Could Las Vegas be run entirely on solar power?
I am already preparing for a lot of criticism from ESG-sceptic US readers, but a study from Ember caught my eye that makes an intriguing claim. Solar power with battery energy storage may now be so cheap that a city like Las Vegas could cover almost all their electricity needs from solar 24 hours a day.
Historically, the main objections to solar power were that it was expensive and the energy supply was intermittent. Well, costs have come down dramatically, and utility-scale solar PV is now the cheapest form of electricity in California (even without subsidies), but also in countries like Spain and Italy.
But the intermittency problem remains. After all, the sun doesn’t shine at night, which means solar PV won’t produce any electricity then either. To store solar power and release it overnight, one needs batteries or other forms of energy storage. Unfortunately, one needs quite a lot of battery storage to store enough solar power to overcome this intermittency problem. The Ember report calculates that for every 1 kWh of electricity produced, approximately 6 kWh of solar PV capacity and a substantial 17 kWh of battery capacity are required. And that assumes that the sun is shining nonstop during the day.
How to flatten solar power generation to a 24-hour, reliable supply
Source: Ember. Note: This assumes a solar PV system with a battery. Losses 3.8% PV to grid, 5.6% PV to grid via battery, 90% usable battery capacity.
If we stick with the theory for a moment, they calculate that the sunniest cities in the world, such as Las Vegas, could meet 97% of their electricity needs with a combination of solar PV and massive amounts of battery storage. Even sunnier cities in Europe like Madrid could come close to 90% of electricity provided by solar + battery, while we in the UK would struggle to do that (for obvious reasons).
How much electricity could be provided 24/365 from solar across the world?
Source: Ember
Alas, just because we could doesn’t mean it makes economic sense. After all, batteries are expensive. But according to Ember, their prices have declined significantly. In 2024 alone, they estimate that battery costs have dropped by 40% compared to the previous year, reducing overall costs for battery power by 22%. In the five years from 2019 to 2024, they estimate that battery costs (LCOE) have roughly halved.
For a city like Las Vegas, this means that solar PV + battery storage could cover 60% of the city’s electricity needs round the clock at a total lifetime cost below that of natural gas. It could cover 97% of electricity needs at a cost below that of coal power, but still one-third more expensive than gas.
Evolution of LCOE 2019 to 2024 for Las Vegas
Source: Ember
All of that is based on modelling assumptions, of course, and in practice, the economics can become worse if one assumes a higher cost of capital for the solar + battery plant. Plus, in practice, one likely needs more than 17kWh of battery storage and 6kWh of solar PV to generate 1kWh of constant supply for 24 hours.
But what the charts show is that technology progresses so fast that the cost competitiveness of solar power without the problems of intermittency is near. Indeed, in a couple of years, we might be in a situation where battery storage has become so cheap as to allow overcoming intermittency issues with wind and solar power. And what is the fossil fuel lobby going to say against renewables then?
Battery isn't even the most economical tech for nighttime storage. Pumping water up hills works fine, as does pumping into a tower. Thermal is also good, like molten-salt or underground quasi-geothermal.
Renewables are lousy in places like Germany where you have little reliable solar and wind, but using them in the desert or by the windy seaside is as right as rain.
We think their answer to your final question is “no worries. Show us when that happens.”