Take the example of carbon emissions reductions from coal-fired power generation: with a carbon tax, the generator would choose an efficient least-cost mix of technical abatement, e.g. more efficient boilers, and reductions in the output of electricity to achieve the intended level of emissions. With a quantity-based standard instead, generators would overinvest in technical abatement and underinvest in output reductions, thus selling more electricity than with a carbon tax. This is because, in the example of the standard case, infra-marginal emissions are costless and only the last unit of emissions elicits compliance. What looks like an advantage, i.e. more electricity sold at the same amount of emissions, is in fact an economic disadvantage. By levying a Pigouvian tax, the government could have generated a higher value for the overall economy than the added surplus for the electricity customers resulting from the standard.