Stanford study casts doubt on carbon capture

Stanford study casts doubt on carbon capture

SOURCE: Stanford DATE: October 25, 2019 SNIP: One proposed method for reducing carbon dioxide (CO2) levels in the atmosphere – and reducing the risk of climate change – is to capture carbon from the air or prevent it from getting there in the first place. However, research from Mark Z. Jacobson at Stanford University, published in Energy and Environmental Science, suggests that carbon capture technologies can cause more harm than good. “All sorts of scenarios have been developed under the assumption that carbon capture actually reduces substantial amounts of carbon. However, this research finds that it reduces only a small fraction of carbon emissions, and it usually increases air pollution,” said Jacobson, who is a professor of civil and environmental engineering. Jacobson, who is also a senior fellow at the Stanford Woods Institute for the Environment, examined public data from a coal with carbon capture electric power plant and a plant that removes carbon from the air directly. In both cases, electricity to run the carbon capture came from natural gas. He calculated the net CO2 reduction and total cost of the carbon capture process in each case, accounting for the electricity needed to run the carbon capture equipment, the combustion and upstream emissions resulting from that electricity, and, in the case of the coal plant, its upstream emissions. (Upstream emissions are emissions, including from leaks and combustion, from mining and transporting a fuel such as coal or natural gas.) Common estimates of carbon capture technologies – which only look at the carbon captured from energy production at a fossil fuel plant itself and not upstream emissions – say...
Direct CO2 capture machines could use ‘a quarter of global energy’ in 2100

Direct CO2 capture machines could use ‘a quarter of global energy’ in 2100

SOURCE: CarbonBrief DATE: July 22, 2019 SNIP: Machines that suck CO2 directly from the air could cut the cost of meeting global climate goals, a new study finds, but they would need as much as a quarter of global energy supplies in 2100. The research, published today in Nature Communications, is the first to explore the use of direct air capture (DAC) in multiple computer models. The two DAC technologies included in the study are based on different ways to adsorb CO2 from the air, which are being developed by a number of startup companies around the world. One, typically used in larger industrial-scale facilities such as those being piloted by Canadian firm Carbon Engineering, uses a solution of hydroxide to capture CO2. This mixture must then be heated to high temperatures to release the CO2 so it can be stored and the hydroxide reused. The process uses existing technology and is currently thought to have the lower cost of the two alternatives. The second technology uses amine adsorbents in small, modular reactors such as those being developed by Swiss firm Climeworks. Costs are currently higher, but the potential for savings is thought to be greater, the paper suggests. This is due to the modular design that could be made on an industrial production line, along with lower temperatures needed to release CO2 for storage, meaning waste heat could be used. The energy needed to run direct air capture machines in 2100 is up to 300 exajoules each year, according to the paper. This is more than half of overall global demand today, from all sources, and despite rising...