Lightcell: An engine that uses light to make electricity

Bottom line: 40% efficiency, which is better than I expected but the competition is batteries at 80+% efficiency. It's a hard sell, especially as continual improvements in battery storage will continue to eat away at their niche.

5,000 W/kg sounds great on paper compared to 150 W/kg for batteries and is even in the same ballpark as gasoline at 12,000 W/kg, but I think that's just the figure for the fuel. I don't think it includes storage, the solar panels, the burner, etc... The cost is an open ended question as well. Maybe this will pan out for aircraft?

If that is 40% efficient as in 40% of the theoretical energy input comes out as electricity then it's quite incredible but I find that hard to believe. It would put it in the same range as diesel engines.

The 40% figure is supposed to be "wire-to-wire", but they do list that as the "target efficiency" which suggests it may be somewhat aspirational. It presumably doesn't include the energy needed to extract and refine the oil into whatever kind of burnable fuel you are using, nor the energy necessary to extract and then blend in the sodium additive.

The better comparison is Fuel Cells and vehicle based electrical generators. So you could put this in a vehicle or remote location, run it off hydrogen or natural gas, and get better efficiency. Potentially this could be a much better option for longer term storage in remote areas as well, where excess solar/wind could be used to crack hydrogen which then gets stored and later burned in one of these instead of a much much larger battery installation.

You still need to truck in the sodium additive even if you're cracking water on site to store the H2. Dunno if you need a couple of mg/kg or if it is like 5% of the fuel to make it burn at the right color.

The gasoline vs H2 ballpark is a little wider because storage is not trivial for H2 -- you need to carry around a cryogenic and/or high pressure vessel instead of a plastic box -- which will detract from your p/w ratio. It also wants to leak out, so H2 is maybe better for fleet vehicle applications where they can refill daily. Granted, anything is better than burning more hydrocarbons!

And at the bottom they seem to indicate they are still in the "proving feasibility" stage.

I read this all as: "this is a POC we have, and if we can get it to 40% efficiency than it might make sense (otherwise who cares, just use a conventional generator)"

Do you mean watts or watt-hours?

My understanding of fuel cells is they are rather sensitive to the purity of the fuel and oxygen. I wonder if this system is less sensitive such that, say, piped hydrogen can be used.

It might not be a hard sell compared to home generators. Forget hydrogen. Think natgas.

Rechargeables/battery packs have inefficiencies due to the grid and/or solar cells though, in terms of where to measure inefficiency?

What does "wire to wire" even mean? The input isn't a wire! (Do they mean they think they can synthesize fuel and burn it at 40% overall efficiency? If so, that's pretty good.)

we think it will be, it's a good bet

and better than small diesels / turbines / internal combustion engines, at closer to 20%

If you electrolyse water with electricity into h2 and o2 then you have tour first wire.

When you reform the electrons via this engine and the photovoltaic cell you have your second wire.

500 MW GE turbines claim 64% efficiency, and one can use the wasted heat for district heating. If we have to burn something then using these turbines seems to be the best option, running 2-3 electric cars for the emissions of one. And probably 3000 e-bikes. Shouldn't you compete in this range of efficiency?

Battery densities are going towards > 500 wh/kg. There's some talk of batteries of several kw/kg long term. And since we're talking technology that is very much in the early stages of development (see the helpful image in the article), that would be an apples to apples comparison. 500wh/kg is basically a done deal. Several battery companies have announced products that are shipping in the next 2-3 years. From there to 1kw/kg seems very feasible. Several companies have hinted at that being a goal for them.

There's only so much district heating that is needed. And mostly only in the winter. You'd actually need more energy for cooling in the summer when nobody wants to heat their place. District heating is a nice creative solution for waste heat. But there's a limit to how much of it you can use and how practical it is to use it. Mostly it's still waste heat that's going to be wasted (blasted straight into the atmosphere and space).

And we don't have to burn stuff. Which is why coal and gas powered electricity generation is a bit under pressure in most markets. There are cheaper and better ways to get energy now.

This would be a great addition to the website. Also, talk about applications, even show a comparison chart vs existing solutions

It's useful for grid storage. Very large amounts of hydrogen are already stored in salt domes[0]. Current salt domes have volumes in the range of hundreds of cubic kilometers and can support pressures around 50-150 bar, translating into storage of thousands of tons of hydrogen. Along the texas gulf coast, there are hydrogen storage facilities that each store enough hydrogen to translate to around 100 GWh chemical energy. Being able to convert that chemical energy with 40% end to end efficiency means one site could store 40 GWh. In comparison, in 2023 the entire world had only around 56-200 GWh of battery storage capacity[1] installed.

[0]https://energnet.eu/wp-content/uploads/2021/02/3-Hevin-Under... [1]https://www.rethinkx.com/blog/where-is-all-the-battery-stora...

How is efficiency for say, propane? No need to worry about hydrogen embrittlement or invisible flames around residential areas.

eventually we would hope to get there, but, we are trying to have an edge somewhere that isn't the literal most refined and large capex part of the market first. if we can have a 10x edge