Tuesday, February 3, 2015

Solar and Smart Grids

I recently realized something about solar power and smart electrical grids and I feel sort of stupid for not realizing it earlier.  But rather than stew in shame I should probably share it with all of you since I expect most of my readers, not having had the benefit of working at Ember, have no idea what a smart grid is.

But first, solar power.  For a while now the prices of solar cells has been plummeting.  Not with the outstanding reliability of Moore's law but at a fearsome rate nonetheless.  Which is really awesome in terms of reducing carbon use!  But there's a problem.  Solar energy only works when the sun is shining.  At night, there's no solar energy at all so you need to run some other sort of electrical generation to keep things running.  You still have to build enough non-solar infrastructure that you can keep things going even at night.

But there's an even worse problem.  It can take up to an hour to spin up a conventional power plant to the point where it can start generating useful grid power.  That's fine for the nice, predictable fall of night but what about when a cloud passes in front of the sun?  Falling solar prices mean we want to start building more and more solar generation capacity but if it all goes away suddenly that becomes a bigger and bigger problem.

That's where smart grids come in.  We can't change how much energy we produce from minute to minute, but it's a lot easier to change how much energy we use from minute to minute.  The lights have to stay on but you can hold off running a compression cycle on your refrigerator for another 5 minutes.  Or if there's a lot of excess power just go ahead and run it early.  And you can do the same with air conditioning, recharging batteries, many industrial process, etc.  I'd thought that smart grids were a sort of nifty efficiency but I'm coming to view them more as a critical tool in making the widespread use of solar possible feasible.

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