The science is clearer than ever that to prevent the most dangerous impacts of climate change, we not only have to reduce emissions, but also pull CO2 directly out of the air with carbon removal. The U.S. Long-Term Strategy indicates that in addition to reducing emissions by at least 85% around half a billion tons of technological carbon removal will likely be needed by mid-century to meet our net-zero climate goal.
One technology used for carbon removal, direct air capture (DAC), has seen growing private investment, public research funding and most recently $3.5 billion under the United States’ Bipartisan Infrastructure Law to build four large-scale DAC projects.
With all of this interest and investment, the coming years will more than likely see an increasing number of DAC plants constructed across the country. But what impacts will these projects have on nearby communities? As DAC is scaled to provide necessary carbon removal, how can we avoid historical and present practices in infrastructure siting that burden communities of color and fail to bring benefits to communities that need them most?
Because DAC is only operational on a small scale today, it can be difficult to assess the future impacts of expanding DAC capacity and their supporting infrastructure in the U.S. Doing so, however, is critical to scaling DAC in an equitable and environmentally friendly way.
To begin to answer some of these critical questions, a new WRI working paper synthesizes the best available data on the impacts of various DAC systems, and offers preliminary recommendations for community engagement and policy guardrails that will help ensure DAC is scaled up responsibly.
What does it mean to scale Direct Air Capture responsibly?
Responsibly scaling DAC requires the thorough assessment of the economic, environmental and social impacts of siting and operating plants, paired with effective action to reduce potentially detrimental impacts and equitably provide benefits. We break down the components of a responsible scale-up and lay out what we know about potential impacts of building DAC plants.
Assessing environmental impacts of Direct Air Capture
To understand the environmental impacts of DAC plants, it’s first helpful to conceptualize a DAC plant. DAC plants are machines that push air over certain types of chemicals, which selectively react with CO2 in the air. Once captured, heat is typically applied to release the CO2, which is then compressed and sequestered underground or sold for use in certain products, such as concrete building materials.
DAC plants today vary in scale from capturing 1 metric ton (tonne) of CO2 per year up to 1 million tonnes (Mt) per year — the largest plant in operation today captures 4,000 tCO2/yr with one MtCO2/yr scale plant in development; for comparison, a typical passenger vehicle in the U.S. emits 4.6 tonnes of CO2 per year. The different sizes and possible configurations of DAC plants mean that DAC plants can be sited in a variety of locations and can be tailored to local needs. It also means that the impact of DAC will differ from plant to plant.