During a recent conference in Flagstaff, Ted Geisler, President of the Arizona Public Service (APS), spoke to community officials about the energy company’s goal of becoming fully carbon-free by 2050.
The plan involves a heavy reliance on three key factors: nuclear power, new technologies and natural gas.
The push to make the state zero-carbon by 2050 stemmed from a 2020 proposal by the Arizona Corporation Commission that would require a transition similar to that seen in neighboring states like Colorado and New Mexico. Despite initial bipartisan support, the proposal was amended, extended to a 2070 due date, but eventually rejected outright by Republican utility regulators earlier this year.
Despite this, APS has publicly committed to a 2050 goal, including a complete phase-out of coal by 2031. According to Geisler, carbon-free energy resources are not only “the most affordable,” but are in the “general interest” of society.
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“As the state’s largest utility, we have an obligation to respond to our customers’ needs,” said Geisler. “And that means we need to responsibly transition our power generation fleet to zero-carbon over time.”
Currently, APS generates 11,719 megawatts (MW) of electricity for Arizona, with 5,146 MW coming from nuclear, microgrids, and renewables such as solar and wind. The other 6,573 MW comes from natural gas and coal – both contributing to CO2 emissions.
To complete the zero-carbon transition, APS needs to increase energy production from sources such as nuclear and renewables. Nuclear power, as embodied in the Palo Verde nuclear power plant, will be a key element of that transition, Geisler said.
“Palo Verde now supplies 70% of our region’s carbon-free energy,” he reported. “It’s the state’s largest individual taxpayer, is 100% carbon-free, and is actually four times less carbon-intensive than solar when you look at the full life cycle of a resource.”
He added: “Without Palo Verde, we will not achieve a zero-carbon future.”
Uranium mining in Arizona, which drives nuclear energy, has been the subject of controversy, most recently addressed by the Grand Canyon Protection Act, which aims to ban uranium mining on over a million acres of northern Arizona state. Regional bans like these would not affect APS, Geisler said.
“We do not rely on uranium being sourced locally to fuel Palo Verde,” he said.
He was unwilling to disclose Palo Verde’s uranium source, but claimed that they are “strongly supportive of continued uranium mining.” According to the US Energy Information Administration, in 2021 the US imported most of its uranium from Kazakhstan (35%), Canada (15%), Australia (14%) and Russia (14%).
Natural gas is the other “critical transition fuel,” Geisler said.
While not inherently carbon-free, natural gas is “significantly lower-carbon compared to coal-fired power plants” and, like nuclear power, will help “ensure reliability while introducing such a high level of new renewable technology to the grid.”
APS currently generates 5,216 MW – almost 45% of its total energy – from natural gas.
One of the reasons natural gas is such an important resource in power generation is that it’s “flexible,” Geisler said, meaning APS can use it as a “shock absorber” when power grid demands fluctuate.
“We relied on that [natural gas] especially now that we are withdrawing from coal and expanding our clean portfolio,” said Geisler. “But maintaining reliability during this period will be crucial.”
The final piece of the puzzle is new technology that will help renewable sources work on a larger and more reliable scale, Geisler said.
A key example is the widespread implementation of battery storage systems that can store solar energy to provide reliable solar power to the power grid even after the sun has set.
“By the end of this year we will have around 300 megawatts of new storage on the grid,” said Geisler. “And we expect that number to increase to nearly 3,000 by the end of the decade. Storage is becoming more and more affordable.”
New technologies are also part of what Geisler called “the nuclear renaissance.”
“I’ll never see a large nuclear power plant like Palo Verde being built again,” said Geisler. “But there’s a lot of interest and investment in small nuclear, small modular reactors, which we call SMRs.”
According to Geisler, SMRs can be mass-produced, are easy to ship, and can generate 400-500 MW each.
“This can be a beautiful technology for us in the future,” he said, adding that nuclear SMRs would not “crowd out” renewable energy but contribute to a “diverse portfolio” of carbon-free energy sources.
Natural gas is also about to undergo a technological overhaul, said Geisler.
Existing natural gas plants could potentially be converted to run on hydrogen.
“We’ve partnered with Idaho National Labs and other utilities and are developing a small hydrogen production facility in southern Arizona,” Geisler said. “The intent is to study how using a hydrogen fuel source works in a natural gas fleet.”
As promising as new technologies are, don’t expect APS to be up to date, Geisler said. In some cases, like SMR, he expects to wait “8 to 10 years” to let other companies develop and implement new technologies.
“Frankly, Arizona isn’t big enough to take risks on new technologies like this,” Geisler said. “We don’t want to risk your dollar for that either.”
The technology to support zero-carbon energy isn’t a risk, it’s already established, said Tom Acker, director of the Sustainable Energy Solution Group at Northern Arizona University.
The transition to 2050 is “very feasible,” said Acker.
“The technologies there actually already exist in a form that could work,” he said. “Utilities just don’t have a lot of operational experience with it. You need to gain experience and confidence.”
Acker also mentioned that while technological advances in nuclear energy — like SMR — may be entering an affordable and functional future, the industry still doesn’t have a solution to the waste.
Nuclear waste can remain dangerous for thousands of years, Acker said, and that should be a concern.
“It’s not necessarily the economics of nuclear power that will be their biggest challenge,” he said. “The biggest challenge is where to implement it. Since we don’t have a long-term storage facility, the waste will be on site. Whatever waste a nuclear facility produces, it will likely have to store it indefinitely.”
To gain the lead
Not only does the technology exist, Arizona has the potential to become a “world leader” in renewable solar energy, said Karla Morales, vice president of the Arizona Technology Council’s southern regional office.
For Morales, Arizona not only has “an abundant natural resource” of sunlight, but also university-level research initiatives, technical prowess at utility companies, and “high energy demands to grow our homes and buildings and grow the electric vehicle market.” .
“I think we have the perfect environment,” Morales said. “We could really be a leader in solar energy.”
Arizona’s natural and technological environment is so perfect, Morales said, that the APS timeline to go carbon-free by 2050 is “reasonable,” but she would “push that we move a little bit faster.”
The impact of accelerating the zero-carbon transition could be “massive,” Morales said, “in terms of job creation and local economic growth. There are just so many options.”