1. Fair enough.

2. Your change to the text is still slightly misleading, as is note 2 itself. UNESA’s 22% estimate was for ‘renovables y residuos’, not just wind and solar. (I took ‘residuos’ to mean ‘other stuff’ but it probably means ‘rubbish’. Methane?) And although the percentage increase in solar-powered generation was much larger than the percentage increase in wind-powered generation, in absolute terms the increases were about the same. RED’s preliminary 2009 report suggests that the increases in 2009 generation (for peninsular Spain; couldn’t isolate national totals) were about 4,900 GWh for solar and 4,100 GWh for wind. (For ‘residuos’? No idea. The RED reports lump it in with cogeneration and other non-wind Special Regime sources.)

Incidentally, the RED report says that wind-powered generation increased nationally by 13% in 2009 (to about 13% of the total). I got the 16% estimate from the Spanish Wind Energy Association (AEE). Treat with suspicion. It looks like it routinely puffs wind with inflated figures. (Geddit?)

And RED says CO2 emissions from electricity generation fell by 15.5 %. (UNESA said 17%.)

3. I can’t remember where I got the ‘about three times the size’ from. The numbers in RED’s preliminary 2009 report show that the absolute increase from hydro power plus non-wind Special Regime sources (solar, cogeneration, ‘residuos’ and possibly some SR hydro and other bits and bobs) was about two and a half times the size of the wind-generated increase. I probably did a rough calc based on data from UNESA or AEE and misidentified cogeneration as combined-cycle.

4.The 16% figure came from your earlier blogpost. Perhaps I misunderstood. You wrote: ‘The outturn was about 16% for most of the night.’ I took this to mean that wind provided about 16% of Spain’s electricity for most of the night. The average for the year was 13%. OK, the average for that (particularly windy?) November was 23% but 16% isn’t much of a drop from that.

But yes, I take your point that the Spanish grid coped with an unexpected shortfall from wind turbines. (Though I still think an analysis of the 1% day in August would be instructive.)

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None of that is particularly important. Your main (should-be-obvious) point in this blogpost stands: wind power can help reduce emissions. Cost, reliability, national circumstances bla bla bla: separate issues. (As is NW’s point about how much of the burden wind and solar can feasibly be expected to supply.)

The Spanish data does nothing to refute this, as clearly if the amount of wind farms were doubled (to 30% or so of demand), there would be many times when much of the wind power would be unneeded and go to waste, driving up the cost.

The problem is the variability of the wind: some days there is a lot, other very little. In Europe, solar is not much better, with many a cloudy day. Both require a breakthrough in energy storage in order be viable as the main source of electricity.

Solar thermal plants can accomodate storage, and if placed in the desert, could be a large energy source. But the cost of long distance transmission adds to the already high cost of solar.

A couple of comments

1) The claim that wind power doesn’t reduce emissions because other power stations ‘have to work anyway because you can’t rely on wind’ is a very frequent comment across the internet and in places like the Daily Telegraph and Mail. The Spanish data was the first explicit linking I have seen of the month to month impact of wind and other renewables on emissions. That’s why I thought it was worth noting.

2) You are right to point out that the 22% increase in renewables disguises a more rapid increase from solar than from wind. Apologies. I have changed the text to reflect the comment.

3) I don’t think your wider conclusion that ‘The combined contribution from other ‘green’ sources (combined-cycle, hydro, ‘etcetera’ and solar) increased by a lot more than that’ is true. Combined cycle (gas) was down 9% and hydro was up by only 8%. Solar, but only solar, did indeed grow more rapidly than wind.

4) The point in the earlier article was simply that the Spanish grid had no problems coping with 54% wind share early in the morning of 8th November in contrast to a 2008 episode when high wind speeds caused the grid to have to disconnect a lot of turbines. I don’t know where the 16% figure you mention came from. Early November was extremely windy and across the whole month, wind gave Spain 23% of its electricity.

What I’m trying to do in these two articles is show that the evidence from Spain is that wind can make a big difference to carbon emissions and contribute effectively to an electricity generation portfolio. This is perhaps a obvious point but I can say from extensive personal experience that this assertion is very widely contested in the UK.