40% of US electricity is now emissions-free...

[hunter]

Just before the holiday break, the US Energy Information Agency released data on the country's electrical generation. Because of delays in reporting, the monthly data runs through October, so it doesn't provide a complete picture of the changes we've seen in 2023. But some of the trends now seem locked in for the year: wind and solar are likely to be in a dead heat with coal, and all carbon-emissions-free sources combined will account for roughly 40 percent of US electricity production.

--more--

https://arstechnica.com/science/2023/12/40-of-us-electricity-is-now-emissions-free/

There's a nice pie chart at the link showing the 2023 mix.

44% natural gas
18% nuclear
16% coal
10% wind
6% hydro
6% solar

Good news, right?

Maybe not.

Let's look at nuclear power. If we build more nuclear power plants we can displace every other energy source on the chart, starting with fossil fuels. It's been done before. France closed its last coal mines a little over two decades ago.

Can we do the same with wind and solar power? No. For every gigawatt of solar or wind power installed there must be another gigawatt of gas power to back it up whenever the wind isn't blowing and the sun isn't shining. In actual practice gas becomes a primary power source. We can reduce our gas consumption, but we cannot displace it entirely. The damage we'd do by extracting and burning gas exclusively in a gigawatt power plant in one year is simply spread out over a couple of years when we install an additional gigawatt of solar and wind capacity. In the long run we are doing nothing to reduce the total amount of greenhouse gasses humans eventually dump into the atmosphere.

In popular imagination batteries are often proposed as a solution to the dilemma of fossil fuel backup power. Simply install more solar panels and wind turbines and store whatever excess energy they generate for use later. Unfortunately the amount of batteries that would be required to carry an electric grid through weeks when the sun isn't shining and the wind isn't blowing is entirely ludicrous.

Two frequently cited success stories of wind and solar power are Uruguay and South Australia.

Uruguay's primary power source is hydroelectricity. Facing power shortages Uruguay upgraded their grid with wind turbines. Wind power and hydroelectricity work very well together. When the wind isn't blowing hydroelectric plants take up the slack. When the wind is blowing less water can be released by the dams. The hydroelectric plants also play an important role in grid stability. Unfortunately this hybrid system does not reduce Uruguay's vulnerability to extreme drought.

Venezuela is another nation that is almost entirely dependent upon hydroelectricity for electric power. An extreme drought and shortages of electricity were aggravating factors in the collapse of their national economy.

The success of renewable energy in South Australia is somewhat of an accounting trick. Their state is connected to an electric grid that covers the entire east coast of Australia, but they attribute all the positive features of their renewable electric supply to themselves even though they depend upon their neighbors, who have much dirtier electric supplies, for the stability and economic viability of their grid. Excess renewable energy can be exported which pays for wind turbines that would be otherwise spinning uselessly when supply exceeded demand.

In the past year the carbon intensity of South Australia has been 147 gCO₂eq/kWh. Compare that to France at 52gCO₂eq/kWh. (Lower numbers are better.)

https://app.electricitymaps.com/zone/AU-SA

[Beachnutt]

1. How about ocean waves producing

electricity ?
Do waves ever stop ?

[PSPS]

2. I think that's included in "hydro." Anything that's tide or gravity based works the same way.

[DBoon]

3. so we should use the spare photovoltaic power to create fissionable material?

[NickB79]

4. That's actually a pretty good idea

The Chinese have been working with extracting uranium from sea water:

https://www.scmp.com/news/china/science/article/3245779/how-chinese-scientists-are-extracting-uranium-seawater-faster-ever

[CoopersDad]

5. Can we do the same with wind and solar power? YES

The claim that we must use natural gas as back up fails to appreciate the role played by storage systems.
Sure, we will need much more than we have but storage could permit 100% renewable energy reliably, 24/7.
Pumped hydro and Battery Storage are the more common technologies, I live just a few miles away from the world's largest battery at Moss Landing, CA.

[hunter]

6. I am very familiar with that battery installation.

It's purpose is not to store energy for days or weeks, rather it's there to stabilize the grid when wind or solar power drop out, allowing sufficient time for the idling gas plants to power up and pick up the load.

California has a great deal of experience with gigawatt scale pumped storage systems. The state water project can source or sink quite a lot of electric power, for example, the Castaic Power Plant which has a nominal capacity of 1.5 gigawatts.

But you can do the math yourself. If you had an off-grid house, how many solar panels and batteries would you need to get yourself a 99% reliable source of electricity? (Mind you, that's three and a half days without power each year...) Now multiply that cost by 8 billion. The problem is the same at any scale.

You can watch California's electric grid in action here:

https://www.caiso.com/TodaysOutlook/Pages/supply.html

If you want to model how a 100% renewable energy grid might work you can examine real world data from California's gigawatt scale solar, wind, and storage infrastructure.

It's clear that storage is the limiting factor.

[CoopersDad]

7. Thanks. I've been to the ISO several times.

They moved over the years to a new facility and I am always fascinated to learn how they manage the grid.
I'm working now on a field trip to the Helms facility but it's really only accessible six months of the year.
Also setting up a tour of Moss Landing for a couple county supervisors.
I think we'll find more and more distributed storage, residential and commercial, so that it doesn't all fall to the utility company.
I'm a fan of keeping Diablo online and interested in smaller modular nuclear reactors.

All of the above meaning that I maintain that we can reach a 100% carbon-free without much difficulty and eventually 100% renewable.

Cheers!

[OKIsItJustMe]

8. NREL: 100% Clean Electricity by 2035 Study

https://democraticunderground.com/1127166861