Renewables: growth and challenges


Rapid progress but nothing is easy

Here’s how big solar energy has become in the United States: A total solar eclipse coming August 21 has utilities planning to prevent power outages when the moon blocks the sun for two minutes and 40 seconds over the middle of North America.

You needn’t worry about losing electricity—your local electric cooperative knows what’s coming. But the long-forecast astronomical event shows how, rather suddenly, renewable energy is making a serious difference as solar and wind power elbow their way into roles traditionally occupied by electricity generated from fuels like coal, natural gas, and uranium.

“Electric Industry Generation, Capacity and Market Outlook,” a new report from the National Rural Electric Cooperative Association (NRECA), describes those changes and what they mean for electric co-ops and their member-owners.

“The (U.S. Department of Energy’s) Energy Information Administration (EIA) projects that by 2018, non-hydroelectric renewables will be about 10 percent of the generation mix, which is a really big deal,” says Lauren Khair, an NRECA regional economic analyst and an author of the report. “Back in 2008, just to give you an idea, the share of non-hydro renewables was around 3 percent.”

But the rapid rise is only half the story. Wind and solar generate electricity differently than coal-fired and nuclear “baseload” generation that can run continuously for—literally—months at a time or longer. And that has utilities making changes in an increasingly complicated system of generation and transmission.

Eclipse Lessons  

When the moon moves in front of the sun during an eclipse, “Solar shuts off very quickly,” says Michael Leitman, NRECA strategic analyst. “Then it comes right back to full power.”

That can cause problems for an electric grid designed to generate power exactly when it’s needed, and to keep that electricity at a consistent frequency.

Traditional baseload resources, like coal, nuclear, and natural gas, provide stability to a grid that must continuously match power supply with demand and prevent sudden frequency shifts. Because they operate intermittently, wind and solar don’t guarantee that crucial stability. As the percentage of wind and solar in use at any given moment increases, the grid operator’s balancing act grows more complicated. Luckily, emerging inverter technologies can provide synthetic inertia to help alleviate this problem, in conjunction with additional natural gas resources more nimble than coal at adjusting to sudden supply and demand shifts. Further, these flexible resources can ramp up faster to compensate when the wind calms or the sun is obscured.

The organization responsible for assuring resource adequacy of the grid, the North American Electric Reliability Corporation (NERC), issued a report suggesting utilities prepare for the eclipse. NERC identifies California and North Carolina as states near the path of total eclipse and heavily reliant on solar power. NERC says those states should “perform detailed studies and retain necessary resources to meet the increased and varying load” as the expected drop in solar calls for more electricity from other sources during those few minutes. The path of total eclipse will enter Oregon at 10:15 a.m. Pacific time and cross the country during the next hour and a half, exiting South Carolina at 2:49 p.m. Eastern time. A much wider band paralleling the route will be affected by a partial eclipse.

Policy Choices Add Momentum  

Rising consumer demand is a strong driver of growth in renewable energy, and Wisconsin’s electric cooperatives have moved more aggressively than other power providers to supply the renewables their members request. Government policies are another big reason for expansion of renewable energy. Solar and wind power grew rapidly in response to federal tax credits in 2012, slowed when credits were expected to be discontinued, and accelerated again when they were extended. These subsidies even affect the time of year when renewable projects are built. As NRECA’s report states, “Most renewable projects are completed in the fourth quarter of the year, due in part to the timing of qualifications for federal, state or local tax incentives.” Projections for renewable energy show strong growth until 2020, then a leveling for several years as tax credits phase out.

State governments also stimulate growth, with laws mandating renewables as a percentage of energy use, known as Renewable Portfolio Standards (RPS). Washington, D.C., and 29 states have adopted various mandatory standards. Several other states have set voluntary targets. In 2005, Wisconsin enacted an RPS requiring all power providers to source at least 10 percent of their electricity sales from renewables by 2015. All providers achieved the standard. Wisconsin’s electric cooperatives met and surpassed the standard years ahead of the deadline.

Improved technology and lower prices also push renewable growth. The NRECA report says, “States have been able to meet or surpass these [Renewable Portfolio] Standards, in part because of declining costs of solar and wind … utility-scale solar costs for crystalline panels dropped 85 percent and utility-scale wind costs dropped 66 percent in the last seven years.”

New Energy = More Infrastructure  

Large-scale wind and solar installations tend to sit in wide-open spaces, so the electricity needs new transmission lines to reach where people live. Moreover, transmission systems increasingly need to accommodate generation that occurs only when the wind blows or sun shines. “The increase in variable generation to the wholesale market has led to increasing concerns about transmission congestion,” says the NRECA report.

Citing an estimate from Edison Electric Institute that investor-owned utilities plan to spend $22 billion this year on transmission projects, the report notes another speed bump to renewable energy development: “As transmission projects become more difficult to site due to environmental concerns, land availability, local opposition and other constraints, planners will need to find innovative ways to meet these challenges.”

The lesson: Even though some energy choices enjoy widespread public enthusiasm, building the necessary infrastructure is never easy to do.

Paul Wesslund writes on cooperative issues for the National Rural Electric Cooperative Association, the service arm of the nation’s 900-plus electric cooperatives. WECA’s Dave Hoopman contributed to this report.