The EMR Delivery Body has published for consultation potential derating factors for wind and solar power if it were allowed to participate in the Capacity Market. The assessment, described as ‘harsh’, would credit solar PV with little over 1% of ‘equivalent firm capacity’ (EFC), while onshore wind would be credited with less than 10%.

The assessment combined weather data with real performance data from solar, offshore wind and onshore wind (as opposed to manufacturers’ predictions), modelled along with interactions, for example with storage