[jws]

He doesn't. The energy at the NC datacenter is a combination of solar, fuel cells driven by biogas†, and grid power offset with purchased clean energy credits‡.

␄

† This doesn't mean that the methane molecules entering the fuel cell came from the biogas facility. The biogas gets pumped into the natural gas system, and gas comes out at the Apple spigot, but no one tags and sorts the methane molecules in between. That would be silly.

‡ Which means they pay a premium to cause renewable energy to be produced. If tagging molecules was silly in the gas section, there isn't even a physical thing you could tag on the grid. The electrons only move back and forth a few inches in the wires, and joules aren't “real”. A lot of the joules going into that grid are cheap coal, a tiny bit of them are the more expensive renewables. Apple is paying to put enough renewables in to cover their use.

[marshray]

Apple is paying to put enough renewables in to cover their use

How is this different than what the rest of us call "the power bill"?

Is there some higher rate you can choose to pay for renewable Joules?

[singlow]

yes

[marshray]

So there is a special thing called "renewable energy" which travels over the same grid as ordinary energy. It can be substituted for ordinary energy (but not vice-versa) and commands a premium price over ordinary energy.

This site looks pretty authoritative: http://www.nrel.gov/learning/re_basics.html

Hydroelectric power is considered "renewable" for what seem like good reasons. Yet, if I lived next door to Hoover Dam I would not expect to be charged extra for the privilege of consuming its locally-grown renewability. In fact, I would expect to pay less because there would be less transport loss to offset.

I'm trying to figure out to what extent this amounts to Apple writing a check to someone to bless their electricity, much like the selling of indulgences.

[raverbashing]

More or less what happens is

There's a pool of generators that put energy onto the grid. Each one has a price per MW generated (or MW/$)

Generation is metered and consumption is metered.

So the consumer will say "bill me for the cheapest one" or "bill me for renewal one" (or better, contract a certain amount of power from 'FlowerPower Gen'), and the producer will have "I'll have to produce X MW to provide for contracted demand"

But in the grid it's mixed, of course.

[socillion]

Producing renewable energy gives you credits which represent a cost difference between regular electricity and renewable.

The actual renewable electricity counts as regular energy, and anyone across the country can buy credits to say they subsidized renewable energy somewhere.

[marshray]

OK, I'm not saying this a bad thing to do.

I'm wondering where's the ROI for a for-profit corporation in "buying credits to say they subsidized renewable energy somewhere" other than, say, Marketing?

When one sets out to write checks to charities the Hoover Dam isn't exactly the first to come to mind.

[socillion]

Yeah, it's just marketing.