FAQs

The government says it's because they are more expensive. It has also argued in the past that it is better known, so doesn't need so much incentive.

Chapter 6 of the government's RHI announcement says

Solar Thermal

For reasons of cost-effectiveness, a different approach has been applied in order to determine the solar thermal tariff. Solar thermal heat is, at present, more costly per unit of energy than other technologies. If solar thermal received support in accordance with those costs plus a rate of return (as for the other technologies), we would risk dedicating significant proportion of the RHI budget to solar thermal, to the possible detriment of support available for more deployment of cheaper technologies. On the other hand, the costs of renewable heat across the sector are lower than those of renewable electricity, so the fact that solar thermal is expensive as a renewable heat technology should as such not lead to the conclusion that solar thermal should not be supported. The Government has therefore concluded that the tariff for solar thermal installations will be set at a level which is roughly equivalent, in terms of financial support per unit of energy output, to the level allocated to what is currently considered to be the marginal cost effective technology required to deliver the UK’s 15 per cent renewable target, offshore wind. This results in a support level of 8.5p/KWh.