A major research initiative is targeting carbon dioxide and acid rain caused by coal burning, writes Dick Ahlstrom
Coal is a mixed blessing when considering future energy requirements. We can't live with it, but we can't live without it, at least in the short term.
There are plentiful supplies available from politically secure countries that at current demand levels will last for centuries. However, as a fossil fuel, coal-burning can only add to the dangers caused by rising carbon dioxide levels, not to mention nitrogen and sulphur discharges that can lead to acid rain .
Tom Feeley hopes to change all of that. He leads a research initiative into "clean coal" technology at the National Energy and Technology Laboratory within the US Department of Energy. He oversees the lab's research and development programmes, including efforts to achieve cost-effective carbon sequestration.
Feeley was in Ireland several weeks ago on a planned visit to meet officials from a number of departments including environment, communications, marine and natural resources and the Geological Survey.
He also toured our coal-fired Moneypoint power station and participated in a roundtable discussion with the Institute of European Affairs energy group.
He was appreciative of the opportunity to meet officials here and tell them about progress in sequestration research. "They were interested in what we are doing," says Feeley.
He acknowledges the environmental difficulties associated with coal-based energy production, the main question being, "If we keep coal in the mix can we also address the carbon dioxide releases?" Yet it is currently unthinkable that the US, or Ireland for that matter, could walk away from coal as an energy source. More than half of US energy production comes from coal plants, he notes.
Coal is inexpensive compared with other fossil fuel sources. There are huge reserves and much of this lies in secure countries including the US and Australia.
For this reason the US energy department has ramped up research on coal technology. It started about 10 years ago with a $1 million (€746,158) budget and this has since grown to $100 million (€74.6m), he says.
His group is focusing on three technologies designed to take current pollution levels out of the coal equation: coal gasification before burning, akin to coking; discharge scrubbers after burning used to take carbon dioxide out; and "oxicombustion", the introduction of oxygen to change the discharge chemistry.
All three are equally promising but impossibly expensive at the moment. However, he is confident that in time the engineering problems can be overcome. "We are probably a decade away. We are at the point where we are taking concepts from the lab and testing them at a larger scale."
Sequestration of carbon dioxide is a key element of the research effort, he says. "It is challenging because not only do you capture CO2 but you have to have somewhere to put it."
The goal would be to capture the carbon dioxide, liquify it and then inject it into geological formations, for example spent oil or gas bearing rock.
"We are pretty confident that once it is in the ground it will stay there," says Feeley. Current calculations suggest 95 per cent of it would remain underground for at least 100 years.
"There is always the possibility that some technical difficulty will arise [ that] you can't overcome in a cost-effective manner." He points out, however, that several decades ago it was considered impossible to scrub sulphur out of coal-plant discharges and now up to 99 per cent can be taken out.