It used that much for heating purposes alone.

Mond gas is a cheap coal gas was used for most industrial heating purposes.

Biogas can be used as a fuel in any country for any heating purpose, such as cooking.

In the case of combined heat and power systems, the engine's cooling water is used directly or indirectly for heating purposes.

The advantage of steam is that in addition to heating purposes it can be used in industrial processes due to its higher temperature.

A shaft from the uranium mining era provides today thermal water for heating purposes.

The only differents are that instead of opium Chinese get the paper dollars that they may as well burn for heating purposes.

The raw oil was mixed with saw dust and formed into balls that were used for heating purposes.

Some types are also used for heating purposes.

There is a good deal more potential with biomass, and also in the use of heat, that is, solar energy for heating purposes.