Geothermal Grid Integration
NREL works with industry partners to optimize strategies for effectively interconnecting renewable generation with the electric power grid.
As more variable renewable generation resources are added to the electric grid, NREL is demonstrating how geothermal can bring value in the areas of cybersecurity, flexible generation, storage, and additional grid services.
Beyond Levelized Cost of Energy
As the penetration of variable renewable energy resources such as wind and solar increases, the relative net value of geothermal projects to overall grid operations changes, making levelized cost of electricity (LCOE) alone a poor indicator a project's true value. Although LCOE is a necessary component, additional models that take into account grid makeup and operation are needed to assess the true value of a geothermal project. NREL researchers are developing methodologies and performing analyses that move beyond LCOE as the metric for evaluating geothermal projects and assess the true or “net” value to the grid.
NREL's cybersecurity research is strengthening our grid against tomorrow’s threats. It spans the fundamentals—from cryptography for distributed energy systems to cybersecurity industry standards for interconnecting new devices. With billions of new intelligent, connected electronics entering our grid every year, diligent focus on cybersecurity for an evolving grid is crucial.
Flexible and Hybrid Generation
Geothermal can provide flexible, baseload power to a national or regional grid. Flexible operation can be achieved through advanced well flow control, power system configuration, and adoption of surface energy storage systems.
In a future grid with a high penetration of renewable energy, geothermal is also well positioned to provide value in hybrid energy systems. It can be directly integrated with solar thermal technologies (such as concentrating solar power) and fossil fuel power generation and co-located with other flexible or nonflexible renewable energy technologies (such as PV and wind) to provide a more resilient hybrid energy system.
NREL led an analysis of geothermal sector cybersecurity vulnerabilities and risks, which are relevant to achieving the technological advancements and expected sector growth outlined in the 2019 GeoVision Study. This analysis is a proactive effort to enhance cybersecurity in geothermal development and operations. As the geothermal industry grows, the cybersecurity strategies to be deployed will be of increasing importance to ensure resilient, reliable, and secure clean energy for years to come.
Of the eight vulnerabilities analyzed, the review identified reservoir data system monitoring as one that is unique to geothermal systems and may warrant further investigation to better understand risk and mitigation. A detailed analysis of the other vulnerabilities may highlight additional uniqueness or solutions relative to other industries.
This project identified areas to enhance cybersecurity in geothermal development and operations. It offers pathways that may improve risk quantification and enhance cybersecurity preparedness of the sector.
Lawrence Berkeley National Laboratory, Kitzworks LLC
In Assessing Geothermal/Solar Hybridization – Integrating a Solar Thermal Topping Cycle into a Geothermal Bottoming Cycle with Energy Storage, NREL evaluated solar thermal hybridization for geothermal production improvement. With the assistance of real-time operational data at multiple geothermal power plants, researchers developed and optimized advanced power cycles to accommodate brown-field and green-field geothermal power systems with solar thermal hybridization.
Analysis shows that a geo/solar thermal hybrid system with a thermal storage component may be economically superior to a PV system with batteries.
In this project, NREL evaluated the technical and economic benefits of hybrid power generation by combining geothermal energy with concentrating solar power technology. The work used data from the Stillwater geothermal-photovoltaic hybrid plant in Fallon, Nevada. Modeled results achieved a 5% reduction in the levelized cost of energy (LCOE) by using a retrofit geothermal-solar hybrid plant. The magnitude of the results is dependent on resource productivity, power purchase agreement penalties, solar collector array costs, and solar array installation parameters. The results also indicate that further savings are possible if reduced risk associated with the solar heat source translates to more favorable pre-operation project financing terms. Federal and state renewable energy incentives or tax credits could further decrease LCOE. Additional work is planned to evaluate commercial opportunities and alternatives for geothermal/solar hybrid systems.
The positive results demonstrated could enhance deployment of clean, renewable energy technologies in regions where geothermal and solar resources overlap.
Idaho National Laboratory, Enel Green Power
NREL works with industry partners to design and model widespread, cost-effective, and grid-friendly geothermal power plants that will enable the deployment of geothermal across the entire United States. NREL's geothermal capabilities run the gamut from analysis to downhole tools and sensors and from reservoir modeling to full-scale field research validation.
These capabilities also support NREL's geothermal grid integration activities: