At the end of 2018, 500 gigawatts (GW) of solar power capacity had been installed worldwide. By 2022–2023, another 500 GW is expected, welcoming an era of terawatt-scale solar power. Realizing the potential in this growth and envisioning it growing further, a group of 45 international solar energy scientists and industry leaders wrote a paper focusing on the challenges associated with reaching ten terawatts (TW) of solar power deployment globally by 2030, and up to 70 TW by 2050. Such a feat would make solar power the world’s dominant energy source.
Co-author Robert Margolis, who is part of an international group of leading PV (photovoltaic) scientists assembled by the Global Alliance for Solar Energy Research Institutes and group manager of the U.S. Department of Energy’s National Renewable Energy Laboratory, told Solar Magazine in an interview:
The very rapid decline in PV pricing realized to date—the price of PV has declined more than two orders of magnitude in the last 40 years—and the prospect for continued declines at both the PV module and system levels creates an opportunity for PV to serve as a central contributor to all segments of the global energy system in a cost-effective and environmentally sound manner.
To go from 500GW now to twenty times that amount by the end of the decade would require a 30% average annual growth (based on rates observed from 2008-2018) in PV deployments. But substantial energy storage will need to be involved. So will other complementary technologies, such as power-to-gas, liquid fuels (like hydrogen and ammonia) and chemicals (used in industrial processes), and the electrification across multiple economic sectors, including transportation, heating, desalination, and industrial sectors.
Electrification is essential towards the path to 30 to 70 terawatts of PV globally from 2030 to 2050. Transitioning the transport sector to take advantage of PV generation will make a huge impact. So will electrifying heating by using heat pumps, which could even enable thermal storage as an option instead of battery storage, a much cheaper choice.
The authors wrote:
A growing body of research concludes that decarbonization of electricity followed by electrification of almost all parts of the energy system is a least-cost pathway for a low-carbon sustainable energy system, with many possible scenarios for PV growth.
Industrial production of cement, iron, and steel, aluminum, pulp and paper, and chemicals and the like consumes about 27% of the fossil-fuel portion of total fuel consumption. Very low-cost solar could be used to produce hydrogen and ammonia, which could provide a pathway to substantially reduce greenhouse gas emissions associated with the iron and steel and fertilizer industries and provide precursors for chemical and materials industries.
Similarly, electricity from very low-cost PV and wind energy resources can be used to produce hydrogen, methane, or more complex hydrocarbons. Power-to-gas (PtG) or power-to-X (PtX) approaches could use many TWs of installed capacity of solar and wind generation. That would enable solar energy to have an impact across many industrial uses of fossil-fuel energy, steam, and heat, such as metals refining, biofuels upgrading, ammonia synthesis for fertilizer production, and synthetic fuel generation.
The substantial growth of PV generation to date is thanks to the fact that PV is (or will very soon become) cost-competitive with fossil fuels in most parts of the world. In California, the in-state generation had gone from under 1% in 2010 to about 18% in 2018. And it’s only going to increase faster as solar gets cheaper.
PV researchers are figuring out how to increase solar cells efficiency more and more, and their progress will help drive costs down, especially as the market grows to terawatt-scale. One, because increased cell efficiency means more watts per module and, therefore, more megawatts per installation, which brings down the cost per watt.
Margolis explained in the interview:
As the PV industry has scaled production, it has developed a dedicated supply chain for both manufacturing equipment and materials, which has brought down the cost dramatically. The industry is also in a period of fierce competition, which has pushed companies to take out cost where ever they can and to push innovation to increase the efficiency of PV technology as well as the efficiency of their manufacturing processes.
A separate study by researchers from Lawrence Berkeley National Laboratory and Stony Brook University highlights specifically how renewable energy (both solar and wind) and storage prices have fallen dramatically in recent years. Their paper focuses on how China could hit 62% clean power by 2030 while cutting costs. Meanwhile, a similar reporting issued by the Goldman School of Public Policy at the University of California, Berkeley, shows the United States can reach 90% clean energy by 2035, also while cutting costs.
