A dairy farm in China is about to implement the world’s largest system for converting methane from fermenting cow manure into electricity. The Huishan Diary has imported a GE Jenbacher engine and adapted it for use with biogas, expecting to generate as much as 5.6 megawatts of power.
The 60,000 cows at Huishan will provide the “fuel” for the electricity generator which, at the same time with producing energy, will also make an organic fertilizer that it much safer than raw manure, in the sense that the methane that would otherwise get released in the atmosphere will be collected and burned.
Methane, by the way, is a 23 times more greenhouse gas than CO2, and cows have been blamed for some 60% of the total methane emitted worldwide by man intervention.
The engineers at Huishan have overcome the problem of corrosion due to the hydrogen sulfide by coating the engine parts exposed to the gas with anti-corrosive materials. Normally, the solution is the exposition of the gas to iron oxide, which cleans it from hydrogen sulfides through a process called hydrodesulfurization.
Although there are other farms that had implemented this kind of systems, Huishan’s is 10 times bigger than the average, and this is what makes it even more economical. For smaller dairies, such as those in the US, buying a system that produces 300 to 500 kW of electricity just isn’t worth the investment, since it’s two times more expensive in a 100-cows farm than it is for a 2,000-cows.
Huishan doesn’t have this problem, though. They import around 3,000 cows from Australia every month and have a skyrocketing total of 250,000 cows, so a multi-megawatt biogas system is worth buying. At this size, they will capture 20 million cubic meters of biogas a year, so you do the math.
A similar Jenbacher engine has been installed at a 4,000 cows dairy farm in Ukraine, and already produces 1.3 MW of electricity.
[via technologyreview]
