You mean like this? https://www.nimbus.green/

It's worse than I thought. I dug until I found out how they expect to meet demand using non-dispatchable generation (emphasis in bold added): The provision of reliable capacity (MW) in a decarbonized electricity system is fundamentally separate from the provision of energy (MWh). The capacity resource that pairs best with a high VRE system is one with very low capital cost, because its role is to provide reliability for a limited number of hours per year (average capacity factors ~10%; Figures 7b and S17), rather than zero‐carbon energy in bulk. In this analysis, reliable capacity came mostly from thermal generation using gas without carbon capture (Figure S28). The much higher initial capital cost of CCS and nuclear plants as currently forecast could not be justified for such low utilization rates, and at the same time, they were uncompetitive with VRE for the bulk of operating hours unless VRE buildout was constrained. The gas generation fleet in the central case was 590 GW and ranged between 470 and 675 GW across scenarios, compared to 480 GW today (Figure 7a). To remain within carbon constraints, gas‐fired plants without carbon capture either burned carbon‐neutral fuels or natural gas for which emissions were offset elsewhere, depending on the carbon budget, resource constraints, and relative costs (see section 7.2). It's a fraud from top to bottom.

More pie in the sky that the recipe authors will be long retired or dead before the failures become undeniable.

Substantial increase in unsprung weight, though. It would be better to put the motor at the end of a short propeller shaft and mount it to the frame rails.

The article does say "tow hooks front and rear". I'm more concerned about crush space. There doesn't seem to have been a whole lot of consideration of crash-safety.

Not quite as abundant as sodium and sulfur, but perfect is the enemy of good enough.

Sorry, that should be 4.7¢/kWh for 5000 cycles. I calculated the # of payments wrong.

Hmmm, nothing on cycle life though. At 7% interest, 2000 cycles lifespan and cycling daily, the battery would cost 9.1¢/kWh run through it. At 5000 cycles, it would cost 3.4¢/kWh. At 2000 cycles it appears marginal. At 5000 cycles it looks pretty good for managing evening peaks or time-shifting of overnight nuclear generation to demand peaks.

Now THIS has some potential! $50/kWh!

This integrates even better with advanced nuclear. Nuclear can supply the always-on power to keep the cells hot even when they're not being actively used, and the bias voltage to keep the oxidation state of the electrodes from being reversed and damaging them.

ONLY 45% of the carbon in CO2 can be fixed by these processes? Ridiculously low.

Hmm, I happen to have one of those. It might be a good thing for me.

Hmmm. Other possibilities include managing the rest of the electrical system, e.g. running the alternator at max when braking to recoup energy that would otherwise be lost, and killing the alternator on acceleration to minimize accessory drag while feeding the system bus from the caps.

Oh, no argument. A cold PbSO4 battery is current-limited. But slow-charge an ultracap from it, and you can kick over an engine even on a subzero day.

I mis-estimated. It would take more like 35 kg.

Indeed. Likely not hybrid vehicles, because you'd need 100 kg or so to store the full kinetic energy of a car moving at highway speeds and batteries do fine for that. But start-stop mild hybrids? Feathering wind turbines in a power outage? A natural.

You mis-read the units. Practical specific power 21-27 kW/kg

The purpose of the tiny battery is to make something like the Nissan e-POWER possible at minimum cost. You can keep adding battery, but that also adds weight, bulk and cost; you don't need them if you can charge at 60 C. You get the benefit of the efficiency gains right off the bat; the customer can decide what the best tradeoffs are for the rest.

I find the possibilities associated with animal feed to be interesting. Kelp is becoming more popular as cattle feed, and i wouldn't doubt that rabbits, goats and chickens would do well on it too. You could farm livestock in the middle of the ocean.

This means hybrids are becoming a no-brainer. 60 C performance means 90 kW out of 1.5 kWh of cells, more than enough to propel a vehicle engine-off.

The top image doesn't show significant distortions characteristic of a wide-angle lens (curvature of straight lines) and the bottom image definitely doesn't have any, as shown by the vertical lines of the background remaining vertical from left to right. There's also the issue of what looks like too much ground clearance for the prop. Why not use a bigger prop turning slower to get a higher Froude efficiency? I'd expect optimizations like that in a speed-record aircraft.

I don't get this design at all. The long tail and huge empennage are something you'd put on an aircraft which needs a lot of control authority, such as a twin-engine which has to deal with asymmetric thrust. There's no such requirement here, as it's single-engine; the excess area just creates parasite drag. What gives?

I found a reference at Next Big Future to a 53% thermal efficiency for the Achates engine. Given the differences in form factor between a conventional and opposed-piston engine, this is probably not a significant distinction.

Been saying for many years that the electric side of the system allows the ICE side to be ruthlessly optimized for efficiency, because you don't have to worry about transient response and especially emissions control during transients. Now, how does this compare with the Achates engine?

I saw a preheated catalyst at Ford in the early 90's, I think. Strange that it took this long to come into its own.