Biogas Pakistan

Biogas Pakistan began with a plane that could not land. Flying into Lahore to look at manufacturing, our founding partner Gerard Woerdenbag found a single flight a day getting through the smog — much of it from rice stubble burning at the edge of the city. On the road toward Kasur there was refuse piled along the verges. In the hotel, the power kept cutting out. Three problems, and on inspection one answer: the waste choking the city was also the fuel it was short of.

Anaerobic digestion is a mature and profoundly unglamorous technology. Organic matter — rice straw, market and food waste, slaughter waste, sewage sludge, manure — goes into a sealed tank. With no oxygen present, bacteria break it down through four stages and release biogas: 45–75% methane, most of the balance carbon dioxide. The gas fuels a combustion engine, the engine turns a generator, and the generator puts electricity on the grid.

There is a piece of chemistry here that makes the Pakistani case unusually strong. Methanogens want a carbon-to-nitrogen ratio of about 20 to 35. Rice straw is far too carbon-rich for that on its own; animal manure is far too nitrogen-rich. Put them in the same digester and each one corrects the other. Punjab happens to produce both, in quantity, in the same districts.

And the economics of the straw are the crux of it. Punjab generates about 8.5 million tonnes of rice residue a year, and burns between 3.6 and 5 million tonnes of it — because clearing a field properly costs a farmer roughly $55 an acre, about a third more than a match does. Every mechanical alternative asks the farmer to absorb that cost. A digester that buys the straw turns the same $55 an acre from an expense into income. That is the only version of this that a farmer has a reason to say yes to.

Nothing is wasted at the far end either. What is left is digestate — a stable organic fertiliser, its nitrogen mineralised into a plant-available form, going back onto the fields the straw came from. The carbon released when the gas burns is the carbon the crop absorbed while it grew, which is why biogas counts as renewable rather than fossil.

The plan is an 80 × 100 m site near Lahore — the Karol area or Gujjar Colony — built with as much local supply as possible and the specialist technology imported, in association with HoSt of the Netherlands, a biogas engineering firm from the same town as our founder. The intent was always a social company rather than an extractive one: buy local, train local, employ local.