Solar technology. A guide to solar power at utility scale. in Africa

Transcription

1 Solar technology A guide to solar power at utility scale in Africa

2 About solar power Solar electricity is generated using a free and abundant energy source the sun. In a single hour, the sun transmits more energy to the earth s surface than the world uses in a year. This clean, renewable energy can be converted into free electricity to power your business. Ground-mount, Rustenburg RSA

3 What are solar PV panels? Placed on the roof or on the ground, solar photovoltaic (PV) panels capture the sunlight and convert it into electrical energy, measured in kilowatt hours (kwh) otherwise known as units of electricity. When you group numerous solar panels together to form a complete solar power system, you can use the free solar electricity to power your business, being less reliant on expensive grid or diesel electricity. The size of a solar power system is measured in kilowatt peak (kwp). This is the power the solar would produce under a set of standard test conditions*. Africa is the ideal location for solar electricity; being on the equator where the sun is high in the sky all day provides great conditions for getting the most out of a solar system. Map to show average annual sun accross Kenya SolarGIS 2013 The sunnier it is, the more electricity the solar panels can generate and the less power you import and buy. *Standard Test Conditions for solar panels is 1000W/m 2 irradiance, AM 1.5 spectrum, 25ºC cell temperature.

4 How do solar panels work? 1. The solar panels are frames made up of solar (PV) cells (which are layers of silicon). The sun s radiation hits these cells and is converted to direct current (DC) power. 2. This DC power travels to an electrical inverter, which converts DC power into alternating current (AC) power. 3. A distribution board and smart controls manage the operation of the solar power with the utility grid or generator power. 4. The AC electricity produced is just like the power supplied by your utility company or by standby generators. It can be used to power fans, pumps, lights, computers all the things your business needs to operate. 5. Generator power can continue to be used when necessary. 6. Excess energy can be exported to the grid

5 Why choose solar? There are so many reasons. These are a few of the most important: Reduced costs As the cost of grid power continues to rise, the sun keeps shining for free. Advances in solar technology means that solar electricity is now cheaper than grid electricity in many parts of Africa especially where grid electricity comes from expensive emergency electricity sources such as diesel generators. For many countries the cost of diesel is typically US $1-1.5 per litre, and fuel costs for diesel-generated electricity can be upwards from US $0.30 per kwh*. The lifetime cost of solar electricity (known as the levelised cost of energy (LCOE) is $ per kwh. So where diesel is used to generate grid or standby electricity, electricity from solar power is cheaper. Unlimited and reliable The sun shines every day without fail, so the energy it produces is stable and unlimited; a secure source of power for the future. The solar panels produce energy from daylight, so they still work on overcast days. Clean electricity Unlike fossil fuels which create harmful air pollution and global warming, solar energy is clean and renewable. Businesses that invest in solar show a commitment to environmental performance attractive to customers. Predictable costs Once the solar system has been installed, the price of the electricity it generates is fixed for at least 25 years, so you can generate your own free power without worrying about soaring bills in the future. Easy and flexible Solar is straightforward, easy to install and very low-maintenance. The power from the panels is warrantied for 25 years with an expected lifetime for many years beyond this. Solar can be installed almost anywhere; all you need to get started is a building or some land, then the system can be tailored to the space available and your power demands. *Source:

6 Types of solar Solar power systems can be installed on the roof or on the ground. Features of rooftop solar The solar panels which make up rooftop solar power systems can be arranged in many ways they can fit around skylights, vents and other features on a roof. The solar electricity generated is close to the loads, so transmission loses are minimised. The building and roof is already in existence, so no land space is used up. The rough rule of thumb is that 1kWp needs 8m 2. Often the roof structure can be used as part of the installation, without the need for bulky mounting structures. However some buildings may need reinforcement; the weight of a solar system is typically 25kg/m 2. If necessary the weight can be spread out by making the panels less closely packed together. Rooftop solar is difficult to steal. Solar panels can reduce the thermal gains of a building and reduce air conditioning load. Rooftop solar panels reduce the noise caused by heavy rain on a metal roof. Car ports, Johannesburg RSA Simon Webb Flower farm, Timau Kenya Guy Lawrence, East African Solar Rookery industrial park, Norwich UK CIS offices, Manchester UK

7 Features of ground-mounted solar For very large solar systems, installing on the ground is often the only option since few roofs are large enough for utility scale solar systems. If you have spare land, a solar installation is an ideal way of earning an extra income, if an attractive Feed-in Tariff rate can be negotiated. The land and solar installation will need to be within a secure compound. The land space requirements are 1-1.5Ha per MWp. Tea plantation, Kericho Kenya Ground-mount, Rustenburg RSA Ground-mount, Polignano IT

8 System integration Solar and the grid Solar is often used as a power source where there is no utility grid. But solar can also be used where there IS a grid in fact over 90% of the world s solar electricity systems are connected to the grid. The solar electricity system synchronises with the grid, reducing the amount of electricity you need to import. 1. Savings graph: 1400 PV + G rid 1200 Load/Demand 1000 kw Purchase from utility Solar Generation Electricity Savings Solar and the grid 00:00 00:30 01:00 01:30 02:00 02:30 03:00 03:30 04:00 04:30 05:00 05:30 06:00 06:30 07:00 07:30 08:00 08:30 09:00 09:30 10:00 10:30 11:00 11:30 12:00 12:30 13:00 13:30 14:00 14:30 15:00 15:30 16:00 16:30 17:00 17:30 18:00 18:30 19:00 19:30 20:00 20:30 21:00 21:30 22:00 22:30 23:00 23:30 00:00 It is a simple and safe technology, requiring no batteries, and provides clean electricity as part of the overall energy mix. 2. Solar electricity system working in parallel with the grid: Loads Grid Utility electricity meter M Main distribution board Solar generation meter G DC to AC inverter Solar generator PV array What s more, if your solar is generating more electricity than your business needs, you can export the excess to the grid. Depending on local regulations, this excess can generate another income or create credits. The credits can be used to offset against the cost of the electricity you import at night or when you require more than the solar is producing.

9 Solar and standby generators African businesses that use a high amount of electricity often have a standby generator for grid power-cuts. A solar electricity installation can help reduce the power consumed from the grid, and also reduce the amount of generator fuel consumed during power cuts. Solar with a standby generator When the grid is functioning, the solar installation operates as shown in diagram 1. When the grid is available the PV operates in parallel with the grid. 1. Solar electricity system working in parallel with the grid: Grid M Loads Utility electricity meter Changeover switch Main distribution board Solar generation meter G DC to AC inverter Solar generator Diesel generator F Cost of diesel generated electricity Solar with a standby generator When the grid fails and the generator is running, the solar installation simply synchronises with the generator and operates as shown in diagram 2. The solar PV system can operate in parallel with the generator but a Solar Fuel Saver controller is needed to ensure the optimum peformance of the system. 2. Solar electricity system working in parallel with a standby generator: This ensures that the generator is never operating below a pre-set minimum (usually 25-30% of the rated power). Grid M Loads Utility electricity meter Changeover switch Main distribution board Solar generation meter G DC to AC inverter Solar generator Diesel generator F Cost of diesel generated electricity Solar Fuel Saver controller To protect the generator and ensure that the electrical system is stable, a controller is required, known as the Solar Fuel Saver. This ensures the generator is always running above its minimum threshold. The controller does this by regulating the output from the solar installation. If there are multiple generators, the Solar Fuel Saver can be used to manage the number of generators running, depending on the solar resource available.

10 Consistent electricity flow In Africa the sun can be relied on to provide power but sometimes clouds can cause the energy to drop momentarily, and there is no energy produced at night. In order to provide a stable and consistent electricity supply at a solar installation operating in parallel with a generator, the generator must be big enough to accommodate an increased power demand when the solar electricity generation falls. For every 1000kW of generator power, it is possible to install up to 600kWp of solar power. The Solar Fuel Saver ensures that the generator is always operating at or above its minimum output of 25-30% of its rated power. If the load drops then the Solar Fuel Saver simply reduces the output, i.e. power limits, the solar power system. The chart below shows this process in operation PV + Diesel : Solar Fuel Saver Operation kw 600 Partial Load lower limit 500kW 1.5MVA Generator PV kw PV Load Shed kw Load kw Partial Load Limit kw Diesel gen kw Power Limit ON Power Limit OFF 0 00:00 00:30 01:00 01:30 02:00 02:30 03:00 03:30 04:00 04:30 05:00 05:30 06:00 06:30 07:00 07:30 08:00 08:30 09:00 09:30 10:00 10:30 11:00 11:30 12:00 12:30 13:00 13:30 14:00 14:30 15:00 15:30 16:00 16:30 17:00 17:30 18:00 18:30 19:00 19:30 20:00 20:30 21:00 21:30 22:00 22:30 23:00 23:30 00:00

11 About Solarcentury No substitute for experience We are one of the world s most trusted, respected and longstanding solar companies. With our headquarters in London, we have offices across Europe, Africa and Latin America. In fact, being founded in 1998, we have been around since the early days of the solar industry and have been part of the evolution that has made solar the attractive investment it is today. We are an end-to-end provider of utility scale solar power systems, for the roof or ground-mounted. We ve put solar on more types of sites than any other company in the industry, and have won multiple awards for product innovation. Our people s knowledge is unmatched. Our international project team includes some of Europe s most experienced solar engineers, investment experts and legal specialists, and our engineers have designed and delivered gridconnected and isolated grid services all over the world, from the UK to Africa to the South Pacific Islands. So when you choose Solarcentury, you know you re in very good hands. What s more, we re in it for the long-haul. This isn t just our business, it s our mission. Our commitment to making solar accessible is deep-rooted and long-term, and our solidly established business is growing steadily worldwide.

12 Find out more Call +254 (0) Visit Solarcentury is in business for a purpose to make a big difference in the fight against climate change through widespread adoption of solar power. We are a big believer in helping solar change our world for the better, and we contribute 5% of our net profits every year to our sister charity SolarAid, which aims to eradicate kerosene lamps from Africa by Solarcentury East Africa Ltd, Marula Manor, Marula Lane, Karen, Nairobi, Kenya PO Box 15097, 00509, Nairobi, Kenya Registered in Kenya no. CPR/2013/ London Helmond Milan Johannesburg Nairobi SCSA