Small-scale wind power
Renewable energy in Sri Lanka
Practical Action South Asia is developing reliable and cost effective wind energy systems for charging batteries to help meet the electrical energy needs of rural Sri Lankans who do not have access to the national grid. By working with interested local manufacturers. Practical Action also demonstrate the potential market for and technical viability of locally made small wind energy systems.
Small wind turbine systems
Currently in Sri Lanka, families may have to travel long distances and wait long times for their batteries to be recharged at commercial centres. Small scale wind generators have the potential to stimulate village-level charging enterprises for either community or private use. Around 300 000 vehicle batteries are currently in household use, so the potential demand is vast.
The average electricity consumption per household in the country is approximately 68 kWh per month. Small wind turbine systems, with a capacity ranging from 50 W to 10 kW and rotor diameter ranging from about 0.5 m to 7 m, are primarily used in battery charging. These applications include energy supply for houses (lighting, TV, refrigerator), hospitals, farms, telecommunication, navigation, etc. Wind energy systems can also operate in parallel with diesel sets or solar PV systems.
Small wind turbines are generally horizontal axis type and have an upwind rotor directly coupled to a variable speed electric generator. Power modulation, rotor speed and orientation controls are achieved by passive aerodynamic techniques. These turbines can have a DC or AC generator. There are three different types of AC generators: the synchronous generator, the asynchronous or induction generator and the permanent magnet generator. Some instances, vehicle alternators are used in small wind turbines.
It has been estimated that there are more than 50 mass scale manufacturers of small wind turbines worldwide. One of the most successful small-scale decentralized wind energy programmes is in Inner Mongolia, China, where around 130,000 small-scale wind energy systems (200 W - 1000 W) are in operation providing electricity to over 500,000 people.
In Sri Lanka, four different designs of small scale wind turbine systems have been installed. Practical Action South Asia is also working with communities with small hydro systems and solar PV based home systems (SHS).
Wind power - Nikeweritiya
More than 70 percent of people in Sri Lanka live in poor rural areas, far beyond the reach of the national grid and often miles from the nearest kerosene seller. People face untold hardship every day - and even lethal danger - simply because they cannot get the safe, clean, renewable energy they need.
For Weerasinghe, being without power was much more than an inconvenience. It is a major source of poverty, preventing him from working, stopping his children learning, and forcing him to use up precious natural resources - as well as precious hours that could be spent improving his life instead.
Before he started working with Practical Action, Weerasinghe had no choice but to use energy sources that were either dangerous or hugely expensive in order to get the basic light and heat he needed. The kerosene lamps he used for light were so notorious for causing injuries, especially to children playing or doing their homework (kerosene burns are a major cause of children being admitted to hospital in Sri Lanka). And the old car battery he relied on for a little electricity cost more than eight dollars a month to recharge - a real fortune when money is so scarce.
Weerasinghe now generates light from his own small wind turbine system. Living in Usgala village in the south of Sri Lanka, Weerasinghe's life is hard indeed. Surviving on subsistence farming, he grows just enough to feed his family with little to spare.
"It was wonderful! Straight away there was enough power to light a few light bulbs, so I could work and the children could do their homework. I could charge up my own battery, and earn a little money by charging up those of my friends and neighbours too."
Over the months, the pilot turbine project surpassed all expectations, generating power when there was wind, and storing it for calmer days. Simple - and self-sufficient too. Villagers are trained to do all the installation and maintenance work themselves, and the turbine parts are made by local people, from local materials.