Mt Pleasant News

Wash Journal   Fairfield Ledger
Neighbors Growing Together | Sep 22, 2018

More sun, more wind - But will their success hurt the power grid?

Mitchell Schmidt, The Gazette
By A look at intermittent power sources and reliability | Feb 16, 2018

North of Kalona, near the unincorporated Johnson County community of Frytown, a small electric cooperative has established itself as a solar energy leader.

Farmers Electric Cooperative’s 3,373 cumulative watts of local solar power per customer ranks first in the state and third in the nation.

The co-op, which began investing in solar about a decade ago, now generates about 20 percent of its power from solar panels. The cooperative’s entire grid can be fueled by solar on a sunny Sunday afternoon.

With solar making up less than 1 percent of state or national power generation, Warren McKenna, general manager of the co-op, said there’s room for more.

“For the entire state of Iowa, it would take probably three gigawatts of solar to get to 20 percent to match us,” McKenna said. “There’s a lot of growth potential in Iowa.”

But as cooperatives and utilities expand their renewable portfolios, and businesses and homeowners explore the possibility of adding solar panels to their rooftops, how does that growing solar network — and the intermittent power it generates — affect the state’s power grid?


This past April, U.S. Energy Secretary Rick Perry requested a study to examine U.S. electricity markets and reliability, specifically regarding the impacts of growth and trends in the market.

According to the nearly 200-page report, growth in wind and solar has negatively influenced the economics of baseload plants, which largely include coal, natural gas and nuclear generation.

Solar and wind generators cost less to operate and are dispatched first, which displaces baseload generators, the study states.

The study notes that accelerated wind and solar growth has been spurred by state renewable portfolio standards, which have been adopted by more than half of all U.S. states and require utilities to sell a specified percentage of renewable electricity.

“Competition from resources that benefit from such policies reduces revenues for traditional baseload power plants by lowering the wholesale electric prices they receive and by displacing a portion of their output,” the report says.

The report argues that adding renewables while simultaneously closing baseload plants increases risks to the reliability and resilience of the grid.

However, a separate independent report by economic and financial consultant Analysis Group — commissioned by Advanced Energy Economy and American Wind Energy Association — released in June contradicts the U.S. Department of Energy’s staff report.

“Recently some have raised concerns that current electric market conditions may be undermining the financial viability of certain conventional power plant technologies (like existing coal and nuclear units) and thus jeopardizing electric system reliability. In addition, some point to federal and state policies supporting renewable energy as a primary cause of such impacts,” the Analysis Group report states. “The evidence does not support this view.”

This report also counters that declining natural gas prices and advancements in technology have been the biggest factors contributing to the retirement of aging coal plants, rather than growth in renewable power sources.


But what does adding solar and wind power to the market mean for the grid, or transmission lines, substations and circuits that carry energy from solar panels and wind turbines to homes and businesses?

Earlier this year, as the Iowa Utilities Board debated potential amendments to state interconnection rules, some utility providers argued that solar projects, particularly single-customer rooftop arrays, put added strain on the infrastructure. Officials with Alliant Energy last year cited recent investments in renewables as one reason for customer rate increases.

However, Andy Johnson, director of Winneshiek Energy District in Decorah in northeast Iowa, which has between four and five megawatts of locally owned solar, argued that Iowa still has a long way to go until solar becomes a big enough piece of the power grid to have any major effects on infrastructure.

In Iowa and nationwide, solar is at a mere 1 percent of all power generation.

“At the levels of penetration we’re at — at well under 1 percent — it’s irrelevant, largely,” Johnson said. “You have to deal with it more at the high single digits. But at 1 percent, it doesn’t matter.”

While solar has grown to the mid-single digits of Winneshiek County’s energy production, Johnson said he hasn’t witnessed any major impacts on infrastructure needs so far,

The issue with solar, Johnson said, is it can become an intermittent power source if, for example, homeowners install more solar than they use. Power traveling back and forth on a system can put added wear on some components, he said.

“Circuit by circuit is really where the action is at, I think,” he said. “In a given circuit, if you end up installing a certain amount that ends up becoming as much or more than those consumers use, then that circuit needs to be able to flow backward through the substation.”

Johnson added he is not aware of solar causing any large-scale issues on the grid so far.

Iowa Environmental Council’s Baer said state rules for on-site generation provide the framework for statewide solar growth.

To connect solar to the grid, customers first have to determine the impacts of such an addition. The process — which was developed a few years ago and adopted in 2017 — helps ensure that such connections are done in a safe and efficient manner, Baer said

But most importantly, Baer said, is that wind and solar work together. With a diverse energy portfolio, utilities can dispatch the cheapest option available as conditions and energy prices fluctuate.

“When solar comes on, it can reduce stress in the grid. It can provide clean energy when it’s most expensive,” he said. “Both wind and solar, they’re very complementary.”

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