Does dung hold the answer to easing fuel dependence?

COULD Ireland’s herd of 6.53 million cattle provide the solution to the country’s over-dependence on fuel imports? The question has arisen after reports from the US suggested that the secret to cheaper gas in that country could lie in cow dung.

Experts at the Vehicle Research Institute of Western Washington University have been turning cow manure into fuel that can power a natural-gas car.

Researchers are not shoveling manure straight into the tank but pumping the methane — a gas created by the manure — into the vehicle.

Eric Leonhardt, an engineering technology professor and director of the Vehicle Research Institute, said the cows are well-trained. They feed and do their business in one location.

American cattle are mostly held in feed yards, while their counterparts in Ireland, who produce 9.6 million tonnes of dung a year, spend most of their time out on grass and consequently leave their deposits scattered all over those pastures.

Collecting the cow dung from the fields for pumping into a holding tank, as done in the US experiment, would be time consuming, but the overall concept of converting animal waste into fuel has created renewed interest here.

Using cow dung as an energy source is not, of course, a new idea, but it is attracting greater attention because of rising oil prices and fears over the vulnerability of supplies.

The manure collected by the American researchers is allowed to sit in an underground tank for 21 days.

Using regular garden hoses, the researchers then siphon floating methane out of the holding tank, purify it to remove other gases and then pump it into the car.

Every cow can produce enough manure in a day to make a car go about 24 kilometres. If you take 20 cows, you get 482km of gas in your car, according to the Americans.

Meanwhile, Irish pig farmers faced with the challenge of meeting the requirements of the European Union nitrates directive, which aims to protect water from farm pollution, might be particularly interested in a recently announced breakthrough in porcine petroleum at the University of Illinois.

Professor Yuanhui Zhang, a bio-environmental engineer, and his team have developed a method to feed pig manure continuously into a reactor, essentially an industrial-strength pressurized oven, as part of a process that creates ‘porky petrol’.