vanesch
Staff Emeritus
Science Advisor
Gold Member
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Chi Meson said:Not totally disagreeing here, but the highest peak demands are exactly when the PVs are cranking the most: sunny hot summer days, with ACs in office buildings working to capacity.
You are right that that is a summer day profile. Look at
http://www.rte-france.com/htm/fr/vie/telecharge/prevconsoelec.pdf
which gives some profiles of electricity consumption in France (sorry, it is the market I know best). On the first plot, p.1 you find the annual smoothed consumption profile: lowest in summer, highest in winter (we tend to have much less AC than in the US: matter of habit, living standard, and climate, I guess). Winter has about double consumption than summer.
Second plot on p1: profile for a few consecutive days in summer: indeed a peak around noon. But we are now at about 52 GW.
First plot on p2: a winter day: peak at 19 hr, at 82 GW. That's in winter, and after sun set, when solar doesn't work, and we are at the highest grid consumption over the year (peak in winter).
I'd never recommend wind to any homeowner who doesn't live in a dependably windy location (I live on the Connecticut coast; our neighborhood is called "Windy Hill"; a week without wind is unheard of) and as of now small wind turbines are not as good an investment as PVs. So anyone with a turbine in a location that is subject to a lull is a loon.
I really think that for the moment, PV on a large scale is excessively expensive. Hell, we are an order of magnitude above nuclear/coal! Wind is cheaper in that respect, although it is still a factor of 2 or 3 more expensive than coal.
If local PVs were installed in 100s of thousands of homes this year, the grid would have a hard time dealing with the fluctuations, but I'm thinking of the progress over decades. As the input of local PVs increases, the fluctuations will become more predictable, and the buffers and adjustments in output should become more flexible.
Yes, but you remain with the principal problem: highest consumption in winter, when it is dark. At least in France (and I think it is a typical consumption profile in Europe, which must even be worse in less sunny places like Northern Germany). I suppose that if you live in a warm place, where the main consumption is AC, then there is of course a strong correlation between consumption and solar irradiation, so there it might be a good idea.
Lastly, I thought 30% nuclear generation was being optimistic. I'd love for it to be 50% or more. Based on current consumption, would anyone expect a greater nuclear contribution? (think realistically, 20 years from now).
France went from about 1% nuclear to over 70% nuclear in 20 years, between 1977 and 1997. That shows that it is technologically, industrially and economically possible.
Belgium went from 0% to 55% in 11 years. (now these fools - I can say that, I'm Belgian - want to phase out by 2015, but I hope they will come to reason before they do damage).
If we want to make plans for 30 years ahead, I think that is risky. Technology might have changed. It is possible that solar is extremely competitive by then. That would be great. Maybe electricity storage will have a solution then. But one shouldn't wait 30 years for the miracle solution and do nothing right now. I agree with you that the best thing to do is to switch as much as possible from coal to nuclear right now. The technology exists and is operational. If 30 years from now, things are different, we can do different things then. Most nuclear power plants will then be halfway through their life anyway, and one should start thinking of their replacement, with whatever is the best technology at that point. Maybe in the mean time we've found out that AGW is not an issue. We can then use fossil fuels again. Maybe we find out that it IS an issue, and then we will be happy to have done something about it.
My idea is that the local investment that DOES really make sense, is not too expensive and is very efficient, is thermal solar, to make hot water. It is totally ridiculous that houses have an AC, and heat water in summer using electricity.
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