Study Warns that Gas Plants Could become Stranded Assets

Utilities, investors and regulators should stop the rush to natural gas and choose clean energy portfolios (CEP) made up of combinations of solar, wind, storage, efficiency and demand response, warns a new report from the Rocky Mountain Institute (RMI).

If they don’t, many gas plants will become stranded assets, raising the specter that ratepayers will have to pay for them, said Chaz Teplin, a manager in RMI’s electricity practice.

“We’re hoping that regulators, utilities and investors think really hard about whether new gas plants are wise investments,” said Teplin.

To study this issue, RMI created computer models that compare the price of energy from natural gas plants to electricity from CEPs. The researchers optimized wind, solar, storage, efficiency and demand response in ways that ensured these portfolios meet peak demand and produce the same amount of energy each month, he explained.

The report, ‘The Growing Market for Clean Energy Portfolios,” focuses on aggressive plans by utilities, investors and regulators to invest in natural gas plants, even as clean energy portfolios become less expensive than natural gas.

Colorado as example

Some regions are already moving to clean energy and retiring natural gas plants, Teplin said.

“Our home state, Colorado, is retiring coal plants early and is doing it without doing new gas,” Teplin said. “They’ve stated their goals of reducing emissions by 80%, and they are happy to do that because when they went to market for solar, wind and storage, the costs had gone so low that they were excited to go that route.”

The cost of a CEP equivalent to a combined-cycle gas plant has fallen by 80% since 2010 and now undercuts the cost to build and run a typical new gas-fired power plant, said the report.

These results do not assume any cost of carbon emissions from gas plants or associated carbon taxes that would make the cost advantage of clean energy portfolios even larger.

By the mid 2030s, the cost of building a new CEP will be lower than the cost to operate an existing gas-fired power plant, according to RMI.

“For the first time, the rapidly falling costs of renewables and batteries are allowing optimized combinations of these resources…to systematically outcompete gas-fired generation on a cost basis while providing all the same grid services,” said the report.

RMI used a region-based approach to compare traditional gas-fired generation with CEPs, and estimated the reductions in expected gas use that resulted from choosing cost-effective CEPs. The report concluded that the less expensive CEPs would lead to stranded gas assets.

The dispatchability challenge

Other studies have shown that on a dollar-per-megawatt (MW) basis, solar and wind are cheaper than gas, Teplin noted. But what makes this study unique is how it responds to criticism that gas is dispatchable, and therefore can be used any time, while renewables are not always dispatchable and are therefore less reliable.

“So what we’ve done is try to say, ‘When is the energy needed, how will that gas plant actually be operated?’ and then combine the clean energy technology components to mimic that usage pattern,” Teplin said.

In creating their model, the RMI researchers asked themselves when peak demand occurs in a particular region, and tried to project that into the future.

“We expect peak demand to fall on the same days and require the portfolios to provide power at that time,” Teplin explained.

Four main conclusions of RMI study

The study reached four main conclusions. First, the CEPS are lower cost than over 80% of proposed gas-fired power plants in the focus regions. Second, if the proposed gas plants are built, the decreasing costs of clean energy will likely lead to over 70% of planned capacity being uneconomic by 2035. Third, competition from clean energy will nearly eliminate expected demand growth for gas from the power sector. Fourth, lower-than-expected demand will increase the per-unit cost of gas from newly built pipelines.