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?

The stated energy density is "> 500 watthours/liter".

But higher on the page we see a relative-energy-density bar graph shows lightcell at 5x the energy density of lithium batteries, and (38/5 =) 7.6x less dense then petrol. This implies an energy density for lightcell of 1250 Wh/liter, as (according to Google) petrol clocks in just under 9500 Wh/liter, and (again according to Google) lithium batteries can reach 300 Wh/liter so let's call it 250 for the math to work out.

I'm curious which number is closer to truth: 500Wh/liter, or 1250? Is 1250 the theoretical max and 500 the current output in a test rig?

I know next to nothing about the field / tech, but a portion of folks seem to be like "incredible visionary etc. etc." and the another portion like "fringe science / complete bullshit / this is as realistic as cold fusion" kind of thing.

Very interested to hear from folks more in the know of like, high level long term viability / what the implications are etc.

I felt it was a bit light on putting the system energy efficiency/losses up front. I am sure they're stated but it was hard to work out how it compared to normal PV efficiency, or steam turbine efficiency.

Heat exchangers are applicable to lots of things. I am skeptical that this is significant because almost any heat energy process does reclaim and preheat, and so the size of the thermal mass and efficiency here would be exceptionally well studied and if they have made improvements, they may be as, or more valuable as IPR overall. So while it looks amazing, unless they are spinning it out into wider industry it will be a small increment over things in deployment.

Oh no...