‘Green’ energy solutions – how much CO2 do solar panels actually save?
Please also refer to our latest article ‘The true energy cost of solar’ for further information
A single solar panel will produce around 211 kWh of power each year (based on an REC250 panel in a UK location). Switching to solar will reduce our carbon footprint but but what about the carbon footprint of the panel itself? In order to calculate total energy savings (and consequent CO2 savings) our calculations must first deduct the amount of energy that was required to manufacture the panel.
We can then translate these energy savings into greenhouse gas CO2 savings that would have been released into the atmosphere if the same energy were produced through burning fossil fuels.
Critics will often highlight the amount of energy it takes to produce a solar panel so lets first take a look at the manufacturing process…
Silicon is refined and then manufactured into thin solar cells that make up a solar panel. In high-end panel factories the process is almost entirely automated using robots to minimise handling of the materials and hence the risk of defects in the panel’s later life.
- Silicon is melted and cast in a 250Kg ingot block
- This is then cut into bricks before being sliced into around 600 wafers. This is enough silicon to produce around 165 panels
- The wafers, or cells, are loaded into the production line and given an anti-reflective coating before being doped with chemicals to induce the PV properties
- Each individual cell is uniquely identified so it can be traced back to its original ingot
- Cells are then arranged in strings and fitted to a panel.
What about other factors?
In order to get a true picture about how much energy solar panels actually save we need to look at a complete Lifecycle Analysis (LCA). This includes additional energy used for transportation, installation and recycling at the end of the panel life.
If we look at the carbon footprint of a solar panel (taking into account its entire lifecycle) the CO2 emission equivalent is around 30g / kWh on average.
In the UK the amount of CO2 emission equivalent from our current electricity supply is calculated to be 451g / kWh since our supply comprises of predominantly fossil fuel sources. From this figure we can see that solar panels are a far ‘greener’ energy source.
How can we further reduce the carbon footprint of solar panels?
This might seem a little obvious but why not power your panel factory using solar panels!? REC is one of the world’s leading low-carbon panel manufacturers with several factories currently powered by solar and hydroelectric power. This gives their product the lowest carbon footprint of any panel available on the market!
Use of renewable energy to power the manufacturing process means that REC panels produce just 21g / kWh of CO2 equivalent emissions. The energy ‘payback’ of REC solar panels can be as little as one year!
What about pollution and waste?
In recent years we have become fixated on the effects of climate change and reducing CO2. Whilst climate change is arguably the most challenging and pressing global issue we face, lets not forget that our environment is intrinsically connected. Our contributions to waste, resources and climate change will all have an impact on one another.
Solar panels are manufactured from silicon, a substance that is made from sand and is a readily available resource. When it comes to recycling around 90% of the solar panel components (including glass, aluminium and semiconductor materials) can be reused in the production of more solar panels or other products.
Solar panels are expected to last for around 25 years or more; however, in 2007 a report funded by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) estimated that there will be around 35,000 tonnes of PV waste by 2020 as older systems reach the end of their life and the number of defect and damaged panels increases. In 2007 the European PV industry established PV CYCLE to set up a recycling system that will handle this relatively new waste stream.
Looking back to the carbon footprint again PV CYCLE estimates that recycling 1 tonne of silicon based PV modules can save around 800Kg of CO2 equivalent and up to 1200Kg where the module is manufactured from 100% primary materials.
What more can be done?
One idea manufacturers are developing to help reduce the carbon footprint of solar panels further and make them even more affordable is to manufacture them from biological materials. We will explore the feasibility of this in our next blog about PV panels…
In the meantime, we have highlighted the importance of choosing a PV manufacturer who is making a conscious effort to reduce their carbon footprint and create a long-lasting and high performance solar panel. You may also want to read more about choosing an installer and selecting your panels to learn about some of the other important aspects of solar you should also consider before signing up for an installation.