The role of innovation - Solar, Wind and Land: Conflicts in Renewable Energy Development - page 202

resources—the wind is not always blowing and the sun is not always
shining. Finding more efficient and cost-effective ways of storing wind- or
solar-generated energy over time will thus be essential if these resources are
ever to stand alone as electricity sources without the aid of backup power
from fossil fuels or nuclear energy. Even when backup power sources are
involved, low-cost energy storage technologies could greatly reduce the
extent to which wind and solar energy resources complicate operators'
efforts to balance power loads on the world's electricity grids.
Recognizing the importance of energy storage to the renewable energy
movement, countries throughout the world are beginning to invest more
attention and funding toward efforts to advance this growing research area.
The German government plans to set aside roughly €200 million (US$270
million) toward developing better energy storage technologies, and the
Japanese and United States governments have begun allocating more
financial resources to this research as well. 31 In all, the research company
IHS predicts that more than $19 billion will be invested worldwide in
energy storage by the year 2017. 32
The rechargeable lithium ion batteries that power common phones and
flashlights have existed for decades but involve technologies that are far
too expensive to employ on a large scale. Fortunately, numerous other
energy storage strategies exist or are in development that could poten-
tially prove far more cost-effective. Pumped storage facilities represent one
interesting approach to storing energy that has existed for many years but
has received increased attention as the wind and solar energy movements
have grown. When there is an excess supply of electricity on the grid, a
pumped storage facility uses that energy to pump water from one reservoir
to another reservoir located uphill. Then, when electricity demand on the
grid rises, facility operators release water from the upper reservoir, sending
it through hydro-turbines that generate electricity as the water makes its
way down to the lower reservoir. 33 Eventually, when there is once again
an excess supply of electricity on the grid, the facility uses this low-cost
electricity to pump water back into the upper reservoir so that the cycle
can continue.
One major disadvantage of pumped storage facilities is that they are a
relatively inefficient means of storing energy. The developer of one modern
pumped storage facility noted that the system was capable of providing
only about 3 kWh of future electricity for every 4 kWh it consumed—an
energy loss of roughly 33 percent. 34 For obvious reasons, pumped storage
facilities are also rarely cost-justifiable in locations that lack natural
elevation changes or an ample supply of available water. Nonetheless,
pumped storage systems can sometimes be a useful way of mitigating the
intermittency problems associated with renewables. They tend to be most
useful when sited near large solar energy projects or wind farms, where they
can make use of the transmission infrastructure already in place for those
projects.