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Going green

Chris Pearson
The debate in another thread has shifted to the climate debate, so perhaps we should keep it separate.


Publication bias may be detected by what I think is called a funnel plot. Imagine a funnel lying on its side.


On the X-axis, you have the power of the study - high powered studies are nearer to the truth so they lie in the stem of the funnel.


On the Y-axis you have the finding of each study - whether the activity is beneficial or not. The middle of the neck of the funnel is the best estimate of the true value.


At the left of the plot, the wide bit of the funnel, lie low powered studies. Some will show that the activity is beneficial, some the reverse. So if you look at the risk of smoking, some low powered studies should have shown that it was beneficial. IIRC, studies showing that smoking was beneficial were not published. That may be because the authors chose not to submit, or editors chose not to accept.


I have no idea whether this sort of plot has been done for the climate debate, but it ought to have been.


I accept David Z's argument that the climate has warmed and cooled long before industry appeared (even on a Roman scale), but what bugs me is the doctrine that we cannot afford to get it wrong.


Does anybody here know how man-made energy compares with the amount which arrives from the sun?
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    According to the speaker at an IET lecture a while back, offshore wind is more like 30% utilization, rather than 25%, and the UK is moving more to offshore these days.  That's largely political, to appease the NIMBYs.  But whether it's 25% or 30% isn't so important if you build enough of them.  If you need 1GW, just build 4GW of wind turbines, spread over a wide enough area that it will be windy somewhere.


    Domestic and other rooftop solar export is usually not even metered.  Its contribution to the grid is tiny, and probably just goes some way to reducing the transmission losses in the system.  This does give microgenerators a strange incentive to use as much of the electricity as possible themselves.  Anything that's exported earns no money.


    My figures were for electricity only.  My cooking is a mixture of gas & electricity, and I do have a gas boiler.  I could probably produce all my hot water in summer from solar, if I was willing to spend more on a "diverter" to power the immersion heater.  A lot of people do that, and if domestic gas was banned, I would get one.


    But I agree that a solar-only system is only useful when it's sunny, or at least only light cloud.  Last week (as I write), we had several days in a row with heavy cloud all day.  The solar panels just about covered the base load while I was out, and didn't generate enough to put any useful charge into the battery.  It was already flat by the time I got home.  I could uprate the battery to tide me through one bad day, but it would cost more money, and would do nothing useful in sunny weather.


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    According to the speaker at an IET lecture a while back, offshore wind is more like 30% utilization, rather than 25%, and the UK is moving more to offshore these days.  That's largely political, to appease the NIMBYs.  But whether it's 25% or 30% isn't so important if you build enough of them.  If you need 1GW, just build 4GW of wind turbines, spread over a wide enough area that it will be windy somewhere.


    Domestic and other rooftop solar export is usually not even metered.  Its contribution to the grid is tiny, and probably just goes some way to reducing the transmission losses in the system.  This does give microgenerators a strange incentive to use as much of the electricity as possible themselves.  Anything that's exported earns no money.


    My figures were for electricity only.  My cooking is a mixture of gas & electricity, and I do have a gas boiler.  I could probably produce all my hot water in summer from solar, if I was willing to spend more on a "diverter" to power the immersion heater.  A lot of people do that, and if domestic gas was banned, I would get one.


    But I agree that a solar-only system is only useful when it's sunny, or at least only light cloud.  Last week (as I write), we had several days in a row with heavy cloud all day.  The solar panels just about covered the base load while I was out, and didn't generate enough to put any useful charge into the battery.  It was already flat by the time I got home.  I could uprate the battery to tide me through one bad day, but it would cost more money, and would do nothing useful in sunny weather.


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