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Comment by rmcginnis | Hacker News Reader

We expect a gallon of gasoline to require approx. 60 kWh of electrical energy. If the price of that electricity is below 5 cents, the economics work. If the price is lower, the efficiency of the conversion could also be lower if that optimized other costs (like capital). Electricity is routinely below 5 cents now at utility scale (wholesale), which is where we will want to be.

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60 kWh capacity EV will get you (realisticaly) 200 miles.

A gallon of petrol - 40 miles (realistcally and using UK gallon).

According to Tesla their charging is 92% efficient so reduce that 200 to 184 miles.

Your process is 4.5 times less efficient than just putting that electricity into the EV? Is that right?

If so - and your process is carbon neutral (big if) - what's the point in a future where EVs dominate?

4.5 is not so much. Gasoline is very energy dense, stores well (especially synthetic) and transports well. This is great - gas will be around for a long time to come - if we can shift the source of it to something better, I'm all for it.

> what's the point in a future where EVs dominate?

EVs won't dominate some important uses for a long time, e.g. aviation and marine shipping.

In the long term, electric vehicles may indeed replace ICE cars. That would be awesome. One way to see what we're doing is to make sure the path to that future is good. We can't burn fossil fuels while we wait to replace the existing vehicle fleet with electric cars. By using zero carbon we make sure that we are solving the problem right away.

You might want to focus on jet fuel, since we don't know how to make batteries with sufficient energy density for long range flights and don't know if such energy density will ever become possible.

It might also be worth looking at where airplanes tanker fuel, that is to say, carry more fuel than they need for their current leg because refueling at the next stop would be difficult or expensive. Apparently a lot of that currently happens on short flights to small islands; while I hope Wright Electric and/or the EViation Alice will eventually take over that market, in the short term that's a market that might be willing to pay a bit more for liquid fuel made from air plus local solar panels.

Fuel oil that can be burned in combined cycle power plants in the winter may also be valuable for dealing with seasonal imbalances in demand vs renewable generation that lithium ion batteries can't cost effectively balance.

Aircraft and cargo ships simply can't use batteries.

1. Airplanes and boats will still need gas for a while 2. We’ll need to suck carbon out of the atmosphere anyway. So a process like this will be necessary, even if in the end the product needn’t be turned back into gasoline. This will be costly, but it’s the price we pay for all of the fuel we burn currently.

Ah, that certainly explains it. I'm still highly skeptical of how widespread this will ever be, since electric cars will become even more compelling as electricity costs decrease, but you've convinced me to not dismiss this completely as impractical. Thanks for the context.

But liquids fuels like ethanol are used for MANY more things than just transport – plus the cost of fossil fuels can only go up on any reasonable timeline.

Batteries still are the main issue with electric cars. The range, charging time and battery life are getting better but still don't match hydrocarbons.

It's just a great storage mechanism.

Storage is also a big issue when it comes to renewables. You could take in carbon in areas with lots of sun and ship the fuel to areas not well suited for solar generation.

This really would be a game changer for lowing the net carbon output.

This also means you could solve one of the big problems in the power grid, peak generation. Use the extra capacity during off peak hours to generate fuel that is later used to fire up power stations to supply peak demand.

Intermittent renewable energy like wind also drives cost really low sometimes. This could be an alternative to grid-based storage of electricity. Comparison of capital cost and loss and value of the byproduct would be interesting.

No the economics does not work, if you include the "externalities" of that gallon of gas. You are continually creating waste heat and carbon emissions, while using naive reasoning based on Gas Buddy prices.

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