Preface. This is a brief summary of the Capellan-Perez paper that calculates the land needed to use solar to replace electricity as well as the land needed if solar were to replace all of societies use of energy (i.e. transportation, manufacturing, industry, heating of homes and buildings, and so on). The land needed in 40 different nations was estimated for each of these cases.
Another study I stumbled on looking for more insight into this paper estimates that 16 of 48 states in the U.S. have insufficient land for solar power to replace fossil fuels (Li 2018).
The authors estimates of the land needed, while five to ten times higher than other researchers, is still quite generous. They don’t subtract land total unsuitable for solar farms, which require: level ground, preferably south-facing, near high transmission capacity lines, within a power grid that can handle the excess capacity produced, not in a sensitive or protected area, and able to overcome all opposition such as military objections, NIMBY, and financially feasible, since often in areas with several solar farms speculators drive up land prices. So whatever their land estimates, the actual suitable land is probably much less.
Here is the press release from Universidad de Valladolid that does a good job of summarizing the paper which I found at the last minute:
“While fossil fuels represent concentrated underground deposits of energy, renewable energy sources are spread and dispersed along the territory. Hence, the transition to renewable energies will intensify the global competition for land. In this analysis, we have estimated the land-use requirements to supply all currently consumed electricity and final energy with domestic solar energy for 40 countries (27 member states of the European Union (EU-27), and 13 non-EU countries: Australia, Brazil, Canada, China, India, Indonesia, Japan, South Korea, Mexico, Russia, Turkey, and the USA). We focus on solar since it has the highest power density and biophysical potential among renewables.
The results show that for many advanced capitalist economies the land requirements to cover their current electricity consumption would be substantial, the situation being especially challenging for those located in northern latitudes with high population densities and high electricity consumption per capita. Replication of the exercise to explore the land-use requirements associated with a transition to a 100% solar powered economy indicates this transition may be physically unfeasible for countries such as Japan and most of the EU-27 member states. Their vulnerability is aggravated when accounting for the electricity and final energy footprint, i.e., the net embodied energy in international trade. If current dynamics continue, emerging countries such as India might reach a similar situation in the future.
Overall, our results indicate that the transition to renewable energies maintaining the current levels of energy consumption has the potential to create new vulnerabilities and/or reinforce existing ones in terms of energy, food security and biodiversity conservation.”
Alice Friedemann www.energyskeptic.com author of “When Trucks Stop Running: Energy and the Future of Transportation”, 2015, Springer and “Crunch! Whole Grain Artisan Chips and Crackers”. Podcasts: Practical Prepping, KunstlerCast 253, KunstlerCast278, Peak Prosperity , XX2 report
Capellan-Perez, I., et al. 2017. Assessing vulnerabilities and limits in the transition to renewable energies: Land requirements under 100% solar energy scenarios. Renewable and Sustainable Energy Reviews 77: 760-782
The transition to renewable energies will intensify the global competition for land because wind and solar energy are highly dispersed and need large areas to capture this energy. Yet most analyses have concluded that land will not pose a problem. We focus on solar alone because it has a higher power density than wind, hydro, or biomass.
In this paper we estimate the land-use requirements to supply all currently consumed electricity and final energy with domestic solar energy for 40 countries considering two key issues that are usually not taken into account: (1) the need to cope with the variability of the solar resource from the highs of summer to the lows of winter, and (2) a realistic estimate of the land solar technologies will occupy.
Our results show that for many advanced capitalist economies the land requirements to cover their current electricity consumption would be substantial, the situation being especially challenging for those located in northern latitudes with high populations and electricity consumption per capita.
Assessing the implications in terms of land availability (i.e., land not already used for human activities), to generate electricity only, the EU-27 requires half of its available land.
If solar power were to supply all energy used, not just electricity – in other words, the energy contained in oil, coal, and natural gas used for transportation, industry, chemicals, cement, steel, mining, and myriad other endeavors, there isn’t enough land in Japan and most of the EU-27 states.
Why? Because the power density of solar is such a tiny fraction of what fossils provide us now. Fossils are very concentrated energy that can be consumed at high power rates of up to 11,000 electric averaged watts per square meter (We/m2). But the net power density of solar power plants is just 2–10 We/m2) which is 1,100 to 5,500 times less than fossils. Wind requires even more space than solar at 0.5–2 We/m2, and hydropower as well with 0.5–7 We/m2, with biomass coming in dead last ~0.1 We/m2 at over one hundred thousand times less energy per square meter.
Solar power is intermittent and has high seasonal variability, so a redundant capacity as well as storage capacity is essential. So for redundant capacity, if one megawatt of solar is produced on 6-8 acres of land, at least three times more land would be needed to gather solar power for the majority of the day (in the united states solar availability is on average 4.8 hours/day) when there’s little or no sun and during winter. Additional land would be also be needed for energy storage, especially for the only commercial solution that exists, hydroelectric and pumped hydro storage, whose reservoirs take up a great deal of land. For these reasons and many others, the authors estimate that a realistic land area is five to ten times higher than what other scientists have estimated.
The authors also note that their calculations are very conservative since they don’t take into account the International Energy Agency (IEA) estimate that world electricity demand will grow 2.1% per year on average between 2012 and 2040 (i.e., +80% cumulative growth in the period). In that case the amount of land needed is much higher than our estimate for current electricity consumption.
Another disadvantage of solar PV farms is that they compete with agriculture for land, both of which need level land, and solar can also reduce biodiversity where ever it’s placed.
When the authors say “available land”, that means solar farms are competing for all the other uses we have for land, to build homes, infrastructure, grow fiber, food, and so on.
Solar to replace all electricity generation only
Our findings show that the land needed is substantial, especially for those in northern latitudes with high population densities and high electricity consumption per capita such as the Netherlands, Belgium, the UK, Luxembourg, South Korea, Germany, Finland, Taiwan, Denmark and Japan (10–50% of available land). Moreover, accounting for the electricity footprint, i.e., for the net energy embodied in international trade (the energy used in China and India would need to come back to these 40 nations to provide power in a world fueled only by solar power), which increases the amount of land to 11 to 60%.
Solar to replace all energy used by societ
This is not possible for many nations within their own borders, especially the Netherlands, Luxembourg, Belgium, the UK, Denmark, Germany, South Korea, Taiwan, Finland, Japan, Ireland, Czech Republic, Sweden, Poland, Estonia and Italy.
End note: I had some trouble understanding this paper, partly because of the English used, and the academic language nearly all papers are written in, which is always a battle to translate. I’m sure I missed a lot of good stuff because of it, so read the paper if this interests you.
Li, Y., et al. 2018. Land availability, utilization, and intensification for a solar powered economy. Proceedings of the 13th international symposioum on process systems engineering.