“Our results imply that the energy roadmaps for climate change mitigation bring co-benefits, such as a reduction in the emissions of air pollutants, namely particulate matter, or other toxic compounds, thus lessening the threat on human and ecosystems’ health,” Thomas Gibon of the Norwegian University of Science and Technology told environmentalresearchweb. “Moreover, we can afford this necessary shift of energy systems, from fossil to renewable and carbon dioxide capture and storage; the material requirements to build new energy plants are realistic, for example, the amount of copper needed to build out photovoltaic systems by 2050 represents just two years of current copper production.”

The team, from Norway, the US, the Netherlands, Chile and China, modelled two energy scenarios from the International Energy Agency (IEA) – the business-as-usual Baseline scenario and the BLUE Map scenario in which solar, wind and hydropower combine to make up 39% of total electricity generation by 2050. In 2010 their share was 16.5%.

The Baseline scenario saw emissions of air and water pollutants more than double by 2050 whereas the BLUE Map scenario brought a doubling of electricity supply while stabilizing or even reducing pollution, according to Gibon and colleagues’ paper in PNAS.

Low-carbon technologies often require more materials per unit of electricity generated than conventional fossil fuels, for example photovoltaic systems need 11–40 times more copper and wind power plants consume 6–14 times more iron. That said, just one year of the world’s current iron production would be enough to build a low-carbon energy system that could meet global electricity demand in 2050.

“We felt there was a need to evaluate the environmental impacts (i.e. the side effects) of climate change mitigation,” said Gibon. “Energy scenarios are based on greenhouse gas emissions targets, but too little is known about other environmental impacts such as toxicity or land occupation. Environmental assessment studies focus too often on one pollutant, or one technology, or one regional context.”

With that in mind, Gibon and colleagues carried out a lifecycle assessment that considered all flows of material and energy during the lifetime of the renewable energy systems, as well as emissions and water. The team used data from traditional lifecycle inventories along with economic tables of monetary flows between sectors, and analysed the emissions causing particulate matter exposure, freshwater ecotoxicity, freshwater eutrophication and climate change.

“Our study also accounts for the interactions between the technologies we model, i.e. solar photovoltaics, concentrating solar power, hydropower, wind, coal and natural gas with and without carbon dioxide capture and storage,” said Gibon. “Finally, we have modelled the impacts from the building, the operation and the decommissioning of power plants separately, so that impacts actually occur at the right time in our scenarios – time aggregation of impacts is often a criticized aspect of lifecycle assessment.”

Gibon believes the findings indicate that climate mitigation targets for electricity production could well be a win-win situation from a policy perspective. “Reducing greenhouse gas emissions also means reducing other environmental impacts,” he said.

Now the team would like to pursue the same approach with other scenarios, such as the IPCC’s. “This work is also part of a forthcoming report by the UNEP International Resource Panel, which we hope will help disseminating these results forward,” said Gibon.

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