As the world has successively blown past various emissions reductions targets over the past generation, climate and energy modelers have had to rely more and more on 'negative emissions' to achieve their goals (in models). While negative emissions are not a substitute for near-term mitigation, they offer some flexibility if emissions overshoot targets. For a time, the main negative-emissions technology used in climate models was bioenergy with carbon capture and storage, or BECCS. But real-world deployment of BECCS would require vast amounts of land — an area up to to five times the size of India — which would compete with other land uses and threaten ecosystems. Natural carbon sequestration, including large-scale reforestation, is a more promising option, but it would only replace the carbon released when those forests were first cut down — it won't be enough to substantially reduce future warming.
Arguably the most promising source of large scale negative emissions is a newer and growing set of solutions known as direct-air capture (DAC) technologies, which pull CO2 directly from the atmosphere. But despite the early success of some DAC startups, the industry has a long way to go before it can deliver results at scale.
The problem is that wide-scale deployment of DAC may be as hard, or harder, than developing the core technology itself. Unlike clean energy technologies such as wind and solar, DAC can’t plug into the grid. Scaling DAC would require a massive investment in its own supporting infrastructure: a new system of pipelines at a magnitude that could rival that of the United States Interstate System. To ensure scalable DAC, we need to take the policy implications seriously and chart a course to deployment.
The US boasts some of the most progressive policies in the world on carbon removal. The FUTURE Act, which passed in 2018 as part of the broader Bipartisan Budget Act of 2018, incorporates tax incentives for permanent carbon storage under the 45Q tax credit, including a 10-year ramp up to $50 per ton for CO2 stored in geologic formations. (The tax credit has yet to be formally implemented as developers are waiting on the IRS to publish draft guidance.)
The state of California also amended its Low Carbon Fuel Standard to establish one of the most impressive carbon capture incentives, one that applies anywhere in the world. On average, over the past 12 months, carbon in California is traded at a price between $122/tCO2 and $190/tCO2. When these credits are combined with 45Q, they will dramatically change the economic viability of DAC development and deployment.
These carbon removal initiatives are helpful for investing in direct air capture technology, but there is a glaring policy gap regarding investment in the systems we will need to support it. Although the need for new CO2 infrastructure can be reduced somewhat — by developing DAC facilities near either storage basins or other sources of captured carbon such major industrial centers — it can’t be eliminated. And as with all large infrastructure systems, building it will require considerable government funding and planning.
Wide-scale deployment of direct air capture may be as hard, or harder, than developing the core technology itself.
States and the federal government must address these funding needs with the same level of attention that innovation in negative emission technology has received. Though there are existing federal legislative proposals, they have not yet been enacted into law. The Utilizing Significant Emissions with Innovative Technologies (USE IT) Act would clarify that CCUS projects and CO2 pipelines are eligible for the permitting review process established by the 2015 Fixing America’s Surface Transportation (FAST) Act. Representative Cheri Bustos (D-Ill.) has also introduced a carbon dioxide bill that would establish a low-interest loan program within the Department of Transportation for trunk and feeder lines to enable a robust build-out of the existing CO2 networks. The program would have an authorized funding level of $500 million.
The US currently has approximately 5,000 miles of CO2 pipelines, which have been built in response to private companies’ demand for enhanced oil recovery (EOR) and have been mostly limited to oil fields. While 5,000 miles may seem extensive, for comparison, the US natural gas pipeline network has about 3,000,000 miles of pipelines that link natural gas production areas, storage facilities, and end-users. Estimates of the scale of additional CO2 pipelines vary widely depending on the amount of future negative emissions, ranging from between 11,000 and 23,000 additional miles on the low end to as much as 120,000 miles by 2050. So while Rep. Bustos’ pipeline legislation is a good start, it's clear we are going to need a bigger bill.
States will also need to take action. The design, routing, construction, and operation of CO2 pipelines is regulated at the state level. States must develop additional policies that clarify and support the permitting process for entities that plan to utilize future federal incentives to develop this system beyond oil fields. Preferably, these policies will aim to minimize environmental impacts, site new pipelines along existing infrastructure, and will ensure vulnerable species habitat is not significantly impacted.
Among the biggest hurdles to large-scale DAC, however, could well be organized public opposition to the necessary infrastructure. There is a risk that without sufficient public engagement, new CO2 pipelines for DAC could also be perceived as an safety and environmental threat. Organized public opposition is a common reaction to large new infrastructure on the landscape, whatever its function, and lack of understanding regarding the role of CO2 pipelines (and associated risks) could increase the chance of community mobilization and NIMBYism. Ensuring that CO2 pipelines are viewed as positive for the environment, and as a climate solution, will be a critical step in deploying a more extensive network.