I've been curious about power to gas technology.
I've been curious about it too.
Do we know given the energy prices of solar or wind power, what the price/unit of the generated natural gas is compared to say, mined natural gas?
I suspect you'll find that with the current carbon price (zero in practice, or very near zero), the synthetic methane is more expensive. Otherwise it would already be done in massive scale.
However, businesses are currently investigating synthetic methane, constructing experimental small scale plants. Thus, they expect that:
- Either the cost of carbon capture and purification / electrolysis / Sabatier reaction goes down
- Or the cost of renewable power (wind power, solar power) goes down, thus bringing electricity price down intermittently during periods there's more energy than needed
- Or high carbon tax will be imposed for burning of fossil natural gas
- Or some combination of the these.
And how does this scale with the price of solar/wind power dropping?
It scales extremely well. If price of electricity is at or near zero for extended periods due to plentiful and cheap solar / wind power, the production of synthetic methane will become less expensive and thus possibly competitive with natural gas.
You'll also find that a carbon tax would make synthetic methane more competitive.
However, do note that to create not only methane but also liquid fuels, more processes are needed. Those processes reduce the energy efficiency of the whole production chain. Thus, even though we will likely see power-to-gas replacing natural gas, we won't necessarily see power-to-liquids replacing fossil fuel liquids.