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Thursday, January 16, 2014

Should Renewable Energy be Necessarily Stored?

The question if Renewable Energy should be stored or not is an important one. The Technology about Energy Storage Systems is improving day by day but the costs are still high. So it's important to understand if there are different ways to use Renewable Energy since is the Energy of future.

At the moment one can think about Renewable Energy generation that since the global quota produced is small compared to the global quota of Energy produced it would be convenient to use it at the same moment when Renewable Energy is produced.

This could be true if the Global net we know with the name grid would so simple to understand as to switch a button. Unfortunately it is not!

What seems so straightforward on our end –turn on the lights and bam, electricity! – is truly a complex system designed to move huge amounts of power staggering distances, all so that we can exercise our right to run the washing machine, dishwasher, and power drill all at the same time.

When you plug your smartphone into the wall outlet, you’re tapping into the grid. “The power grid is like a massive pool,” says Charles Barnhart, a postdoctoral fellow at Stanford’s Global Climate and Energy Project. “There are lots of hoses pouring in, and lots of taps pouring out.” The hoses pouring in come from power generators, including everything from coal to nuclear to hydroelectric to wind to solar sources. The taps pouring out are our smoothie blenders, refrigerators, stereos – and that dead phone battery of yours.

 Here’s one key thing to know about the grid: It doesn’t function unless energy demand (from us) and energy supply (from power plants) balance out. Too much demand, and we lose power. Too much supply, and we also lose power, as the aging grid can’t handle much surplus energy. Grid operators prevent this by carefully monitoring and predicting energy demand (for example, they often expect a surge in demand on hot days when we all crank up our air conditioners), then calling on power producers to deliver that precise amount.

The problem with the ever-fickle wind and sun is that they’re not so easy to predict and control.

Overall, energy from renewable sources does make up a decent slice of the country’s total power – about 13 percent. But the grid is constantly fluctuating, and at any given (sunny, windy) time and place, renewables might be humming hard enough to overwhelm our demand for energy (as it did during this Pacific Northwest storm, or on most nights in Texas).

All right, you might say. I get it – but when wind and solar are pumping, shouldn’t we dial back all the grid’s dirty power sources and let renewables shine? I’ll let Paul Denholm, Senior Energy Analyst at the National Renewable Energy Laboratory, handle this: “You can only turn a power plant down so much. A Prius comes to a stop at a red light and the engine shuts off. When the light turns green, the engine starts up again. Power plants aren’t like that – if you turn it off, you have to keep it off for hours. Also, it’s really expensive to turn a power plant on and off. “It would be great if in the middle of the day, when the sun is shining, we could turn power plants off.

But the sun will set, and you wouldn’t have the plants back on again in time.” And so we’re left with a situation where we use renewable energy when the demand is high enough. When the wind is blowing/ sun is shining but we don’t need the energy, however, we can either curtailwind/solar production or figure out a decent way to store the excess.

That’s why renewable energy storage is a bright idea today, not years in the future. There’s lots of exciting science being done in this department, from high-tech batteries to pressurized air stored in volcanic rocks to hydropower reservoirs to residential water heaters. This is all part of the Smart Grid, a broad collection of ideas aimed at modernizing our creaky power system and integrating renewables more seamlessly. Some day, we may wash our hands of our dirty power sources.


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