What is the carbon impact of manufacturing renewable energy technology and how does it affect Zero Carbon pathways? Design Director Marie-Louise Schembri examines how the carbon savings of renewables compare to the embodied carbon of the system.
Theoretically, we need over 50 million photovoltaic (PV) panels (over 800km2) to replace all of the energy generated by fossil fuels in the UK. The UK has committed heavily to use offshore wind farms to decarbonise energy, planning to increase the current 11GW capacity to 40GW by 2030, which equals approximately 30% of electricity demand.
While this is all very positive for reducing carbon emissions from energy use, it is important to remember that everything we manufacture has a carbon footprint, resulting from the extraction of raw materials, transportation across supply chains, the manufacturing process and delivery to a final destination. So how do the carbon savings of renewables compare to the embodied carbon of the system?
Historically, embodied carbon emissions have been mostly ignored by government and business policy and have only recently started to get the attention they need. Buildings in the UK contribute 49% of the UK’s overall greenhouse gas emissions, and about 20% of this can be attributed to embodied carbon.
Policy in the built environment has so far focussed on reducing energy consumption and generating as much renewable energy as is feasibly possible. There is nothing wrong with the latter part, but in the face of a Climate Emergency we need to keep an eye out on unintended consequences of focusing too much on energy consumption.
Over the past 15 or so years, local planning policy has driven new developments to install renewable energy systems. In dense urban settings – office buildings for example – the result is typically a relatively small array of roof photovoltaic panels that generate approximately 1% of a building’s annual energy requirement. They are a lot more effective where the ratio of PV area to floor area is more balanced, such as on the tops of houses, logistics buildings and sports stadia, but commercial developers have begun to question the value of PV and small scale renewables, labelling them as tick-box symbols of greenwash.
So, are they worth the carbon impact?