Fans of nuclear energy have been running defense for decades, especially after an earthquake touched off a tsunami that sparked a catastrophic meltdown at the Fukushima Daiichi power plant in Japan, back in March of 2011. However, much has changed in the past 10 years, and one of them is the growing demand for new sources of hydrogen.
Nuclear Energy Loses Luster In US…
The ripple effect of the Fukushima disaster barely dented the thirst for nuclear energy in some nations. Just two years after the meltdown, for example, Saudi Arabia projected it would have 17 gigawatts under its belt by 2032. That target was ditched, but earlier this summer it was back on board with plans for two new nuclear power plants, each with a capacity of 1.4 gigawatts.
Here in the US, though, the outlook for new nuclear energy is rather dim. Less expensive alternatives are at hand in the renewable energy field. Wind farms and solar arrays also take far less time to construct. The US has yet to tap its vast offshore wind resources and the Atlantic coast alone is on a pathway to develop more than 35 gigawatts of offshore wind, even without the ongoing political roadblocks in South Carolina, Georgia, and Florida.
Energy efficiency is another relatively quick fix that will tamp down demand for new nuclear power plants. The heat pump trend is getting a lot of attention these days. There is much more to come through the Bipartisan Infrastructure Law and the newly minted Inflation Reduction Act.
Another source of pressure is national security. The US Department of Energy has been promoting renewables-fueled microgrids and other distributed energy resources as a means of improving energy resiliency and security for military bases, and for the general public. Russia’s murderous rampage through Ukraine also underscores how large, centralized nuclear facilities meant for peaceful use can be weaponized for war.
…And Yet Somehow Clings To Life
As dim as the outlook is for more nuclear energy in the US, the nation’s current fleet is still up and running. The number of commercial nuclear reactors in the US peaked at 104 in 2012 and dropped to 93 by 2021, distributed among 55 power plants in 28 states. However, in an interesting twist, the total capacity of the fleet increased throughout that period, reaching 95,492 megawatts in 2021. According to the US Energy Information Agency, the fleet still holds a 20% share of electricity generation in the US.
Efficiency upgrades and other tweaks account for part of the growth in fleet capacity. Another element to consider is something called capacity factors, which the EIA defines as “the ratio of the electrical energy produced by a generating unit for the period of time considered to the electrical energy that could have been produced at continuous full power operation during the same period.”
The Department of Energy advises not to confuse capacity factor with electricity generation.
“Capacity factors allow energy buffs to examine the reliability of various power plants. It basically measures how often a plant is running at maximum power. A plant with a capacity factor of 100% means it’s producing power all of the time,” they explain, adding that “Nuclear has the highest capacity factor of any other energy source—producing reliable, carbon-free power more than 92% of the time in 2021.”
For those of you keeping score at home, that beats coal and natural gas by a mile (49.3% and 54.4%, respectively), as well as the intermittent sources of wind (34.6%) and solar (24.6%).
The Flexibility Angle
If all this sounds like CleanTechnica is rooting for more nuclear energy, not particularly. In addition to the drawbacks listed above, the water resource issue is moving to the front of the line as climate change draws more intense periods of heat and drought into the picture, and that is shaping up to be another hot mess.
Our friends over at SP Global explain that “climate change-exacerbated water shortage issues pose a near-term and longer-term performance risk to power plants, such as hydropower and nuclear, around the world.”
“And in the Lower 48, more than half of the fossil-fueled and nuclear fleet is located in areas forecast to face climate-related water stress by the end of this decade under a business-as-usual scenario,” they add.
Nevertheless, to the extent that nuclear energy is around now, and will be around for the foreseeable future, there are opportunities to deploy nuclear energy as another tool in energy transition toolbox.
If nuclear power plants could ramp up and down, they could more easily adjust to the intermittent inflow of wind and solar energy into the grid. That kind of flexibility would have been impossible up until just a few years ago. Older nuclear power plants were designed to operate at full capacity all the time. However, the research has shown that, technically speaking, they are capable of far more flexibility than previously thought.
That line of thinking has been pursued by a multinational consortium called the Clean Energy Ministerial, which produced a report on nuclear flexibility and renewable energy integration in 2020. The US Energy Department was among those leading the charge.
“The main takeaway is very clear. Nuclear is more flexible than many of us thought and its FULL potential can be realized by teaming up with renewables to create new hybrid energy systems that could ultimately lead to new jobs, thriving economies and lower emissions,” the Energy Department enthused.
And, That’s Where The Hydrogen Comes In
The elements of capacity factors, reliability, flexibility, and intermittency add more context to an emerging mashup between nuclear energy and hydrogen production, which is being pitched as “clean hydrogen.”
The idea is to fill up gaps in electricity demand by shunting nuclear-sourced kilowatts over to electrolysis facilities, which deploy electricity to boost hydrogen gas from water.
In terms of greenhouse gas emissions, general environmental issues, water resource issues, quality of life issues, and ongoing public health impacts that is an improvement over the primary source of hydrogen in the global market today, which is natural gas.
One recent development in the nuclear-to-hydrogen field involves the firm Bloom Energy.
Last year the company partnered with Idaho National Laboratory in a pilot project aimed at showing how “nuclear energy can be a highly efficient input into [a] solid oxide electrolyzer system for carbon-free hydrogen production.”
“When the electric grid has ample power, rather than ramping down power generation, the electricity generated by nuclear plants can be used to produce cost-effective hydrogen in support of the burgeoning hydrogen economy,” Bloom explained.
Bloom introduced its solid oxide electrolyzer just two years ago and it looks like they’re already off to the races. The latest thing in electrolyzer systems is a high-efficiency, high-temperature process.”
“Bloom Energy’s electrolyzer has a higher efficiency than low-temperature electrolyzer technologies, thereby reducing the amount of electricity needed to produce hydrogen,” they explain.
That’s not as simple as it sounds. The plan is for INL to deploy its Dynamic Energy Testing and Integration Laboratory to simulate the operation of Bloom’s electrolysis design in concert with nuclear energy.
“The high-temperature electrolyzers take advantage of both the thermal and the electrical power that are available at nuclear power plants,” said Tyler Westover, the Hydrogen and Thermal Systems Group lead at INL. “This expands the markets for nuclear power plants by allowing them to switch between sending power to the electrical grid and producing clean hydrogen for transportation and industry energy sectors.”
So far, so good. Earlier this month Bloom announced the initial results of the pilot project.
“With nearly 500 hours of full load operation completed at the laboratory, Bloom’s high-temperature electrolyzer is producing hydrogen more efficiently than other commercially available electrolyzers, including PEM and alkaline,” they stated.
“Running at high temperatures and high availability, the pilot results reveal the Bloom Electrolyzer is producing hydrogen at 37.7 kWh per kilogram of hydrogen and with 88.5 percent LHV (Lower Heating Value) to DC. Dynamic testing has also been conducted and included ramping the system from 100 percent of rated power to 5 percent in less than 10 minutes without adverse system impacts,” they added.
Nuclear energy is not out of the woods yet. For that matter, concentrating solar power systems are emerging as a resource for high-temperature electrolysis systems. If you have any thoughts about that, drop us a note in the comment thread.
Follow me on Twitter @TinaMCasey.
Image: Solid oxide electrolysis systems courtesy of Bloom Energy.
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