New Cost-Effective Battery Tested to Store Wind-Power
For the first time in America, a company has developed an efficient battery solution to storing wind power, a clear answer to critics who claim turbines are unreliable.
Xcel Energy’s “Wind-to-Battery” project is currently being tested on a Minnesota wind farm. The company believes that the 80-ton battery will power 500 homes for 7 hours when fully charged. The battery’s 20 50-kilowatt modules together are roughly the size of two semi- trailers and can store 7.2 megawatt-hours of electricity.
- » See also: Storing Renewable Energy in Boxes of Air
- » Get CleanTechnica by RSS or sign up by email.
“Energy storage is key to expanding the use of renewable energy,” said Dick Kelly, Xcel Energy Chairman, President and CEO. “This technology has the potential to reduce the impact caused by the variability and limited predictability of wind energy generation. As the nation’s leader in distributing wind energy, this will be very important to both us and our customers.”
The sodium-sulfur battery technology has already been used in a variety of forms in the United States, but Xcel says their pilot program is the first time any practical and efficient battery storage technology has been used on a wind farm.
Photo Credit: Ryan McD on Flickr under Creative Commons license.
Why is energy storage so important?
For the power industry integrating renewables is not so simple. The load (power that the customers use) varies throught the day with peaks and lows but it can be predicted and accounted for. The power companies use the preditction to set their generation schedules and make minute adjustments. When you have a renewable like wind/solar/wave which can suddenly stop or start producing power the Power Plants generating units must now make large adjustments because the load at that time will still remain the same. This can work both ways too. At a load peak the renewable drops to 0 and the PP must ramp up and generate more. Lets also postulate when the load is at the daily minimum. The PP will also be at a minimum. What if the renewables are at 0 MW and suddenly the renewables start pumping MW into the grid? What do the PP do? There is more generation than load, now they must decrease output. However the PP units are aready at thier lowest output so one of two things will happen. The PP will either trip offline or the operators will pull equipment offline in a hurry to avoid a unit trip. Neither is good for PPs which are supposed to constantly operate. Having a combination of steady renewable power output and a “smart” electric grid will prevent PP from dancing around. Utilities will be much more open to having renewables tied into the grid.
Why can’t PP react quickly to grid changes? The most efficient type of PP we have are based on the steam cycle. Fuel is burnt in a boiler to heat up water to steam which is shot through a turnbine conencted to a generator. Whatever is left over is condensed back to water and then goes back to the boiler to be heated again. Control of the boiler is very slow compared to the type of MW fluxuations that could come from a renewable source.
As mentioned above, storage on the grid is one of the key issues with aggressively moving ahead on the alternative energy front. And while we should continue advancing battery technology for many situations, I would like to see other alternatives investigated that don’t carry the same issues as battery maintenance and recycling.
sane : “I assume you are not suggesting that someone would let water flow through a dam to generate electricity so as to then pump water up hill…” This is exactly what Pump Storage is; the water is pumped at a time when generation is greater than demand (say, at night) and released at a time when demand exceeds the normal generation, such as morning and evening peaks.
This is similar to charging a battery overnight so you can use it during the day, you are effectively deferring the load (of course there are many other considerations, and I’ll agree, something about it just seems wrong…)
I wonder about this whole claim of cost-effectiveness.How much energy cost goes into maintaining molten sulfur at such a high temperature? Seems like batteries that operate at normal environmental temperatures would be more efficient.