals etc.) in 70 CHP plants with a size ranging from 5 kwel to 000 kwel (German federal bank). Background Co-generation for district heating has a long tradition. In 189, a coal-fired power station started electricity production. The first CHP-plant started operation in 1926, supplying the University Hospital complex and the office buildings in the nearby harbour as well as dwellings in the city with steam. The next step in extending the district heating from co-generation was done in , when a large area in the northwest of Frankfurt was designated for new residential buildings. This development area was supplied with heat (hot water) from a CHP-plant using the steam from a waste-incineration plant. In a third district-heating network was established, supplying heat (hot water) from a gas-fired CHP to Frankfurt airport and a new developed urban district, mainly comprising office buildings. Two new coalfired CHP-plants for the City centre were build in the 90ties and a gas turbine with waste-heat boiler was added in 199. The total heat capacity for the three district heating systems is 1,002 MW. This includes 583 MW for industry and offices, 258 MW for the residential sector and 161 MW for public buildings (including airport). In consideration of the steam supply in the city area, a capacity of 60 MW absorptionchillers is installed for cooling requirement. In addition to the further extension of the district-heating network, decentralized co-generation is one of the most effective measures to improve energy efficiency and to reduce CO 2 -emissions. Copyright Dr. Werner Neumann, Energiereferat, Stadt Frankfurt 1 of 1

2 Systematic implementation of decentralized co-generation The City Council decided in 1990 that decentralized co-generation should become a major part of the City s climate protection program. Following the resolutions of the City Council, the Energiereferat started in 1990 to perform systematic studies on potential sites for decentralized co-generation systems. For the project a consistent method for evaluating the technical feasibility and economic viability was developed. The studies for also covered the environmental impact of co-and, in some cases, tri-generation. Discovery planning as an implementation tool In a first step, thirteen sites with a high heat and power demand (hospitals, public swimming pools, offices) have been selected for feasibility studies. To avoid competition between district heating and co-generation, only sites outside the district-heating areas were investigated at the beginning. In these first series of studies, the focus was on technical viability, taking into account neither the state of the installed heating system nor the readiness of the building-operator to invest in a new technology. As a result, only one project in a hospital was realized as an immediate outcome from these studies in 199. With an annual operating time above 8,200 hours in the first year of operation, this tri-generation project in a hospital was very successful and assisted us to convince potential customers to consider our recommendations. Following the experience for the first studies, sites for further studies were not only selected from a technical point of view but taking into account economical and emotional aspects. In addition to studies for single customers surveys for special application areas (homes for elder people; hostels and workshops for special people) were carried out. Up until now, more than 10 feasibility studies for hospitals, office buildings, homes for old people and other areas with high heat and/or electricity consumption have been prepared. In addition to feasibility studies for new or existing buildings, the Energiereferat is preparing case studies on energy supply alternatives for new urban development schemes. As a result of the (systematic) discovery planning, and due to favourable economic conditions in the years 1992 until 2002, the co-generation capacity in small and medium size units increased from 100 kw(el) in 1991 to almost 2,000 kw(el) in 2002 (Figure 1). The surveys carried out show that there is a further potential for decentralized small and medium size co-generation units of at least 20 to 30 MW. Figure 1: Development of decentralized co-generation am Main 1 28 yearly installations in (MW; number of units) installed electrical power number of units cumulated electrical power cumulated electrical power output (MW) year of installation - The co-generation plants are financed and operated either by the owner of the building itself or by contracting companies (e.g. local utility, private contractors, building department). Most of the plants are Copyright Dr. Werner Neumann, Energiereferat, Stadt Frankfurt 2 of 2

3 powered by natural gas, which easily allows reduction of CO and NO x emissions to a level 50% below the legal requirements. Fuel oil is also used in some of the plants. The first co-generation plant using biogas from a compost-plant started operation in With a new German law (EEG), rates for electricity from renewable energy have been fixed to decent levels so that in the future co-generations plants using renewables (biogas or bio-fuel) might become more important. Electric capacity of the already realized 70 co-generation plants range from 5 kw to,000 kw. The wide range of application areas, i.e. hospitals, schools, offices, small residential district heating systems, private houses, swimming pool, botanical garden and hostels, demonstrate that co-generation is not only limited to industry. Figure 2: Installed generating capacity and number of installations for various application areas 9.000,00 1 Capacity (kw el) 8.000, , , ,00.000, , , , No. of installations 0,00 Offices Industries Dwellings Hospitals Schools Other Hostels Sport facilities 0 Tools for technical and economical comparison During the last ten years, various tools for technical, economical and environmental evaluation of cogeneration projects have been developed by the Energiereferat. This includes spreadsheet programs to evaluate the annual heat-demand curve for various applications, programs to estimate operating hours for co-generation plants and spreadsheets for economical comparisons based on German engineering guidelines (VDI 2067). In order to have actual price information on various co-generation units available for our studies, standardized price indications are requested from European suppliers on a yearly basis since 199. Due to the high demand, especially from engineering and planning offices Energiereferat started to publish a summary of this survey in In the year 2001 edition, information on investment, maintenance costs and prices for overhaul are compiled for more then 250 co-generation units covering various fuels (natural gas, fuel oil, biogas and bio-fuel). This information is an integral part of an engineering handbook for co-generation plants and also included in a computer program (BHKW-PLAN; ZSW Stuttgart) for design and economical evaluation of co-generation units. A special tool for comparing the heat costs of individual gas-boilers with heat costs from a district heating with co-generation has been developed in co-operation between the Cities of Hanover and Frankfurt. This tool is especially designed to assist urban development planers in checking energy supply alternatives for new development areas. The above-mentioned tools allow preparing feasibility studies within a short time in a standardized and comparable way. Copyright Dr. Werner Neumann, Energiereferat, Stadt Frankfurt 3 of 3

4 Practical experience Since 1998, operators and users of co-generation units are invited for a round-table discussion on problems in operation, maintenance and performance. In the year 2002 meeting, data from plants with a total number of 59 engines and a generating capacity of 9,700 kw were analysed. Figure 3: Operating hours of different co-generation plants (2001) Office (3) Business (1).715 Industry (1) Hospital (2) 7.5 District heating (6) School (9) Swimming bath (2) Others (7) Hostel (9) Operating hours varied from 800 hours per year up to 8,715 hours per year and the average availability was above 95 percent. Actual maintenance costs range from 0.35 Cents/kWh (generating capacity: 1,000 kw) to 3.15 Cents/kWh (generating capacity: below 30 kw) and are in accordance with the information obtained from our price survey. Figure : Maintenance costs for co-generation plants 3,5 Database: 20 units maintenance in Ct/kWhel 3 2,5 2 1,5 1 standard-price-function from "BHKW Kenndaten" 0, electrical power output in kw Copyright Dr. Werner Neumann, Energiereferat, Stadt Frankfurt of

5 Innovative techniques Beside the implementation of standard engine-driven co-generation, the Energiereferat together with local utilities and other cooperating partners try to demonstrate and test innovative and/or improved cogeneration units. The first project of this type was a demonstration project for small-scale co-generators (5.5 kw) financed by the Government of Hesse in co-operation with the regional energy agency and local utilities. In this project, 15 units (5 ) were installed in early 199. Till now some of the engines have operated for more than 50,000 hours without any major failures. In 1998, a fuel-cell co-generation unit (ONSI PC25; 200 kw(el)) has been installed to provide the heat and electricity for a public swimming pool. This project is realized by our local utility (MAINOVA AG) and subsidised from an energy saving fund provided by the utility (E.ON). Project evaluation is accomplished by the engineering academy of Frankfurt university. MAINOVA AG also started a pilot project with a 10 kw(el) Stirling-engine. The positive results of this pilot project convinced the utility to start a field testing of two additional engine with different fuels (natural gas and biogas). This field testing program is planned to start end of A co-generation unit in a hostel (50 kw) was equipped with an additional heat exchanger to utilize the sensible heat in the flue-gases (condensation-heat exchanger) for pre-heating hot water for the building. This installation proved to be very successful, boosting the overall energy efficiency to above 95%. A proto-type of a high-temperature heat-transformer using an absorption process driven by the heat from exhaust gases was added to the co-generation unit in the botanical garden and tested under practical operating conditions. While with a standard condensing-heat exchanger the delivery temperature is limited to approximately 50 C, this unit allows delivery temperatures up to 90 C. The additional cost for this unit will be recovered in less than four years. After the positive test results of this innovative technique two additional units of this type are planned in Cologne and Frankfurt. In July 2002 a micro-gas turbine with a electric capacity of 100 kw will be installed in a public indoor swimming pool providing heat and electricity. Summary Experience demonstrated that co-generation could assist communities in reducing CO 2 - emissions and improving energy efficiency. The 70 plants in operation reduce CO 2 by more than tons per annum. The great number of already realized projects as well as the long list of further possible sites for cogeneration plants shows clearly that there is still a high potential for CHP plants and on site electricity production as part of an integrated supply and Europe. The experiences of Frankfurt may by transformed and applied in other European banks and office cities. Advanced buildings should have CHP plants which will result in at least a 30% saving of primary energy. But it is necessary to enforce regulations on a national or European level to improve the economic conditions for one of the most effective measures on CO 2 reduction. It seems to be, that a certification scheme with a increasing quota of CHP electricity can meet the European Commissions aims for increasing the part of CHP electricity at best. REFERENCES Wendelin Friedel, Fighting to protect the climate evaluating the experience, Salamanca, Spain, 1998 Wendelin Friedel, Co-generation units with capacities up to kw, Clermont-Ferrand, France, 1999 Wendelin Friedel, Implementing decentralized co-generation the Frankfurt case study, Cogen Europe, 7th annual meeting, Brussels, Belgium, 2000 Paul Fay, BHKW-Kenndaten, published by ASUE, Germany, 2001 Copyright Dr. Werner Neumann, Energiereferat, Stadt Frankfurt 5 of 5

6 Paul Fay, Experience with decentralized co-generation, Annual meeting of co-generation operators, Frankfurt, Germany, 2002 Copyright Dr. Werner Neumann, Energiereferat, Stadt Frankfurt 6 of 6

7 Systematic implementation of CHP plants Dr. Werner Neumann Municipal Energy Agency City of Frankfurt am Main, Germany 2nd International Conference on Energy Efficiency in Commercial Buildings Nice, May 2002 E N E R G I E R E F E R A T INTRODUCTION City of Frankfurt: Founding member of Climate Alliance GOAL: 50 % CO2-Reduction until 2010 Energiereferat established in 1989 Energy saving Energy efficiency Renewable energies E³ Folie 2 May-02

8 HISTORY OF CO-GENERATION ¾ First coal-fired CHP for district-heating (steam) (Client: hospital, harbour) ¾ CHP Nordweststadt/waste incineration district-heating (water) for new dwellings ¾ CHP Niederrad (natural gas) district-heating for airport and office-area ¾ CHP West (coal, natural gas) new coal-fired CHP, gas-turbine STADT FRANKFURT AM MAIN Folie 3 May-02 IMPLEMENTING DECENTRALIZED CO-GENERATION ¾ first decentral co-generation unit ¾ da Nidda Nid Nidda till more than 10 feasibility studies M M Maaiain nin MMM aainainin ¾ decentralized co-generation units Folie May-02 STADT FRANKFURT AM MAIN

9 yearly installations in (MW; number of units) DEVELOPMENT OF CO-GENERATION installed electrical power number of units cumulated electrical power cumulated electrical power output (MW) year of installation Folie 5 May-02 APPLICATION AREAS 9.000,00 1 Capacity (kwel) 8.000, , , ,00.000, , , , No. of installations 0,00 Offices Industries Dwellings Hospitals Schools Other Hostels Sport facilities 0 Folie 6 May-02

10 CO-GENERATION IN OFFICE BUILDINGS Environmental Department Deutsche Bank European Central Bank Kreditanstalt für Wiederaufbau Maintower German Federal Bank Folie 7 May-02 EVALUATION TOOLS Actual cost information for co-generation units Available since 199 Data for more than 250 co-generation units Information on investment and maintenance costs Folie 8 May-02

11 EVALUATION TOOLS Spreadsheet-program for cost-comparison of different heating systems Contains standard costfunctions Specially designed for urban development areas Cost comparison for Individual boilers Central heating plant Central heating plant plus cogeneration District heating Folie 9 May-02 PRACTICAL EXPERIENCE Operating hours Office (3) Business (1).715 Industry (1) Hospital (2) 7.5 District heating (6) School (9) Swimming bath (2) Others (7) Hostel (9) Folie 10 May-02

12 MAINTENANCE COST Comparison of actual costs and standard prices 3,5 Database: 20 units maintenance in Ct/kWhel 3 2,5 2 1,5 1 standard-price-function from "BHKW Kenndaten" 0, electrical power output in kw Folie 11 May-02 INNOVATIVE TECHNIQUES Mini co-generation units (5.5 kwel) (Demonstration project in 199) Fuel cell project (for public swimming pool) Stirling engine (10 kwel) Co-generation with an additional heat-exchanger utilizing higher heating value (condensing) Heat transformer to improve energy utilization from the exhaust gases (high temperature absorption process) Micro-gasturbine (100 kw) - start-up mid 2002 Folie May-02

13 Summary Achievement: 2 MW generating capacity in 70 units, CO2-reduction tons per annum Potential: Total of at least 50 MW of co-generation capacity Obstacles: Low electricity and high natural gas prizes Requirements: National (or European) regulations to improve economic conditions Share our experiences! Folie 13 May-02