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Comment by mrfusion | Hacker News Reader

I'm confused why these are in units of energy kWh? Shouldn't the just be watts a unit of power?

I'm confused why you're confused. You pay for energy, not for power. You wouldn't pay the same for a kW delivered for 1 hour as you would for a kW delivered for a whole year, right?

When you buy solar panels, or build what TFA called "a solar plant capable of generating at least 350 megawatts" (note the units) you certainly are paying for power. Quoting an energy price hides all sorts of assumptions about finance, equipment longevity, and maintenance costs, so it's clear that doing so is just an excuse to say "cheapest solar on record".

The people who build the power plant pay for MW of solar panels. The people who buy the energy from the power plant pay for kWh. Notice that this an interesting article because the plant is going to have a power purchase agreement price of under 2.5 cents per kWh. We don't know what the equipment costs per Watt.

It's IAAS (infrastructure as a service (a term I just made up, but I think it is appropriate))

Governments nowadays don't buy a solar plant, they put out a tender "we're willing to buy X GWh of solar power a year for Y years. Solar panels can be placed in area A, and must be removed afterwards. Please quote us a price per kWh."

Advantage of that for the buyer is that, if they get a offer that is too good to be true, they haven't paid the full sum when the seller goes bankrupt.

Also, because the seller has to operate and maintain what he sells, he will think harder about maintenance costs, ease of removal, etc.

Another example of this is the recent auction for a sea-based wind farm in the Netherlands (http://www.offshorewind.biz/2016/07/06/borssele-12-worlds-ch..., 7.27 eurocents/kWh)

Risk for the buyer is that he commits to buy a fixed amount of power at a fixed price over the lifetime of the plant. Worst-case for the buyer, we develop cheap fusion next year, so that electricity prices drop to zero.

Watts are joules per second.

1 kWh is 3,600,000 Joules but it is more convenient to use some unit of watt because the power rating of the things you're attaching it to are often rated in Watts also.

Besides it is just the way things evolved. Like batteries being rated in mAh.

Because the unit of measure takes into account how long you used a watt. It's a measure of rate... Sort of like a car uses mph.

I don't think you've addressed his question.

GP was expecting to see a price in terms of $/W, because that's what matters to consumers interesting in purchasing panels: https://en.wikipedia.org/wiki/Price_per_watt

The article quotes a price in terms of $/kWh, because that's how a bid from an industrial electricity provider is stated.

GP was confused / frustrated because a bid in $/kWh completely obscures the cost of the hardware, which is what he's interested in.

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