Why couldn’t you use the steam to generate electricity (turn a dynamo) which charges a battery, which runs an electric motor?
Replace the gas engine in the Prius with a few e-cats. At 14kw/ecat, (that’s about 20hp), 5 would give you 100hp - I think that’s more than the Prius engine provides. I don’t know how quickly you can charge the batteries though.
Or use the electricity generated to run the motor directly and use any excess to charge the battery.
If you have a 15 KW generator, you'll need 30 HP to turn it effectively.
> Replace the gas engine in the Prius with a few e-cats
At least initially, E-cat units are not going to be so cheap. I read that Rossi is planning on pricing a 35Kw(thermal) E-cat at 5000 Euros = $7k
> At 14kw/ecat, (that’s about 20hp), 5 would give you 100hp
Actually, from each 35Kw(thermal) E-cat, you could expect to get about 15hp from a fairly lightweight steam engine. Six E-cats (at a cost of $42k!) would get you up to 90hp.
However, $42,000 will buy about 12,000 gallons of gas, which can drive you about 420,000 miles in a fairly fuel-efficient car.
Therefore, if you want 90hp continuous from your e-cats, you’d need to drive it over 420,000 miles before they have become cost-competitive with a similar gas-powered car (at current gas prices).
If you’re willing to settle for 45hp continuous and sell the cars in a country with very expensive gasoline (U.K. or Israel, for example), you could expect payback in 70k miles or less, which would be reasonable.