Photo courtesy of JohnKit at Flickr.com.
Trash, trash, trash. We’ve got plenty of it! Just take a look around your neighborhood on trash pickup day – all those bulging bags are headed to the landfill, where they’ll be buried and put out of sight, out of mind. Yet those bags may contain a solution to high fuel prices.
In the near future, our cars could be powered with gases produced by decaying waste. A test project is underway that will effectively convert a 30 acre cell of the McComas landfill into a giant compost pile. For the project, researchers are laying 7 pipes in various layers in the landfill, and the pipes will recirculate leachate through the trash heap. By adding nutrient rich moisture to the pile, these pipes will allow bacteria to digest the trash at an accelerated rate (200-300% the rate of decomposition in other landfills).
This accelerated decomposition will help conserve space in the landfill, but it will also produce methane gas as a byproduct. Methane gas (also known as natural gas) is distributed to homes and businesses by natural gas utilities. Methane from the McComas landfill will be transported by Atmos Energy, and sold to heat buildings, run industrial machinery, and generate electricity. Methane can also be compressed for use by buses that use natural gas for fuel , or even processed into hydrogen for the next generation of gasoline-free cars.
Landfill gas is an alternative source for hydrogen fuel, and using waste to produce our fuel is one way to reduce our dependence on fossil fuels. The majority of hydrogen produced today is derived from petroleum products. Converting landfill methane into fuel is a double win, because it reduces the use of gasoline while also preventing the release of methane into the atmosphere. This is important, because methane gas has an even greater effect on climate change than carbon dioxide.
So, how much gas are we talking about here?
As it stands, McCommas already captures about 5.6 million cubic feet of methane a day, which is piped to an on-site plant operated by the independent company, Dallas Clean Energy. Some of the cityâ€™s estimates show that by 2012, output could exceed 20 million cubic feet per day.
The conversion rate from methane into hydrogen is about 66%. That means the McComas landfill could produce 13.2 million cubic feet of hydrogen daily. Across the entire country, our current production of Hydrogen amounts to about 3 billion cubic feet per year, so this one landfill could more than double our current hydrogen production.
There are many more landfills in the US. We have about 3,000 active landfills and 10,000 old landfills, all full of trash that’s breaking down into methane. Tapping them to produce hydrogen gas would be a great way to escape our addiction to oil.