But man I hate them freaking batteries.  Waste of money and then they go bad.  A new battery can be recharged about 80 percent. An old battery maybe 30 percent - then nothing. My point is that by design they WASTE electricity.

Onward through the fog

What do we need to run 24/7?  Does this fast paced world have us on a treadmill?  When you think about it -- why?  Where is it getting us?  

Unless we can think outside the box we'll be constrained by this kind of "can't".  

Plus, small scale, decentralized storage will probably be more feasible than large scale, centralized storage.

Living with renewable energy will entail a true revolution.  The power centers that be will fight it tooth and nail.  It does not lend itself to maintaining the status quo or the drive toward globalization.  Choosing to go this route sets up a real conflict between world views.  

Some will try to make it an ad on to the main operating system.  But try making it the alternate operating system and you got yourself a real fight.

This logic has limits - indeed, some have suggested that the huge amount of wind in Denmark has caused grid disruptions as wind died down and voltage sagged on the system.  But given as we are so far from those limits in most of the world, why is this AEP project a big deal?  And why are they doing it at all?  The only reason I can see for coupling storage to renewables in today's environment is if you can save power at off-peak hours and sell it when prices go up during peak.  But this is a pretty thin arbitrage opportunity in most parts of the grid, especially once you take into account the round-trip efficiency of storage technologies and the need to recover their capex off that price differential.

What am I missing?

In that vein, $4500/kW looks awfully high.  My guess is that they've either included other unassociated costs with that storage or else are doing something unique - but that's certainly more than I'd expect for this class of technology.

A range of options is available for the remainder of the storage, including the use of plug-in hybrid cars, Mr. English said. The idea behind plug-in hybrids is that the owner of a car would charge the batteries every night when demand and cost of electricity were low. The next day, under a contract between the utility company and the driver, the car would be left plugged when not in use, and the power company could reverse the flow of electricity and draw power out of its batteries during times of peak demand.

The idea of moving our cars with wind-generated electricity sounds great to me.

Its puzzling to me though that they didn't mention compressed air energy storage (CAES), which as the ESA figure linked to above shows, is the lowest cost bulk storage technology. It can also ramp quickly, operate at high efficiency under part load, and appears to be widely available in wind-rich regions throughout the continental united states. The capital cost looks too high to make it readily economic, but it certainly looks better than sodium sulfur batteries in the short run. I guess blowing air underground is less sexy than high-tech batteries.

(Matt Wald's "Storing Sunshine" in the  July 16th NYT does mention CAES however)

Sean asked about additional motivations for storage beyond simple arbitrage. One big one is transmission constraints. Storage allows you to put much more wind capacity behind a given transmission line and also allows you to run the line from the wind farm at a higher capacity factor thus better utilizing the transmission capital. If we start building dedicated transmission lines to remote wind resources, storage may become increasingly important.

Another reason to consider storage is that at high penetrations wind gets a smaller capacity credit. The declining load carrying capacity means that you need something else on line to come on when there is a lull. In the limit of high wind penetrations the value of wind is just the variable cost of running an open cycle gas turbine or something similar which can ramp quickly. So storage (together with other strategies like coupling geographically separated and temporally uncorrelated wind farms) can help firm up wind at high penetrations.

It also means that you use less fossil fired capacity to back wind. Remember that wind capacity factors are like 25-35%, so even if you have your wind capacity matched to your peak load, a large chunk of your energy is still coming from some other source. If that source is hydro (as in Denmark, with neighboring Norway providing lots of balancing) then no problem. If you are balancing with natural gas or even worse an old intermediate load coal plant, then you are really not doing a great job cutting CO2 emissions.

So if you have lots of transmission capacity to spare and can tie wind farms across the country, or if you have lots of eco-friendly hydro (not a lot of that in the great plains though), then you might not need storage. Otherwise, storage might be a good thing to consider. And considering lots of transmission projects are facing huge NIMBY (not in my backyard) and BANANA (build absolutley nothing anywhere near anything) issues, storage could likely play a big role as wind continues to expand

The efficiency is comparable to the figure given above for batteries, and the up-front costs of installation are much lower.

a sibilant intake of breath