A new report from Bloomberg New Energy Finance, a research group, suggests that the price of plug-in cars is falling much faster than expected, spurred by cheaper batteries and aggressive policies promoting zero-emission vehicles in China and Europe.

Between 2025 and 2030, the group predicts, plug-in vehicles will become cost competitive with traditional petroleum-powered cars, even without subsidies, and even before taking fuel savings into account. Once that happens, mass adoption should quickly follow.