(EnergyAsia, September 7 2011, Wednesday) — A leading Australian energy company, Origin Energy, said there is no certainty over whether coal or gas-fired power generation produces more greenhouse gas (GHG) emissions.

In a statement, it said: “Evidence to assess the more specific question of how the lifecycle emissions of a baseload gas-fired plant fuelled by coal seam gas compare to the lifecycle emissions from a coal-fired plant is less readily available. This is in part because interest in the issue has only arisen recently and in part because actual results will vary according to specific plant and equipment being used by different owners and operators along the supply chain.

“However, the conclusion that lifecycle emissions from coal seam gas are substantially lower than from coal is clear in all but the most improbable scenarios.”

The company said that the least intensive GHG coal plants, IGCC and ultra-supercritical black coal-fired power stations, operate on cutting-edge technology not currently used in Australia and for which only two demonstration plants exist in the US. But even this technology emits approximately twice the emissions of an equivalent baseload combined cycle gas plant such as Origin’s Darling Downs power station.

Generally, coal-fired power plants in Australia and most of the world emit greenhouse gases in the range two to three times higher than a gas-fired power station.

They are also well above the emissions even from open cycle gas turbine plant or peaker gas plant which play a crucial role in Australia’s electricity supply when demand is at its highest and when power from intermittent renewable technologies such as wind is not available. Because they run for only up to a few days every year, they emit only tiny amounts of greenhouse gases.

As nearly all the equipment used by the emerging coal seam gas-to-LNG industry will be brand new, including processing plants and pipelines, it is likely that this energy source will emit the lowest greenhouse gases, said Origin Energy.

“When the most pessimistic assumptions are used for both coal seam gas and coal, emissions from coal are between 200% and 250% those from coal seam gas,” it said. \

The company’s head of corporate affairs, Carl McCamish, issued this comment in response to the recent and increasingly heated debate in Australia on the relationship between the greenhouse gas emissions (GHG) from the use of coal and gas to generate electricity.

Origin Energy is Australia’s leading integrated energy company focused on gas and oil exploration and production, power generation and energy retailing.