Indeed, researchers at MIT and at the National Renewable Energy Laboratory (NREL) have outlined a pathway to slashing costs further, this time by slimming down the silicon cells themselves.
Currently, 90 percent of the world’s solar panels are made from crystalline silicon, and the industry continues to grow at a rate of about 30 percent per year, the researchers say. Today’s silicon photovoltaic cells are made from wafers of silicon that are 160 micrometers thick, but with improved handling methods, the researchers propose this could be shaved down to 100 micrometers — and eventually as little as 40 micrometers or less, which would only require one-fourth as much silicon for a given size of panel.
That could not only reduce the cost of the individual panels, they say, but even more importantly it could allow for rapid expansion of solar panel manufacturing capacity. That’s because the expansion can be constrained by limits on how fast new plants can be built to produce the silicon crystal ingots that are then sliced like salami to make the wafers. These plants, which are generally separate from the solar cell manufacturing plants themselves, tend to be capital-intensive and time-consuming to build, which could lead to a bottleneck in the rate of expansion of solar panel production. Reducing wafer thickness could potentially alleviate that problem, the researchers say.
The new findings are detailed in a paper in the journal Energy and Environmental Science, co-authored by MIT postdoc Zhe Liu, professor of mechanical engineering Tonio Buonassisi, and five others at MIT and NREL. The researchers describe their approach as “technoeconomic,” stressing that at this point economic considerations are as crucial as the technological ones in achieving further improvements in affordability of solar panels.