The UK Emissions Trading Scheme was a voluntary emissions trading system created as a pilot prior to the mandatory European Union Emissions Trading Scheme which it now runs in parallel with. It ran from 2002 and it closed to new entrants in 2009. Management of the scheme transferred to the Department of Energy and Climate Change in 2008.
At the time, the scheme was a novel economic approach, being the first multi-industry carbon trading system in the world. (Denmark ran a pilot greenhouse gas trading scheme between 2001 and 2003 but this only involved eight electricity companies). It took note of the emerging international consensus on the benefits of carbon trading that were being proposed in the mandatory Kyoto Protocol, which had not been ratified at that time, and allowed government and corporate early movers and to gain experience in the auction process and the trading system that the later schemes have entailed. It ran in parallel to a tax on energy use, the Climate Change Levy, introduced in April 2001, but companies could get a discount on the tax if they elected to make reductions through participation in the trading scheme.
The voluntary trading scheme recruited 34 participants from UK industries and organisations who promised to make reductions in their carbon emissions, this has since expanded to 54 sectors of the UK economy. In return they received a share of a £215 million "incentive fund" from the Department for Environment, Food and Rural Affairs (DEFRA). Each agreed to hold sufficient allowances to cover its actual emissions for that year, and participate in a cap and trade system, with an annually-reducing cap. Each participant could then decide to take action to manage its emissions to exactly meet its target, or reduce its actual emissions below its target (thereby releasing allowances that it could sell on, or save for use in future years), or buy allowances from other participants to cover any excess[1].
From March 2002, DEFRA ran an auction of emission allowances to perform allocations to participants, after the start of the mandatory EU scheme.
The UK's National Audit Office[2] and DEFRA's consultants[3] ran reviews of the system in order to establish its basis and drew lessons from it.
They concluded that the scheme did achieve some emission reductions from the participants, although more could have been achieved had targets been more demanding.