Offshore wind: a platform opportunity for carbon removal

What is offshore wind?

Offshore wind (OSW) is booming. Last month’s U.S. federal auctions for six leases covering 488,000 acres in the New York Bight netted a record $4.37B, and are expected to generate 7 gigawatts (GW) of electricity, enough to power 2 million homes. More than 2,000 wind turbines are forecast for the U.S.’s Atlantic coast by 2030, and a similar scale of expansion is expected globally, with $810B set to be invested this decade to bring global installed OSW capacity to over 250 GW by 2030.

OSW is a critical tool in our efforts to decarbonize the energy sector, one of the global community’s primary tasks in confronting the climate emergency. Beyond OSW, the vast majority of climate work and investment must focus on reducing greenhouse gas (GHG) emissions and decarbonizing the global economy more generally, in order to reach a target of net-zero emissions by 2050. However certain emissions sectors – such as agriculture, shipping, and aviation – will be impossible to abate in a climate-relevant time frame. As such, there is growing scientific consensus that carbon dioxide removal (CDR) will be required at immense scale – 1.5 to 3.1 gigatonnes (Gts) or more – by mid-century for us to have any chance of meeting our climate goals and limiting warming to 1.5 to 2 degrees Celsius above pre-industrial levels.

In addition to hundreds of GW of renewable electricity, the global economy’s large investments in OSW create two conditions that represent a significant opportunity for the integrated deployment of CDR. First, the tens of thousands of wind turbines that will be built, operated, and maintained over the coming decades offer a physical platform that can be leveraged for colocation of certain CDR pathways. In addition to the structures themselves, there will be regular service personnel and ship traffic in and around the OSW that can deploy and maintain offshore CDR projects. Second, due to its intermittent nature, OSW globally will generate thousands of gigawatt-hours (GWh) of annual curtailment, electricity that cannot be fed into the grid. Of course every electron generated that can be fed into the grid, must be fed into the grid. For the electrons that remain, CDR can beneficially use this curtailed energy resource.

The way(s) ahead

Three promising CDR pathways that can potentially be colocated with OSW deployment are marine permaculture; integrated direct air capture (DAC) with geologic sequestration; and electro-chemical ocean-based CDR. Each of these pathways is being advanced independently, both in terms of research and development (R&D) as well as commercialization. However, the opportunity to create leverage via integrating with OSW deployment remains largely untapped by OSW developers.

Marine permaculture is the ocean farming of kelp or other macroalgae, which can be harvested for use as food or to create bio-plastics and other products, as well as be employed for CDR. In addition to these economic uses of the resulting biomass, marine permaculture offers a number of co-benefits including ocean deacidification, restoration of marine ecosystems, and provision of forage for aquatic life, all of which can augment artisanal and commercial fisheries – which are frequently and in some cases vehemently oppositional to the deployment of OSW. Initial pilot deployments of marine permaculture with OSW exist in the North Sea, and the opportunity to scale this integration is low-cost and high-leverage for OSW developers and operators.

The challenges

There has been recent discussion and exploration of integrating DAC with OSW’s curtailed energy resource and the offshore geologic CO2 sequestration opportunity that coincides at scale with OSW deployments around the globe. Potential locations include the North Sea, which has been extensively studied, and the New York Bight, identified by Dr. David Goldberg of Columbia University’s Lamont-Doherty Earth Observatory as being another area with high potential storage capacity. Additionally Solid Carbon is researching, and seeking to advance, a pilot deployment of the concept off the coast of British Columbia. Offshore CO2 sequestration will require site-specific survey and research to operationalize, but the science and the injection process is generally well understood.

Two primary techno-economic challenges remain to be solved with respect to integrating DAC with OSW. First, DAC mechanics must be adapted to the harsh marine environment – moisture, salinity, storms, etc. (These conditions can be mitigated somewhat by siting the DAC onshore, but then CO2 transport will be required to the offshore storage site.) Second, it will be challenging to amortize the DAC capital expenditure against a curtailed energy resource. Emergent DAC pathways are being developed that minimize capex in order to take advantage of an intermittent renewable energy resource, but more innovation here is needed, and at greater scale.

Electrochemical ocean-based CDR pathways are currently at a lower technological readiness level (TRL) than DAC, but startups including Ebb Carbon, SeaChange, and Planetary Technologies will be opening demonstration plants over the next 12-24 months. Each of these companies employ renewable electricity, in differing ways, to increase ocean alkalinity or reduce acidification which – as with marine permaculture – is beneficial to marine ecosystems and fisheries, in addition to causing the ocean to draw CO2 down from the atmosphere in scientifically predictable quantities. These technologies would most practically be deployed onshore and be powered by curtailment from OSW generation. As with DAC, amortizing capex will be a challenge, but as these technologies move down the cost curve and potentially optimize capex to leverage the curtailed energy resource, or supplement the curtailment with dedicated renewable generation, the integration opportunity could be significant.

CDR represents a very material incremental revenue opportunity for OSW developers, in addition to the extensive potential climate benefit. Integrating CDR with OSW projects will certainly require additional capital. However, the high leverage of these incremental investments, given the existing infrastructure and operations for OSW, represents a meaningful opportunity for OSW project developers to more fully monetize their investments via the sale of carbon credits from the integrated CDR projects.

Integrating CDR with OSW will require advance planning; permitting and regulatory issues must be addressed upfront; and further innovation will be required to adapt DAC and electrochemical ocean-based CDR pathways to take full advantage of an intermittent renewable energy resource. For such an opportunity to be realized at a scale and time frame relevant to climate, the moment for Equinor, Orsted, and other major developers to begin exploring the integration of CDR with OSW is now. And because deployment at scale will by necessity be capital and resource intensive, and will involve complex regulatory factors, both state and federal governments have a potentially important, indeed critical, role to play in facilitating near-term progress. The rewards on offer are great, both economic and a potentially meaningful contribution to the restoration of our climate and oceans to a healthier state.

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