Priced out of the market

The UK’s first gasified coal power station will be unable to compete with the price of imported natural gas, a senior consulting engineer working on the project warned this week.

The station – to be built by the firm Coalpower at a site near Doncaster – recently gained government approval and local planning permission.

Gasified coal is receiving interest as a potential source of natural gas. Similar projects are underway in the US, the Netherlands and Spain. Natural gas power plants create less pollution than that generated by coal power stations.

The UK has more reserves of coal than natural gas. So by utilising these abundant reserves the UK would be able to reduce its dependence on imported gas, an increasing amount of which is likely to come from volatile states such as those of the former Soviet Union, the Middle East and Africa, as international demand rises.

The power station, known as an Integrated Gasification Combined Cycle plant, will use heat and pressure to extract gases such as hydrogen and sulphur from the coal. It is due to begin operating in 2006.

But John Griffith, senior consultant at Jacobs, which is managing the project, said the station is unlikely to be built in time.

‘It will be a difficult task to get it built by 2006. Any large utility plant will normally take a long time to complete – five to six years at least.’

Griffith also claimed the gasified coal plant will not be able to produce power competitively until the cost of natural gas increases significantly. ‘There is no point using coal. The price of gas is so low it is the cheaper option,’ he said.

A spokesman for Coalpower said the price of the electricity would work out at 3p per kW/h when all the by-products of the process are sold off. He also insisted the power station would be completed on time.

The plant is to be built on the site of Hatfield Colliery near Doncaster, which has 100m tonnes of coal and could supply the plant for the next 40 years. The 77-hectare mine site could also potentially contain a second power station.

The gasification process involves grinding up the locally supplied coal and mixing it with water to create a slurry. This slurry, which is 65 per cent coal and 35 per cent water, is pumped at high pressure, with oxygen, into a pressurised vessel.

There it is heated to 1,400 degrees C to release hydrogen, sulphur, carbon monoxide, carbon dioxide and other trace gases. The sulphur can be captured and sold for industrial use and the remaining slag can be sold for construction use.

The other gases drawn off are put through a shift reactor, where steam reacts with the CO to create more CO2 and hydrogen.

All the hydrogen from both processes could theoretically be fed into the turbine to generate electricity.

But according to Griffith, a hydrogen flame’s temperature is too high for the turbine. Instead the hydrogen supply would be ‘diluted’ with CO2 to lower the temperature.

The company is investigating the use of sequestration, allowing the remaining captured CO2 to be stored underground, and is also considering the use of CO2 for enhanced oil recovery in the North Sea, where the gas is pumped into wells to release trapped oil.