September 19, 2013
Opinions, U.S.

Google’s not using wind electricity at all

Tim Worstall, Contributor | Forbes | 9/18/2013 |

Google’s just announced that they’ve made an agreement to purchase some more wind turbine generated electricity. Which is wonderful if you like that sort of thing. But we do need to note that Google’s not actually using that wind generated electricity they’ve just announced they’re going to buy. Indeed, they explain that they cannot actually use it. So it’s not really the great victory in favour of renewables that some seem to think.

Here’s the announcement:

As part of our quest to power our operations with 100% renewable energy, we’ve agreed to purchase the entire output of the 240 MW Happy Hereford wind farm outside of Amarillo, Texas. This agreement represents our fifth long-term agreement and our largest commitment yet; we’ve now contracted for more than 570 MW of wind energy, which is enough energy to power approximately 170,000 U.S. households.

The Happy Hereford wind farm, which is expected to start producing energy in late 2014, is being developed by Chermac Energy, a small, Native American-owned company based in Oklahoma. The wind farm will provide energy to the Southwest Power Pool, the regional grid that serves our Mayes County, Okla. data center.

Wondrous I hope we all agree. But the very first sentence of this announcement is not actually true. Indeed, for technical reasons cannot be true. As Google goes on to explain:

Due to the current structure of the market, we can’t consume the renewable energy produced by the wind farm directly, but the impact on our overall carbon footprint and the amount of renewable energy on the grid is the same as if we could consume it.

Google isn’t using that wind powered electricity, indeed for technical reasons they cannot. Google’s server farm is powered by whatever the mix is on the local grid: some coal, some gas, a bit of wind powered no doubt, possibly some nuclear. And the reason that Google has to sell the renewable power to the grid and then buy back the standard mix is because wind power is hugely variable. And variability is not what you need when you’re running a server farm. For the obvious reason that the whole point of having a server farm is that it’s running 24/7/365.

Now you might think that this is just being trivial: but it becomes a serious problem when you try to scale up the amount of renewables in an electricity grid. Hydro is fine because that is controllable. Solar not so much but at least that’s reasonably predictable (outside Spain and their incredible subsidy system solar isn’t going to be generating at night) but wind really is something of a problem. It’s variable in output in minutes: your system can be humming along and then there’s a drop in wind speed and you’ve not enough to keep the network going. Or alternatively wind speeds are low so you’ve got other forms of electricity producing then wind speed picks up. This dumps vast amounts of electricity into the grid and you’ve then got to do one of two things. Either dump those windmills off the grid (this does happen) or dump the surplus electricity somewhere. This is what Germany (which has the highest large country renewables penetration) typically does. To the point that the Czech electricity grid is threatening to cut the link between the two countries because such surges can damage that very grid itself.

It actually not even certain that the German windmills reduce carbon emissions at all. The combination of having to have spinning reserve and also dumping surplus electricity at times means that it’s a close run thing at least.

It is true that Google can say that they’re buying as much renewably generated electricity as they’re using. But whether this actually, as in hte German example, reduces emissions at all is a much trickier question to answer. At the current level of grid technology, quite possibly not.

[rest of article available at source]

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