WILLMAR -- For those Willmar Municipal Utilities electric customers interested in supporting renewable energy, they will soon be able to purchase renewable energy certificates through the utilities as part of a new program.

The Municipal Utilities Commission unanimously approved participation in the program, which is being headed by Missouri River Energy Services.

The new program is entirely voluntary for customers, who must opt in for an entire year. It will be available starting in 2020.

"It is a program to opt in to support renewable energy," Commissioner Nathan Weber said during Monday's meeting.

There is a cost for participating in the program. For all electric customers -- residential, commercial and industrial -- it will cost an additional $0.0033 per kilowatt-hour per month to participate in the renewable energy certificate program. A customer who uses the average amount of power per month, approximately 700 kilowatt-hours, will see an extra $2.31 charge on their utility bill.

Customers wanting to take part will be able to sign up on the Willmar Municipal Utilities website by the end of the week. They can also go to the main offices at 700 Litchfield Ave. S.W. in Willmar for a form.

"It is really something that we need to encourage," Commissioner Abdirizak Mahboub said.

A renewable energy certificate is legal proof that one megawatt-hour of power was produced by a renewable energy source, such as wind or hydroelectric. Once power reaches the power grid, it can no longer be distinguished from power produced by coal or natural gas. A renewable energy certificate allows people to support renewable energy without having to produce their own renewable energy off the grid.

"That is the real advantage to it," said General Manager John Harren. "This is a very affordable and cost-effective way to do that."

Willmar Municipal Utilities itself will be purchasing approximately $10,000 worth of the certificates to cover all of the power the utilities uses for its operations.

"In an effort to lead by example, we recommended the utilities opt in for ourselves," Weber said.

An electric customer, including industries, municipalities and individuals, can purchase renewable energy certificates to cover their power usage, which legally allows them to say they are powered 100 percent by renewable energy, even if the electricity powering their home or business does not come entirely from renewable sources.

Willmar Municipal Utilities' power makeup includes 31 percent from nuclear, 34 percent from renewables and 1 percent from other sources. The remaining 34 percent comes from natural gas and coal. However, if a customer buys renewable energy certificates to cover their power usage, they can say they are powered by 100 percent renewables.

"I think it is important that we understand we are not buying renewable energy, these are just credits," Commissioner Justin Mattern said. "I think it is important the public understands this."

Owners of renewable energy generation, such as solar panel farms or wind turbines, can sell the renewable energy certificates to customers as a secondary source of revenue, which can then be used to build more renewable energy generators.

A renewable energy certificate is only produced after a megawatt-hour of electricity produced by a renewable energy generator is reported to a regional tracking system, according to the Environmental Tracking Network of North America . The tracking system will issue the certificate, with a unique identification number, and track it. Once a specific renewable energy certificate is sold, it is retired to make sure it is not sold again.

"The RECs are coming from renewable energy," Harren said.

The new program at Willmar Municipal Utilities will be run by Missouri River Energy Services, the joint action agency to which the utilities belongs. Once Willmar Municipal Utilities knows how many renewable energy certificates it will need, based on customer signup and the utilities' own needs, it will let Missouri River know, Harren said. Missouri River will then send out requests for proposals for renewable energy certificates and purchase them.

"We have to make a commitment by Aug. 1," Harren said.