Wednesday, April 30, 2014

Warming Wednesdays: energy storage

Take it from Steven Chu, the Obama administration's first energy secretary:

Wind and solar power are going to keep increasing. Wind is already the second-cheapest form of new energy, after shale gas, and it will become the cheapest within a decade. Right now utility companies get about 4 percent of their power from renewable sources other than hydro—and that 4 percent is roughly all from wind. You want to see a day when renewables are 50, 60, 70 percent. Utility companies will need batteries to stabilize the flow of renewable energy into the grid, plus a better electrical control system to do the switching. People may have these batteries at their houses instead of generators.

[Locations now off the grid] will have solar and wind power—which, in 10 or 15 years, are going to be as cheap as any other form of energy, or cheaper. Once you have storage systems, you can put a little solar installation on your roof or a plot of land, and now you have your electric supply! It will be like cellphones’ leapfrogging the land-line era. It will transform the prosperity of the world.

Chu isn't predicting which of several battery breakthrough technologies will win out, but he says this is where the action is in getting the planet off carbon polluting fuels.
An installation south of Phoenix, the Solana concentrated solar power (CSP) plant, solves the difficulty of storing renewable energy supplies by using molten salt. Hal Hudson writing in the New Scientist, explains:

Opened in October 2013, it's a zero-carbon power plant that could underpin the energy grid of the future.

I'm standing on a raised platform at its centre, decked out in clunky safety boots and a high-vis jacket. Thick pipes run away beneath me like arteries, pumping oil out to the mirror field. There, it is channelled into thinner piping that runs right through the focal points of the mirror troughs, absorbing the heat of the Arizona sun until the oil reaches nearly 400 °C. It then returns to the plant, where the oil superheats water vapour that spins two 140-megawatt turbines.

Six enormous white tanks surround the platform. Filled with molten salt, they can store enough heat to keep those turbines spinning at full capacity for 6 hours. The oil from the mirror field unloads its heat into the salt when the generators are at capacity. These tanks are what make Solana truly useful, not just producing carbon-free energy for Arizona, but storing it for use whenever the grid operator needs it.

We've got the wits to invent these technologies; do we have the wits and determination to implement them over the opposition of entrenched owners of polluting systems?

Photo by way of

1 comment:

Hattie said...

Big Island gets 40 % of energy from renewable resources. But we fly a lot.

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