New report identifies technology gaps to developing superhot rock geothermal

The Cascade Institute and CATF have published a report identifying technological gaps in harnessing energy from superhot rock geothermal systems.

A new report published by the Cascade Institute and the Clean Air Task Force (CATF) explores the current state of geothermal drilling and well construction technologies in the context of identifying the technology gaps development of superhot rock (SHR) geothermal systems.

The full report “Drilling for Superhot Geothermal Energy: A Technology Gap Analysis” written by Rebecca Pearce (Cascade Institute) and Tony Pink (Pink Granite Consulting) can be accessed via this link.

The research frontier of drilling and well construction for SHR geothermal energy systems – the production of renewable, baseload electricity by circulating water in deep (>5 km), hot (>374?C) rock – is steadily advancing. However, several key technology gaps still stand in the way of deep drilling in hostile subsurface geological environments. To bring SHR geothermal to commercial viability, technology companies and laboratories must rapidly develop, test, and deploy new technologies.

This report reviews state-of-the-art deep geothermal drilling and well construction technologies, identifies existing technology gaps, and suggests strategies to overcome these gaps. Each technology is given a technology readiness level (TRL) between 1-9, from theoretical to commercially scalable.

Big-picture technology gaps

The report identifies “big-picture” technology gaps to make SHR drilling and well construction technically and economically viable:

Improve the ROP when drilling into crystalline basement rock
Develop ultra-high temperature electronic downhole tools and temperature management requirement.

In the category of drilling technologies, three types are considered: conventional rotary drilling, hybrid conventional drilling, and direct energy drilling.

In the conventional drilling space, there are already specialized bits that are suited for extreme temperatures, interbedded formations, or extended bit life. However, no single bit incorporates all these specifications. Hybrid conventional drilling techniques encompass a wide range of non-conventional mechanical drilling technologies including particle drilling, waterjet or percussion drilling in combination with conventional drill bits. However, these are still in the early stage of technological readiness in SHR conditions.

Direct energy drilling technologies (plasma and millimeter wave) are in relatively early stages of technological development, and thus have several gaps to address before commercialization. They are, however, important technologies to consider for regions where superhot conditions can be found at depths greater than 15 kilometers.

In the field of downhole tools and temperature management equipment, the most promising option is to combine cooling techniques and increase the temperature threshold of downhole tools. There are many options for temperature management that can be explored. Technology companies must continue to improve high-temperature-resistant electronics.

All of the technology categories share three overarching challenges:

Lack of access to SHR in controlled laboratory settings
Lack of access to SHR in in-field settings
Lack of incentives for collaboration between major drilling firms

Across all well-construction technology domains, one theme is clear: the technology to complete superhot or ultradeep geothermal boreholes and wells exists. However, further work needs to be done to reduce the overall cost and time to drill a deep, superhot geothermal well.

Source: Cascade Institute

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