[euroderf]

> A cheap pathway to ethylene from captured CO2 and water would be huge.

Is it considered cheap if the marginal cost of a PV MWh is close to zero ?

[jjk166]

How close to zero? 1 MWh at 100% efficiency is enough to convert 180 kg of CO2 to ethylene (note this only produces 51 kg ethylene). Annual excess carbon emissions are 36.8 trillion kg of CO2. At a cost of $0.10 per MWh, which is about 3-4 orders of magnitude lower than it currently is, that's still $20 Billion per year. A cheaper pathway is still going to save an incredible amount of money even if solar power got ridiculously cheap.

[euroderf]

$20 Billion per year worldwide is chump change. But that's 3 or 4 orders of magnitude away eh ?

[rcxdude]

The energy costs are only part of the equation, though. Especially if your plan is to use excess renewable energy, the cost of your plant is a much bigger concern, because you can't run it all the time.

[euroderf]

Marginal cost. And one might reasonably expect fixed costs too to keep dropping, altho not as spectacularly quickly.