STORE OR SEND THE WIND?

Ill Wind Blows Over Storage Market
John Gartner, July 15, 2009 (Matter Network via Reuters)

"…The majority of wind energy development companies…say there's no need for storage; any limitations in the ability to distribute wind power are due to a lack of transmission infrastructure. By contrast, many energy insiders say storage could make the business case for wind even stronger…[W]hile need may be too strong of a word…storage would greatly benefit wind.

"The American Wind Energy Association (AWEA), has taken a firm position against storage, especially onsite at wind generation facilities…[S]torage systems are not required to integrate wind energy into electric power systems....[and] developers do not want to bear the additional cost of storage…[W]ind power is now approaching the cost of fossil fuel energy in many locations (grid parity), so wind developers don't want to scare investors or lending institutions into thinking that storage is required…"

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"…[Many] wind projects [are] only harnessing a fraction of the available wind because of low demand at night or insufficient transmission capabilities…[W]ind farms in West Texas have a 9 gigawatt capacity, but 4 gigawatts of the wind can't get back to the grid. Just imagine all that energy being wasted, while during the day natural gas and coal plants are in full effect to meet peak demand…

"…[T]he problem in Texas is insufficient transmission -- an easy argument to make because…power producers usually don't foot [that] bill…Negotations often require transmission commitments to match the wind project before going forward…Conversely…[some] Japanese wind farms …don't put any of their power on the grid at night, instead storing it all and selling the power during peak hours. And they're profitable…[W]here wind energy is plentiful during off-peak hours, coal plants (because of CO2 emissions) are being spun down or even mothballed at great cost to their operators…If storage were available, then the excess energy could be stored and used at peak, with a very low CO2 footprint…"

Compressed Air Energy Storage (CAES) is nearing utility-scale trials in the U.S. - but is it affordable? Necessary? (click to enlarge)

"…[I]t's best to ask the economic questions…What is the model for cheap and abundant off-peak wind to be stored and sold during peak times? What can be paid per megawatt of storage capacity to turn a profit? …[A]t what point is it better to invest in storage as an alternative to adding transmission lines? In simplistic terms, if you build the transmission line to meet the maximum wind output, you've overbuilt for what you need during the vast majority of the day. But if you build smaller lines and add some storage, you might get greater efficiency.

"The biggest related question of them all has yet to be studied: how does the cost per megawatt of storage equate to cost per megawatt per mile of transmission lines, and what's the relative energy efficiency when including losses? …[B]ecause of the complexity of the model [and] variables…[there is no answer yet]… [I]f the wind industry is afraid to ask the question, perhaps third party storage companies will…[the next questions:] Where should the storage be located? At the wind farm? At substations? Closer to the edge?"