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Even as public officials in the state bend over backwards to protect fossil energy interests, the renewable energy knights continue to work in Texas. Lately, Texas has established itself as a potential market for new concentrated solar energy technology that can produce electricity or industrial process heat on a 24/7 basis, regardless of what the sun is doing.
Texas is still a coal state…
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Anytime renewables beat out fossil fuels is big news, especially in Texas, where oil and gas anchor the economy. The state’s coal industry is no slouch either. In a summary of the state of coal last year, Texas State Comptroller Glenn Hegar noted that Texas is the No. 2 largest producer of lignite coal in the U.S. by 2022, second only to North Dakota. For all types of coal, Texas ranked a respectable #7.
The U.S. Energy Information Agency also notes that Texas is the largest consumer of coal in the U.S., and much of it comes from coal mines within the state. “On a ton basis, Texas lignite accounts for almost one-third of the state’s coal consumption,” the EIA explains.
The EIA further notes that almost none of Texas’ lignite is exported to other states. All this refers to the generation of electricity in domestic power plants.
By 2023, Texas had 15 coal-fired power plants, Hegar said. With a capacity of almost 20,000 megawatts, they accounted for almost 11% of the electric grid operated by the Electric Reliability Board of Texas, which covers 90% of the state.
… But the Sun Comes Strong…
How things have changed in one year. The organization Institute for Energy Economics and Financial Analysis (IEEFA) looked at the latest figures for March 2024. They released two reports that bode ill for the future of coal power in Texas.
“First, solar generation surpassed coal generation for the first time in any month, sending 3.26 million megawatt-hours (MWh) to the grid, compared to 2.96 million MWh supplied by coal,” IEEFA said.
“Secondly, coal’s market share fell below 10% for the first time to just over 9%. “The decline continued a long slide that began a decade ago, while noting that solar’s market share rose above 10% in the same month,” they said.
March’s numbers are all the more impressive given that the sun has been far less visible on the ERCOT display over the years. In 2017, it accounted for only 0.6% of all electricity demand.
… And Here Comes a New Generation of Concentrating Solar Energy
The solar industry can’t take all the credit for pushing coal aside. Natural gas began competing with coal for ERCOT grid dominance years before the solar industry entered the scene.
In another interesting twist, Texas voters last November approved Proposition 7, a ballot measure that created a new state fund aimed at supporting the construction of additional thermal power plants. Most of the money is said to be earmarked for new natural gas power plants.
Proposition 7 throws another element into the mess of the ERCOT network, which is already groaning under the weight of seasonal demand swings, weather-related emergencies and a rapidly growing population. .
To add more fuel to the fire, Proposition 7 funds cannot be applied to battery maintenance. That’s bad news for renewable energy producers who depend on energy storage to make up for bumps in wind and solar availability.
One solution proposed by the Baker Institute, a public policy organization hosted by Rice University, is to reconfigure ERCOT to optimize coordination between wind farms and photovoltaic arrays, helping to fill gaps in wind and solar energy resources.
The role of CSP
New geothermal energy technology is another renewable energy source with growth potential in Texas. Still, the missing link is a long-term, utility-scale energy storage platform that can transform the state of wind and solar power into a 24/7 dispatchable resource at the level of conventional power plants.
Lithium-ion battery arrays fill in the gaps, but they only provide a limited amount of time, typically 4-6 hours. The search is on for longer-term solutions that can accommodate increased wind and solar resources.
Concentrated solar power fits the bill. Concentrating systems collect and focus solar energy from special mirror areas or long, curved holes called heliostats. The goal is to create high heat in a solution of molten salt or other medium, which can then be sent to a generating station to run steam-driven turbines. The heated solution also works as an energy storage platform, easily beating lithium-ion batteries for eight hours or more.
The U.S. Department of Energy unveiled five concentrated solar projects during the Obama administration in hopes of jump-starting the domestic CSP industry. The technology has been adopted elsewhere in the world, even in desert environments where keeping the collectors clean adds another layer of cost.
The US solar industry was less enthusiastic, but the Department of Energy found a solution to attract investors’ attention. They focused on next-generation technologies that increase heat and reduce the physical footprint of concentration systems.
The main thing is that supercritical carbon dioxide is used instead of steam to run the turbines. When heated and pressurized to a critical state, carbon dioxide turns into a liquid state. According to the Department of Energy, sCO2 can run turbines about 10% more than steam.
Next Generation CSP could be the next big thing in Texas
On top of the increase in efficiency, there is a surprising reduction in the size of the turbine. As the Department of Energy describes, an sCO2 turbine is about 1/10 the size of a conventional turbine. In addition to saving on materials and manufacturing costs, smaller turbines allow larger areas to be considered for concentrating solar systems, with industrial facilities being a leading example.
This would be a good fit for Texas, where the industrial sector accounts for a significant portion of energy consumption.
“Texas leads the nation in energy consumption across all sectors and is the nation’s largest energy consumer,” the U.S. EIA reported last summer. “The industrial sector, including the state’s oil refineries and petrochemical plants, accounts for more than half of the state’s energy consumption and 23% of the country’s total industrial sector energy use.”
And here it gets interesting. Concentrating systems fall into the dispatchable category, so it is possible that they may be eligible for financial support under Proposition 7. As it happens, the Department of Energy’s new sCO2 showcase is just getting underway in San Antonio, Texas. The plant will be operating at full capacity in the next few months.
Texas firm GTI Energy is a project partner and they have good things to say about the sCO2 system. “It can operate using a wide range of low- and zero-emission heat sources, including gas turbine, concentrated solar power, biomass combustion, geothermal and nuclear sources, and support grid stability and resilience by quickly responding to changes in energy demand. driving industrial decarbonisation.
Interesting! In the latest development, the Department of Energy announced a new $30 million round of funding for new concentrated solar projects in three subject areas designed for new sCO2 turbochargers. The awardees will be tasked with laying the groundwork to reach US$0.02 per kilowatt-hour of thermal energy and US$0.05 per kilowatt-hour of electricity by 2030.
Consider California CSP firm Heliogen. In 2020, the startup received $39 million to combine a ceramic particle CSP system with sCO2. Last December, the company announced a milestone for its highly efficient heliostat tracking software, which it plans to license to the CSP industry.
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Image: California firm Heliogen is developing a next-generation ceramic particle concentrating solar energy system that can run a sCO2 system to decarbonize industrial operations (courtesy of Heliogen).
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