Annual sales will hit no more than 465,000 by 2020, according to Deloitte—a mere rounding error in a 250-million-car national fleet. This projection is consistent with others by Boston Consulting Group, Resources for the Future, PriceWaterhouseCoopers, and Honda Motor Corp., whose head of research and development recently declared that “we lack confidence” in the electric-vehicle business…

The administration’s theory is plausible enough: Ramp up production of the electric car’s most expensive component, the battery, and its price will come down to mass-market levels. Economies of scale, and all that. It’s worked for other former luxury products, like cell phones and laptops. As the president argued in Michigan, “Because of advances in the manufacturing, [battery] costs are expected to come down by nearly 70 percent in the next few years. That’s going to make electric and hybrid cars and trucks more affordable for more Americans.”

But the technical challenges of mass-producing cell phone batteries are relatively modest compared to mass-producing batteries for cars, and for the most part, cell phone and computer industries grew with private, not public, capital at risk. Notice that the president said “more” affordable, not “affordable.” Cutting through the hype and bias that plagues official advanced-battery cost forecasting, a recent study by Boston Consulting Group projects a 60 percent to 65 percent reduction in the cost of batteries to car manufacturers by 2020—smaller and later than Obama’s bullish claim.