Solid Energy plans Underground Coal Gasification
Solid Energy plans Underground Coal Gasification pilot
plant in Waikato
Solid Energy plans to build and commission, by the beginning of 2011, a $22 million Underground Coal Gasification (UCG) pilot plant in the Waikato.
The successful application of the UCG process will open up access to coal seams which would otherwise be nearly impossible to mine using conventional mining technology. UCG complements traditional mining because it works best where conventional mining does not – in deep, difficult-to-reach coal seams.
Solid Energy will shortly lodge the necessary consent applications to build and operate the UCG plant which will convert up to 30,000 tonnes of coal into synthetic gas (syngas). The pilot will operate for up to two years on private property within the company’s existing Huntly West Coal Mining Licence area. Work will begin on the proposed plant once consents are granted.
Solid Energy’s General Manager New Energy Brett Gamble, says the launch of the pilot plant, which will employ up to 10 people, is the culmination of five years’ investigation by Solid Energy into UCG’s suitability for New Zealand conditions. Solid Energy is working with Ergo Exergy, a proven technology supplier who has successfully developed UCG projects in several countries around the world, meeting stringent safety and environmental standards.
The UCG process gasifies coal very deep underground, producing syngas that can be used in electricity generation, the production of pure hydrogen and to make a range of high-value products such as methanol, synthetic transport fuel, fertilisers or waxes, plastics and detergents.
“UCG technology represents a huge opportunity for New Zealand to further ensure our energy security by using our most ample mineral resource, coal,” Mr Gamble says. “This is a safe, credible technology which is carried out deep below the ground yet is fully controlled by operators on the surface.
“An operator pumps air hundreds of metres deep into an ignited coal seam which, when combined with the huge pressure of the earth above it, causes a reaction that turns coal into syngas. By controlling the air flow into the seam, the operator regulates the speed of the gasification reaction and, if needed, can put it out rapidly and completely,” Mr Gamble says.
For the pilot plant, Solid Energy plans to drill up to seven wells about 25 to 50 metres apart into an underground coal seam 400 metres below the surface. The company is also installing a number of other wells on site to gather process and environmental data. The surface plant, including wells, is expected to be contained within an area measuring 300 metres long and 150 metres wide.
The pilot plant will yield process, technical and geological information, and verify modelled environmental effects. Once the required information has been gathered, Solid Energy will shut down the pilot plant. Results from the pilot will determine whether Solid Energy takes the project further to a commercial operation.
The project builds on an earlier UCG trial undertaken in 1994 by the then Electricity Corporation of New Zealand (ECNZ) in partnership with Glencoal Energy and Energy International. The ECNZ trials were abandoned because UCG did not prove cost-effective at that time. Increasing energy prices and further advances in UCG technology, however, make UCG a viable energy option again.