Coal mine methane is a viable feedstock for electric power generation in South Africa.

This is according to Southern African Caterpillar dealer Barloworld business development manager Nalen Alwar, who spoke at a conference held in Johannesburg last month.

Sharing the podium with Caterpillar and industry experts, Alwar focused on Barloworld’s capabilities in the gas segment, which is still relatively untapped in Southern Africa. Only 2% of South Africa’s energy demand is currently met by gas.

“The potential value of harnessing methane from coal beds is significant as South Africa is the sixth-largest coal producer in the world, with reserves estimated at 30-billion tons, half of which is mined underground. It is estimated that mining of known reserves will continue for well over 100 years,” he said.

He noted that methane is a naturally occurring gas formed during the mining of coal, and added that it is highly flammable and hazardous to mining operations, which means that coal seams have to be degassed prior to mining.

“As a greenhouse gas (GHG), methane released into the atmosphere does 20 times more damage than carbon dioxide. This is cause for serious concern as coal mining is still the world’s biggest contributor to feedstock for electrical power generation. Unburnt methane can remain in the atmosphere for 9 to 15 years,” Alwara cited.

He emphasised that GHG emissions in the US decreased by more than 20% between 1994 and 2005 owing to increased recovery and use of coal mine methane.

He further explained that methane could be safely extracted and, following a treatment process, fed into Caterpillar gas generator sets to produce electric and thermal power.

“Infrastructural and energy efficiency projects can be undertaken by coal mining companies to generate their own electricity or provide revenue- earning opportunities as independent power producers (IPPs),” he pointed out.

He said new methane gas-to-power projects had the advantage of short lead times in the supply and commissioning of proven and reliable Caterpillar gas engine solutions; assisting the growth of a gas economy; wide acceptance as a technology for cogeneration in parallel with the grid supply; private-sector participation in the generation of electric power; reduction of stress on the grid; and the potential for hybrid solutions with other IPP technologies.

Alwar cited Caterpillar’s key technology strength as the ability to use gas with varying methane concentrations over the life of a mining operation. This means power production during pre-mine drainage, active mining and abandoned mine operations, supported by Barloworld Power’s project management and maintenance capabilities.

Caterpillar has several reference sites for the conversion of coal mine methane to electric power in the UK, China, Australia and Russia.