Geoscience is pivotal in solving the energy trilemma

With the recent launch of Geoenergy, Max Brouwers (Getech) highlights the importance of geoscience in this new era of sustainable energy.

The energy transition is well underway and the speed of change is accelerating. With the shift from fossil-based energy systems to renewable sources, the associated trilemma of challenges – access to affordable, secure, and clean energy – becomes clearer too.

Recent rises in fuel and electricity prices highlight the affordability challenge. Energy costs are poised to hit an all-time high of more than 13% of global gross domestic product (Bloomberg 2022) as the price of keeping the world running surges. Electricity is crucial for poverty alleviation, economic growth, and improved living standards (Ritchie 2022), but nearly one billion people still live without electricity altogether.  

Current events such as the war in Ukraine have pushed energy security to the forefront of global agendas again as Europe aims to find alternative fuel sources. The uneven distribution of oil and gas resources among countries has led to significant vulnerabilities, with energy supply being used as a strategic weapon.

Meeting the Paris Climate Agreement, to keep the rise in mean global temperature to less than 2 °C (3.6 °F) above pre-industrial levels, remains the biggest and most important global challenge. With  3.3 to 3.6 billion people living in circumstances that are increasingly susceptible to climate change, and a high proportion of species vulnerable, any further delay in concerted global action will miss a rapidly closing window to secure a sustainable future (IPCC 2022).

Each of the elements that make up the energy trilemma requires geoscientists to help find solutions.

Geoscience to ensure affordable energy

Approximately 90% of the world has net zero targets (Net Zero 2021) and all the technologies needed to achieve the necessary deep cuts in global emissions by 2030 already exist. The policies that can drive their deployment are proven (IEA 2021) and progress in rolling them out is made with for example the the Inflation Reduction Act in the USA and The European Green Deal in the EU.

Nevertheless, progress is slow as the magnitude of switch-over required for the global transition is daunting. In addition to the time required to permit and build sufficient clean energy sources, structural issues such as grid capacity limitations need large amounts of capital.

To provide sufficient and affordable energy during the transition, the world will still need oil and gas, but produced at as low a carbon footprint as possible, for example by safely storing the CO₂ emitted from burning fossil fuel, or by removing and storing the carbon before combustion, as is done in blue hydrogen generation. Most international climate change models indicate that carbon capture and storage (CCS) is required for the world to stay below a 2 °C temperature increase. CCS is a technically proven solution – e.g. Equinor’s Sleipner field (Skalmeraas 2017) – and its business model is not dissimilar to other methods of waste collection and disposal.  

The total market value of the CCS sector could reach $55 billion annually by 2030 (Rystad 2022). However, significantly more investment is required to meet the IEA’s net-zero scenario (see Figure 1). The amount of CO₂ captured must grow by a factor of 40 from around 40 Mt today to over 1.6 Gt in 2030, and up to 7.6 Gt per annum by 2050 (IEA 2021).

Many of the skills required to identify, develop, and operate a hydrocarbon field are equally applicable to carbon storage. Both involve locating suitable reservoirs and making predictions about the movement of gas and fluids through pore spaces deep underground.

For example, Common Risk Segment (CRS) mapping is a standard approach used by oil companies to evaluate the petroleum potential of a sedimentary basin and identify subsurface sweet spots. The methodology serves as the basis to decide exploration strategy, helping to delineate areas with the lowest geological risk. A similar CRS approach is now being used to define regional ‘sweet spots’ for subsurface carbon storage (Bump 2021).

At the field scale, predicting porosity and permeability is just as important for carbon sequestration as for hydrocarbon production. Understanding depositional environments, grainsize and mineralogy, burial history, plus diagenesis, are all input factors to determine storage capacity.

There are material differences too. CCS requires geoscientists to make forward predictions on the suitability of a storage site. The long-term reliability of a site requires assessment of, for example, the risk of future seal breach caused by a variety of potential factors such as acidified downhole brine due to CO₂ dissolution, or fault movement including induced seismicity due to CO₂ injection. Reduced injectivity due to growth of salt or other minerals in the reservoir pore space could also be an issue.

When a storage site is commissioned, detailed long-term monitoring will be required to confirm that the CO₂ remains where it is supposed to be. Geophysical data acquisition and interpretation are essential, and innovations will be required to make these techniques more suitable for carbon storage projects.

Geoscience to provide reliable and secure energy

The renewable energy potential from wind and solar is more equitably distributed across the globe than fossil fuel deposits. However, intermittency of these sources makes them less reliable as standalone energy solutions. Excess energy must be stored for periods when demand outstrips supply. This storage becomes increasingly relevant as the proportion of solar and wind rises in the overall energy mix.

Whereas batteries might be suitable for limited-scale and short-term storage, a larger scale solution is subsurface energy storage that can cater for high demand over longer periods. Energy storage increases the flexibility to generate, deliver and consume renewable electricity. It provides the ability to balance power supply and demand, making power networks more resilient, efficient, and cleaner.

Subsurface storage can be achieved in a number of ways; by pumping hydrogen, compressed air, natural gas, or hot water into the ground, and releasing it when required. Hydrogen storage in salt caverns and depleted gas fields is expected to increase with the step-up in the production and international transport of blue and green hydrogen.

Hydrogen is predicted to meet around 15% of world energy demand by mid-century if we are to reach the Paris Climate Agreement targets (DNV 2022), and the storage of hydrogen will need to rise sharply in line with this. In addition to balancing supply and demand, large scale hydrogen storage may also become critical from a national energy security perspective, just like strategic oil and gas reserves are today.

Subsurface energy storage requires a deep and integrated understanding of local geology. This includes assessments of lithology, estimating volumetric capacity, seal strength, potential for geochemical alterations and fault behaviour under different pressure regimes. The storage site needs to be safe and able to withstand repeated cycles of fill and discharge.

An additional low carbon solution that supports energy security is geothermal. It is one of the most reliable, sustainable and potentially efficient energy sources available. It is theoretically accessible everywhere in the world and, unlike many other low carbon solutions, it is not affected by the weather. This makes it a perfect green baseload and/or dispatchable energy source. Crucially, it can also provide domestic energy security, reducing reliance on imports. However, despite its potential and century-long track record, geothermal energy remains vastly underexploited due to a combination of up-front drilling costs and geological risk. Recent technological innovations, such as faster drilling techniques, new closed loop systems, alongside increased governmental support for transitioning to green energy, should expand geothermal use well beyond traditional hotspots such as Iceland, New Zealand and Indonesia. With these innovations in progress, geoscientists will be increasingly tasked to identify suitable geothermal locations, while seeking to minimize exploration and exploitation risks. In addition, when identifying the most favourable sites, the potential for valuable minerals (such as lithium) in the brine should be considered (Warren 2021).

Geoscience to counter climate change

Annual investment in climate solutions across the entire value chain needs to rise from its present level of just over $1 trillion, to around $4 trillion a year, to achieve net-zero by 2050 (IEA 2021). Many of these investments are linked directly or indirectly to exploiting natural resources from the earth.

A successful low carbon global economy requires critical minerals to enable the transition. Copper, cobalt, lithium and rare earth metals such as neodymium are fundamental to batteries and power transmission systems. Lithium demand is expected to grow 40 times by 2040, followed closely by graphite, cobalt and nickel. The expansion of electricity grids will more than double the need for copper for networks over the same period (IEA 2021).

Battery, solar and wind have had decades of reducing costs due to economies of scale and technological advances, but they are all currently experiencing cost increases due to shortages in critical raw mineral supply, as traditional resources are being depleted and the effects of historic under-investment in mineral exploration are becoming more apparent. Major investment is needed in the exploration and exploitation of critical minerals, and industry will increasingly look to geoscience for solutions.

The exploration for strategic minerals benefits greatly from petroleum system-style workflows (McCuaig 2017), and common risk segment ‘favourability’ mapping. Geoscientists in the petroleum industry identify paleoenvironmental conditions responsible for creating organic-rich hydrocarbon source rocks. Those same organic-rich rocks also enable subsurface redox conditions responsible for many sediment-hosted mineralisation of critical electrification metals like copper and zinc.

As an example, Figure 2 shows a study carried out on the Kupferschiefer sedimentary unit in North and Central Europe, predicting areas with high concentrations of sedimentary copper (Getech 2022). The results show an excellent correlation between the predictions and the location of known copper deposits, as well as highlighting potential zones of copper mineralisation that appear to be under-explored.

A second example is the repurposing of Geographic Information System (GIS) based geoscience knowledge bases, which were originally built for petroleum exploration, to locate mineral deposits such as lithium. The systematic integration of scientific insights on the presence of long lived endorheic basins; paleo wind directions; river drainage patterns relative to igneous activity; and paleo-evaporation rates is proving effective to predict critical mineral sweet-spots when combined with a mineral systems approach (Munk 2016).

Conclusion

Geoscience has a pivotal role in tackling the energy trilemma of providing affordable, secure, and clean energy – arguably the largest global challenge of our lifetime.  

To overcome this challenge, geoscience is required not just to support the ongoing exploration and production of hydrocarbons to ensure energy security, but also to enable the safe storage of the resulting CO₂. Furthermore, geoscientists play a key role in assessing subsurface energy storage solutions, and making geothermal energy available on a broader scale to enhance the reliability of energy systems.

Novel geoscience innovations are important to secure the large variety and volumes of critical minerals that the world needs for the electrification of societies and the development of other green technologies. All these processes depend on a fundamental understanding of geological systems and evolution at macro and micro scale, as well as ongoing innovation to increase their effectiveness and cost-efficiency.

Geoenergy is a new co-owned journal of the Geological Society and the European Association of Geoscientists and Engineers (EAGE). Continuing the mission of its sister journal, Petroleum Geoscience, Geoenergy focuses on the publication of timely and topical research in subsurface geoscience, critical for this new era of sustainable energy. The journal is open for submissions now! Full details can be found here: https://www.geolsoc.org.uk/geoenergy

References

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