The rapid closure of coal-fired power plants in the United States is forcing power companies to confront the next climate challenge: embrace natural gas or actively shift to renewable energy? Some large utilities, such as Xcel Energy in the northern Midwest, are planning to drastically reduce their use of coal and natural gas in favor of low-pollution, abundant, and decreasing-cost wind and solar power. However, natural gas remains dominant in the Southeast and other regions, thanks to the rise of reliable and inexpensive hydraulic fracturing technology. Across the U.S., energy companies plan to build at least 150 new natural gas power plants and thousands of miles of pipelines in the coming years. Although natural gas power plants emit only half the carbon pollution of coal-fired power plants, the ongoing expansion of gas-fired power plants could pave the way for a trend toward new fossil fuels in the coming decades, prompting scientists to say that significant reductions in carbon emissions are needed before the middle of this century to prevent the severe effects of global warming. "The natural gas infrastructure built today will be with us for 30 years," said Daniel Cohan, associate professor of civil and environmental engineering at Rice University. "If we're serious about climate change, we need to achieve net-zero emissions by 2050, and natural gas plants that can't collect carbon are not helping." In some states, policymakers are accelerating regulations to reduce natural gas consumption in order to achieve ambitious climate goals. In June, the New York State legislature passed a major energy bill requiring the state to switch to zero-carbon electricity by 2040. California and New Mexico have already passed similar laws. Since 2005, most power companies have significantly reduced their carbon dioxide emissions, largely due to the switch from coal to natural gas. Although the Trump administration relaxed federal pollution regulations to save coal-fired power plants, in many parts of the country, coal-fired power plants have lost competitiveness compared to other energy sources. David Pomerantz, executive director of the Energy and Policy Institute, an organization that supports renewable energy, recently conducted an analysis examining the long-term plans of 22 of the largest private utilities. Some companies in the Midwest have planned to accelerate carbon emission reductions from now until 2030. However, some large companies, such as Duke Energy and U.S. Electric, predict that carbon reduction will be slower over the next decade than it has been in the past. Mr. Pomerantz stated, "I really think natural gas is key. You've seen some utilities say to natural gas, 'No, thank you, we think there are cheaper and less polluting ways to generate electricity.' But conversely, you've seen other companies fully committed to natural gas power generation." Regarding natural gas plant expansion, last fall, in Northern and Southern California, Duke Energy's utility submitted plans to state regulators to continue closing coal-fired power plants and to replace gas with over 9,500 MW of new natural gas capacity by 2023. "Right now, natural gas remains the most cost-effective option," said Kenneth Jennings, executive director of renewable energy strategy and policy at Duke. He pointed out that the challenge of large-scale solar power is providing electricity even without sunlight. While Duke has installed some large lithium-ion batteries to store solar energy during sunny periods, the company says that using batteries is not as cheap or efficient as using natural gas, and that gas-fired power plants are always operational. Mr. Jennings also stated that using wind power in California is difficult because the state's terrain is not as expansive as the Midwest, and legislature restrictions limit the installation of wind turbines on coastal ridges or near military bases. Duke's plan has sparked opposition, including from environmental groups and local renewable energy companies, who have strongly urged state regulators to reconsider the utility's proposal. These opponents seriously question Duke's analysis, arguing that the company underestimates the potential of solar, wind, and battery capacity. Similar controversy exists in Florida, where the Sierra Club opposes Tampa Electric's plan to replace two older coal-fired power plants with a large new natural gas power plant. The Sierra Club's proposal, requiring governor's approval, argues that Florida's continued reliance on natural gas for power generation cannot withstand climate change and rising sea levels. For Tampa Electric, the choice is complex; the plan mentions increasing solar power to 7% by 2021, but natural gas will remain the mainstay of power generation until solar storage technology improves, primarily to meet the electricity needs of the state's rapidly growing regions. These controversies persist across states. For the past decade, organizations like the Sierra Club have tried to persuade utilities and regulators that while power companies can save costs by replacing coal with low-pollution natural gas and renewable energy sources, these groups oppose natural gas, arguing that the rapid decline in the cost of wind, solar, and battery power necessitates a halt to the construction of new natural gas power plants. So far, the results have been mixed: regulators in Arizona and Indiana have recently blocked plans for new natural gas plants, agreeing with opponents that utilities haven't comprehensively considered alternatives, and that building new large-scale natural gas power plants amidst the rapid development of low-pollution energy technologies is a risky gamble. But last year in Michigan, regulators approved DTE Energy's plans to build a new $1 billion natural gas power plant, ignoring external objections, even though the company could use abandoned plants and save taxpayers money by using wind, solar, and energy efficiency. Meanwhile, some utilities have found that adopting renewable energy is more economically viable. Last year in Indiana, Northern Indiana Public Service (Nipsco) began soliciting bids from external energy developers and found that adding wind, solar, and battery power plants was more cost-effective than building a new natural gas plant to replace coal. (The company continues to operate its existing natural gas plant as a supplement when wind and solar power are not available.) The company estimates that by 2023, its emissions will be 90% lower than in 2005. Nipsco CEO Joe Hamrock said, "We were surprised by this; renewable energy is more competitive than we thought." He pointed out that the company has an advantage that others don't: a prime location for wind development, making it easier to install wind turbines without the need for expensive new transmission lines. He said, "For people 100 miles away, the thinking might be different." In fact, the situation is different for those connected to PJM's vast power grid, which serves nearly 65 million people from Ohio to New Jersey. In this heavily deregulated market, power plants are competing fiercely, with many companies expected to build new natural gas plants totaling over 10,000 MW by 2024, fueled by cheap natural gas produced in Ohio, Pennsylvania, and West Virginia, states known for their fracking technology. "The natural gas revolution will stifle the development of renewable energy," said Stu Bresler, senior vice president of operations and marketing at PJM Interconnection. Wind and solar power account for less than 6% of the region's electricity, far below the U.S. average. State Policy Trends: State legislatures are increasingly focusing on which energy sources to adopt, and so far, 29 states have passed laws requiring power companies to have a certain percentage of wind and solar power generation. Currently, some states are setting longer-term goals. In the past year, states such as California, Colorado, Maine, Nevada, New Mexico, New York, and Washington have passed legislation aiming for 100% zero-carbon power generation by mid-century, meaning the gradual phasing out of traditional natural gas power plants. However, even though many utilities have switched to renewable energy, they say completely weaning off natural gas remains a challenge. Last year, Xcel Energy, which serves eight states including Colorado and Minnesota, announced it would close its remaining coal-fired power plants in the coming years and achieve a completely carbon-free plan by 2050. Renewable energy, with its price falling due to federal subsidies, is a cost-effective option for the company. While the company believes it can reduce carbon emissions by 80% by 2030 through a mix of wind, solar, batteries, and existing nuclear power plants, it will still rely on natural gas to supply insufficient electricity. It is currently building a new natural gas plant in Minnesota to balance supply and demand. Xcel Energy CEO Ben Fowke stated that achieving a cost-effective alternative to natural gas by using 100% carbon-free electricity as a backup fuel requires new technologies. Possible alternatives include power plants burning low-pollution hydrogen instead of natural gas, developing new technologies to collect and store carbon generated by natural gas plants underground, or inventing advanced nuclear power plant or renewable energy storage technologies. The development of these technologies may require significant R&D investment and government support. He added, "But I believe we can achieve our goal."
