World's biggest offshore wind farm

In his latest Powering Britain report, Joe visits what will be the biggest offshore wind farm in the world.

The London Array is being built in the Thames Estuary at the moment and will eventually have 175 turbines installed across a vast area.

These turbines are big - each one is higher than the London Eye!

When the wind farm is completed at the end of the year, it will be able to power 470,000 homes.

The government wants 15% of our energy to come from renewable sources by the year 2020.

While wind is more environmentally friendly than options like coal, gas and nuclear, critics say the wind doesn't always blow and turbines can harm local wildlife.

Watch Joe's report to find out more.

london array in thames est

175 turbines installed across vast area

each one higher thjanm the london eye

end of the year, last turbine

470000 uk homes

drive for renewable energy - wind

more than 7mph

it pushes blades of wind turbines around - energy converted elec

takes a lot of wind and a lot of turbines - coal, gas or nuclear

but env friendly

15% of renew energy by 2020

critics - don't always blow - could harm local wildlife