How green are solar panels?
Posted by Alex Barrett on 25 April 2016 at 12:05 pm
Renewable energy is an important tool to build a more sustainable future, and solar power is central to our green energy arsenal. But can anything be truly green? What impacts do solar panels have on our environment? And what are the costs of manufacturing these devices?
First things first, installing solar panels is a good idea. The more energy we can generate from renewable means the better. However it is always worth considering the invisible costs of any technology, so that we can properly understand and counter the impact that it has on our environment. There are two broad areas to consider here, the environmental impact of the installation and use of solar power generation systems, and the cost, in terms of energy and CO2, of their manufacture.
A recent study  classifies the different impacts of the installation of large scale, industrial solar power stations in regions with sunny climates. They considered changes in land use and biodiversity as a result of setting up solar plants, and the impacts of solar facilities on human health. The study contrasts the impacts of solar power with those produced by generating the same amount of electricity using fossil fuels. The results are encouraging. These solar facilities inevitably affect the biodiversity of the areas where they are built, and are far from carbon neutral. However they are substantially better than the infrastructure needed to provide the same energy using fossil fuels.
The cost of producing solar panels can be determined through Life Cycle Assessment (LCA) . This considers the amount of energy needed to manufacture every component, how they are transported and how they will ultimately be disposed of. The life expectancy of a solar cell could be as much as 30 years, but this will depend on how well it is manufactured .
Manufacturing solar cells is energy intensive, and requires large quantity of rare earth elements. It also produces a variety of polluting chemicals. Care needs to be taken that these are not introduced into the environment. The total life cycle CO2 emissions of a large scale solar power plant is likely to be between 16 and 86.3 gCO2e /kWh . For domestic solar cells this could be as low as 30 gCO2e/kWh .
However concerns have been raised that many published LCAs for solar panels assume European manufacturing techniques and installation in sunny environments . It is often claimed that solar panels are 15% less carbon intensive than natural gas, but this may no longer be the case. Solar panel production has shifted to China in recent years. This has reduced the cost, but has increased the carbon footprint. The energy sector in China has been estimated to be twice as carbon intensive as that of Europe and the USA, and accurate LCAs for Chinese solar panels have yet to be produced. [5, 6].
It has been estimated that Chinese solar panels installed in northern Europe, where the intensity of sunlight isn’t optimal, could have a carbon footprint of 120 gCO2e/kWh. This is still 3.75 times less carbon-intensive than equivalent natural gas production  but the environmental cost of solar panels may be higher than often reported.
On balance solar panels are good for the environment. Even with the worst case estimates they produce less greenhouse gas emissions than the burning of fossil fuels. Replacing fossil fuel use with solar has a net positive effect on the environment, and their manufacture depletes a different set of non-renewable resources. However they are not perfect. There is doubt as to whether the solar industry is really sustainable and, as with any electronic device, their production will inevitably have an environmental cost.
- Turney, D., & Fthenakis, V. (2011). Environmental impacts from the installation and operation of large-scale solar power plants. Renewable and Sustainable Energy Reviews, 15(6), 3261–3270. (Links to pdf)
- United Nations Environment Program: Explanation of Life Cycle Assessment
- Centre for Alternative Technologies
- Low Tech Magazine
- Yue, D., You, F., & Darling, S. B. (2014). Domestic and overseas manufacturing scenarios of silicon-based photovoltaics: Life cycle energy and environmental comparative analysis. Solar Energy, 105, 669–678.
- National Geographic
More information about Solar Electricity on YouGen.
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