LEBANON — Work crews are beginning to construct a $6.6 million facility that will convert greenhouse gas emissions from the city’s landfill into electricity that will be redistributed to the electrical grid and used to power the city’s buildings. 

The project, when complete, is projected to reduce greenhouse gas emissions by 3,500 tons per year — equivalent to more than 23,000 gasoline-powered cars, according to the federal Environmental Protection Agency, or EPA. The project aims to help the city meet its goal to reduce its carbon emissions by about a quarter by 2025.

The city held a groundbreaking ceremony on May 28 to commemorate the start of construction this month. The new facility is expected to be complete by the end of the year, Erica Douglas, Lebanon’s solid waste manager, said. 

“This project has been a long time coming,” Douglas said in an interview. “Not only will it generate a profit for the city but we will be able to send electricity out to the power grid.” 

Meanwhile, a related city initiative — to replace two diesel-fueled street sweepers with electric vehicles that would have been powered by the landfill gas — stalled earlier this month when Gov. Chris Sununu denied the city’s request for a state funding grant. The city’s grant request would have also funded a charging station for the electric vehicles that would have been powered by electricity generated at the landfill. 

The new system, designed by Capstone Green Energy, a company based in California, employs five microturbines to process gasses emitted from decomposing waste into renewable energy.

Revenues from selling the facility’s power output to the grid are expected to offset the full cost of the project, Douglas said in an online presentation. There will be no impact on municipal property taxes or user fees at the transfer station, she added. 

The project also is expected to save city taxpayers on energy costs to power Lebanon’s municipal buildings. The new generator is expected to provide 80% of the electricity used by city facilities. The remaining 20% is being provided by solar panels.

The project is expected to generate up to a 12% annual return on investment over the next 20 years, said Assistant Mayor Clif Below. 

Below, a former member of New Hampshire Public Utilities Commission and the Lebanon Energy Advisory Committee, said the city has been working on ways to reduce or eliminate the landfill’s carbon footprint for at least 15 years. 

“There used to be no gas collection at the landfill,” Below said in a phone interview. “On warm, sunny days, you could catch a smell of rotten eggs due to the sulfur (and other airborne chemicals) produced from the decomposition of organic materials.”

In 2013, the city installed a “flare system,” which uses suction to collect methane gas emissions, which are then burned by a flare. In addition to reducing the landfill’s odor, the system converts the methane into carbon dioxide, Below said.

Methane, which accounts for about 16% of global emissions, is more than 28 times as potent as carbon dioxide at trapping heat in the atmosphere, according to the EPA. Methane gas, though shorter-lived than carbon dioxide, has more than doubled its concentrations in the atmosphere over the last two centuries due to human-related activities, which include oil and gas systems, livestock, and landfills. 

“We are excited to get that (new system) up and running,” City Manager Shaun Mulholland said in a phone interview. “Instead of just burning that gas, we will be turning it into electricity (and benefiting the community).”

Once the new system is operational, the flare system will only be used in the event that the microturbines are not running, whether due to maintenance or another issue, Douglas said. 

The new system does not require frequent maintenance, Below said. The turbines do not require lubricants, for example, and in the event that one turbine must be stopped for cleaning, the other turbines continue to run — at 80% system capacity, he said. 

The system’s filtration and treatment equipment — which removes chemicals from the gas that can cause wear on the turbines — needs to be cleaned more frequently than the turbines, he noted.

City officials also had hoped to connect a charging station to the new system that could be used to power city-owned electric vehicles — including two street sweepers that the city had sought to purchase this year. 

Lebanon had submitted two funding requests, totaling $2.8 million, to the Granite State Clean Fleets Grant Program, which provides financial support to help municipalities lower their overall vehicle emissions. Lebanon’s proposal included the purchase of two electric street sweepers and an electric vehicle charging station that would serve municipal vehicles. 

Earlier this month, Sununu removed Lebanon’s projects from a list of municipal proposals awaiting funding approval from the Governor’s Executive Council — a five-member board of elected officials that have oversight over spending not sanctioned by the Legislature. 

“I was very supportive of these projects … and I was surprised that they were pulled,” said Executive Councilor Cinde Warmington, District 2. 

Lebanon’s two projects scored 94 and 91 points, out of a possible 135, based on a criteria including project readiness and estimated reductions in diesel emissions, according to the grant program’s final score sheet.

Only two applications, out of 43 submissions, scored higher than Lebanon — a $40,000 project from the University of New Hampshire, in Durham, 107 points, and a $683,000 project by the Town of Pembroke, N.H., 95 points.

Lebanon’s requested amount was significantly higher than any other applicant. Most proposals sought less than $300,000, according to the score sheet.

Warmington, who is running for governor, said in a phone interview she plans to investigate why Lebanon’s applications were removed from consideration, though she was initially advised that there were possible concerns about directing too much money to a single community.

A phone message to the governor’s office seeking comment was not returned. 

Patrick Adrian may be reached at padrian@vnews.com or 603-727-3216.