landfills are the biggest man-made producer of methane
When you think of the South you think of big old trees with Spanish moss dripping from every limb and Palmetto trees. Palmetto trees are intrinsic in the history of the Southeast. Back in the Revolutionary War, a fort was made out of Palmetto logs. Cannonballs were deflected off the spongy logs. The Palmetto tree symbolizes the defeat of the British in the Revolutionary war. South Carolina is known as the Palmetto State.
It came as quite the shock then, that ten miles north of the BMW manufacturing plant is the Palmetto landfill. A garbage dump named after the great tree is a juxtaposition between the history it is steeped in and the reality of the day. Oddly, the landfill may be a boom for the state. It has been a boom for BMW.
Landfills are the biggest man-made producer of methane. As trash decomposes, methane is produced. As the methane seeps out of the trash into the air it creates greenhouse gas emissions.
Seven years ago the Palmetto landfill was creating so much methane that they had to burn it off every day. The methane, and the CO2 it carries with it, created 92,000 tons of emissions a day.
Robert Hitt, broke it down for me, “Those numbers didn’t mean anything to me. I asked my guys to break it down so that people could understand that number. Based on calculations provided by the EPA, the reduction of 92,000 tons per year of carbon dioxide emissions is equivalent to the benefit of planting over 23,000 acres of trees annually or 30 times the size of New York’s Central Park.” Imagine taking 1/3 of all of Yosemite national parks trees away. That is equal to the savings in emissions!
There are other companies that siphon off the methane from landfills and use it instead of natural gas to power their plant. Those companies are usually adjacent to the landfill. But there were no companies around the Palmetto landfill. The closest plant that was big enough was the BMW manufacturing plant, ten miles away.
Clearly, something had to be done. It was such a concern of the Federal Environmental Protection Agency (EPA) that they developed a plan and brought it to BMW.
BMW studied the project for two years, but BMW is a car company. They would need partners with expertise in landfill gas and gas exchange. BMW would have to change over the turbines they had for natural gas to work with methane. And, of course, they studied the cost. The methane wasn’t going to be free, but Briggs Hamilton, Section Manager, Environmental Services for BMW Manufacturing Co. had been watching the volatility in the price of natural gas for years. If the methane gas from the Palmetto landfill was going to be as volatile as natural gas it would be hard to decide if the project would be profitable.
Natural gas is almost 100 percent methane. Landfill gas is about 50 percent methane, 50 percent CO2. It would be important to get a cost that was reflective of the amount of true energy BMW would get from landfill methane versus natural gas. The EPA agreed to give BMW a fixed rate cost for twenty years. This sealed the deal.
BMW worked with partners Ameresco and Waste Management to lay a pipe from the landfill all the way to a spot on the 1,150 acres that BMW calls home to the production of the X5, and X6. Ameresco owns the pipe and the methane gas that comes out of the pipeline. BMW buys the methane at the point of recovery from the ground.
The original Landfill Gas Project was implemented in early 2003. The infrastructure Ameresco installed at the landfill is able to collect, clean and compress the methane gas. Hamilton said part of the process in the cleanup is wicking off any water before it is transported through a 9.5-mile pipeline to the BMW plant. Just like in a car, water and gas don’t mix. Neither does methane and water.
Recently, BMW replaced four older, less-efficient turbines with two new co-generation turbines. These two new highly-efficient gas turbine generators are capable of producing 11,000 kilowatts (kW) of electricity, which is 30 percent of the electricity used by the BMW plant.
The turbines, the generators for electricity, are housed in big rectangular metal buildings with doors that are locked at all times. Each turbine is connected to two stacks. The first stack is before the heat recovery. A lot of heat is created in recovery, so water is run through the hot coils to heat the water for use in the paint plant. BMW was told by the EPA that they are the first company to have 100 percent recovery of all energies from the use of landfill gas.
The overall energy BMW gets from the landfill methane gas is sixty percent of what the plant uses. BMW is saving $5 million a year on energy costs, and they have created their own miniature electricity company. It’s hard to imagine that they will stop there. I have my own well, my own septic system, my own leach lines in my yard. The closer I get to getting off the grid the happier I become. I can imagine a day when BMW will tell us that they have found a way to make electricity out of garbage.
Then they can call it Palmetto!
