Everybody has that one argument, one point, one opinion, the thing that nobody is asking about, but it consumes you. It’s not unhealthy, it’s just so unrealistic that you harp on it, because if it ever did happen you’d get to say “I told you so,” and there’s absolutely no phrase more satisfying.
For this writer, it’s allowing NFL players to participate in Olympic Rugby, so that the U.S. could dominate for gold every four years, for Elon Musk, it’s converting 100 square miles of the Arizona desert into a solar project with enough capacity to power the country. It’s an old argument of Musk’s, but one he brings up frequently.
He’s def wrong. Solar power is a Gigawatt per square km! All you need is a 100 by 100 mile patch in a deserted corner of Arizona, Texas or Utah (or anywhere) to more than power the entire USA. This analysis goes through calcs https://t.co/fI1I452tm6
— Elon Musk (@elonmusk) December 7, 2019
It’s also an argument that, as ludicrous as it sounds and logistically flawed as it is, is technically possible – the best kind of possible. Musk’s supermassive solar project would require a patch of land measuring 10,000 square miles, with an accompanying battery in the one square mile ballpark.
Assuming the use of 24% efficient modules across the entire project, researchers at University College London found that even under conservative figures (100×100 kilometers instead of miles), projection would feasibly work. 10,000 square kilometers, multiplied by 0.24 GW per square kilometer, multiplied by 0.21 comes out to around 500 gigawatts. By comparison, the country’s annual electricity consumption rate was 425 gigawatts as of 2013, when this test was conducted.
In reality, there’s a difference between a possibility and a solution. What Musk is providing is a possibility. We could cover 10,000 square miles of desert in solar panels, but an entirely centralized national power supply leaves the country vulnerable to continental outages in the event of a storm or cyber attack. While catastrophic storms aren’t common in the desert and the energy grid has never sustained anything near that high-level of an attack, why even pose the risk? THis is even before going into the regulatory and permitting sleep paralysis nightmare that would be securing land and public/government approval for the project.
But you know what? Now that we’re talking about it, is there a more feasible way to entirely power the country with solar energy?
Making the impossible a reality
In 2017, a group of researchers from Michigan State published a paper suggesting that the United States could get 40% of its electricity from solar windows. Their projection suggested 5 to 7 billion square meters of usable window space existed, and that a 15% efficient solar window product applied across the area would get close that 40% number. The team was then awarded a $1.3 million grant to further develop its organic solar cell window technology. By April 2018, they were already hitting 15% with their organic solar cells, and projected 18% soon to come.
So, if we could hit 18% and cover all our windows with solar, that 40% value noted above would grow by 20% – meaning that perfect United States would get its first 50% of electricity from 5-7 billion square meters of solar power collecting windows.
Next, enter the Energy Department’s National Renewable Energy Laboratory (NREL). In 2016, researchers at the lab:
used detailed light detection and ranging (LiDAR) data for 128 cities nationwide, along with improved data analysis methods and simulation tools, to update its estimate of total U.S. technical potential for rooftop photovoltaic (PV) systems. The analysis reveals a technical potential of 1,118 gigawatts (GW) of capacity and 1,432 terawatt-hours (TWh) of annual energy generation, equivalent to 39 percent of the nation’s electricity sales.
This report notes that the above values are based on a 16% efficient solar module, and that if modules increased to 20% efficiency (or 21.7% if you’re REC), then that 39% number would grow by 25% to 48.75% of the US annual electricity demand value.
So, just based on roofs and windows alone, we’re at 98.75%, not a bad start.
Then, late last year, NREL came back to say that the U.S. technical potential for floating PV, described by NREL as a “rapidly emerging technology,”at 2100 gigawatts, which could generate 9.6% of current electricity generation (before we upsize for module efficiency gains).
The methodology behind this estimation began with a dataset of all man-made reservoirs, with those used for recreation, navigation, fish and wildlife, those located more than 50 miles from a transmission line and small water bodies removed from the set. Of the remaining reservoirs, NREL assumed that 27% of the surface area could be covered with floating PV, based on the median coverage value of existing floating PV projects. The projection also assumed the technical factors of a fixed tilt angle of 11 degrees and a capacity density of 10,000 square meters per megawatt, both of which are common among existing floating PV projects.
So, using all of the resources listed above, we could hypothetically reach 108.35% of the nation’s current electricity demand, all without retro-forming 10,000 square miles of desert into the largest power project ever conceived. This is all before we consider any land solar or parking lot solar. For some quick math, a parking spot can hold about 9 solar modules, if they’re 400 watts each, and we can use half of the roughly 2 billion parking spots in the country – that’d total about 3.6 TW of solar capacity. This might conservatively 5,000 TWh/year – which would all on its own cover US’ approximate usage of 4,000 TWh/year.