KJ Tait

Paying Back the Embodied Carbon of PV

25 September 2023

We have recently been investigating PV and whether the carbon associated with manufacture, transport to site and installation would actually pay off over a 20 year lifespan. 


Ordinarily when assessing this, we would calculate the yearly generation and multiply this by today’s carbon factor to work out whether the carbon is indeed paid back.  However, for our most recent assessment we have used the Future Energy Scenario of a steady transition to Net Zero that is provided by the National Grid.  This assumes that the carbon factor for grid electricity will have reduced to 0.0294kgCO2/kWh by 2050.  This is a 79% reduction compared to SAP10.2 (todays carbon factor) which is 0.14kgCO2/kWh. 


Investigating SAP10.2 against actual grid carbon figures also throws up a challenge where in the summer months the carbon factor for the last 5 years has been lower than 0.14kgCO2/kWh. 


Our analysis found that monocrystalline and polycrystalline panels manufactured in China would not payback over 20 years using this method.  The polycrystalline panels performed better; however, stakeholders may not be keen on using these panels due to their blue hue. 


However, are there bigger considerations at play here? is the carbon factor of the grid only reducing, particularly in the summer months. because buildings are having PV installed on them?  We may also have to consider that if PV is not installed on buildings, then would we need to build more power stations?  These new power stations would surely have more embodied carbon per kW than a PV panel. 


Lastly, do we need to ramp up manufacturing of PV in the UK?  Our research suggests that only one company currently manufacturers PV within the UK.  If panels were manufactured here, the likelihood would be that the embodied carbon would reduce.  We definitely need to think about all these aspects on the journey to Net Zero Carbon.