Agency looks to clamp down on power station emissions

The Environment Agency is planning to tighten up limits on emissions of acid gases from coal-fired power stations in England and Wales. The regulator also plans to go considerably further than constraints under the EU large combustion plant Directive (LCPD) - although it has decided not to press for costly NOx abatement technology.

Power stations in England and Wales came under integrated pollution control (IPC) in 1991. However, the Agency’s efforts to set meaningful emission limits fell foul of the Government’s desire to protect the coal industry and to liberalise the electricity market.

In 2000, the Agency introduced a complex system which set station-specific controls together with a cap, known as a "B-limit", on each company’s sulphur dioxide (SO2) emissions. It also offered incentives for companies to fit flue gas desulphurisation (FGD) equipment, in the form of a temporary increase in the B-limit (ENDS Report 300, pp 9-10 ).

The existing IPC controls expire at the end of September. ENDS has learnt that the Agency will shortly announce a new framework which will run to the start of 2008, when the LCPD comes into force. The new controls will be introduced by variations to each power station’s IPC authorisation.

Under the existing B-limits, the 17 coal- and oil-fired power stations in England and Wales are allowed to release 405,000 tonnes of SO2 each year. In practice, the generators are able to release up to 515,000 tonnes per year, mainly because they took up FGD incentives much later than the Agency expected.

The Agency now plans to restrict total SO2 emissions to 399,000 tonnes for the next two years - largely by scrapping the FGD incentives (see table). The figure is a compromise between the Agency’s view of what could be achieved and the generators’ concerns about maintaining security of supply.

Even so, emissions will be much higher than initially promised. In a 1998 energy White Paper, the Government announced that SO2 emissions from power stations in England and Wales would fall to 365,000 tonnes by 2005 (ENDS Report 281, pp 30-32 ). Indeed, the Agency had wanted to apply this limit from 2001.

The new regime will also introduce sulphur trading between companies. At present an operator can transfer allowances between its own stations, but trade between companies can take place when a station is sold. The Government is pressing for a revision of the IPPC Directive, which is currently focused on site-specific controls, to make explicit provision for emissions trading schemes (ENDS Report 358, p 60 ).

The Agency is also developing proposals for regulating the power sector beyond the start of 2008, when the LCPD comes into force. Its work has been held back by ongoing uncertainty over how the Government intends to implement the Directive (ENDS Report 359, pp 51-52 ).

A spokesman told ENDS that the Agency hopes to limit annual emissions to "a ballpark" of 200,000 tonnes for SO2, and also to introduce a limit for oxides of nitrogen (NOx) at around the same level. The new B-limits for both SO2 and NOx would run in parallel with emission limits under the LCPD, but could be significantly tighter. The Agency hopes that the Scottish authorities will agree to sign up to a common regulatory system.

The Agency also plans to apply B-limits to stations with a limited life expectancy which opt out of the LCPD. Such stations will not need to fit FGD, but the Agency is likely to require them to use coal with a very low sulphur content of less than 0.4%.

All stations will be expected to introduce over-fire air systems which can reduce NOx emissions by a relatively modest 20-25%. Controversially, the Agency has ruled out more effective selective catalytic reduction (SCR) abatement on cost grounds - even though new EU guidance specifies this as the "best available technique" for both new and existing plant (see p 46 ).

It now seems likely that FGD will be installed on some 13GW of capacity by the time the LCPD comes into force. The figure compares to the 12GW of FGD which was promised in the late 1980s by the Conservative Government as part of the run-up to electricity privatisation. FGD is already fitted to the 4GW Drax station, the 2GW West Burton and Ratcliffe plants and the 0.4GW Uskmouth station. British Energy is commissioning 1GW of FGD capacity at its Eggborough station, and EdF is fitting abatement to its 2GW Cottam station. RWE Npower has been given consent to fit a seawater scrubber to the 1.5GW Aberthaw plant, but it is not yet clear if it will proceed.

Seawater scrubbing is also proposed for the Kilroot station in Northern Ireland. However, Scottish Power’s longstanding proposals to fit a seawater scrubber appear to be on ice.

Meanwhile, E.ON, Powergen’s parent company, has applied for consent to convert two units at its Grain station to run on gas. The 2.4GW station currently burns oil, and is rarely used. In a further sign of a revived "dash for gas", RWE Npower has applied for consent for a new 2GW CCGT station on the site of the former oil-fired station in Pembroke, south Wales.

E.ON says that the combined impact of the LCPD, the EU greenhouse gas emissions trading scheme and the retirement of most of the UK’s nuclear capacity "is expected to result in the need to replace almost half of the UK’s power stations before 2016."

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