in germany the tariffs and the degression rates are usually revised every four years but some additional adjustments are possible and have been recently used for photovoltaics in response to the increasingly rapid deployment of solar power the government introduced a volume responsive degression system in for photovoltaics the system was revised in and in as solar generation capacities continue to expand at a high pace these adjustments have been insufficient to control the development of photovoltaics and the government is revising again the support measures feedin tariffs should be cut further and the degression system could be made more efficient by basing it on an analysis of price elasticities