It is now widely acknowledged that human’s need to find renewable ways to power our lives and businesses, that do not rely on fossil fuels. Critically, we need to find new ways to keep ourselves warm, because some 60% of the world’s energy usage is for heating.
At the same time, it is also generally accepted that geothermal energy has the potential to reduce carbon emissions significantly. We also know that the deeper you drill, the higher the temperatures and the greater the potential geothermal energy has, to provide renewable energy for us. In fact, is it estimated that our planet has the potential to provide 45TW of geothermal energy – continually. In 2013 the International Energy Agency estimated that the world needed 18TW of energy per year to ‘run’. While difficult to precisely calculate, this figure was based on existing energy consumption of oil, coal, gas, nuclear sources and renewable sources. To put things another way – if we can truly find a way to access geothermal energy, we could power the whole earth, cleanly, reliably and permanently. So why, given we are now in the midst of a climate crisis, haven’t we solved the problem of cost-effective deep drilling yet?
The innovation and development of deep drilling technology has traditionally been driven by the search for hydrocarbons, predominantly found within sedimentary formations, which are of low to medium strength. Hydrocarbon reservoirs pose very different problems to those associated with geothermal heat sources, especially within micro-crystalline rocks, with high strengths.
Currently, percussive hammer drilling is the best way to drill through medium to high strength rocks, and the majority of percussive hammers are powered by air. Unfortunately, compressing air is extremely energy-intensive, and air-powered hammers often have limited drilling depths, especially in formations that have high water levels or are unstable due to high pore pressure. This makes this approach less effective when it comes to accessing deep geothermal energy sources.
Of course, there are other types of hammer drilling besides air powered – what about water? Water hammer technology, while very effective for many types of project, has always had some operational restrictions if applied to deep drilling to geothermal sources. Most notably water hammer drilling has the requirement for large amounts of very clean water. It also required a restrictive space between the borehole wall and the drill pipe, to ensure enough up-hole fluid velocity to carry drilled cuttings. While an incredible technology in many ways, these factors mean that water hammers are unsuitable for geothermal drilling, in their existing form.
The good news is that innovation is happening in the water hammer space. It seems that the limitations posed by current water hammers could be largely addressed by Strada’s Fluid Hammer Operating System (FHOS), through the utilisation of dual circulation drill pipe. This system will enable clean fluid for the hammer operation and a separate supply of flushing fluid, which is a major step forward. It means that fluids, capable of carrying drilled cuttings, without affecting the hammer performance or lifecycle, will allow deep holes to be drilled through both high strength and reduced stability formations.
Whilst the technology is still under development and currently has some restrictions with interfacing to available topside equipment (drill rigs, fluid pumps), these problems should soon be solved. By reducing drilling risks/costs associated with deep geothermal developments, and building on well-proven methodologies, with lower specific energy inputs and simplicity of use, Strada’s technology could soon become the cornerstone of the renewable energy sector.
Correctly applied, this technology not only opens up the potential for geothermal energy but also lends itself to other areas in the sector of ‘climate change mitigation’, including Carbon Sequestration and Deep Geological Nuclear Waste Storage.
Everyone in the renewable energy sector should be monitoring the results of Strada’s testing, which is anticipated to be completed this year. If the technology delivers everything it is designed to; it could be the game-changer we’ve all been hoping for.