In cases Page | 8 where RE would be driven by the C02 price alone and RE incentives were to persist, the additional support only creates windfall profits. It depends on the cost of the promoted RE sources and on the amount of C02 they avoid, and on the cost of avoiding same quantities through other measures that would have been mobilised, had renewables not been promoted. Electricity generation from renewables is particularly challenging: it requires an assessment of the C02 content of the kWh they displace, which depends on the merit order (i.e. the last production capacity required to fulfil the demand at every moment).