Quote:
Originally Posted by Blue Bomber Man
The fact of the matter is a decentralized power grid based soley on renewables (that obviously have varying outputs) can be 100% reliable and cover 100% of the nations power needs, provided that we advance our distribution network far enough.
The reason for this is averages. Say you have a small system with 10 sources of power. The probability of having enough power during all times would be fairly close to zero. However as you add millions of different sources, such as hometop solar panels, wind arrays, hydro, geothermal etc, the probably approaches 100%, which would actually be higher then the current systems capabilties.
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No. Unfortunately, the two sources most people mean when they talk about "renewables", wind and solar, aren't random at all. They're connected by high-level physical processes such as weather and the Earth's rotation. Take the simplest case: PV cells generate electricity when the sun is shining. So assume the sun shines half the time, build twice as many arrays, and you should be able to get 24-hour power 'cause of the randomness, right?
For a less obvious case, consider weather. It's not just random clouds here, wind there. Suppose you've got your solar grid that provides plenty of power under average conditions. What happens when you get say a Pacific storm system that puts cloud cover over most of the western US? What happens when you get a series of storms lasting a week or two? (Which does happen every few years.) And at the same time you have a couple of blizzards moving down out of Canada, so the midwest & east coast are socked in? Your solar isn't producing much, most of the wind turbines are iced up, and your pumped storage all went down the tubes by about day 5. What do you do? Crank up the coal-fired plants? But the owners weren't making any money from them, so they sold them off as scrap :-)