WastedEnergy

The following is a guest post by Robert M. Whitson, a program analyst with New West Technologies LLC who currently works for the Department of Energy Wind & Water Power Program.

How do we store energy today? Those two double-A batteries you’ve got in your yellow Sony Walkman?
 
No large-scale energy storage exists for utililty power today other than pumped-storage hydroelectricity. Although much discussion today surrounds the potential for utility-scale storage in electric car batteries, the technology is not yet commercially available, as evidenced by the uncertain range on these cars, which may be as little as 100 miles to a full charge (caveat: see automaker BYD, who claims its E6 model can get 250 miles). At best, these cars are another 10 years out from “commercial,” and bidirectional car-grid energy storage technology may be as much as 15 years away, possibly more.
 
But what happens to these batteries when they go into a landfill? And did you know that: oil isn’t the only energy carrier that causes pollution when it spills? What happens when sodium acids from littered batteries leach into our sewers? No one has yet implemented a good solution for wide-scale disposal, and US battery manufacturers don’t exactly have recycling programs. Now, what happens when you spill water? Well, things get a bit wet sometimes, but the expression applied to small-scale water spills at the dinner table still applies: “Eh, it’s just water.”
 

Where do you go when the lights go out?
 
Water is the only utility-scale energy storage option available today – and more of it needs to be developed if we want to keep developing wind and other renewables around the world.
 
Water in this form is called pumped-storage hydropower. During times of excess generation, like at night when the wind blows and there is no demand for this power (apparently Germany is forced to keep its lights on at all hours of the night because of this) – water is pumped through a turbine to a higher reservoir where it is stored until the grid needs it and it is run back through this variable speed reversible turbine-pump. Because of the need for load balancing, pumped-storage is very good at quickly smoothing out fluctuations caused by other sources of electricity. Utility-wise, a combination of on- or offshore wind married with pumped-storage seems to make a lot of sense for providing baseload and peaking capacity. 
 

Above: Seawater pumped-storage system on Okinawa, Japan
Below: London Array, world’s largest offshore wind farm, UK

 
DOE’s Energy Information Agency’s (EIA) most recent figures claim the US has 21.5 gigawatts of pumped-storage capacity, with about 2.5% accounting for baseload power needs (2009).  However, not much more stands to be built (based on FERC permits) since it’s largely not “economical.” But economical begs the question of by whom and how this form of power is being valued.
 
Currently, there are only a few markets out west that value the added benefits that pumped-storage provides to the electricity grid. If the US were to create a unified market (wherein multiple utilities from across the nation can purchase wholesale power) for pumped-storage, this country stands to add an additional 30 GW in capacity, which doesn’t even account for the possibility of doing sea pumped-storage.
 
At some point this country will need to talk about storage when all the proposed on- and offshore wind is built out, not to mention a myriad of other utility and residential-scale renewables that will continue to be added to the grid. Battery technology is not quite here, but pumped-storage has arrived… in the early 20th century.