The total of 2000 tonnes is equivalent to taking 1,000 cars off the road for a year or the annual emissions from heating 750 homes.

In some cases it is possible to use waste heat, for instance in heating homes by cogeneration.

The gas was later also used for cooking, refrigeration, and heating homes and water.

Steam and hot water from the geysers has also been used for heating homes since 1943 in Iceland.

"Customers are more cautious, especially with the cost of heating homes this size," Ms. Hayden said.

He added that wood fuel was a low-carbon way of heating homes.

The heat is then used in local applications such as heating homes.

Widespread archaeological evidence shows that after 850 BC the technology for heating homes changed.

A refrigeration plant capable of heating 4,800 homes had to be built to generate and maintain the ice.

Coal combustion in developing countries is the primary method for heating homes and supplying energy.