The re-emergence of coal as the current fuel of choice in the UK was illustrated this week when Innogy’s Tilbury B power station achieved a 1000 MW electricity output for the first time in three years, following the recommissioning of a third generating unit. Tilbury, a former CEGB facility, was slated for closure prior to privatization but its 1960s design, offering a combination of clean coal burning and predicable output, has transformed the Thameside plant into one of Innogy’s most important base-load facilities.

Tilbury B was commissioned in 1969 with a 25-year lifespan and the “dash for gas” in power generation appeared to have sealed its fate. Few would have even predicted that in 2001, two out its four units would be operational. But with soaring UK gas prices and the introduction in March of a new wholesale trading market (Neta), Innogy took the decision to recommission a third 350 MW unit which had been mothballed for three years.

The cost of the recommissioning was £13m($18.5m) including the addition of low NOx burners. This created generating capacity of £39 per kW compared with new build costs which are typically £400 per kW. “It made economic sense to restore the unit”, said Brian Senior, Innogy director of trading and asset management.

Since the third unit was powered up in August maintenance has been undertaken on another unit but on Monday all three units were operational and the 1000 MW output mark was achieved. ” This is quite a fillip for us” said Colin Potter, head of Thameside maintenance for Innogy.

Tilbury’s unique design allows it to burn cleaner, lower carbon emissions coal, which is currently imported from Russia. The residue from the relatively cheap clean-burn coal is run through electrostatic precipitators. These remove 99 per cent of the ash and produce an emission level which is valuable to Innogy in the context of its overall generating portfolio emissions limits.

Despite this, environmental groups are concerned by the renaissance of coal and say that burning coal to produce electricity produces on average double the amount of carbon dioxide for every kWh compared with gas.

Government figures show that in the first quarter of 2001, coal consumption rose 17.4 per cent against 3.6 per cent for gas. Analysts point to the relative costs to explain this. Producing electricity using coal currently costs about £12 per MWh compared with £12.5 when burning gas.

But the introduction of Neta has also tipped the scales back in favour of fuel sources which have the benefit of predictability such as coal by heavily penalising those generators unable to fulfil their commitments under the half-hourly Neta trading arrangements. Gas-fired generation is less predicable as, to an even greater extent, are many renewable sources such as wind and hydropower.

So for the time being at least, the chill waters of the River Thames will continue to supply cooling water to the ageing generating facility on its northern shore and the colliers will continue to ply their trade linking Tilbury to the open coal faces of Russia, America and beyond. Tilbury B stands as proof that, despite its shortcomings, coal will remain part of the UK energy mix for at least the next decade.