The National Solar Thermal Test Facility operated by the Energy Department’s Sandia National Laboratory in Albuquerque, New Mexico.
Wind turbines and solar panels have finally surged into the mainstream of the U.S. energy profile, but that doesn't mean the renewable energy field has fully matured. Vast new clean power resources are yet to be tapped, and the U.S. Department of Energy is leveraging its financial muscle to lift new, sustainable energy systems from the design table to commercial production.
Concentrating solar power plants do just what the name implies. Using specialized mirrors, they pull sunlight from a range of inputs and concentrate it on a central point. The result is a powerful blast of heat that can be transferred to a liquid medium, such as molten salt or a specialized oil.
The heated medium can be used to supply clean power for industrial processes that require high temperatures. It can also be sent to a boiler room to produce steam to generate electricity.
Concentrating solar systems are large, complex and expensive compared to conventional arrays of solar panels, but they do have a key advantage. The heated medium acts as a built-in storage reservoir, enabling the solar energy to keep working long after the sun goes down.
These solar-thermal systems are gaining traction as a clean power solution in some parts of the world, but they have been slow to catch on in the U.S. The U.S. Energy Department showcased a group of five concentrating solar projects during the Barack Obama administration, but investor follow-through did not materialize after the White House changed hands.
The apparent lack of private-sector interest did not deter the Energy Department. During former President Donald Trump’s first year in office, the agency launched a $100 million research effort called Gen3 CSP — which aimed to drive down the cost of solar-plus-storage to 5 cents per kilowatt-hour, with facilities in the range of 100 megawatts capable of delivering clean power on a 24/7 basis. At that scale, concentrating solar systems would replace conventional fossil energy power plants and nuclear energy, too.
There are two key, intertwined differences between the Gen3 program and the Obama-era projects. One is the use of ceramic particles instead of molten salt. The ceramic formula can withstand higher temperatures of more than 800 degrees Celsius.
That high temperature calls the second key element into play. The range of 800 degrees Celsius enables the storage medium to power a turbine that runs on a fluid state of carbon dioxide instead of conventional steam. These “supercritical CO2” turbines are much more compact and efficient than conventional turbines, leading to the potential for reducing costs.
Gen3 passed a significant milestone last month when the Energy Department’s Sandia National Laboratory broke ground on the construction of a pilot project at the National Solar Thermal Test Facility in Albuquerque, New Mexico. Researchers in Saudi Arabia and Australia are also contributing to the pilot project, which is on track for completion in 2024.
Another emerging clean power technology to watch is the area of synthetic liquid fuels. Until recently, synthetic hydrocarbon products were made by liquifying coal, gas or other fossil energy inputs. The next generation of synthetic fuels revolves around electrofuels, which are made from captured carbon and green hydrogen.
Much of the activity in the green hydrogen field is centered on electrolysis systems that push hydrogen gas from water with electricity from wind turbines, solar panels or other renewable resources. Of particular note is the offshore wind industry, which is beginning to adopt green hydrogen systems as a complementary technology that puts wind turbines to use at night and at times when demand for electricity normally drops.
The carbon-capture field is also showing signs of moving out to sea. Conventional carbon-capture systems are designed to process ambient air or industrial gases on land. However, researchers note that seawater is already a carbon-capture medium, holding up to 150 times more carbon than air by volume.
Supported by a $650,000 grant from the Energy Department’s ARPA-E funding office, a research team from the Massachusetts Institute of Technology has proposed an offshore seawater carbon extraction system that could be used to help prevent the over-carbonization of seawater from fish farms and other aquaculture activities. The team also makes a case for attaching the system to desalination facilities, and they anticipate that cargo ships could install the system to offset their carbon emissions.
If the MIT system achieves widespread use, the researchers anticipate it would capture far more carbon than existing markets can absorb. Most of the captured carbon would have to be stored in underground formations, they presume.
However, activity in the green hydrogen field shows no signs of slowing down. That presents an opportunity to use the captured carbon for electrofuel systems, which could be located offshore as well as onshore. Recycled-carbon markets — which utilize captured carbon to create raw materials for new products — are also emerging in the plastics and synthetic fabric industries, among others.
The Energy Department seems determined to ensure the supply of captured carbon is sufficient to feed these growing markets. On Feb. 16, the agency’s ARPA-E energy innovation office announced a new $45 million funding program aimed at supporting the development of a commercial seawater carbon extraction industry.
The U.S. Navy has also been providing financial support in the seawater-to-fuel field. That includes a collaboration with the University of Rochester, the University of Pittsburgh and the company OxEon Energy. In 2020, the team demonstrated a new catalyst to convert captured carbon dioxide to carbon monoxide, a necessary step toward producing liquid fuels from gases. OxEon has also received Energy Department funding to develop its technology.
Additionally, in 2022 the Navy awarded $3 million to the University of South Carolina to work on systems for producing ammonia fuel with hydrogen extracted from seawater.
Geothermal resources are the sleeping giant of U.S. clean power production, limited to just a few parts of the country by suitable subsurface opportunities. The Energy Department has been working with academic researchers and industry stakeholders to develop a new approach called enhanced geothermal, which involves engineering human-made reservoirs in subsurface formations.
In February, the agency launched a new $74 million grant program for enhanced geothermal systems aimed at unlocking the potential for at least 90 gigawatts of geothermal energy by 2050 over wide areas of the U.S. In comparison, the nation’s current geothermal capacity rests at only 3.7 gigawatts.
Alongside the rapid increase in geothermal development, the Energy Department is also targeting a game-changing 90 percent drop in costs by 2035. “Investments in [enhanced geothermal systems] can unlock affordable clean energy for over 40 million American homes and exponentially increase opportunities for geothermal heating and cooling solutions nationwide,” according to the agency.
The work in geothermal comes under the DOE's “Energy Earthshots” program, the Joe Biden administration’s signature program for accelerating the clean power transition in tandem with new job creation and more equitable economic development opportunities.
Including the geothermal program, Earthshots has already launched six initiatives that pair private-sector partners with research teams and federal financial resources. The five other programs involve green hydrogen, long-duration energy storage, carbon-negative technologies, floating offshore wind turbines, and new approaches for industrial heat.
Leadership in the Republican Party may continue to rail against “woke capitalism” and advocate for a government “so small you don’t even realize it’s there,” as the Republican National Committee tweeted on March 2. However, that ship has clearly sailed. U.S. businesses and innovators are moving on to create a new energy paradigm with the collective support of U.S. taxpayers, regardless of anything that opportunistic Republican leadership can say or do.
Image credits: Sandia Labs/Flickr and U.S. Department of Energy
Tina writes frequently for TriplePundit and other websites, with a focus on military, government and corporate sustainability, clean tech research and emerging energy technologies. She is a former Deputy Director of Public Affairs of the New York City Department of Environmental Protection, and author of books and articles on recycling and other conservation themes. She is currently Deputy Director of Public Information for the County of Union, New Jersey. Views expressed here are her own and do not necessarily reflect agency policy.