Google, Amazon and other cloud providers could be underestimating their use of fossil fuels according to a report that came up in a couple of places this week. Can this be true?
The basic story is this: an analyst firm reckons that large companies are not using good data on the energy sources used by the US grid. Because a clumsy average is used, the quoted figures are inaccurate, and a better model of the US grid leads to figures which tend to show more coal is burnt in powering these data centers than we have been led to believe.
Emerging technology analyst Lux Research says most firms use information produced by the the US Environmental Protection Agency (EPA), called the Emissions & Generation Resource Integrated Database (eGRID). The EPA’s eGRID divides the US electricity grid into just 24 broad regions, and isn’t often updated.
Lux data scientists, led by Ory Zik, broke the grid into 134 regions and used different US government data - monthly figures from the US Energy Information Administration (EIA). Lux’s Grid Network Analysis (GNA) increased accuracy by “a factor of 80” said Zik.
The resulting picture has a lot more variation in the amount of coal used at different sites than is shown in the official EPA figures, Lux says. And it turns out that a lot of data centers are located in places whose coal use has been under-reported.
“For example, we found that Google underestimates its dependence on coal in four out of seven data centers, in particular at its Berkeley County, South Carolina location,” said Zik. This puts Google’s actual carbon usage up by 42,000 megatonnes (MT) of CO2 equivalent (CO2e) per year, Lux believes.
Amazon has more data centers, and is a lot less transparent about its carbon emissions, but Lux estimates that it is underestimating carbon emissions in a lot of sites. For instance, Virginia gets 35 percent of its electricity from coak, according to the eGRID estimate, but Lux’ GNA calculates this at 43 percent, which would increase Amazon’s usage by up to 85,000 MT of CO2e per year.
“With the tools now available, it’s time for data center owners to bring to their energy decisions the same data-driven rigor they use in the rest of their businesses,” says Lux.
The results are interesting - but it’s worth noting that while some areas’ coal usage is shown to be higher in the Lux analysis, other areas actually use less. So according to more detailed Lux figures, Google’s data center in Jacksonville Alabama, and Amazon’s data centers in Oregon use less coal than Amazon has admitted to.
Also the change in carbon usage is small in the context of the whole companies’ usage, according to a reader comment on one story based on the Lux report: Google reported 1.5MT of carbon emissions in 2014, so 42,000 MT more in South Carolina is about three percent of this.
Also, cloud providers are increasingly quoting figures based on carbon offsets and power purchase agreements which disconnect the quoted figures from the actual mix of energy used.
So for instance, Google claims to be 37 percent powered by renewable energy, when the average amount of renewable sourced energy it actually uses is much less, because it has funded a lot of wind and solar power projects that make up an equivalent amount of energy.
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