Wind Power & Biomass

Wind turbines use the natural power of the wind to drive a generator and produce electricity. Wind is a clean and sustainable fuel source - it creates no pollution and it will never run out.

Wind energy technology is developing fast - in the last 20 years, the power production of wind turbines has increased by a factor of 100, while the costs of generating electricity from the wind has fallen by 80%.

The diagram opposite shows the components of a wind turbine,
which converts kinetic energy into electrical energy by the following process:

• the wind blows the blades making them turn;
• the blades turn a shaft inside the nacelle, which connects to the gearbox
• the gearbox increases the rotation speed enough for the generator, which uses magnetic fields to convert the rotational energy into electrical energy (these are similar to those found in normal power stations); and
• the power output goes to a transformer, which converts the electricity coming out of the generator at around 700 Volts (V) to the right voltage for distribution system, typically 33,000 V.

The power is then transferred to the national grid, which transmits the power around the country using the existing upgraded network.

Instruments to measure the wind speed and direction are fitted
on top of the nacelle. When the wind changes direction motors
turn the nacelle, and the blades along with it, around to face the
wind. The nacelle is also fitted with brakes, so that the turbine can
be switched off in very high winds, for example during storms.

Biomass technology uses animal and plant waste to produce energy by a process of anaerobic digestion. This involves the natural bacterial fermentation of organic material in the absence of free oxygen.

The main products of the process are methane gas, which can be used to power engines to drive electricity generators, and bio fertilisers.

Bio-diesel is mainly produced from specialist biomass crops such as oilseed rape and wastes and can also be used to power vehicles. Solid wastes remaining can then be used as fertiliser or compost or reused in the biomass plant.

The biomass technology proposed at Chelveston Renewable
Energy Park is illustrated in the flow diagram opposite.