Scientists say revolutionary changes in society can limit the worst effects of climate change. None stands out as a candidate for transformation more than the energy sector.

Getting to net-zero emissions there—or close to it—is the easiest way to clear a path for decarbonization in other sectors such as housing and transportation.

Put another way: It doesn’t make much sense to recharge an electric vehicle through an outlet connected to a coal-fired power plant.

“The general idea is to electrify everything and then decarbonize the energy sector,” said Robbie Orvis, the director of energy policy design at Energy Innovation, a San Francisco-based research and analysis firm.

The major challenge for the 2020 Democratic presidential field is that the United States isn’t close to an energy mix that relies on zero- or low-emission sources. And that’s a major hurdle for a sector that accounted for about 28% of U.S. greenhouse gas emissions in 2017, according to EPA data.

The United States generated roughly two-thirds of its power from fossil fuels last year—split mostly between coal and natural gas. Nuclear made up about 19%, and renewable sources such as wind, solar and hydropower constituted another 17%.

The most notable change to this mix in recent years has been the displacement of coal by natural gas. The relatively low cost of gas has hastened the retirements of several major coal plants—including Navajo Generating Station in Arizona, which pumped out as much carbon dioxide annually as 3.3 million passenger cars (Climatewire, Aug. 16).

The switch from coal to natural gas has contributed to a reduction in U.S. carbon emissions, but it comes with its own set of problems. While natural gas emits an estimated 50% to 60% less carbon than coal, it still leaves a significant carbon footprint.

It’s cheap, too. And homegrown.

Which is to say that it won’t be easy or inexpensive to replace fossil fuels in the energy sector.

But former Vice President Joe Biden and Sens. Bernie Sanders (I-Vt.) and Elizabeth Warren (D-Mass.) have a few ideas.

The most direct approach would be to force the United States to change its power mix by adopting a national clean energy standard. Both Sanders and Warren have embraced this tactic.

Warren wants to aggressively remove fossil fuels by requiring U.S. utilities to be 100% carbon neutral by 2030. She would up the ante five years later by requiring “all-clean, renewable, and zero-emission energy” by 2035, according to her climate plan.

Sanders has a similar goal. His plan includes a vow to reach “100 percent energy efficiency and sustainable energy by 2030 at the latest.”

Biden simply calls for a “bold plan to achieve a 100% clean energy economy and net-zero emissions no later than 2050 here at home.”

Several experts said they support the adoption of a national clean energy standard as a means to reduce U.S. emissions.

Old idea, new election

Analysts with the Energy Futures Initiative—a policy shop that counts former Energy Secretary Ernest Moniz as its president and CEO—said this approach could speed up the deployment of transformative energy technologies.

A “national clean energy standard for electricity generation could provide the market-based incentive to accelerate the deployment of innovative clean energy technologies emerging from the R&D process,” they wrote.

Orvis, of Energy Innovation, agreed that a national clean energy standard would be an effective tool, but he warned that 100% decarbonization in the energy sector would be difficult to achieve in a short time.

The problem, he said, is the final 10%. Right now, fossil fuels are the backup plan for when the sun isn’t shining or the wind isn’t blowing.

“It has to do with how you can run the grid reliably,” Orvis said.

Better technology—such as improved battery storage—could change the equation. But the United States isn’t there yet.

An interim step could be the imposition of a renewable portfolio standard, which requires utilities to generate a certain percentage of power from sources such as wind or solar. About 30 states have one—including California, which has found significant success.

“California was an early adopter of the renewable portfolio standards in 2002 and has been a leader in renewable energy ever since; today California leads the United States in renewable energy capacity and generation, and has the most solar generation by percentage, at 13.8 percent in 2016,” wrote Orvis and co-authors Hal Harvey and Jeffrey Rissman in the book “Designing Climate Solutions.”

None of the three candidates has focused much on renewable portfolio standards, though each has vowed to sink billions of dollars into the development of new energy technologies and their deployment. Both Warren and Biden want to spend $400 billion over 10 years on clean energy research. And Sanders’ plan includes a pledge to drop “$1.52 trillion on renewable energy and $852 billion to build energy storage capacity.”

For Warren, one vehicle for that effort is consumer-owned energy cooperatives—a New Deal-era program that helped bring electricity to rural areas. They serve about 42 million Americans, and Warren would use federal dollars to help them transition away from fossil fuels.

“To speed the transition to clean energy, my administration will offer assistance to write down debt and restructure loans to help cooperatives get out of long-term coal contracts, and provide additional low- or no-cost financing for zero-carbon electricity generation and transmission projects for cooperatives via the Rural Utilities Service,” she wrote.

Sanders has a related idea.

He would use existing Power Marketing Administrations, a federal program that oversees hydroelectric dams in 34 states, as a catalyst for clean energy. “We will create one more PMA to cover the remaining states and territories and expand the existing PMAs to build more than enough wind, solar, energy storage and geothermal power plants,” according to his plan.

Democrats divided

The Democratic front-runners don’t agree on everything when it comes to energy policy and climate change.

Both Warren and Sanders want to ban fracking, which has helped to fuel the boom in U.S. natural gas. Biden does not.

Such a proposition likely would result in significant opposition—legal and otherwise—from the fossil fuel industry. “That is completely far-fetched,” said Kathleen Sgamma, president of the Western Energy Alliance. She argued “it would be difficult to ban because states regulate fracking.”

Warren and Sanders also are opposed to an expansion of nuclear energy. Some liberals are opposed to that source of power because of the toxic waste it can generate and its potential to end in radioactive disaster, like the 1986 Chernobyl accident.

“In my administration, we’re not going to build any new nuclear power plants, and we are going to start weaning ourselves off nuclear energy and replacing it with renewable fuels,” said Warren at a CNN climate forum in September.

But Biden and other Democrats such as Sen. Cory Booker of New Jersey have countered that nuclear energy can be an effective tool to fight climate change because it doesn’t produce direct carbon emissions.

“To address the climate emergency threatening our communities, economy, and national security, we must look at all low- and zero-carbon technologies,” said Biden in his climate plan. That includes new research into all facets of nuclear energy, from “cost to safety to waste disposal systems, that remain an ongoing challenge with nuclear power today.”

It’s why the Union of Concerned Scientists warned in 2018 that closing certain nuclear plants could have a negative effect on the climate because it could push power generation toward fossil fuels, at least in the short term.

“Closing unprofitable and marginal at-risk plants early could result in a 4 to 6 percent increase in US power sector emissions,” the group said.

Industry groups have pushed the idea, too. A recent digital ad from the Nuclear Energy Institute sought to “reintroduce” the industry by touting its low emissions.

It’s another question, though, of how effective it would be to build more nuclear power plants to fight climate change. On the one hand, there’s the example of France. The country saw its carbon footprint shrink in the 1970s and 1980s as it expanded the number of nuclear facilities, according to statistics cited by The Atlantic.

On the other hand, it can be expensive. Orvis and his co-authors said a major barrier to using nuclear energy was the cost of building new plants.

“At the time of this writing, renewable energy is often more cost-effective than new nuclear power,” they wrote. But, they added, “the next generation of nuclear reactors may prove much more cost-competitive than today’s reactors, opening the possibility for a significant expansion of nuclear power.”

That includes technology such as advanced small modular reactors. “Advanced SMRs offer many advantages, such as relatively small size, reduced capital investment, ability to be sited in locations not possible for larger nuclear plants, and provisions for incremental power additions,” according to the Energy Department.

Diverting carbon

Nuclear power isn’t the only dividing line among the top Democrats. There’s also division on what to do with emerging technologies such as carbon capture or direct air capture.

Carbon capture is a process in which carbon is prevented from entering the atmosphere—at facilities such as fossil-fueled power plants. Direct air capture is a related procedure in which giant machines suck carbon dioxide directly from the air.

Both technologies have the ability to reduce the amount of carbon dioxide in the atmosphere, but they are not universally loved. Sanders, in particular, is opposed to the procedures because he views them as a way for the United States to continue burning fossil fuels.

“To get to our goal of 100 percent sustainable energy, we will not rely on any false solutions like nuclear, geoengineering, carbon capture and sequestration, or trash incinerators,” wrote Sanders in his plan.

Warren’s campaign declined to comment when asked whether she supported either idea. Biden was much more open to the possibility, noting in his climate proposal that he wanted to “accelerate the development and deployment of carbon capture sequestration.”

To make it work, however, will require significant advances in technology. And the United States hasn’t invested much in the effort. Direct air capture has only received about $11 million in government funding.

But researchers at the Rhodium Group argue that it’s almost impossible to reach net-zero emissions by 2050 without direct air capture.

“We find that even with break-neck electrification of vehicles, buildings, and industry, unprecedented improvements in energy efficiency, completely decarbonized power generation, and [carbon dioxide removal] from enhanced natural sequestration, [direct air capture] technology will be essential for the US to completely decarbonize by midcentury,” they wrote.

But cost is a significant factor.

“The estimated cost of a system that captures 1 million tons of CO 2 per year (roughly 0.02 percent of annual U.S. emissions) was $2.2 billion as of 2011,” wrote Orvis and his co-authors. “Over the plant’s lifetime, the all-in cost is $600 per ton of CO 2 , roughly eight times higher than the cost per ton to capture CO 2 from the flue gas of a coal power plant.”

Reprinted from Climatewire with permission from E&E News. E&E provides daily coverage of essential energy and environmental news at www.eenews.net.