The power station at Uskmouth was shut down by National Power in March 1995, when the plant's IPC authorisation was also revoked. The site was sold to a demolition contractor for a reported £1 million, and the very old Uskmouth A station is currently being taken down.
In January, however, Celtic Energy - which operates opencast coal mines in South Wales - acquired a purchase option on the Uskmouth B station. The company hopes to use the 330MW plant as an entry to the electricity supply market, and to provide a secure outlet for some 400,000 tonnes per year of its coal output.
Built in the mid-1950s, Uskmouth B has a low thermal efficiency and crude emission control systems. At first, the Agency believed it was entitled to require an upgrade to new plant standards. This could have forced Celtic to repower the plant with clean coal technology, the Agency's yardstick for new plant (ENDS Report 251, pp 28-29 ).
The Agency's initial view was based on 1991 regulations setting out the rolling programme under which existing processes were brought under IPC. These made it clear that a process "shall cease to be an existing process" if it is not carried on for a period of more than 12 months, and could not be restarted without being authorised as a new process.
However, the Agency's legal advice has frustrated this interpretation. The apparently clear-cut definition of an existing process under IPC was changed in 1995 by regulations which set out arrangements for transferring some processes between IPC and local authority air pollution control. The regulations define an existing process as one which was operated at any time in the 12 months to 8 January 1996 - which would include Uskmouth B - but make no reference to processes which are shut down and then restarted. The Agency's advice is that the regulations supercede - apparently inadvertently - the earlier definition.
The loophole may have far-reaching implications. Many old power stations which were in operation in 1995 will be shut down in the next few years. The Uskmouth case suggests that they could be brought out of mothballs at any time with little or no environmental improvements - blunting IPC's potency as a mechanism to drive the uptake of cleaner technologies. The Agency and the Department of the Environment are now looking at ways of closing the loophole.
In May, Celtic applied for IPC authorisation to operate Uskmouth B as an existing process. The company is highly sensitive on the matter: a spokesman told ENDS that "we've nothing to add to what is on the public register." This shows that Celtic considered several abatement options, but succeeded in keeping cost data off the register on the grounds that they had "generally been supplied...on a confidential basis."
Celtic argues that abatement of sulphur dioxide emissions would have "very high" capital costs, and does not represent the "best available technique not entailing excessive cost" (BATNEEC) for the station. Coal cleaning is said not to be commercially available, and Celtic has offered merely to restrict the annual average fuel sulphur content to 2%.
Likewise, add-on abatement of nitrogen oxides is dismissed as too costly or technically impractical. Celtic has proposed a three-year programme of fitting low-NOx burners, which could reduce emissions by up to 50%, to each of the three boilers.
The station's existing electrostatic precipitators (ESPs) can meet only a very weak particulate emission limit of 560mg/m3. Celtic accepts that they need to be replaced, but claims that it is "necessary to schedule the improvement over three years to avoid incurring excessive cost." It plans to fit a bag filter to one unit as a trial prior to recommissioning, with filters or ESPs to be fitted to the other units three years later.
The Agency is now considering whether Celtic's proposals constitute BATNEEC for an existing plant. It faces a tricky task in balancing site-specific considerations with the need to ensure parity with the IPC upgrading conditions imposed on the old coal-fired plant operated by National Power, PowerGen and Eastern Group (ENDS Report 254, pp 18-21 ).
Celtic's bid to enter the power generating industry using aged technology obtained at a knock-down price is likely to be greeted with particular dismay by developers of renewable energy and clean coal projects, which need to overcome considerable financial barriers to entry.