Geothermal Power in Oregon-Part II

In Geothermal Power in Oregon – Part I, we explained how geothermal energy works and gave an overview of past, present and potential Geothermal Projects in Oregon. Part II aims to outline the advantages and disadvantages of geothermal power as well as give a brief summary of the future outlook for geothermal energy.

Advantages

Despite there being very few known high temperature geothermal resources in Oregon, there is ample reason to develop geothermal power. Geothermal has a high capacity factor and provides dependable base-load power that can be used to replace coal-fired power plants, which means that actual power production is usually very close to a plant’s rated capacity. This reliable form of renewable energy is more valuable to utilities than variable resources like solar and wind.

Geothermal energy also has environmental advantages, such as a small footprint and low emissions. Geothermal power plants are smaller than coal plants and do not require coal mining or coal transportation infrastructure, and unlike utility-scale solar and wind, geothermal plants only require the space directly surrounding a geothermal well. Geothermal plants use 1-8 acres of land per MW installed, compared to 5-10 acres for nuclear, 19 acres for coal, 4.5-13.5 acres for solar, and 60- 85 acres for wind. In addition to using less space, many geothermal power plants produce nearly zero emissions, since binary systems can inject well water directly back into the ground in a closed loop. Carbon emissions from open systems vary greatly depending on the source, but generally speaking are less than 5% of what is emitted to produce the same amount of electricity using coal.

Disadvantages

Of course, geothermal energy also has limitations and risks associated with it. The biggest constraint to geothermal energy is location. Piping hot water over long distances is not economical, so geothermal applications must be located very close to the resource. Geothermal power plants can be connected to the grid, but are often in remote areas that require significant investment in transmission and interconnection facilities. Geothermal development can also pose a threat to aesthetic quality, since resources are frequently located near geological features or scenic areas.

Because location is a major consideration, land ownership and property rights also play a major role in geothermal developments. There are numerous geothermal resources on public property, but there are significant legal and administrative challenges to developing a project on public property. The application for developing geothermal on public property can take many years to complete and does not always result in approval. Developing geothermal applications on private land is less complicated, but known geothermal resources exponentially increase the value of land and the cost to acquire it. In Oregon, a large majority of land is public; however, both the Neal Hot Springs and Crump Geyser projects are being developed on private property.

In addition to being limited by resource location and availability, there are other risk factors present for developing geothermal power. The cost to drill a single exploratory well to confirm that a significant heat source exists in a certain location can run between $2-5 million. Since there is no way to predict the temperature of a geothermal resource until an exploratory well is sunk, up-front costs to identify and confirm geothermal properties are very high. Even if a geothermal resource is confirmed, a long-term power purchase agreement must be signed to ensure that the project will be financially viable. According to the U.S. Department of Energy, geothermal power plants cost around $2,500 per installed kW and require a power purchase rate of approximately $0.05 per kWh to be commercially viable.

Building and operating a geothermal system also poses a risk of seismic activity, or seismicity. This is not only dangerous to the geothermal operation, but to the entire area. Geological surveys and studies may indicate that there are no active faults in the area, but dormant fault lines may be triggered due to the operation of geothermal energy systems. There is a risk that earthquakes could be induced by geological changes from harnessing geothermal energy, so safety must be a top concern while developing geothermal power.

Future outlook

Available technology is only capable of capturing a small fraction of the near infinite supply of geothermal energy. Current research is focused on drilling deeper wells to access more heat at higher temperatures, increasing the permeability of dry rock to create new reservoirs or to enhance existing resources, expanding permeable area to increase reservoir size, and utilizing lower temperature heat to generate electricity. While new technology is developing, it is important to continue utilizing direct-use systems, as new power plants may be slow to develop. Expanding direct-use geothermal systems is particularly important in Oregon, where there are known low to moderate temperature resources that can be utilized to provide proven energy and cost savings.

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