Fervo Energy is an energy resource company focused on harnessing heat through enhanced geothermal systems (EGS). Co-founded in 2017 by Tim Latimer, a mechanical engineer by background, Latimer worked as a drilling engineer at BHP until 2015. ^[1] His departure from the oil and gas sector was driven by a desire to apply techniques observed during the shale revolution to geothermal extraction. ^{[2] [3]}

On July 18, 2023, Fervo Energy announced that their first pilot geothermal plant was successful in generating 3.5 MW (megawatts) of baseload power and consistently maintained flow rates of 60 liters per second (l/s).

Financing

Fervo Energy has been backed by over $400 million USD in equity or non-equity backed funding and approximately $17 million in non-dilutive grants. ^[3] In the third quarter of 2022, Fervo Energy received $22 million of series C funding from a multitude of venture capitalists. ^[3] In 2021, Fervo Energy partnered with Alphabet, the parent company of Google, in hopes that Fervo can provide green electricity to Alphabet's cooling centres in the Las Vegas cloud region which met the three demands of Alphabet: baseload, green sourced and nearby. ^{[4] [5]}

Background

Petroleum industry applications

By 2005, American oil production had reached a 35-year low, with the United States producing just over 50% of what it had produced in 1976. ^[6] This significant decline led to a reliance on foreign imports, perpetuating a constant feeling of unease in markets due to foreign producers not having common geopolitical interests.^{[ citation needed]} In 2010, two key technologies emerged that allowed the American oil industry to grow at record rates: horizontal drilling and hydraulic fracturing, commonly known as fracking. ^[6] Fracking is a process by which horizontal wells are drilled, stacked one upon another, and then fractures are induced to connect a multitude of horizontal wells. This allows the surface area of the reservoir to grow while improving permeability and consequently achieving higher barrel production daily. ^[6] Fracking has been a controversial method to free up fluids (notably petroleum) from tight hydrocarbon reservoirs.

EGS application

The first time shale fracking methodologies were proposed to be applied for geothermal use was in 2013. It was brought forth by Mark Mclure, who is now a technical consultant at Fervo energy. ^[3]

Mark Mclure, along with co-author Sogo Shiowaza, believed that the combination of horizontal drilling and fracking first utilized in the petroleum sector has the potential to de-risk EGS systems. As long as there is sufficient amounts of heat, the system will produce viable amounts of electrical energy with little risk no matter natural permeability. ^[7]

EGS around the world has struggled in being cost-competitive with other carbon-neutral sourced electricity. ^[8] Vertical wells often encounter thermal short circuiting. ^[9] This is where shallower induced fractures are better transmitters of water then deeper ones. This is often due to less normal stress at shallower depth and higher viscosity where the deeper fractures have the opposite effects. ^[7] This causes certain fractures to produce different water temperatures where they meet at the production well, thus they're heating affects is negated. ^[7]

Another issue is zonal isolation of fracturing, modelling induced fracturing is simple, however the deeper the hole, the less accurate modelling becomes. Thus predicting fracture geometry is much more difficult leading to fractures being disconnected to the production well. ^[7]

Horizontal drilling proposes to tackle both thermal short circuiting and zonal isolation by having the producing reservoir all at the same depth. By having the injection and production drilled horizontally all induced fractures will sit in the same normal stress field, same temperature zone and thus have the same viscosity eliminating the potential of short circuits. To induce optimal fractures, Fervo Energy uses the plug and perforation method, again adopted from the unconventional oil industry. The plug and perforation system isolates stages from one another to decrease chances of unwanted fracture interactions when the fractures are first initiated. ^{[10] [11]}

Pilot projects

Drilling demonstrations & Nevada Operation

On July 18, 2023, Fervo Energy announced the completion of its first geothermal plant in Nevada, USA. ^[13] It marked the first use of horizontal wells in an EGS system in the world. The primary aim of this was to demonstrate to investors the viability of employing horizontal drilling technology in geothermal applications. The two wells attained a true vertical depth of 8000 feet, with horizontal sections extending 3250 feet. ^[3] The project sustained drilling rates of 75 feet per hour, in a geological setting comprising hard metasedimentary and igneous formations. This ranked the project in the top quartile of drilling rates for hard rock formations. ^[3] The geothermal gradient measured approximately 75°C/km. The plant attained flow rates of 60 l/s,generating a baseload of 3.5MW of electric power. ^[3] This output is roughly adequate to satisfy the energy needs of 2000 households. ^[14]

The National Renewable Energy Laboratory (NREL) has previously predicted the technical aspects of EGS over the years. In 2022 it had forecasted that flow rates of 60 l/s would be attainable under a "moderate case" scenario by 2035. ^[15] Fervo Energy accomplished this feat in 2023, albeit at a notably higher levelized cost of electricity (LCOE). Fervo's ongoing efforts are focused on scaling up production and reducing costs. ^[3]

Cape Station Project

On September 25, 2023, Fervo Energy held its groundbreaking ceremony for the Cape Station Geothermal Project in southwest Utah, specifically in Beaver County. Beaver County has geothermal gradients ranging from 50°C to 500°C/km. However, most boreholes indicate a geothermal gradient between 70°C and 100°C/km. ^[16] Fervo estimates that this plant has the potential to generate up to 400MW of electrical power by 2028. To increase electrical production and scale the previous design in Nevada, Fervo Energy proposes that it will have multiple horizontal wells stacked upon each other, with each level having its own injection and production well to limit short-circuiting. Lateral well lengths are also proposed to be increased to beyond 10,000 feet, with casing diameter widened up to 13 3/8" to decrease wellbore friction. ^{[3] [17]}

If successful, this project will be the largest EGS plant in the world (by energy production), surpassing the Cooper Basin Project in Australia by 8-fold. ^[18] Fervo Energy claims this project will generate over 6,000 jobs during construction, generating $437 million in wages. ^[3]

Comparable plants

A vertical EGS systems with similar heat conditions (as the Nevada Fervo operation) in the north eastern part of Nevada produces over ten times more energy. ^[19] However, the project has 5 injection and 6 production wells. On a per well bias, each pair is making around 7MW - twice the amount produced at Fervo's plant. ^[20]

The Vendenheim goethermal plant in eastern France also with a similar heat resource generates 10MW of electrical energy surpassing Fervo's. ^[21]

A paper published by several engineers backed by Baker Hughes notes that horizontally drilled EGS systems have the potential to become cost and energy competitive with conventional reservoirs if downhole directional drills can be rated to temperatures up to 300C^o. Cost competitiveness can also come in the form of combing horizontal EGS with other carbon neutral technologies such as carbon capture. ^[22]

References