Capacity factor
The overall percentage of potential output the generating equipment achieves. For example a wind turbine may run at 25% of its rated capacity due to the average wind speed.
Climate Change Levy
The tax on energy use in agriculture, commerce, industry and the public sector.
Microgeneration
Domestic scale renewable energy including ground source heat systems, roof top wind turbines and solar panels.
Renewables Obligation (UK) and associated Renewables (Scotland) Obligation
These came into force in April 2002 and require power suppliers to derive from renewables a specified proportion of the electricity they supply to their customers. This is driven by the provision of Renewable Obligation Certificates to renewable electricity producers.
Renewable Obligation Certificates (ROCs)
ROCs are awarded to accredited generators of eligible renewable electricity produced within the UK – solar energy (including
photovoltaics), hydro, wave power, tidal energy, geothermal energy, biofuels (including
energy crops) and on- and offshore wind. Energy suppliers that are unable or unwilling to
source the required amounts of certificates to meet the renewable energy target for the year have the option of ‘buying out’ their Obligation. The ‘buy
out’ price was initially set at £30/MWh and is adjusted annually in line
with the retail price index. Monies raised from companies ‘buying out’ in this way is
redistributed to companies that have met their Obligation, in proportion to the number of
ROCs they presented in that year, and their value is derived from the addition of the buyout price and the redistributed income. ROC’s may be traded entirely separately from the electricity they are derived from.
As a result of the Renewable Obligation, Green Certificates traded within England,
Wales
and Scotland are referred to as Renewable Obligation certificates or ROCs. This
is to avoid confusion with carbon trading or International Green Certificate trading. The scheme is regulated by the electricity regulator, OFGEM.
Total Efficiency
The sum of the electrical and thermal efficiency in relation to the fuel consumed.