October 28th, 2010
|04:29 pm - Too Much Power|
In a very odd reversal of what we usually expect to hear about sustainable energy, Germany's active promotion of solar energy via government subsidies has perhaps worked too well. The good news is: "Uptake has been so rapid that solar capacity could reach 30 gigawatts, equal to the country's weekend power consumption, by the end of next year."
The bad news is: "Solar power is intermittent and can arrive in huge surges when the sun comes out. These most often happen near midday rather than when demand for power is high, such as in the evenings. A small surge can be accommodated by switching off conventional power station generators, to keep the overall supply to the grid the same. But if the solar power input is too large it will exceed demand even with all the generators switched off. Stephan Köhler, head of Germany's energy agency, DENA, warned in an interview with the Berliner Zeitung on 17 October that at current rates of installation, solar capacity will soon reach those levels, and could trigger blackouts."
Some infrastructure work will help, and one excellent answer is: "The best long-term solution is to install region-wide grids, says Tim Nuthall of the European Climate Foundation in Brussels, Belgium. 'In Europe, you need a grid that balances the sun in the south with the wind in the north.'" Power grids that extend over multiple time zones would also obviously help even out demand.
In any case, the dual lessons of this problem are the everything has unexpected consequences and that with the right incentives, solar power can become an exceedingly viable energy source.
Current Mood: impressed
That is way encouraging news!
Now their grid just needs great big capacitors to store excess energy!
But if the solar power input is too large it will exceed demand even with all the generators switched off. ... [S]olar capacity will soon reach those levels, and could trigger blackouts.
Wait a minute. The availability of too much power can trigger blackouts? Who designed this grid, Gene Roddenberry?
|Date:||October 29th, 2010 04:27 am (UTC)|| |
I assume it's kind of like... the disruption in power cycles can cause a problem, just like how lightning can do that even though it's technically too much power rather than not enough. But your comment made me laugh.
Quickly, eat five hundred pounds of beef! Don't tell me that too much food can be bad for you!
Better analogy: most people can dine at an all-you-can-eat buffet without making their stomachs explode. Why? Because they have built-in sensors which monitor their capacity to absorb more food, and when they are nearing their capacity limits, a mechanism kicks in to protect the safety of the system. "I'm full!" then announce. And then they go home.
Power grids have circuit breakers
to perform this function. (Lightning can defeat these devices occasionally because of the unpredictability, speed and magnitude of the "spike." Lightning is a little bit faster and less predictable than the sun coming up
, for example.)
My Gene Roddenberry comment was an allusion to frequent Star Trek
trope in which Our Heroes can make supercomputers explode by posing well-known paradoxes. The joke around COF ("Cranky Old Fandom," the codgers who don't feel it's necessary to qualify Star Trek
with "The Original Series" 'cause what else would we be talking about
?) was that circuit breakers were lost technology by the 23rd century.
Ah, I now follow your logic.
Once the circuit breaks, though... is that what causes the blackout? I mean, when the circuit breaker in your home triggers, you lose power.
Of course...I am kidding around.
What seems to be going on here is that it didn't occur to anyone that decentralized co-generation could yield so much output that, all by itself, it could exceed the capacity of (some parts of) the grid. Grid operators have the ability to take ordinary, centralized generators out of service when their output isn't needed, but, apparently, they can't do this with the decentralized solar co-generation facilities. (Which makes a certain amount of sense -- presumably we're dealing with lots and lots of small generators, no one of which is a major contributor, and which probably have cheap "dumb" connections.)
So instead of having an orderly way of managing "excess" power generation, we have to fall back on mechanisms designed for actual emergencies, which have inconvenient side effects.
Better inter-connection (including storage, which is simply the ability to connect the grid with the future) seems like a reasonable solution. But we also might want to look into ways to make the decentralized generating nodes "smarter" if it can be done cheaply enough. (Since power companies are installing "smart" meters for ordinary household consumers, I'd speculate that "smart" solar-to-grid connections wouldn't be cost prohibitive.)