City Hall, Lebanon. (Jon Platek, Wikimedia Commons, CC-BY-SA 3.0. https://bit.ly/LebanonCityHall)
George Harvey
The city of Lebanon, New Hampshire has worked for a long time to convert to renewable energy. Some of its attempts have been notably successful. It has solar panels on the rooftops of several city buildings, which now get about 20% of their electricity from the sun.
Lebanon also has opportunities that have been known for a long time but not yet developed. Possibly the most important of these is the city’s landfill, which has been generating methane for decades. Methane is a dangerous greenhouse gas, and it is generated by anaerobic digestion of waste in landfills. The landfill at Lebanon produces about 350 cubic feet of methane every minute, and it does this all the time, day and night, in rain and in sun, summer and winter. This gas has been gathered and burned, a process called ‘flaring,’ because methane is much more harmful to the atmosphere than carbon dioxide. (CO2 is less than 5% as destructive to the environment as methane.)
More than ten years ago, Lebanon’s policy makers decided to do more with landfill methane than they had been. They started what turned out to be a long process of putting together a system that would send the methane gathered at the landfill to generators, so burning it did not merely make waste heat. The same methane that was being flared could be used by generators for fuel to make electricity.
After some investigation to determine what kinds of generators would be used, the city ordered five micro turbines. These arrived at the Solid Waste Facility in a shipping container in October 2022. But after that time, they sat for quite a while as other developments caught up with them.
Together, the five turbines will be able to produce 1,000 kilowatts (kW) of electric power. For the sake of those people who cannot envision quite what that means, please let me translate. 1,000 kW equals 1,341 horsepower. So that is not a huge amount of power, but it is also not trivial. It is much more than some people would visualize it being, because a car only delivers about one sixth to one third of its rated power to move the car.
That much energy can supply power needs of about 900 average households in New England. The energy can be used by the city, and any excess can be sold to the grid. According to an announcement from the city, it and the solar panels that were already installed will be enough to supply all the municipal electric needs.
Please bear in mind that while solar panels only generate electricity during daylight hours, landfill gas is a full-time operation. There are ways to vary the amount of electricity produced with changes in demand, but in general, the power supply is constant.
Burning the methane as fuel in turbines does produce carbon dioxide, and so this is not a solution for fully converting the city to zero-emissions energy. Nevertheless, the emissions from the turbines represent production of electricity, where the alternative is simply flaring to reduce methane emissions.
The landfill will not produce methane forever. Landfill gas projects often have lifetimes that measure along the lines of two decades, which could be about the lifetime of a turbine. But by the time the turbines finally get shut down, there will be other forms of renewable energy available to use to replace them.
One of the holdups for the project has been a study by Liberty to determine whether the 1,000-kW produced by the turbines can be added to the grid. That holdup took a surprisingly long time, which is why the turbines arrived well over a year before they could be installed.
Groundbreaking for the landfill gas project was set for May 28, 2024. A short public groundbreaking event provided the ceremonial beginning of the project installation. Next, the concrete foundation for the equipment is to be installed. The five turbines will be put up on it, along with a transformer, panels, switches, and other equipment.
With installation beginning in June, the project should be completed by the end of this year. When that happens, the city of Lebanon will immediately start saving money it is now spending on electricity from Liberty. With that, taxpayer money will be saved and the burden on our environment will be reduced a little.
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