Here's Elon Musk's Plan To Power the US on Solar Energy (inverse.com)

An anonymous reader shares an excerpt from Musk's keynote speech: Tesla CEO Elon Musk -- whose company makes electric cars and has a new solar roof panel division -- reminded more than 30 state governors at the National Governors Association meeting this weekend exactly how much real-estate is needed to make sure America can run totally on solar energy. "If you wanted to power the entire United States with solar panels, it would take a fairly small corner of Nevada or Texas or Utah; you only need about 100 miles by 100 miles of solar panels to power the entire United States," Musk said during his keynote conversation on Saturday at the event in Rhode Island. "The batteries you need to store the energy, so you have 24/7 power, is 1 mile by 1 mile. One square-mile." It's "a little square on the U.S. map, and then there's a little pixel inside there, and that's the size of the battery park that you need to support that. Real tiny."

Comments

Double Checking

[rjstanford]

I didn't do the maths myself beyond the back of a mental napkin, but these folks have http://blogs.ucl.ac.uk/energy/... and apparently the overall space checks out. Its far from the first time that similar scale claims have been made, and no, consolidating our entire solar grid into a single spot wouldn't make much sense from a security standpoint, but its interesting to think that we could get from here to there with no more (or less) effort for the country than, say, the Apollo program took.

Re:Double Checking

[Maury Markowitz]

It is worth putting this into perspective:

The US has about 16 million hectares of pavement.

100 by 100 miles is about 2.6 million hectares.

Re:Double Checking

[Enigma2175]

First, we need to drop our average per capita energy usage from 250 kWh/day to 125 kWh/day.

That number seems wrong. I looked at his website (the design is Geocities, circa 1998 - nice!) and it's not immediately obvious where that number came from, but it appears to be too high. In 2015 the US generated 4,077.6 TWh of electricity so that's around 35 kWh per capita per day. That year 3.22 trillion miles were driven, if everyone magically had a Telsa Model S (which uses 340 wh/mi, smack dab in the middle in efficiency for electric cars listed by the EPA) instead of their current car that would be another 9.3 KWh per day per capita.

So that's around 45 kWh for electricity and transportation, where does the other 205 kWh come from? Heating? The electricity number already includes all the electric heating (as well as commercial and industrial use) so it would just be oil and natural gas - do those really add up to 205 kWh? We used 27.3 trillion cubic feet of natural gas, but a ton of that is already included in the electric number. According to the EIA it was closer to 15 trillion for residential, commercial and industrial use. That would be another 38 kWh. We burned around 390 billion gallons of heating oil, that's another 1.5 kWh. I don't necessarily think that converting the total heat available in those substances to kWh is a valid comparison but let's ignore that for now. We are still only to 84 kWh per person per day, where is the missing 166 kWh?

Looking further on his site I think I see what the issue is. He just makes up numbers and then adds those to his total. For example, on this page he guesses at a number for kWh per airline passenger and then rather than using data like actual miles flown he just assumes every person makes exactly one intercontinental trip (from London to Cape Town) per year and extrapolates a 30 kWh usage for that. He does similar things throughout the site, instead of using actual consumption data he makes estimates based on broad assumptions. I'm sure he has interesting things to say but there's certainly no rigor in his numbers and it's a poor site on which to base a numbers post.

He seems to have let off a number....

[CrimsonAvenger]

Specifically, the cost part.

A quick google and a couple minutes with a calculator comes up with ~$1.5T for the solar panels, assuming sunny days all year round.

Plus the cost of the batteries, of course. And extra panels to cover rainy days.

And let's not forget the distribution system (which ranges from negligible to horrendous, depending on a lot of factors).

And the factories to build 50 billion or so solar panels.....

So, doable? Yeah, could be done. Cheap and easy? Not hardly.....

Re:He seems to have let off a number....

[Anonymous Coward]

Specifically, the cost part.

A quick google and a couple minutes with a calculator comes up with ~$1.5T for the solar panels,

more quick googling:

Total electric company revenues from sales to ultimate customers equaled $381 billion

so in other words it's only four years of revenue to totally replace the system

The problem is still grid storage

[atomicalgebra]

Solar has a very low capacity factor (~20%-30%) which means we need to find a way to store the electricity. The majority of storage is done thru pumped-hydro. Most of those locations are already tapped. Batteries won't solve it either. Tesla's gigafactory is not going to be able to produce enough batteries for grid level storage. Current storage can be counted in the minutes, but we will need several weeks of storage to make this plan viable.

This plan will end up costing trillions and still will not work. It will also will cost trillions in grid improvements and probably tens of trillions in storage. I am sure Musk likes the idea of the US giving him trillions, but I think their are better and cheaper options.

Re:No Faith.

[sycodon]

If you took $250 million from each Billionaire jetting around the world talking about Global Warming, they could probably build a demonstration plant that could run Vegas or Tuscon.

Do that, prove it works, then come to the taxpayers.

2 birds, 1 stone?

[Darth Twon]

Southern US border = 1989 miles (source)
100 miles x 100 miles = 10,000 sq miles (source)

Thickness of solar wall needed: 10,000sq miles / 1989 miles = 5.03 miles

... with a little bit of nuclear

[blindseer]

Every time I hear people speak of a carbon free future they will mention wind, solar, hydro, and geothermal but add the caveat of something like "with a little bit of nuclear" as if to try to please the entirety of the crowd.

Musk is doing the same in his talks, he'll say that solar would work to meet our energy needs. Of course he'd say that, he's a salesman trying to sell his products. I ask, how much would it cost? Not just in dollars but in lives.

According to this study the safest energy source we have is nuclear power.
https://www.nextbigfuture.com/...

According to the EIA nuclear is very low cost in dollars too.
https://en.wikipedia.org/wiki/...

I've had people dispute the numbers on nuclear power safety by claiming those numbers did not include large scale accidents like Chernobyl. As far as I can tell the numbers not only include Chernobyl but also expected reduced lifespan from the survivors. Chernobyl is also largely irrelevant, no one builds nuclear power like that any more and no one would be foolish enough to do so in the future.

People then tend to dispute the solar death numbers by claiming that trip and fall deaths "don't count" for some reason. These are still people dead from the construction and maintenance of solar power, even if it's because people failed to follow the safety rules and paid with their lives for it. By this metric we could say Chernobyl deaths "don't count" because they failed to adhere to proper safety protocols and many died as a result. Dead is dead, and if we are honest about the deaths then nuclear is much safer than even solar.

Then there is the carbon footprint, the whole reason we are having this discussion.
https://en.wikipedia.org/wiki/...

Nuclear power has nearly half the carbon output per energy produced than solar photovoltaic power. Concentrated solar thermal power has a lower carbon footprint than nuclear but that is not what Musk is selling, likely because those cannot be put on the roof of your house and because at current estimates it would cost double what PV does.

I look at the math and I found that Musk has it backwards. The future isn't solar "with a little bit of nuclear", it's nuclear with a little bit of solar.