Abby L. Harvey
GHG Monitor
10/17/2014
When looking beyond the simple measure of greenhouse gas emissions to the total environmental impacts of the implementation of low carbon technology, carbon capture and storage falls behind other low carbon technologies such as wind and solar power generation, a life cycle study published this week in the Proceedings of the National Academy of Sciences concludes. The study looked into the materials needed for a full-scale transition to low-carbon energy production, such as cement, iron and aluminum and weighed the negative environmental effects involved in the production of these materials with the positive environmental effects of switching to low carbon energy generation. Unsurprisingly, the research group, which comprised of scientist from the Norwegian University of Science and Technology, The University of California, the National Renewable Energy Laboratory in Golden, Colo., Utrecht University in the Netherlands, the University of Concepción in Chili and Tsinghua University in Beijing, China, found that while a transition to low carbon energy generation would result in increased materials requirements, the negative environmental impacts of this increase are insignificant when compared to the reduction of direct emissions from fossil fuel fired energy production.
That benefit, however, is reduced greatly for the implementation of CCS, the report says. The analysis compared a “BLUE Map” climate-change-mitigation scenario and a baseline scenario based on International Energy Agency definitions. “These scenarios use a combination of energy conservation, renewable and nuclear energy, and CCS. Our analysis suggests that an electricity supply system with a high share of wind energy, solar energy, and hydropower would lead to lower environmental impacts than a system with a high share of CCS.”
According to the study, a large percentage of the total environmental impact of renewable energies is due to materials requirements, however, with fossil energy, indirect impacts due to materials are minimal when compared to high direct environmental impacts. When CCS is added to the mix, the need for additional materials increases these indirect effects. “Wind and solar power plants tend to require more bulk materials (namely, iron, copper, aluminum, and cement) than coal- and gas-based electricity per unit of generation. For fossil fuel-based power systems, materials contribute a small fraction to total environmental impacts, corresponding to [less than] 1 [percent] of GHG emissions for systems without CCS and 2 [percent] for systems with CCS. For renewables, however, materials contribute 20–50 [percent] of the total impacts,” the study says.
The study explores further the direct and indirect environmental impacts of fossil fuel generation with CSS. “CCS reduces CO2 emissions of fossil fuel-based power plants but increases life-cycle indicators for particulate matter, ecotoxicity, and eutrophication by 5–60 [percent]. Both postcombustion and precombustion CCS require roughly double the materials of a fossil plant without CCS. The carbon capture process itself requires energy and therefore reduces efficiency, explaining much of the increase in air pollution and material requirements per unit of generation,” the study says.
