Southern Utah Geology & Geothermal Power Plants

34 GRC Bulletin l www.geothermal.org

Wednesday October 4, 12:30 pm–Thursday October 5, about 6:00 pm.

In 2005 coal-fired power was 94% of Utah’s power consumption—today it is 69%, and by 2025 it could be close to 50%. At the moment, natural gas, solar and wind power are the main growth areas. What is needed to stimulate development of the geothermal potential that exists in Utah?

Wednesday, October 4• We leave the Salt Palace Convention Center

at 12:30pm. On the trip south, geologic features such as the Wasatch fault, paleo-Lake Bonneville shorelines, 100-million-year-old thrust faults preserved in the adjacent mountains and Quaternary basaltic volcanoes will be pointed out.

• In addition, the route passes several peaking natural gas-fired power plants and a wind farm that have been built in the last ten years as Utah transitions from predominantly coal-fired power generation to a more diversified generation mix.

• The first main stop is at ENEL’s - Cove Fort geothermal power plant, about three hours south of Salt Lake City. Cove Fort is an air-cooled binary plant with a gross capacity of 25 MW and net generation of about 18 MW, commissioned in 2013. The reservoir is fractured carbonate rock with a water temperature of 150°C. Production wells have submersible pumps, and recently, because of the water level in the reservoir at about 400 m

A cross section of the geology around the FORGE Utah site in southern Utah. COURTESY UTAH FORGE

A GRC Fieldtrip led by Rick Allis (Utah Geological Survey)

Cove Fort geothermal power plant. COURTESY ENEL GREEN POWER

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depth, downhole turbines in injection wells are being tested to convert some of the kinetic energy from the downflowing injectate into power.

Thursday, October 5• We begin the day by visiting Cyrq Energy’s

geothermal power plant at Thermo. This is a water-cooled binary plant with a capacity of 10 MW. The reservoir is predominantly carbonate rock, and the production temperature is about 150°C (300°F) at 1.5 km depth. The generation equipment was upgraded in 2013 from UTC micro-turbines to an Ormat dual turbine unit. The power is sold to the City of Anaheim, California.

• The next stop will be at PacifiCorp’s Blundell geothermal power plant at Roosevelt Hot Springs (RHS) near Milford. The plant was originally built in 1984 as a single-stage flash plant with a 23 MW net installed capacity. In 2007 a binary plant was installed to generate 10 MW of additional power from the separated hot liquid. The typical deep production temperature today is about 245–250°C (470–480°F), although temperatures close to the original upflow temperature of 270°C still exist on the east side of the reservoir. The brine from the separators has a temperature of 175–180°C, and it exits the binary plant for the injection wells at a temperature of 104°C. The reservoir is fractured granitic rock adjacent to the Opal Mound fault. Lunch will be on the siliceous sinter mound that the fault is named after.

• Afterwards, the nearby Utah-FORGE (Frontier Observatory for Research in Geothermal Energy) site will be visited—it should have a deep well by the time of the fieldtrip. The cross section shows a vast amount of thermal energy is stored in the granite adjacent to the RHS, which would be accessible if the granite can be fractured.

• We will also drive through the 300 MW SunEdison wind farm and overlook the Dominion-NRG’s 240 MW solar PV facility. The capacity factor of the wind and solar facilities is typically 20–25%, in contrast to Blundell’s capacity factor of about 90%.

Cyrq Energy’s power plant at Thermo. COURTESY CYRQ ENERGY

PacifiCorp’s Blundell geothermal power plant with SunEdison wind farm behind.

A cross-section showing the geology of the FORGE-Utah well site.

36 GRC Bulletin l www.geothermal.org

• The final stop will be at Magnum’s Western Energy Hub near Delta. Here, underground salt caverns are being developed to store petroleum products such as natural gas and natural gas liquids, and they may also be used for compressed air energy storage (CAES). The CAES process involves converting off-peak renewable power into compressed air that can be stored in commercial-scale solution mined caverns. This stored air becomes an energy reserve that can be released to produce electric power at any time. Currently, there are only two CAES facilities in operation worldwide: McIntosh, Alabama and Huntorf, Germany.

• Opposite the Western Energy Hub is Utah’s largest coal-fired power plant—the Intermountain Power Project, which generates 1900 MW, most of which is sent down a DC line to southern California. However, it is scheduled to close in 2025 due to the new emission standards in California. There are plans to replace the plant with a 1200 MW natural gas power plant on the same site.

• We return to the Salt Palace Convention Center at about 6:00pm

• For more information about Utah’s changing energy scene, go to: http://ugspub.nr.utah.gov/publications/circular/c-121.pdf

• For information about Department of Energy FORGE initiative: https://energy.gov/eere/

forge/forge-home• For information about the FORGE site near Milford: https://energy.gov/eere/forge/forge-home

Trip LeaderRick has been the

Director and State Geologist of the Utah Geological

Survey since 2000. He is also the Technical Lead of Environmental, Permitting, and Outreach activities for the FORGE Utah project.

Dr. Allis has extensive geothermal experience, having previously worked on geothermal systems in the Basin and Range (Utah and Nevada), Indonesia, and The Geysers (California) while a Research Professor at the Energy & Geoscience Institute at the University of Utah between 1997 and 2000. Between 1977 and 1997 he worked for

New Zealand geoscience organizations and was involved in many geothermal and oil and gas projects in New Zealand, Papua-New Guinea, Indonesia, Japan and Vietnam. During this time he spent 18 months as a visiting scientist at the Geology and Geophysics Department of the University of Utah on a Fulbright scholarship working on geothermal topics. Dr. Allis is a licensed geologist and serves on Utah’s Division of Professional Licensing Board for Professional Geologists. He has an Adjunct Research Professor position with the Department of Geology and Geophysics at the University of Utah. n

Dr. Rick Allis

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Aerial view showing the location of the Magnum Western Energy Hub salt caverns (marked by an X) next to the 1900 MW coal-fired Intermountain Power Project. COURTESY MAGNUM WESTERN ENERGY

Fieldtrip RegistrationCost: $350 (Before 31 August); $500 (from 1

September)Sign-up with GRC Annual Meeting

registration on the GRC Annual Meeting webpage at https://geothermal.org/meet-new.html. Seats are limited, so register as soon as you can.

Included in the cost of the fieldtrip is transport in luxury minibuses and single occupancy accommodation at the Best Western Paradise Inn in Beaver City.

-------For the most up-to-date

information on this fieldtrip go to the Fieldtrips webpage for the GRC Annual Meeting at: https://goo.gl/1P6C4R

A view of the area around the FORGE Utah site in southern Utah. The well is located near the center of the photo, between the SunEdison wind farm (far left) and the Blundell geothermal plant (to the right). COURTESY FORGE UTAH.

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