By Elly Dinnadge
“Setting aside economic constraint and public objection, it is technically possible to power the world on 100% renewable sources”, according to the late David MacKay, Chief Scientific Advisor to the Department of Energy and Climate Change 2009-2014.
Without a doubt, renewable energy is on a roll. It is now cost competitive with fossil fuels in many markets, and a growing number of cities, companies, and even countries are committing to the “100% renewable” movement.
So what’re we missing? What’s not to like? (besides something beginning with T…..rump and perhaps a worrying lack of support from our own government).
Unfortunately, renewable energy is not all daisies and dandelions. Although fossil fuels are substantially more damaging, all sources of energy have some form of impact on the environment.
Let’s start with our baby. Solar. Although no greenhouse gas emissions are released during power generation, the production of solar panels is by no means zero-carbon. During the manufacturing process, harmful materials are used, which, if not recycled or properly disposed of during decommissioning, could cause environmental contamination. The panels must be transported to the site of installation (often coming from China), which adds to their carbon footprint. Construction of solar farms in rural landscapes can encroach on habitats important for biodiversity conservation, if planning is not effectively managed. This is less of an issue in urban areas where rooftops are generally available.
Hydropower is perhaps the most damaging renewable energy source. Selected sites for hydroelectric plants must be flooded, which decomposes vegetation and soil, releasing carbon dioxide and methane into the atmosphere. Both large dams and run-of-river systems significantly alter aquatic ecosystems which affects wildlife throughout the food chain; from algae to fish and even mammals. Not to mention, the thousands or even millions of indigenous people who are forcefully displaced due to dam construction.
Wind power has also fallen under intense scrutiny due to its negative impact on bird and bat species. Collisions with turbines, meteorological towers and transmission lines have reportedly caused deaths. The National Wind Coordination Collaborative recommends several pre-development strategies which can mitigate, to a certain extent, these risks. For example, siting turbines in areas of low prey density for raptor species.
One way of assessing the carbon footprint of different energy sources is to carry out a Life Cycle Assessment (LCA). This entails consideration of emissions generated from the start of the manufacturing process through to decommissioning. Turconi et al. (2013) analysed over one hundred LCA studies and found that hydroelectric dams release 11-20 kg CO₂-eq/MWh during their lifetime, wind 3-28 kg CO₂-eq/MWh and solar PV varied between 13 and 130 kg CO₂-eq/MWh, depending mainly on local conditions such as source of electricity used during manufacturing and typology of panels. This is compared to 530 kg CO₂-eq/MWh for oil and 750 kg CO₂-eq/MWh for coal.
Solar SOAS’s shiny panels are sourced from Amerisolar Ltd which is accredited with PV Cycle recognition to ensure decommissioned panels are recycled after their operating life. Amongst several other certifications (see here: http://www.weamerisolar.com/certifications.html ). Our panels, like most PV goods, were manufactured in China and this is something we aim to consider in any potential future projects. Yet we must owe it to her, for without China’s mass production, it is unlikely we would have been anywhere near able to afford panels at all.
For now, we’re proud of the 10.22 tons of CO₂ we save each year but we’re not quite done yet…