Apart from cooking, Zhang also boils water on her methane gas stove, which is connected to a methane gas pond dug beneath the family's pig sty via a white plastic tube.

Zhang is just one of the many beneficiaries from a provincial new energy promotion scheme for rural areas, with financial support from the provincial government of Gansu, according to Pan Xiaoren, an official with the office for promotion of new energiesin rural areas of Gansu Province.

Under the program, each rural household is provided with construction materials worth 1,200 yuan (about 147.97 US dollars) for building methane gas ponds.

Duan Chengyi, chief of the station for the promotion of agrotechniques with Dalu Township, which exercises jurisdiction over Zhang's village, said methane gas ponds were now very popular among rural households as they found using methane gas as a source of energy caused no smoke.

Up to now, rural households in Gansu have built 123,000 methanegas ponds.

With the energy provided by methane gas ponds around legions ofrural houses, farmers in Gansu burn less straws or firewood for cooking or keeping warmth, saving 20,000 hectares of forested land from destruction or energy equivalent to 1.5 million tons of standard coal, said Pan.

In the meantime, methane gas ponds have offered organic fertilizers to 4,667 hectares of arable land in this landlocked province, said Pan, who added that each rural household that uses methane gas as a source of energy could save 1,000 yuan (123.4 US dollars) a year.