Technology Advancements Allow Batteries To Store More Wind Energy

The 32-megawatt (MW) wind park in Sorne Hill will be the first in Europe to integrate a big back-up battery system that will ensure a reliable supply of electricity no matter how big the fluctuations in the wind might be.

"The battery enables large amounts of energy from wind or solar power to be stored, managed, controlled and sent into the electricity grid when it is needed. It doesn't matter whether the wind is blowing or not, the battery makes the electricity output predictable and reliable," said Tim Hennessy, CEO of VRB Power Systems, the Canadian manufacturers of the battery.

Analysts say the potential market for technology that can provide reliable storage for large amounts of energy from wind and solar power is huge.

Battery storage could be especially useful when wind power feeds into a grid that belongs to a so-called "island" such as in the UK and Ireland, but also in Spain on the Iberian Peninsula — in effect an electrical island with limited interconnections with France in the north and Morocco in North Africa.

By contrast, the electricity grids of the big European wind nations of Germany and Denmark are interconnected with their northern neighbors. Excess wind power from these countries goes all over Europe with the grid effectively acting as a huge storage system.

Also, Germany is harnessing the full spectrum of renewable sources such as hydropower with dams and biomass to provide a back up to wind. It also has lots of salt mines to store energy in the form of compressed air.

However, the "electrical islands" of Ireland and Great Britain with little hydropower and a scarcity of salt mines could need huge amounts of battery storage as they expand their use of wind power so that the ingress of wind power into the system doesn't lead to grid instability.

Wind parks on a colossal scale are being planned in the UK and Ireland. The UK is planning to install 33 GW of capacity of offshore wind power by 2020. Ireland has 1000 MW of wind power but is planning to install 2,400 MW of wind by 2016 and 4,300 MW by 2020 to reduce the country's reliance on imported fossil fuels and cut harmful greenhouse gas emissions.

That means the 2-MW battery in Sorne Hill, Buncara, due to be in operation in 2009, could be just the start. Hugh Sharman of Incoteco ApS, Denmark, a contractor with VRB, estimates that Ireland could need as much as 1000 MW of battery storage capacity by 2016.

As oil and gas prices continue to rise, the battery storage system will become more cost effective.

A Mwh of electricity generated by wind turbines in Ireland costs 70 euros [US $106], making it much cheaper than the equivalent electricity generated by natural gas, said Sharman. These prices offset the high initial investment costs of the battery.

The battery could also be used to capitalize on different tariffs for peak and off-peak electricity: electricity could be stored during off-peak hours when the cost is low and fed into the system in peak hours when the price is high.

The UK would need up to 12,000 MW of battery storage to balance out the system if the country goes ahead with its plan to install 33 GW of wind capacity by 2020 and decides to use batteries as a back up, Sharman said.

Nuclear and clean coal will supply a base load of 20 GW, with wind power supplying 33 GW under the plans. However, the country's summer valley load is 20 GW and winter valley load is about 33 GW, and the base load will be difficult to operate with so much fluctuating wind load.

The battery can be used to store not only wind but also solar energy, for example, in the million-roof program in California, Sharman said.

Replacing the centralized electricity generation system with a million mini solar power plants on roofs might find a storage system useful, he said.

The flow battery was developed at the University of New South Wales in Australia in the early 1980s and developed by Vancouver-based VRB power systems. It generates a current by putting large amounts of oppositely charged electrolytes in a vanadium sulphate solution in motion between positively and negatively charged electrolytes.

The battery soaks up electricity when the wind turbines produce an excess amount for the system. It then feeds the electricity into the system almost instantaneously as soon as the wind speed drops. It can make electricity from wind 95 percent constant.

The VRB battery can be deep-cycled 14,000 times, much more than a conventional lead-acid battery. It is also greener than other batteries and made without toxic metals as lead, cadmium, zinc, and nickel.

Ralf Bischof from the German Wind Energy Association (Bundesverband WindEnergie) said that any battery system would need to be more cost effective to be viable for storing wind power for Germany given the cheaper alternatives.

"A wind back up system would be economical from about one euro cent per Kwh in Germany. Wind electricity is 8 cents per Kw/h. Right now we use all the power the wind power that wind parks can generate in Germany. There's none left over to store," he said.

He said that battery storage technology for cars had huge potential market in Germany.

"Electrical cars will need to recharge their batteries from clean sources such as wind power, for example," he said.

The huge market for batteries for electric cars that can be recharged using wind or solar power could be captured by EnerDel. The U.S. company has produced a lithium-ion battery that will be used by electric vehicles to be mass manufactured in Norway and rolled out in 2009.

EnerDel says its batteries made of lithium ion are cheaper and lighter than the nickel metal hybrid batteries now used in hybrid electric cars.

"It is vital to develop battery technology for storing energy from renewable energy sources," Bischof said.

Jane Burgermeiser is a writer based in Austria.