The 1 MW photovoltaic array at NREL’s Flatirons Campus. (Photo: Werner Slocum, NREL)
In their new paper in Joule, “Embodied Energy and Carbon from the Manufacture of Cadmium Telluride and Silicon Photovoltaics,” National Renewable Energy Laboratory (NREL) researchers Hope Wikoff, Samantha Reese and Matthew Reese deal with the 2 dominant deployed photovoltaic (PV) applied sciences: silicon (Si) and cadmium telluride (CdTe) PV. These inexperienced applied sciences assist cut back carbon emissions and meet world decarbonization targets – however their manufacturing processes can themselves lead to greenhouse gasoline emissions.
“Green technologies are awesome, but as we are working to scale them up to an incredible magnitude, it makes sense to take a close look to see what can be done to minimize the impact,” says Samantha Reese, a senior engineer and analyst in NREL’s Strategic Energy Analysis Center.
To perceive the general influence of those inexperienced applied sciences on world decarbonization targets, the workforce appeared past conventional metrics like price, efficiency and reliability. They evaluated “embodied” energy and carbon – the sunk energy and carbon emissions concerned in manufacturing a PV module – in addition to the energy payback time (the time it takes a PV system to generate the identical quantity of energy as was required to supply it).
“Most advances have been driven by cost and efficiency because those metrics are easy to evaluate,” states Matthew Reese, a physics researcher at NREL. “But if part of our goal is to decarbonize, then it makes sense to look at the bigger picture. There is certainly a benefit to trying to push efficiencies, but other factors are also influential when it comes to decarbonization efforts.”
“One of the unique things that was done in this paper is that the manufacturing and science perspectives were brought together,” Samantha Reese continues. “We combined life-cycle analysis with materials science to explain the emission results for each technology and to examine effects of future advances. We want to use these results to identify areas where additional research is needed.”
The manufacturing location and the know-how sort each have a significant influence on embodied carbon and signify two key knobs that may be turned to affect decarbonization. By taking a look at present-day grid mixes in international locations that manufacture solar, the authors discovered that manufacturing with a cleaner energy combine – in comparison with utilizing a coal-rich combine – can cut back emissions by an element of two. Furthermore, though Si PV presently dominates the market, thin-film PV applied sciences like CdTe and perovskites present one other path to lowering carbon depth by a further issue of two.
This perception issues due to the restricted carbon finances out there to assist the anticipated scale of PV manufacturing within the coming many years.
“If we want to hit the decarbonization goals set by the Intergovernmental Panel on Climate Change, as much as a sixth of the remaining carbon budget could be used to manufacture PV modules,” Matthew Reese provides. “That’s the scale of the problem – it’s a massive amount of manufacturing that has to be done in order to replace the energy sources being used today.”
The authors’ hope is that by illustrating the magnitude of the issue, their paper will trigger folks to take one other have a look at the potential use of thin-film PV applied sciences, equivalent to CdTe, and manufacturing with clear grid mixes.
Ultimately, accelerating the incorporation of low-carbon energy sources into {the electrical} grid combine is paramount.
“One of the big strengths of PV is that it has this positive feedback loop,” mentions Nancy Haegel, heart director of NREL’s Materials Science Center. “As we clean up the grid – in part by adding more PV to the grid – PV manufacturing will become cleaner, in turn making PV an even better product.”
Read the total paper right here.