Technology Focus: Decarbonization (July 2024)
Authors: Gupta Subodh 
Published: July 2024

While significant progress has been made in carbon abatement, evidenced in literature produced over the past year, particularly within the realm of carbon capture and storage (CCS), I’d like to invite your attention to three key topics in this discussion.
First, despite more than 3 decades of intense focus on emissions issues, highlighted since the 1980s and formalized with the establishment of the United Nations Framework Convention on Climate Change in 1992, global emissions have only increased instead of going down. It’s imperative to question the efficacy, premises, practicality, and overlooked hurdles of current approaches. Paper SPE 214950, summarized here, sheds light on some of these challenges. It emphasizes that implementing costly carbon-abatement methods in a world marked by sharp regional economic disparities with wealth concentrated in a few countries could worsen economic inequalities by making access to energy even less equitable. Additionally, paper SPE 215050 (included in the list for further reading) underscores the priority of energy security over carbon reduction, citing recent evidence from leading proponent nations of climate action resorting to the use of coal. Failing to address energy security and economic disparity, though these are not the only obstacles, could hinder progress toward societal carbon-reduction goals.
My second topic for your kind attention is the progress made on the CCS front, on which an overwhelming number of papers (approximately 75% of those reviewed) were presented at SPE conferences last year. An ongoing challenge with CCS, particularly in deep saline aquifers, is the prolonged period required for injected CO2 to chemically react and solidify for permanent storage. Paper SPE 215352, summarized here, introduces a different perspective based on the author’s exposure to another industry: proposing the coinjection of CaCl2 to expedite the permanent storage of CO2, potentially addressing this issue.
The third topic that you will find interesting is developments on the hydrogen front, aimed at replacing direct use of fossil fuels as energy vectors. The cost of producing green hydrogen is expected to come down with advancement of technology, at least in some geographical areas, as the second paper shortlisted for further reading, paper IPTC 23652, suggests. One promising application involves using excess solar power during the day to convert hydrogen and store it underground for use when sunlight is unavailable. This could green the so-called peaker plants.
While the approach of underground hydrogen storage (UHS) undoubtedly has the advantage of storing large amounts of energy, it may still struggle to compete with utility-scale battery storage in terms of the associated round-trip energy efficiency.
There are many technoeconomic challenges to be solved in the hydrogen-based energy approach, including in the UHS context, before it can be used at a significant scale. Despite some previous experience with controlled and small-scale application of UHS, much remains to be learned about its safety and economics. The risks include leakage hazards, underground chemical reactions, loss from residual trapping, and contamination, among others. However, papers like IPTC 23943, one summarized here, along with the third one selected for further reading, paper SPE 215489, underline the necessity and the strides being made by the engineering community in overcoming these technological challenges.
Recommended additional reading at OnePetro: www.onepetro.org.
SPE 215050 Energy Transition or Energy Advancement! by Sami A. Alnuaim, King Fahd University of Petroleum and Minerals, et al.
IPTC 23652 Sun-Powered Green Hydrogen—A Comparative Analysis From the Kingdoms of Morocco and Saudi Arabia by Waldemar Szemat-Vielma, SLB, et al.
SPE 215489 Role of Hydrogen Storage for UK Energy Resilience for Net Zero by S.K. Kimpton, DNV, et al.