It seems to me….
“Solar power is going to be absolutely essential to meeting growing energy demands while staving off climate change.” ~ Ramez Naam.
The U.S., as well as much of the entire world, is undergoing a sustainable-energy revolution where renewable sources such as wind and solar have become increasingly cost effective. Since 2008, the price of solar panels has dropped almost 80 percent and solar energy may soon be the world’s largest source of renewable energy.
China has led the world in manufacturing and exporting ever-cheaper solar panels for the past three years. During that same time, its domestic market increased to surpass Germany’s in 2015 as the world’s leading market for installed solar capacity.
The solar industry in the U.S., where solar-powered photovoltaics (PV) were originally invented, provided over 260,000 American jobs in 2016 according to National Renewable Energy Laboratory (NREL) in Boulder, Colorado, and its hiring rate is growing 17 times faster than the U.S. economy. The solar industry workforce exceeds that of oil and gas construction and is nearly three times the size of the entire coal mining workforce.
The solar market, however, is dominated by China who heavily subsidizes its solar market and industries. China’s silicon-based solar products have become cheap and reliable enough to control 70 percent of the world’s trade in solar modules while the U.S. has only about 1 percent of the current market.
Swiftly decreasing prices, which some have dubbed the “solar coaster”, have been devastating for companies incapable of responding. Some large U.S. panel manufacturers; e.g., Solyndra; were pushed into bankruptcy and others appear to be heading in that direction. The only two remaining large American panel makers are now outsold by at least six Chinese competitors. China eclipsed the leadership of the U.S. solar industry, which invented the technology, still holds many of the world’s patents, and led the industry for more than three decades due to insufficient public-funded development support.
This, however, is still subject to change as energy systems become re-engineered. Unfortunately, some denial of climate change exists as a few politically-motivated politicians fail to recognize the substantial economic opportunity of solar energy where markets are predicted to expand by 13 percent a year. In the U.S., for example, electric utilities are now the nation’s largest customers for solar panels, constituting 60 percent of the market that was until recently dominated by homeowners and commercial buyers of rooftop solar installations. Utility-scale systems can be installed at lower costs when compared with commercial or residential systems making the price of solar-generated electricity by utilities close to competitive with conventional sources in some locations.
40 percent of global carbon emissions result from the transportation-sector, industrial processes, and building operation. De-carbonization of the commercial and industrial infrastructure is achievable through increased energy efficiency along all parts of the energy chain from production or resources to final consumption. Increased investment in renewable energy can provide abundant clean, and increasingly inexpensive, electrical power further encouraging additional electrification. In 2015, for the first time, more renewable capacity was built than conventional fossil generation.
If the U.S. innovates, cuts costs, and nurtures newer technologies, it could emerge as the world’s second largest solar panel manufacturer by 2020. This opportunity window partially results from discovery of a new substance called perovskite providing increased solar efficiency. This, however, would be dependent upon some degree of public-sector investment.
Perovskite is a metallic-looking rock originally found in the Russian Ural Mountains in 1839 named for Lev Perovski, a Russian mineral expert who died in 1856, who first studied it. It is not a particular mineral but a class of minerals that share a common crystalline structure of cubes and diamondlike shapes. Almost all solar cells are currently made from crystalline silicon but researchers continue in their efforts to develop a more efficient material. A perovskite is any material with the same type of crystal structure as calcium titanium oxide (CaTiO3).
Perovskite panels, while still less efficient than silicon, could potentially be less expensive than silicon as it can be made at substantially lower temperatures (100C vs. 900C), is flexible enabling it to be rolled in long sheets, and can be made in a variety of colors for use in a wider variety of applications than silicon.
The best silicon cells achieve about 25.6 percent efficiency compared to only about 20 percent for perovskite but where silicon efficiency has plateaued, perovskite researchers are making rapid improvements and believe 30 percent efficiency is possible (33 percent is considered about the theoretical maximum efficiency for a single cell).
A property called BandGap – the minimum energy level required to liberate electrons – determines the amount of solar energy a semiconductor can convert to electrical power. The BandGap is different for each substance. Sunlight is composed of all wavelengths of light but only a portion of those wavelengths exceed the necessary energy BandGap to produce useable power. The lower the BandGap, the more of the sun’s spectrum a cell can absorb but the lower energy level each electron will have.
Silicon’s BandGap is fixed but perovskite’s can be changed by varying its chemical composition. Additional perovskite cells with different BandGaps can be stacked to increase total electrical power output.
The biggest remaining challenges prior to wide commercialization are scaling production to larger size cells and sealing out moisture. Perovskite is moisture sensitive and quickly degrades when exposed. Glass panels used to produce silicon panels would reduce flexibility which is one advantage perovskites have over silicon. The current industry standard for solar panel life is 25 years, about 54,000 hours of continuous bright sun light, but perovskite is currently only able to survive about 2,000 hours.
At this time, though promising, much research and development remains prior to perovskite mounting any significant challenge to silicon. Regardless of materials innovation, solar energy is rapidly becoming the power source of choice in the U.S. It no longer is only a possible major energy source for the future, that future has now arrived.
That’s what I think, what about you?
 Ramez Naam is a professional technologist and science fiction writer.
 Sivaram, Varun, Samuel D. Stranks, and Henry J. Smith. Outshining Silicon, Scientific American, July 2015 pp54-59.