In one of my other classes, Environmental Geoscience, we had a unit on renewable energy sources. As my research paper is about solar panels, I was naturally intrigued to see if the lecture would present new ideas about solar power I could utilize in my research paper. One slide about solar power showed this image that shows the amount of land that would have to be covered by solar panels in order to meet our global energy needs, which is 18 TWh’s per hour. TW stands for Tera-Watt hours, which is equivalent to one trillion watt hours. A watt-hour is a unit representing the total energy supplied if a power of one watt is maintained for one hour.
The map shows the daily global solar irradiance in Watts/square meter. I found this very interesting. Aside from being as entirely impractical as these placements are – not taking into account geographic features or existing structures – it also shows that global sustainable energy production is less out of reach than it may seem. Impractical as the image may be, the many things it doesn’t take into account actually provide a greater argument for the achievability of global sustainable energy. For one, the solar irradiance displayed on the map is what hits the earth straight on, whereas solar panels are tilted in order to better absorb sunlight. Secondly, it also only took into account 8% efficient panels, whereas todays are anywhere from 15-25% effective, meaning that the land usage would be at least 50% less if using todays panels.
Furthermore, the image doesn’t take into account existing renewable energy sources currently in place. Currently, renewable energy production accounts for 30% of our global energy production, with about 15% from hydro power, 5% from solar, 7% from wind, and about 3% from other renewable sources. Another 9% is produced by nuclear power which, while not a renewable source, is a very low carbon emitting source of energy. These already implemented renewable and low-carbon sources further cut down the land required another almost 40%.
The land estimation required to fully power the world is estimated to be about half a million square kilometers. With the reductions above factored in, the actual land required to bring global energy production to 100% sustainability is about 150,000 square kilometers which, while a very large amount of land, is not unreasonable or infeasible.
Another factor to take into consideration is location. Loster’s estimation takes into account only area, not the geographic features underneath, nor the people and ecosystems that call those places their home. It seems impossible that we could possibly spare that much land to install solar panels as such a scale, let alone that we have so much land available. However, we do have this land available. It just isn’t thousands of uninterrupted square kilometers in the middle of the desert, its all around us. Our rooftops and parking lots are prime real estate for solar installations without requiring the unnecessary development of untouched land. With parking lots covering approximately 5% of urban land in the United States, equivalent to about 13,778 square miles. Now, not every square inch of every parking lot is ideal for solar generation, but even estimating that a quarter of this land would be viable for solar production would produce a significant of energy. This alone would make a very significant impact on sustainable energy production; combined with the estimated 8 billion square meters of suitable rooftops in the United States this represents a staggering amount of land with solar potential. Expanded to the global scale, this very well could represent more than enough land to generate solar power to make non-renewable sources obsolete.
Johnson, Scott K. “A Solar Panel on Every Roof in the US? Here Are the Numbers.” Ars Technica, 16 Feb. 2018, arstechnica.com/science/2018/02/a-solar-panel-on-every-roof-in-the-us-here-are-the-numbers/.
Schrenker, Nadine. In Situ Microscopy Study on the Mechanical Integrity of Flexible Silver Nanowire Electrodes. 1 Jan. 2021
“The Overlooked Solar Power Potential of U.S. Parking Lots.” Time, 8 Dec. 2022, time.com/6239651/solar-parking-lots-france-us/.
van de Ven, Dirk-Jan, et al. “The Potential Land Requirements and Related Land Use Change Emissions of Solar Energy.” Scientific Reports, vol. 11, no. 1, 3 Feb. 2021, p. 2907, www.nature.com/articles/s41598-021-82042-5, https://doi.org/10.1038/s41598-021-82042-5.