Rice farmer Cheng Leng used to spend hours scouring the forest surrounding his Kampong Speu farm for firewood, which then had to be dried for the better part of a day before he could use it.

Today, a cistern-like structure behind Leng’s home has spelled the end of the labourious process. When Leng wants to boil water or cook food for his family of seven, all the 60-year-old farmer has to do is flick a switch and his methane-powered stove sputters to life.

“[With biogas] we don’t have smoke in the house like when we burn firewood; it is much better for our health,” Leng told the Post in a recent interview. “When it rains, we also do not have a problem with the firewood getting wet. We can use biogas anytime.”

Leng’s biodigester is just one of some 20,000 that have so far been built around the country by the National Biodigester Programme (NBP) – a project headed by the Ministry of Agriculture, Forestry and Fisheries and supported by the Netherlands Development Organisation.

In total, roughly 25 per cent of the approximately two million rural households here could benefit from biogas over the next few decades, according to statistics from the NBP.

The program, which started in 2006 and just entered its second phase, aims to build an additional 25,000 plants by the end of 2016, bringing coverage to almost 10 per cent of suitable households.

Biodigesters create an anaerobic or low-oxygen environment in which bacteria break down organic matter – typically animal manure - to produce methane gas. The alternative form of energy is slowly gaining traction with rural households in the Kingdom.

Piped to their homes, farmers use the methane produced by the biodigesters to power gas stoves and lamps. Even the by-product, known as bioslurry, can be used as fertiliser.

Though initial costs for a biodigester can be high – Leng’s model cost him over $400, of which $100 was subsidised by the NBP – the other alternatives can be prohibitively expensive, say experts.

Only about 24 per cent of the country has access to electricity – most of which is centred in provincial towns and cities – according to figures from the Alliance for Rural Electrification.

Because the electrical grid is installed solely along the national roads and in provincial towns, the only source of power in remote farms and villages are from car batteries and private power-supply companies known as Rural Electrification Enterprises (REE), said energy researcher San Vibol from the Royal University of Phnom Penh.

“These REEs run their own diesel generators, but the price can be very expensive,” he added, pointing out that it could cost up to 2,700 riel for one kilowatt hour of electricity – more than three times the price of power in cities like Phnom Penh.

Most of this power goes toward running lights and electrical appliances like radios. While biogas cannot power electrical appliances, it can feed gas lamps to provide a steady source of light, said Vibol.

Because much of the country remains “off the power grid,” said Vibol, any future energy plan should decentralise energy production – with individual households or communities responsible for their own energy needs.

He criticised plans by the government to concentrate energy production in massive hydropower projects like the Kamchay and Kirirom dams as unfeasible in the long term.

“Hydropower is not stable; during the dry season, the dams do not have enough water,” he added. Just two months ago, parts of Phnom Penh suffered crippling power cuts because the 190-megawatt Kamchay dam that services the city was only operating at 10 per cent capacity due to a lack of water.

But Cambodia is not alone in its energy woes. Other countries that have tried to diversify their rural energy production have used biodigesters as a way to bear part of the energy burden, said NBP’s technical manager Meng Chanvibol, pointing out that biogas has quite a following amongst farmers in Nepal, China and Vietnam.

Aside from cost, farmers list the main downside is the substantial amount of animal manure required to kick-start biodigestion initially.

About 1,500 kilograms are needed for the smallest four-cubic-metre tank, Chanvibol said.

“After that, they need about 20 kilogram daily, which is about two to three cows [worth],” he added.

For Leng, this became an issue after he sold six of his eight cows in 2008. While in the past all he had to do was collect the manure produced overnight in his cow pen, now he has to spend time combing his field in the day for the material. But the effort is worth it, he said.

“My living standard is better than before I had my biodigester.”