In the world of renewables, geothermal electrical generation is a giant in infancy, ready to be tapped. According to the Department of Energy (DOE) the US is projected to generate 90 gigawatts (GW) of electricity from geothermal sources by 2050. Projections are that this could grow to 300 GW over time. (For perspective the US is currently generating 1,250 GW annually.)
The attributes of geothermal energy are stunning
- It is a 24/7, baseload resource which is carbon free.
- It is flexible – that is, electrical production can be dialed up or down
- There is no fuel cost and very little water needed.
- There is a trained workforce available from the oil and gas industry.
- There is little supply chain risk.
- The footprint is quite small.
- The water used in the wells is 100% reusable on site, avoiding the toxicity of the brines associated with O&G fracking.
- It provides local, safe jobs.
- Project economics are rapidly improving, due to new technology from the oil and gas industry.
Background
The ancient Romans used the heat picked up by mineral springs to heat homes and communal baths. There are 16th century villas in Vicenza, Italy that have been cooled and heated for 600 years using ground source geothermal currents of air. The first geothermal power plant began making electricity over 100 years ago in Italy. Much of Reykjavik, Iceland has been heating its buildings with ground sourced heat for more than 100 years.
The distinction must be drawn here between ground source heat and the geothermal resource used to drive the steam turbines used in large scale power generation. The word “geothermal” is used for both, because both rely on the heat of the earth. One is derived from the earth’s core (approximately 5000 ° C) and the other from the heat of the sun, stored in the earth’s surface. Companies such as Bedrock Energy, Diverso and Dandelion have made great strides in the commercialization of heating and cooling for buildings. While surface heat is ubiquitous, simple to tap and an excellent low heat resource for the heating and cooling of buildings, we will only be addressing the advances made to power generation here.
Traditional Hydrothermal Geothermal
In the past, the high heat necessary to generate electricity (150°C to 200°C degrees) was only available where naturally occurring high heat reservoirs existed. In these conventional “hydrothermal geothermal” installations, open loop wells (drilled wells that contain circulating water) were drilled to the natural reservoirs of high heat below the surface. If subsurface conditions were adequately permeable, the heated water could rise to power a turbine at the surface and produce electricity. Natural reservoirs have proven hard to find and access. The DOE estimates that the US has about 40GW of hydrothermal resource, of which 4GW are on the grid today.
Engineered Enhanced Geothermal Systems, ESG
Commercialization Pathways
Careers: Land the job, get a raise and learn to lead with our weekly Careers newsletter.
Under the Biden Administration the Department of Energy’s Geothermal Technology Office (GTO) issued a report called the Next Generation Geothermal Liftoff report, one of 10 technology reports assessing current and future renewable energy technologies, and outlining their paths to commercialization. It covers several recent technological developments that have made this ancient technology the next “hot” climatetech.
A new technology called Enhanced Geothermal Systems (ESG) creates engineered reservoirs where hot subsurface rock is not permeable and water is scarce. Using techniques borrowed from the oil and gas sector, parallel wells (one up, one down) are drilled and rock permeability is achieved using horizontal fracturing techniques, which connect pairs of open or closed (piped) loop wells. Small amounts of water are needed and are recirculated, without the toxicity created in oil and gas fracking. The DOE’s Frontier Observatory for Research in Geothermal Energy (FORGE)field laboratory conducts tests of all the new relevant technologies, including high temperature sensors, directionally targeted fracking, seismic measurements and extensive data collection. Demonstration work at FORGE has improved drilling speed by 500% over three years and created a drop in costs from $13m per well to $5m per well.
Drilling and exploration technologies adapted from the oil and gas industry, including not only horizontal and directionally radiating fracking, but also laser, microwave and plasma drilling, as well as electron beam, electric arc water jet, and hydrothermal spallation have made the drilling process “faster /better/cheaper.”
Cost Reductions Achieved with Innovations in Geothermal Technology
Several EGS companies are collaborating with FORGE . One, Fervo Energy, founded by former oil and gas drilling engineer, Tim Latimer, is pioneering advanced drilling methods with horizontal fracking, advanced reservoir management and fiber optics data collection. Fervo has made remarkable, well documented advances in reducing drill time, increasing energy output, shrinking the footprint with radial, directional fracking and therefore bringing down the costs of EGS. Quaise Energy uses technology developed at MIT to vaporize rock. Rather than using mechanical drills and bits, Quaise uses microwaves and electrons to melt a hole through rock. Mazama Energy, has made significant advances in very high temperature (Superhot rock, SHR EGS) geothermal, at approximately twice the temperature (374°C vs. 200°C) of similar technologies, resulting in much higher energy density and power generation.
Much of the cost of geothermal projects has been due to the inefficient exploration process. In the past, approximately 90% of test drilling sites failed, despite using the best minds in geology and geological mapping. New AI driven technologies, such as those pioneered at Zanskar, rapidly search data concerning tectonic plates, geology, and temperature and can accurately determine, with 90% success, where to drill for high temperature resources. Overcoming this obstacle will make geothermal drilling far less expensive.
The Future of Geothermal
What are the next steps for geothermal technology commercialization? Much of this research and focus on commercialization has been funded by the Department of Energy and has relied heavily on the IRA funding mechanism. We are facing an enormous uptick in the demand for electricity, largely due to the proliferation of AI data centers, the electrification of buildings and vehicles and even the advent of cryptocurrency mining. Fervo is already providing electricity to a Google data center in Nevada. Sage Geothermal has signed an agreement with META to provide power to a data center. The DOE Liftoff report estimates that the ESG resource in the US, once commercialized, could be over 5 TW (approximately 5x our current US electricity consumption.)
Fortunately, the Secretary of Energy designate, Chris Wright, has a background in drilling technologies. It appears not only that he has invested in some of these technologies, but also that he is an advocate of firm, 24/7 baseload energy generation. Pending legislation to speed up permitting for renewables as well as oil and gas, if approved, will benefit geothermal deployment. The promise of geothermal energy, a firm and flexible resource that is expected to drop in price with the development of the technologies mentioned above, is enormous. It is possible that the advances made in these promising technologies (with the help of the Department of Energy) will continue well into the Trump administration.
Source: https://www.forbes.com/sites/patsapinsley/2024/12/04/geothermal-the-promising–ancient-giant-in-infancy/
