The Center for International Environmental Law (CIEL) published the summary of its report “Deep Trouble: The Risks of Offshore Carbon Capture and Storage” on June 23, 2023, and the full report on November 11, 2023.

As a climate change countermeasure, there has been an increasing focus on offshore as potential storage sites for carbon capture and storage (CCS). Fossil fuel giants and related companies have claimed that, rather than phasing out oil, gas, and coal, they can capture emitted CO₂ and store it semi-permanently under the sea floor or on land storage sites. However, large-scale CCS is currently unproven, and its feasibility and adverse effects on ecosystems, communities, and the climate are highly questionable.

In this report, CIEL points out the problems and challenges of CCS, especially offshore CCS, which is currently being actively planned mainly in fossil fuel-producing countries and developed countries including Japan, and points out that this technology is not a solution for fossil fuel phase-out. It concludes that the most reliable way to reduce CO₂ emissions is to stop production and use of fossil fuels, and that CCS – both onshore and offshore – is nothing but a dangerous distraction from the urgent issue of coal, oil, and natural gas phase-out.

Key Findings

• Offshore CCS is now being proposed at an unprecedented scale.
  There are at least 38 new proposals for offshore carbon sequestration worldwide, the vast majority of which are planned for operation before 2030. Combined, these projects envisage storing more than 165 million tonnes of CO₂ in geological repositories under the seabed per year, nearly 100 times the current offshore injection rate. This massive proposed scaling of offshore CCS is largely concentrated in areas that have been the sites of intense oil and gas drilling for decades, such as the U.S. Gulf of Mexico and the European North Sea.
• The few offshore CCS projects that do exist cast doubt on the technology’s feasibility in general, let alone at massive scale.
  Only two CCS projects in the world, both in Norway, have successfully injected CO₂ into a dedicated offshore storage site. The findings through those two projects led the author to conclude that the world may lack the commitment, technical know-how, and regulatory strength to safely manage large-scale CCS.
• Offshore CCS carries uncalculated risks.
  Injecting CO₂ under the earth’s surface has the potential to contaminate groundwater, cause earthquakes, and displace deposits of toxic brine. Though the consequences can be grave, managing these potential hazards is largely untested. Risks, like leaks, may be more likely to occur in CCS projects located offshore due to the robust transportation and technical requirements, and the difficulties in mitigating problems underwater. These potential leaks pose a major threat to tackling the climate crisis. According to one estimate, if CCS is widely deployed, even a 0.1% leakage rate could cause up to 25 gigatonnes of additional CO₂ emissions in the 21st century.
• The interaction with legacy oil and gas wells exacerbates the risk of leaks.
  Because the legacy wellbores can provide pathways through which CO₂ may escape, they pose the single greatest risk of leakage or ‘containment failure’ at CCS projects. Despite this risk, some of the areas being targeted for offshore CCS, such as the Gulf of Mexico, are pockmarked with oil and gas wells. Regulatory agencies acknowledge that many of these existing wells may already be leaking without detection or oversight.
• Offshore CCS poses untested monitoring challenges.
  Many of the risks of offshore CCS have yet to be fully assessed. Government reports show a systematic lack of monitoring of pipelines and wells, and CCS may have similar oversight challenges for regulators.
• Existing offshore infrastructure routinely fails. Offshore CCS would rely on similar leak-prone systems.
  Offshore pipeline and oil shipping leaks are already so common. The industry’s failure to manage its existing offshore infrastructure calls into question its ability to safely manage the entirely new network of undersea pipelines required for the proposed build-out of offshore CCS.
• Offshore CCS could cause irreversible harm to the ocean, which is already under stress.
  Laying undersea pipelines is complex, costly, and can significantly disturb coastal and marine environments – even if there are no leaks. When a leak or pipeline blowout does occur, the sudden release of significant quantities of CO₂ could be irreversible, hurting sensitive marine organisms and causing a crisis.
• Legal regimes provide important bulwarks against the risks of offshore CCS but need to be strengthened.
  Although regulatory frameworks for offshore CCS are incomplete, any offshore activity implicates existing national and international legal regimes. International laws restrict the types of activity that can be conducted on the ocean. The applicable regulations are in flux, as some international bodies and national authorities evaluate the potential impacts of CCS and consider new rules. It is critical to take stock of the myriad new and unknown risks from offshore CO₂ injection.
• The price of offshore CCS is steep, and it would come largely from the public purse.
  Like onshore CCS, many emerging plans for offshore CO₂ storage depend on government subsidies. Without such public funds, offshore CCS projects would not be economical. Plowing public subsidies into offshore CCS diverts scarce funds needed for proven, available, and essential climate measures that support the transition to a fossil-free future, like investment in renewables and energy demand reduction.
• CCS doesn’t deliver its promised emissions reductions. It keeps fossil fuel facilities running, delaying the energy transition.
  While many CCS proponents promise to drastically reduce or eliminate emissions by capturing carbon, most flagship CCS projects have been resounding failures. It is reported that the vast majority have failed to achieve their promised carbon capture rates. CCS keeps polluting facilities in operation, delaying the phase out of fossil fuels. A large-scale CCS buildout would require constructing a vast array of new infrastructure and those construction would create an enormous monitoring burden for government agencies and exacerbate environmental injustices.

CCS is only an industrial strategy to delay addressing climate change and phasing out fossil fuels and is not a solution to the climate crisis. Urgent action is necessary to accelerate a just and equitable transition away from fossil fuels and to protect critical natural ecosystems such as those in the world’s oceans. However, offshore CCS can not achieve either.

The full report also includes the following recommendations to governments:

• Halt the rush to develop offshore CO₂ storage hubs.
• End public subsidies for CCS, including offshore projects.
• Enshrine protections against and restrictions on international CO₂ trade and storage.
• Avert the risks that the new push for offshore CCS poses to oceans and ocean environments.
• Interpret existing legal frameworks to better protect communities, the environment, and our global climate.
• Strengthen regulatory regimes at the domestic and international levels to prevent harm from offshore CCS.
• Include impacts from the upstream sources of CO₂ in any assessments of offshore storage projects.
• Rule out shipping CO₂ long distances for injection, as an inherently inefficient and intrinsically dangerous strategy for “managing carbon.”
• Prohibit the use of CCS for EOR or EGR, including in offshore environments.
• Prioritize measures that address the root causes of the climate crisis, not its symptoms.

Implications for Japan’s CCS efforts

The Japanese government is currently planning to store a massive amount of CO₂: 6-12 million tons per year both domestically and internationally by 2030, and 120-240 million tons per year by 2050. They are also investing a significant amount of public money to develop technologies, implement model projects, and hasten the establishment of related systems. However, as this report highlights, there are numerous risks associated with offshore CCS, and that cost is very high. Hastily implementing projects and establishing such a system may lead to the manifestation of these risks in the future, or create an increased burden on the public.
The most reliable way to reduce CO₂ emissions is to reduce the production and use of fossil fuels. From that perspective, CCS efforts in Japan should be reconsidered.

Related Links:

CIEL Report
Summary：Deep Trouble: The Risks of Offshore Carbon Capture and Storage (June 2023) (Link)
Full report：Deep Trouble: The Risks of Offshore Carbon Capture and Storage (November 2023) (Link)

Written/Published: Center for International Environmental Law (CIEL)
Published: November 26, 2023