Andrew J. Van Horn Ph.D., Director of Applied Research, GreenFire Energy
California was burning and the western U.S. baking, leading to high electricity demands that taxed generation resources throughout the West. On Friday, August 14, 2020, the California Independent System Operator (CAISO) reported that a 750 MW unit was offline, and a 475 MW natural gas-fired generator went down. Out-of-state imports were constrained, partly because imported power was needed in other states and was not under firm contracts to California. On Saturday, August 15, cloudy and smoky conditions reduced solar generation across the state and breezes were erratic. At 4 pm wind generation increased, requiring other generators to back down quickly, but after 5 pm, about 1 GW of wind stopped blowing, requiring available power resources to ramp up quickly as the sun went down. At 6:13 pm, a generator ramped down quickly from 400 MW due to a scheduling mistake by PG&E. At that point CAISO didn’t have enough of its own capacity for ramping up to meet net load and couldn’t access sufficient imports to avoid a Stage 2 alert. Stage 3 conditions were announced only 9 minutes later. On both Friday and Saturday at about 6:30 pm PDT, load shedding/rolling blackouts were instituted. A continuing 100+ degree heat wave and high loads were forecast, and CAISO issued an Intent to Solicit and Procure Additional Capacity. CAISO also reminded power purchasers not to under-schedule loads in the Day-Ahead market.
Why is California sometimes short of power? There are many reasons and many factors that contributed, including 1.) Heat waves across the West that increased loads and reduced California’s ability to import out-of-state power, when California generators went down, and the wind stopped blowing. 2). A lack of diversity in grid resources added over the last decade, combined with the retirement of the San Onofre nuclear plant and reliance on aging natural gas plants mandated to be retired too soon, before replacement with flexible, dispatchable capacity. This has led to relative over-dependence on intermittent, non-dispatchable wind and solar power plants that require huge late afternoon ramp-ups by the existing older natural gas-fired plants, every day when the sun goes down. 3.) Misplaced regulatory emphasis on “least-cost, best-fit” metrics to develop generation portfolios and add new capacity, along with the failure to consider how to avoid potential adverse impacts (i.e., unpriced externalities) of “worst-case” scenarios that weren’t examined extensively in regulatory proceedings. In its proceedings the California Public Utilities Commission (CPUC) defined procurement mandates for specific technologies to meet “resource adequacy” capacity needs that it determined based on California Energy Commission(CEC) demand forecasts. 4.) Slow implementation and integration of a truly western regional grid, of demand response measures and distributed energy resources. All these take time to implement. 5). The failure to heed some of the key “lessons learned” from California’s 2000-2001 electricity crisis. 6). Other interactions that contributed to the August 14-15 “perfect storm.”
Despite significant changes to our electric system, it is easy to forget that our electric infrastructure is long-lived, capital intensive with lots of equipment beyond originally planned lifetimes and that can’t be entirely revamped in just a few years. One proposed panacea, expensive advanced battery storage, can’t supply energy for longer than four hours and must be replaced and safely disposed of in about 10 years. Like Northwest hydro generation, short-term and seasonal storage is energy-limited.
Have we properly protected our essential electrical system from foreseeable events? What events should be examined more closely? Consider climate change, heat waves, fires and falling trees in forests, or less predictable occurrences, like explosions in natural gas pipelines, gas storage field releases, earthquakes, cyber attacks on the grid, terrorist acts, EMPs, or volcanic eruptions that affect global weather, which in the past have obscured the sun for months. It should be evident that our electrical energy system requires integrated risk assessments and more diverse, fuel secure, resilient, 24/7 reliable generation resources. Are we doing enough RD&D on reliable clean energy technologies? If so, when might we be able to deploy advanced technologies, and how should we pay for them? Are we properly coordinating supply and demand-side options and appropriately modifying wholesale and retail rate designs? Energy and environmental transitions are not easy. It is difficult, but necessary, to examine the timing and interactions of all the elements of our increasingly complex energy system.
What if there were already environmentally preferred resources that could keep our lights on, when intermittent and energy-limited generators are not available? Fortunately, such a resource is already in place, dependably supplying power during all California’s blackouts and ready to expand, as necessary. The CAISO graph shown above for August 15, 2020 demonstrates that California’s most dependable carbon-free renewable resource is geothermal power.
Clean, secure and reliable geothermal energy uses Earth’s abundant heat to generate around the clock, producing electric power and direct heat in worldwide locations. As of year-end 2019, geothermal power generation is being used in 27 countries with 15.4 GW capacity. California remains a world leader with an installed capacity of 2.7 GW in 43 operating geothermal power plants, but it has been almost a decade since a new geothermal plant came online in the state.
In addition to current geothermal power plant designs, recent advancements have made possible closed-loop geothermal (CLG) energy systems, as described in PIVOT 2020 (https://www.texasgeo.org/pivot2020). CLG can produce power from previously unproductive geothermal and oil and gas wells and help balance and stabilize the electric grid. Because CLG can operate in a broader range of temperatures and rock compositions than conventional hydrothermal projects, CLG not only expands the potential supply of clean, carbon-free geothermal power, but does not require fracking and brings versatility by supplying both heat and power to significant new applications.
As examples, CLG can be used to increase the efficiency and reduce the costs of high-value industrial applications, such as hydrogen production, desalination, and lithium extraction. These are all applications that could occur in California, especially in the Salton Sea geothermal area. More geothermal energy could displace fossil energy, charge a growing fleet of electric vehicles, and help countries around the world meet their global greenhouse gas reduction goals.
Renewable CLG technologies require the creation of a sealed well or multiple wells drilled into the subsurface geothermally hot rock strata. These enable a heat transport working fluid to continuously circulate in a sealed pipe (or pipes) and absorb heat, which can then be delivered to the surface. CLG can go much deeper and hotter than conventional hydrothermal projects. Because it only extracts heat, CLG does not produce unwanted substances, does not require fracking and will not cause seismicity.
In 2019, GreenFire Energy’s CLG system was demonstrated at Coso, California for applications in hot dry rock. This successful demonstration extracted heat from an existing unproductive well at the Coso geothermal power plant, separately testing water and supercritical carbon dioxide as working fluids. (California Energy Commission report, CEC-300-2020-007, June 2020.) Eavor Technologies is developing a closed-loop multilateral-pipe energy system for power and district heating. Its demonstration project was done near Rocky Mountain House, Alberta, Canada in 2019. Eavor is now embarking on a project to provide direct heat and power in Germany. Other CLG system projects are being proposed in Asia, Europe, and North America to increase power generation at under-producing geothermal wells and to retrofit oil and gas wells for power production and pumping.
Geothermal energy can help reduce the current high cost of producing green hydrogen and extracting lithium. CLG technologies can be applied to several hydrogen production methods to increase efficiency, reduce costs and improve safety by using geothermal power and heat in various production stages. CLG also offers a fundamentally different approach to simultaneous power generation and lithium extraction, when the CLG system is designed to bring geothermal brine to the surface, while also producing power in a closed-loop system.
Today, both conventional and innovative closed-loop geothermal energy systems are poised to make significant contributions to global energy and environmental needs and to increase employment in the clean energy sector. Now is the time to develop and demonstrate different CLG energy systems and to accelerate its commercialization for power production and high-value applications. CLG applications for electric power generation, hydrogen production and lithium extraction are described in a forthcoming paper: New Opportunities and Applications for Closed-Loop Geothermal Energy Systems to be published in GRC Transactions. In addition, CLG will be discussed in the virtual Geothermal Resources Council Annual Meeting on October 18-23, 2020.