Grid operators have long claimed that the nation's aging electricity network cannot support the enormous expansion of wind and solar power planned by the Obama administration. Now, a new government report says otherwise.
According to the National Renewable Energy Laboratory (NREL), a division of the Department of Energy, it is "operationally feasible" for the power grid to accommodate 30 percent wind and 5 percent solar energy in Western states as early as 2017.
Perhaps even more impressive is that as much as 20 percent power could come from renewable resources without any new long-distance transmission lines.
That conclusion, from NREL's "Western Wind and Solar Integration Study," stands in sharp contrast to previous studies indicating a need for thousands of miles of costly new transmission lines to achieve such penetration of renewables.
"That report and its companion report, the "Eastern Wind Integration and Transmission Study," were real eye-openers for a lot of people," said Charlie Smith, executive director of the Utility Wind Integration Group and member of the technical review committee for the new NREL report.
Renewable Power Growth: Three Scenarios, Same Cost
NREL examined three separate scenarios for how wind and solar power might be incorporated into a Western transmission network called "WestConnect," which includes utilities serving parts or all of Colorado, Wyoming, New Mexico, Arizona and Nevada.
One scenario is an "in-area concept," where no interstate transmission is required, and wind and solar power within each state meet national renewable energy goals. Another, the "local-priority scenario," would require some new long-distance transmission but priority is given to local resources. And lastly, a "mega-project scenario" would build up the windiest sites in America — largely in Wyoming — and construct transmission lines required to move that power off the high plains and into other states.
Notably, the three scenarios did not differ substantially with respect to capital costs. An $11 billion requirement in transmission lines for the mega-project scenario, for instance, was balanced out by almost $12 billion more needed in wind turbine construction in the in-area scenario.
In the end, the local-priority concept, involving a mix of long-distance and locally sourced renewable energy, had a slightly lower price tag of $80.1 billion compared to $81.9 billion and $83.1 billion for the mega project and in-area scenarios, respectively.
Smith said the decision of which scenario to go with likely would not come down to money, but rather the visual impacts of the energy installations.
"I think at the end of the day it ends up being a kind of societal tradeoff between the visual impacts of both the wind turbines and the transmission," Smith told SolveClimate, adding that some would prefer to have turbines nearby while others might rather they be located in remote wilderness locales.
"The cost of transmission is a relatively small part of the total delivered energy cost."
Eastern Grid Operators Want Billions for New Transmission
Others might argue with that last assessment.
A study released last February by a group of transmission owners and operators in the Eastern U.S. estimated that achieving the DOE's goal of 20 percent penetration of wind power would require $100 billion worth of new transmission lines from the Great Plains and heading eastward.
Still, transmission would seem the least of the issues that a rapid wind boom faces. Building out actual wind generation capacity would bear the brunt of the total cost, at $720 billion. Further, progress toward some of the required transmission is already underway. A $12 billion project called the Green Power Express is slated to be fully operational by 2020. It would involve 3,000 miles of transmission between windy North Dakota and Chicago.
In its own report on Eastern states released in January of this year, NREL suggested that the $100 billion price tag for new transmission might be an overestimate. The priciest of the lab's four scenarios showed capital requirements of $93 billion, while cheaper methods of wind integration lowered that figure substantially.
One reason for the discrepancy is that the NREL report contained an important caveat. For the power grid to absorb large amounts of renewable energy, it said, existing systems would need to operate far more efficiently.
Smith said a change in how utilities schedule the power generation and exchange between states is indeed an important piece of the puzzle. At the moment, that scheduling is done once per hour, he said, but the variability of wind power lends itself to a more rapid-fire approach.
"There is an awful lot of flexibility within the system that could be accessed by five minute schedules," Smith said. "And really that flexibility within the system is very important for balancing the variability in the wind plant output."
Studies Are First Step Toward Big Clean Energy Boost
Denise Bode, CEO of the American Wind Energy Association, welcomed NREL's findings and said she is now looking to Congress to act on them.
"Now the only question is whether Congress and the Administration will step up and enact the policies — particularly a strong renewable electricity standard and robust transmission legislation — that will allow us to get there," Bode said.
Four of the five states in WestConnect have renewable portfolio standards requiring between 15 and 30 percent of electricity from renewable sources by 2020 to 2025, providing at least state-level incentive to push for NREL's scenarios.
Bode also said that the "operational feasibility" of such scenarios should come as no surprise, and that the industry has long asserted that large-scale renewable penetration is doable.
Smith, though, said these reports have added concrete plans and much-needed numbers to the field, and are a first step toward making well-informed long-term decisions.
"I don't think anybody really had a comprehensive picture of what it would take to implement very large amounts of renewable energy into the system, and now I think people understand. They're beginning to get a feel for what has to be done and how the system needs to evolve and change over the next decade or two," he said.
"And it's more than the next decade or two, it's over the next 50 years, because the decisions that are made today about what transmission to build, what power plants to build, what power plants to replace, what power plants to retire — they're going to be with us for 50 years."