Summary:

In this episode, we analyze Fervo Energy's recent advancements in enhanced geothermal systems (EGS) technology as part of geothermal power plants. The company's Project Red and Project Cape aim to generate electricity by harnessing deep geothermal heat using hydraulic fracturing techniques. While EGS has the potential to provide constant, baseload power, it faces challenges like low energy density, high water usage, and limited scalability. Despite these challenges, Fervo has achieved significant breakthroughs in drilling efficiency and production, demonstrating the potential for EGS to become a more commercially viable renewable energy source. We examine the advantages and drawbacks of EGS, comparing its performance with other renewable and non-renewable energy sources, ultimately highlighting the need for further research and development to determine its viability in a broader energy policy context.

Questions to consider as you read/listen:

What are the main advantages and disadvantages of Enhanced Geothermal Systems (EGS) compared to other renewable energy sources?

How does Fervo Energy's Project Red and Project Cape differ from traditional geothermal power plants in terms of technology and performance?

What are the key challenges and potential solutions for scaling up EGS geothermal energy to meet broader energy needs?

Long format:

Update on Geothermal Power Plants: Fervo Energy’s Project Red, Project Cape and FORGE

On September 10, 2024 at the Houston Enegery and Climate Startup Week, Fervo energy hosted its 2nd annual Technology Day, and just 2 days ago (October 24, 2024) press embargo for the presentations elapsed thereby permitting the slide ware and white papers to be published. There was some new information, most of it quite promising. It begs an update. The most important of which is this one. https://eartharxiv.org/repository/view/7665/

TL/DR

Fervo Energy’s Projects Red and Cape use enhanced geothermal systems (EGS), which leverage hydraulic fracturing techniques to produce geothermal energy. EGS plants circulate water into deep, hot rock to create steam, driving turbines to generate consistent, emissions-free electricity. Fervo’s drilling innovations have significantly cut drilling time and costs, with Project Cape achieving 12 MW peak output.

Advantages:

EGS is a renewable and offers constant, baseload power, unlike wind and solar.

Early tests show no issues with pressure loss or thermal decline, key concerns in geothermal.

ESG GTPP has a very high capacity factor

Challenges:

EGS plants have very low energy densities, have a relatively low energy rate of investment (EROI), high water usage, and slow cold start up time.

Scalability is limited to areas with specific geological conditions, like California and Nevada.

Fervo’s advancements are promising. At least preliminarily, it appears the ESG GTPP is “king” among the renewables. But it’s uncertain if EGS GTPP will meet broader energy needs and will become truly commerical.

BACKGROUND

Fervo Energy's Project Red and Project Cape Geothermal Production Plant (GTPP) that use hydraulic fracturing horizontal drilling techniques. When the shale methods of unconventional drilling is used in Geothermal is called Enhanced Geothermal Systems (EGS).

THE TECHNOLOGY

Just as a quick reminder and oversimplified EGS systems inject high-pressure water into the ground to reopen fractures in hot rock, creating a reservoir. That reservoir is heated by the naturally occurring hot rock at that depth and in that location. This heat is generated due to the radioactive decay of various materials and continuous formation processes within the Earth’s structure. It is then circulated with the resultant steam brought back to the surface to drive steam turbines. The turning of the steam turbines creates electricity. The steam is then, of course, cooled back into water and reinjected back into the system for reuse. It, unlike other renewables like wind or solar (PV) is not an intermittent and can in theory run constantly. Therefore, it is a base load energy source.

In terms of the two domains of environmental concern, green house gases and water use, here is how ESG GYPP stack up. ESG GTPP is also technically emissions free. However, the other environmental concern, referring to water, is an issue. It does take a lot of water as you can imagine. During geothermal plant construction, water is mainly required for the construction of the production and injection wells. Estimated construction water use for both hydrothermal systems and EGS are less than 0.1 gal/MWh. Then, during operations, water is required for cooling processes (e.g., wet, dry, and hybrid). During plant operation, non-cooling-related consumptive water use was estimated and was found to be in the range of 0.001–0.12 gal/kWh. This water use is related to maintenance activities and other domestic uses. EGS has additional water requirements for simulation techniques, where a fluid which is often water is injected into the geothermal reservoir and circulated between injection and production wells to produce power. Some of this water is lost (1%–10%) as the reservoirs are not confined, and thus additional water is required to maintain system efficiency.

Water Consumption (gallons per MWh)

Process

Geothermal Technology

Meldrum et al. (2013) (Median Estimates)

Sullivan et al. (2013) (Average Estimates)

Plant Construction

EGS

N/A

13

Hydrothermal-flash

N/A

1

Hydrothermal-binary

N/A

1

Plant Operations

Binary: Hybrid Cooling

460

N/A

Binary: Dry Cooling

290

270

Flash

11

10

EGS: Dry Cooling

510

510

For visual learners I offer these two YouTube videos and this diagram:

https://youtu.be/4S3aiMxfwhY?si=fYFlxcM_Kz3kK9Ky

https://youtu.be/3GbEOrzZUBU?si=SN8go_nOlMeKm46Q

FERVO ENERGY SITES

Fervo has claim to have successfully drilled several horizontals. Specifically, at Project Cape fourteen wells have been drilled, and three of them have been stimulated. Meanwhile at Project Red one vertical and two horizontal wells were drilled. This drilling in and of itself isn't technically difficult using polycrystalline diamond compact (PDC) drill bits, but it is a unique use of the unconventional well drilling technology.

Further, according to Servo’s press releases it “has consistently reduced drilling times and costs in horizontal, high-temperature, deep granite drilling. Though Cape wells are hotter and over 2,100 feet deeper than Project Red wells, Fervo drilled its fastest Cape well in just 21 days, a 70% reduction in drilling time from Fervo’s first horizontal well drilled at Project Red in 2022. This increase in drilling efficiency has translated into significant cost reductions, with drilling costs across the first four horizontal wells at Cape falling from $9.4 million to $4.8 million per well.”

What is also claimed is that these EGS power plants do not go down as far as a typical shale well and instead is about half the depth. Less depth means less cost. That is a good thing.

It has resulted in what Fervo has stated in its press release as follows: "Fervo performed a 30 day well test, the results of which established Project Red as the most productive enhanced geothermal system in history."

Sounds amazing, right?

Well, let’s look at the data.

A 30-day production test was performed at the Project Cape three-well pad in July and August 2024. The first production well at the Cape site achieved a peak output of over 12 MW and a sustained output of 8-10 MW. The power capacity density is 9.1 MW per km3, 5-10 times larger than previous estimates for EGS technology.

BUT WHAT DOES THIS MEAN IN ALL PRACTICAL EFFECT?

Here are some comparisons:

The average capacity of a newly installed wind turbine in the U.S. in 2023 was 3.4 MW. However, extremely large wind farms can produce over 700 MW.

The size of solar photovoltaic (PV) power plants can range from less than 1 MW to over 2,000 MW.

The Department of Energy (DOE) defines large hydropower plants as those with a capacity of more than 30 MW. Small hydropower plants generate between 100 kilowatts and 10 MW, while micro hydropower plants have a capacity of up to 100 kilowatts.

Biomass power plants are generally larger than 15 MW, but can range from less than 1 MW to over 50 MW.

A typical natural gas-fired power plant can produce anywhere from 20MW to over 1,000MW, depending on its size and design, with larger, combined-cycle plants generating closer to 1,000MW and smaller plants producing around 20MW; a common range for a single unit within a plant is between 200MW and 500MW.

Coal-fired power plants can produce anywhere from 3,000 to 6,700 megawatts (MW).

A small nuclear plant with one generator can produce 476 MW, while a large plant with multiple generators can produce 3,825 MW.

In summary, while EGS geothermal plants have a peak output of 12 MW and a sustained range of 8-10 MW, they are relatively modest in scale compared to other types of non renewable power plants. However, their constant baseload power generation, independent of weather or time of day, gives them an advantage over wind and solar, which are intermittent. This leads us to understand that ESG GTPP may very well be the king of the renewables. This preliminary data is promising. (But there is the issue of water which we will address later).

BUT THERE IS GOOD

There are a lot of good things to consider. First this is not full production at the site instead it was a select number of horizontals stimulated. If it is all cranked up will it meet its projected goals? Time will tell.

Not well noted but I think is very good is the fact that in this 30 day test at Project Cape as well as at Project Red there has been no reports of pressure issues or thermal decline. One of the early concerns in ESG and GTPP was that there was the potential for declining reservoir pressure due to extraction of hot water and steam without proper reinjection. Further with the pressure issue was fears that there was a potential for induced seismicity caused by injecting high-pressure fluids into deep rock formations to create fractures and extract heat, which can trigger small earthquakes if not carefully managed, potentially leading to instability in the reservoir and surrounding areas; this is a major concern for the widespread adoption of EGS technology. The pressure issues seem to not be an issue which is good. Further, "thermal decline" refers to the gradual decrease in the temperature of the geothermal reservoir over time, which leads to a reduction in the amount of heat available to generate electricity, essentially impacting the plant's power output and efficiency; this decline can occur due to factors like excessive fluid extraction, poor reinjection practices, and the natural cooling of the reservoir rock. This concern also was absent these results which is another great result for the technology.

WHERE DOES ESG GTPP FIT INTO LOGICAL ENERGY POLICY?

Now I have to be a little bit of a Debbie Downer. One of the major drawbacks of geothermal are the big five considerations that I write about all the time.

As I write when we look at logical and unemotional energy policy we can to a degree reduce all of our goals (but for the priority/value judgement involved with environmental issues) into 5 statistics as they are quantifiable: (1) energy density, (2) power density, (3) energy return on investment, (4) capacity factor and (5) cold start up times.

-ESG GTPP energy density: 4.186 MJ/kg (which is the lowest on our chart of power plant designs, even lower than phytomass and dry firewood)

-ESG GTPP power density: 2.88 which puts is at among the highest of the renewable categories, but is an order of magnitude lower than other baseload power plants such as natural gas (482.1), nuclear (240.8) and anthracite (180.9)

-ESG GTPP EROI: unknown but traditional geothermal is at 9 which is less than wind, higher than PV, but no where near piped natural gas fired power plant or any form of hydroelectric or nuclear

-ESG GTPP Capacity factor: 71% which is leagues better than wind (34.6%) and PV (24.6%), better than natural gas fired power plants (54.4%) but less than nuclear (92.7%)

-ESG GTPP cold start up time: 2-4 hours which is bottom of the pack with coal (6-48 hours) and nuclear (12 hours) and way less than natural gas fired power plants (several minutes to 6 hours) and wind, hydroelectric and solar (10 minutes)

Finally, there are scalability issues. ESG and GTPP won’t work everywhere. They are location restricted. The most suitable locations are those with deep, hot rock formations with sufficient permeability to allow for fluid circulation, often found in areas with volcanic activity or tectonic plate boundaries. Current enhanced geothermal systems (EGS) are limited to brittle rock although Fervo is trying to deal with this limitation. In the United States, the best geographic areas that these conditions are thought to be met are California, Nevada, Utah, and Oregon. A significant amount of land area that is suitable for ESG GTPP is with Bureau of Land Management Land. Some research is starting to research of West Virginia and Pennsylvania may be suitable as well.

It’s too early to see if ESG and GTPP will be the “fix” that everyone is looking for. Time will tell.

Sources:

Power Density: A Key to Understanding Energy Sources and Uses (MIT Press) by Vaclav Smil

https://fervoenergy.com/fervo-energy-breaks-ground-on-the-worlds-largest-next-gen-geothermal-project/#:~:text=Earlier%20this%20year%2C%20Fervo%20announced,%2C%20Mayor%20of%20Milford%2C%20Utah

https://fervoenergy.com/fervo-energy-drilling-results-show-rapid-advancement-of-geothermal-performance/#:~:text=This%20increase%20in%20drilling%20efficiency,to%20$4.8%20million%20per%20well

https://linkedin.com/pulse/fervo-energy-technology-day-2024-entering-geothermal-decade-matson-n4stc/?trackingId=qF6bTgyiRICdGFEfX6YRhQ%3D%3D

https://pangea.stanford.edu/ERE/db/GeoConf/papers/SGW/2024/Xing2.pdf

https://pangea.stanford.edu/ERE/db/GeoConf/papers/SGW/2023/Xing.pdf

https://gdr.openei.org/files/1523/2023%20Annual%20Report%20Phase%203B%20and%20Appendices%20for%20GDR.pdf

https://pangea.stanford.edu/ERE/pdf/IGAstandard/SGW/2014/Shiozawa.pdf

https://eartharxiv.org/repository/view/7665/

https://jpt.spe.org/fervo-and-forge-report-breakthrough-test-results-signaling-more-progress-for-enhanced-geothermal

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EP43: Update on Geothermal Power Plants: Fervo Energy’s Project Red, Project Cape and FORGE 27:02 Share

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EP43: Update on Geothermal Power Plants: Fervo Energy’s Project Red, Project Cape and FORGE