Greenspace: Three Green energy sources work 'round the clock

We talk about Green energy all the time, but what are the true benefits of renewable electricity? Well, aside from cutting carbon emissions, there's the nearly non-existent fuel costs and the benefits to the electricity grid that delivers power to homes and businesses.

John Jimison, managing director of the Energy Future Coalition in Washington, D.C., said energy that is produced closer to where it is actually used is more efficient because there's no loss of power as it moves for miles and miles across the power grid.

"Distributed energy has the advantage of being generated at the load," Jimison said.

One of the problems with centralized power production — coal or natural gas plants — is the percentage of power that gets delivered to the end user, Jimison said. The average for coal plants, he said, is 32 percent of the potential energy delivered to the transmission system and another 10 percent lost through the grid.

"We waste a whole lot of energy in our system," he said. Most of that potential power is lost through waste heat in the power generation process. By comparison, power from distributed systems can reach 85 percent efficiency, he said.


There are three basic types of renewable energy, including solar, wind and hydroelectric. RPU customers benefit from all three.

Wind turbines can be found throughout southeast Minnesota. Rooftop solar producers sell back to the grid, which gets used by customers throughout the system. And the Lake Zumbro Hydroelectric Generating Plant produces between 10,000 and 15,000 megawatts on average each year.

"Hydro power has been a mainstay of the economy for decades," Jimison said. "There's potential to do much more hydro."

While hydro power can impact rivers and fisheries, you can get increased power production by putting new turbines in old dams.

Wind energy, Jimison said, is currently the fastest growing segment of the energy by capacity. And solar energy has been rapidly spreading due to declining costs. "The price of solar cells has come down something like 75 percent in the last three years," Jimison said.

The big benefit of these three kinds of power, he said, is there's no fuel to buy. Coal and natural gas plants have their infrastructure costs plus ongoing fuel costs. But once you build a wind generator, Jimison said, the wind — the "fuel" for the system — is free.

The only problem with Green energy, he said, is reliability. "Our overall electric load has gone down," he said, talking about the nation's need for electricity. "But the need for reliability has gone up. When you flip the switch, do the lights go on?"

That's where the grid comes in. Generating power closer to where that power can be used via rooftop solar systems or widespread wind generation can decrease the load on the sensitive grid.


The next step, Jimison said, is getting the renewable sources of energy to work together to fill a bigger part of our electric needs. While a lack of wind or no sunshine mean coal or gas plants must fill the gaps, better hydro power could take up some of that slack.

"Hydro can be a wonderful way of backing up solar and wind production," he said, adding that Canadian hydro producers are looking to do just that in Minnesota. "And electric vehicle batteries are a potentially wonderful source of storing energy."

Brian Todd is a Rochester freelance writer.

What To Read Next
Get Local