Renewables: Storing Wind Energy

Reference: Thwaites, Tim (2007)A Bank for the Wind. New Scientist,193 (2586)13 January 2007 pp39-41.

(The link above only leads to a preview of the full article but if you are a New scientist subscriber or have other access you can view the full text.)

One of the problems with renewable energy is the fluctuations in energy production. With wind energy on a strong day it can produce too much energy and on a poor day too little. So in reserve you have to have non-renewable energy sources such as oil fired stations always available at a flip of a switch. Without being able to store energy you can never just rely on wind energy.

King Island which sits between Australia and Tasmania has a storage system in place.

King Island is a small self contained electrical system. It has a number of wind turbines backed up by diesel generators with no main grid access.

In 2003 the local utility company installed Vanadium flow batteries. The new installation halved the quantity of fuel burnt in the diesel generators and reduced carbon dioxide emissions by 2000 tons per year.

Normal batteries are self contained units but with flow batteries, chemicals cross the interface. Think of Vanadium as an electron storing chemical push it through the battery to store electricity pull it back to release the electricity (For a more technical description try the article or google).

One of the most obvious applications for grid connected wind farms is that Vanadium batteries could be used to guarantee a minimum supply rate, Therefore removing the need for a back up power supply which is often one of the main arguments against renewable energy sources. In fact VRB Power Systems has a contract to construct a 12-mega-watt-hour Vanadium battery at the Sorne Hill wind farm in Donegal, Ireland. Not only will they be able to offer a guaranteed supply of energy but they can sell stored energy at peak times for higher prices.

Or for a blue sky idea how about a new housing estate with a couple of wind turbines, solar panels and a Vanadium battery unit. It would have the potential to be a self contained distributed power grid.

Vanadium as an electron source may have other uses too, as an easily transportable electron source it could be used to power cars. Will we soon start to see petrol stations with a wind turbine attached?