Solar energy could theoretically cover the world's electricity demand by just 0.3% of its land area. This is one of the main conclusions of new research by a group of academic institutions, led by Aarhus University in Denmark. The researchers claim that raw materials and land availability will not present real barriers to PV in its race to dominate the global energy landscape.
The scientists claim that, for an average annual generation for solar of 1,370 kWh/kW, 38 million hectares would be needed. They noted that the world has a total area of 13,003 million hectares.
“Hence, our current electricity consumption could be supplied by solar PV covering 0.3% of the available land,” researcher Marta Victoria told pv magazine.
The researchers said conventional assumptions about global PV deployment for the years to come are generally based on land cover and cost projections that chiefly consider classic, densely packed, utility-scale power plants. They claim such projections ignore the potential of vertical PV, floating installations, agrivoltaics, and building-integrated arrays, as well as other innovative PV system configurations.
“Nevertheless, these embryonic applications show that there is still room for innovation at the system level,” the academics said. “In summary, although available land can limit solar PV at local levels, it will not be a limitation at a larger scale, and therefore, we recommend that models include accurate and up-to-date constraints based on materials and land availability.”
The scientists described their findings in “Solar photovoltaics is ready to power a sustainable future,” which was recently published in Joule. They said the efficiency of solar cell technologies will improve significantly in the future, and that could help to address land-limitation issues in specific locations. They also claimed that raw material availability might only be an issue only for thin-film PV tech, and not for crystalline silicon cells, which currently account for 95% of the global market.
“Thanks to the increase in efficiency and the use of thinner contact fingers, the use of silver per watt has significantly reduced in the last years, and copper or aluminum could be used as a replacement if necessary,” the research group stressed. “The noncell materials in PV (glass, plastic, aluminum, concrete, and steel) are not expected to represent a limit either.”
The researchers also reported that solar maintained a learning rate of 23% since 1976 and that the cost of the PV technology dropped by 23% every time the capacity doubled.
“Given that the learning rate is based on module prices, it also includes the elimination of big parts of the margins in PV manufacturing due to strong competition between suppliers,” the scientists said, noting that the main factors for cost reduction are efficiency increases, economies of scale, and scientific work on silicon materials.
The study also presents some challenges PV should face in the next decade. These include the creation of regulatory frameworks that reduce soft costs, reducing capital expenditure, enabling the electrification of other energy sectors via proper tax schemes, and strengthening research on improving PV efficiency and reliability.
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I think the main problem is timeshifting the power (daily). The earth is not transparent, and so you can only get about 5-8 hours power directly from the sun at any point.
Shifting the time is 15 degrees of latitude per hour, so a 12 hour shift is 180 degrees or 20 000 km at the equator.
Also, you get weather and clouds which will blank it out from time to time.
Also, as you get away from the tropics, the sun gets more and more seasonal. Apart from these issues, it is a good idea.
We’ll need even less when panels become 50% more efficient (from 22% to 33%), plus the hundreds of millions of rooftops and parking lots we can cover, plus reservoirs, dams and rivers with floating PV, plus combining agriculture with PV – agrivotaics.
38 million hectares is unacceptable unless it includes every flat factory rooftop in the world, and places like saltpans that are uninhabitable by any kind of living community.
Land use estimates and technical calculations are easy. The social science of the energy transition is the real challenge. With the end of the era of easily permittable and transmittable greenfield solar, we are now faced with the problem of convincing people in community town halls and lifting county-wide moratoriums on energy land use from wind and solar projects and the high voltage transmission and substations we need to reliably distribute the energy.
That war is silently being lost right now, with hundreds of large solar projects stuck in interconnection queues and facing backlash from concerned citizens who are consuming misinformation about solar panels polluting soils, taking away our farm lands, etc. We need to redouble our efforts to engage communities proactively and to bring as much solar as possible nearer to population centers to ease the burden on rural landscapes and transmission requirements. This will require systems design thinking and creativity that is not frequently exhibited by solar developers today.
Solar Thermal or CSP is the requirement as it gives firm and dispatchable RE 24×7 at competitive rates. Solar PV electricity is highly intermittent and infirm. You cannot say 1 MWh of infirm power is equivalent to firm power’1 MWh. For infirm power you need balancing power which need to come from coal or other high carbon intensity sources mostly. We need firm and dispatchable RE power.