More anaerobic digesters installed in West Michigan


Greg Northrup, Greg Pierce and Pam Landes, from left, at the site of the anaerobic digester in Lowell. Photo by Michael Buck

Consumers Energy is planning to buy more renewable energy generated at four farms in West Michigan, while the city of Lowell soon will begin to tap into electricity derived from waste from a farm and a major food-processing plant there.

Both the Lowell anaerobic digester and one of the new farm anaerobic digesters are being installed by a small Grand Rapids company: Sustainable Partners LLC, or Spart for short.

Electric utility companies in Michigan, including municipal-owned utilities such as Lowell Light & Power, are required by the 2008 Michigan energy legislation to obtain at least 10 percent of their electricity from renewable sources by 2015.

The little town of Lowell will see that bet and raise it.

The new anaerobic digester will provide enough methane gas to generate about 800 kW of electricity for distribution by Lowell Light & Power, added to the renewable energy it already is selling.

“This will put us close to 20 (percent)” — double the 2015 requirement of 10 percent, said Greg Pierce, general manager of LL&P.

He said the LL&P board expects the state of Michigan to raise the renewable energy requirement for utilities in the future, so LL&P will be ahead of the game.

A combustion turbine generator will burn the methane produced at the digester now under construction. The digester is owned by a corporate entity called Lowell Energy Anaerobic Digester LLC, or LEAD, which was formed by the developer, Spart.

LEAD is a private investment estimated to total about $6 million. However, it is located on city property, and in five years, the digester will become the property of Lowell. The city’s partnership with LEAD is aimed at capturing federal tax credits for alternative energy investments, which are not available to nonprofit organizations.

Organic materials, which can range from farm manure to grass clippings to waste vegetable oils, are slowly “cooked” in an anaerobic digester, releasing methane gas that is captured and burned to generate electricity. Any remaining solids in the digester are inert and can be used as farm animal bedding or added to soil as a conditioner.

The Lowell digester is the first in the United States to use an improved process and new technology developed by German firm Enco2. Pierce said it is believed to produce about 20 percent more methane than conventional digesters.

He noted that European countries are far ahead of the U.S. in terms of renewable energy production; he has heard that Austria gets as much as 80 percent of its power from waste.

“They’ve actually mined all their old landfills” for waste that can be used to generate methane, said Pierce.

Litehouse, a major U.S. salad oil producer located in Lowell, will pipe its waste to a city facility that will separate the oils and divert them to the digester, while the remaining effluent will be processed at the Lowell wastewater treatment plant. Litehouse now must truck its waste to the Muskegon County wastewater treatment plant.

A second source of “feedstock” for the Lowell anaerobic digester is dairy livestock waste from Swisslane Farms in Lowell. A third source, which is probably going to be the largest source, according to Pierce, will be waste oils and grease from commercial operations in the region such as restaurants and food processors. Pierce notes this waste now generally goes into landfills.

LL&P has about 2,600 customers and its average daytime load is from 9 to 10 megawatts, but on a hot day when air conditioners are running, it can reach 15 megawatts.

Consumers Energy, which is close to having 8 percent of its electricity from renewable sources, announced in late July it has signed contracts with four farms for their electricity produced by burning methane extracted from manure and agricultural waste. The farms are Beaver Creeks Farms in Coopersville; Brook View Dairy in Freeport; Green Meadow Farms in Elsie; and Scenic View Dairy in Fennville.

All but Beaver Creek already have anaerobic digesters installed and in operation. Spart also is developing the Beaver Creek digester, according to Pam Landes, who founded Spart last year in Grand Rapids with partner Greg Northrup.

“We anticipate creating 1,400 kilowatts of electricity” at Beaver Creek, said Landes. About 1,000 kilowatts will be purchased by Consumers and the remaining 400 used to operate the digester. She said she does not know yet how much will be invested in the Beaver Creek digester.

Landes said Spart intends to find more anaerobic digester projects, with the learning experience gained at the Lowell facility making its development process more rapid and efficient.

Consumers Energy said it developed its new farm anaerobic digester program with Michigan State University and the agricultural community.

The four farms in West Michigan have long-term contracts that will collectively provide 2.6 megawatts of electricity for distribution by Consumers, enough for about 2,800 homes.

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