Despite the fact that the impacts of manmade climate change are already being felt and that failure to mitigate these effects by lessening fossil fuel CO2 emissions could result in dire consequences, policies enacted to reduce these emissions have been grossly insufficient. While there is no one silver bullet to "solve" climate change, many technologically feasible solutions exist that together can work to close the carbon loop and account for net zero carbon emissions.
A New York Times article on July 9th, Blueprints for taming the climate crisis sees "pulling it off" as requiring an overhaul of how we use energy and a huge investment in the development and deployment of new technologies. This sustainable investment requires end-to-end efficiency improvements in all sectors of the economy, decarbonization of centralized energy and fuel substitution. Unfortunately, this ideal of solving climate change stalls against the perception of global climate change as a problem, the struggle to decouple economic growth from carbon emissions growth, the inability to fully account for the damage from CO2 emissions, the abundance of cheap fossil fuels and the fossil fuel industry's embedded interests. Yet as policy makers gear up to "pull it off," more technological options need to be on the table. Though still nascent, and requiring more research and development, direct air capture, a technology that extracts CO2 from ambient air, represents an option to be technologically optimistic. It is economically viable in several areas and can permit negative emissions to eventually stabilize atmospheric concentrations. However, as this technology scales up from demonstrations to pilot scale to commercialization, the deployment is not without risks and challenges that could delay or distract from its use as an effective means to manage our carbon footprint. While current support for the pioneers in this industry comes from private and philanthropic investment, below are 10 reasons why policy makers should take direct air capture seriously.
1. Direct air capture represents a technological fix to climate change
As Klaus Lackner, Director of the Lenfest Center for Sustainable Energy (LCSE) explains, direct air capture fits the requirements laid out by Sarewitz and Nelson for a technological fix. First, it can act directly to reduce CO2 concentrations, independent of the complexities of the global energy system, thereby connecting the problem to solution (ie. in contrast to renewables added to the grid which may simply increase total energy capacity but not reduce emissions). Second, it permits an unambiguous metric to assess direct air capture's effectiveness: the amount of CO2 captured. Lastly, as Lackner notes in The urgency for the development of CO2 capture from ambient air, while more research is required, air capture is clearly technologically feasible.
2. It is different from conventional carbon capture and storage
There is a fundamental difference between direct air capture and conventional carbon capture and storage (CCS). Namely, the former can address excess carbon dioxide independent of its source, while the latter requires a concentrated source (ie. flue gas from a coal fired power plant). While both processes are important in the context of stabilizing carbon emissions and can function in tandem, the former allows for negative emissions and does not directly support the continued use of fossil based energy. This ability can permit offset schemes in regulatory environments.
3. Early private investments demonstrate commercial opportunities
Direct air capture is currently funded by private and philanthropic investors who see opportunities for making a profit off of the availability of a sustainable resource. As LCSE Senior Staff Associate Allen Wright sees it, "right now, direct air capture is very similar to the incipience of the wind industry. Forward thinking innovators are exploring the technology space that could operate in a free market. Yet the current climate condition demands more attention from a broader scope of innovators. This can be incubated and encouraged through public investment and policy." Such public support shapes a framework that could enable negative emissions.
4. Direct air capture can be used to produce renewable fuels
A very commercially attractive opportunity for the use of air captured carbon dioxide is for the production of synthetic hydrocarbon fuels or the enhancement of third generation biofuels. While this is not a negative emission technology because the CO2 is released when the fuel is consumed, it obviates the need to extract fossil fuels, thus closing the carbon loop and enabling carbon neutrality by replacing gasoline. As evidence for market trends, Audi is teaming up with Climeworks and will soon be the first automaker to source CO2 as a fuel. As another application, LCSE PhD Candidate Diego Villarreal-Singer is working on modularizing the synthesis of fuels for seasonal energy storage. Villarreal-Singer notes the potential benefits of this application for the transportation sector (which is significantly more difficult to decarbonize), "Even if we were to switch all cars in the world to electric vehicles we still would need to account for airplanes and shipping vessels whose engines require high energy density fuels. In this regard, liquid hydrocarbon fuels are here to stay for the foreseeable future."
5. Direct air capture can be used to produce fibers
There are several materials markets that direct air capture can support. Instead of sectors of the economy requiring fossil fuels, like plastics or cement, direct air capture could provide a sustainable stream. Companies focused on sustainability are already headed in this direction. For instance, Dell has partnered with Newlight to capture gases to make the packaging for their computers. This permeates consumer consciousness and allows the individual and aggregate to further add negative emissions into calculating their carbon footprint.
6. Direct air capture supports sustainable and resilient agriculture
Greenhouses are another sector of the economy that can greatly benefit from air captured carbon dioxide. Some greenhouses currently maximize their yield with enhanced CO2, a process with significant costs and a high carbon footprint. Air captured CO2 has the potential to entirely transform this sector by providing a cheaper source to enhance yield while also supporting local and resilient food systems. Infinitree is one company in this space that will use Lackner's "artificial tree" technology for such a purpose.
7. Direct air capture will give us more oil
While captured carbon dioxide will enable our addiction to extracting fossil fuels through providing compressed CO2 for enhanced oil recovery (EOR), it presents the opportunity to optimize this technology and bring down costs. Some companies are willing to pay up to $80/ton of CO2 for this tertiary process, and there are several eager suppliers from natural and industrial sources as well as direct air capture. Direct air capture companies such as Carbon Engineering and Global Thermostat are poised to benefit from EOR, with the ability to build distributed units near residual oil zones in remote sites. Though subject to some debate, EOR can permit negative emissions in the balance of CO2 that stays underground. Moreover, using direct air capture for EOR has the distinct advantage as a sustainable and limitless source.
8. Because direct air capture is modular, it can be scaled up rapidly
Lackner's direct air capture units which could theoretically capture one ton of CO2 per day could fit inside a shipping container. Lackner estimates that 10 million air capture units, each capable of capturing 1 ton of CO2/day, could capture approximately 10% of the human CO2 emissions. While this number is large, our global infrastructure is capable of mass production of units of a similar size. For reference, about 83 million vehicle units were produced worldwide in 2013. Moreover, similar to arguments outlined in a paper, Small modular infrastructure by LCSE alumnus Eric Dahlgren, air capture units can demonstrate efficiency in numbers through flexibility and diversification. For instance, one could generate closed-loop fuels from air captured CO2 co-located with a renewable energy source on the residential scale, further empowering the rapid transition to distributed energy generation.
9. Direct air capture requires significant energy
It is important to note that direct air capture units could face constraints as an effective means to manage climate change because of the high energy costs. Ideally, decarbonized sources could power these units, as high-carbon centralized energy sources might put a serious dent in the net emissions achieved. Nevertheless, the demand for distributed clean energy for these units also presents the opportunity to expand the capacity for a renewable energy fleet.
10. We may not have a choice
Ultimately, addressing the effects of climate change requires stabilizing the atmospheric concentration of CO2. It is highly likely that we are engaged in an overshoot scenario where concentrations will surpass what is considered a dangerous threshold. Even in the unlikely event that all fossil energy is switched to renewables, there is still another half of total emissions coming from mobile sources. While afforestation and bio-energy with carbon capture and storage are negative emissions strategies that allow us to draw down the atmospheric concentration of CO2, they have limited scale. Direct air capture combined with carbon sequestration may well be the best option as an insurance against the effects of excess atmospheric CO2.
Explore further: From theory to reality: Carbon capture utilization and storage