20 hursepurses is maybe pushing it, but 30 to 50 kW would actually be plenty if we kept our cars lightweight and aerodynamically efficient instead of insisting on 3-ton ugly boxes with the frontal area of a house.
Hell, for a single-person lightweight (<40 kg empty weight) electrical vehicle that is expected to go no faster than 30 km/h (often legally limited to 25km/h here in EU) and requires no license to operate, 250 to 300 W is more than enough.