Stanford professor Mark Z Jacobson claims to have worked out a viable plan, but he has many critics who say it just plain won't work. The paper describing the plan is 132 pages long, but here is a much shorter Scientific American article describing it.

Jacobson also has a one hour YouTube video describing the plan, and here are the slides for that talk.

Jacobson makes a lot of statements opposing nuclear energy, and he always makes ridiculously pessimistic assumptions when he does. For example,

He dismisses any possibility of using next-generation reactor designs

He never considers new manufacturing techniques, like building small modular reactors on assembly lines, or building reactors on barges in shipyards, that could lower costs and speed construction

He assumes that any future nuclear development will be just the same as American nuclear development in the past, and doesn't even consider the possibility of overhauling American regulation of nuclear to be more efficient like that in France or Sweden

He assumes that using nuclear energy worldwide means massive weapons proliferation, while somehow falsely assuming that not using nuclear energy to generate electricity will somehow prevent weapons proliferation

He assumes that vehicles used for mining uranium will be powered by fossil fuels

Jacobson's plan consists mostly of:

Solar

Wind

Using existing dams, with many times more turbines added to them, to provide power when the weather isn't cooperating with wind and solar

A nationwide power grid to take advantage of differences in weather across the country

Massive energy conservation to reduce the amount of energy needed

The total backup provided by the dams would amount to about 1.5 grid-hours of power. Jacobson says he has done many simulations and this could power the grid, with no CO2 emissions, without having any blackouts. One thing that is observed is that it's generally windier at night, so the wind farms will be able to make up for the absence of solar power at night. And with the US being a large area, he feels that there will always be enough wind somewhere to power the country without needing more than 1.5 hours of backup.

Christopher Clack and 20 co-authors did an analysis of Jacobson's proposal and found many flaws. Their article ends with:

Many researchers have been examining energy system transitions for a long time. Previous detailed studies have generally found that energy system transitions are extremely difficult and that a broad portfolio of technological options eases that transition. If one reaches a new conclusion by not addressing factors considered by others, making a large set of unsupported assumptions, using simpler models that do not consider important features, and then performing an analysis that contains critical mistakes, the anomalous conclusion cannot be heralded as a new discovery. The conclusions reached by the study contained in ref. 11 about the performance and cost of a system of “100% penetration of intermittent wind, water and solar for all purposes” are not supported by adequate and realistic analysis and do not provide a reliable guide to whether and at what cost such a transition might be achieved. In contrast, the weight of the evidence suggests that a broad portfolio of energy options will help facilitate an affordable transition to a near-zero emission energy system.

Jacobson published a paper rebutting the Clack critcisms, and at the same time filed an anti-defamation lawsuit against both the 20 authors of the Clack paper and PNAS, the journal that had published both Jacobson's and Clack's papers. The defamation suit naturally had a massive chilling effect on the debate, so there was no response to the Jacobson rebuttal.

Jacobson withdrew the lawsuit when he realized he was not going to easily win (the people he sued said he dropped it because he could see he was going to lose).

In fact, a federal court found that a lawsuit just wasn't the right way to deal with this dispute because a jury could not be expected to be technically sophisticated enough to form an opinion on the controversy, and ruled the lawsuit was a SLAPP suit (basically a frivolous lawsuit without much merit that is filed to intimidate someone) and Jacobson was forced to pay the legal fees of the people he had sued.

The lawsuit was intimidating, since most scientists are not accustomed to being sued, nor do they have deep pockets with which to fund their defense, and the result was that no one else dared to criticize Jacobson's plan. It wasn't until 2020 that the court ruled that the lawsuit was inappropriate. Other people are criticizing Jacobson.

The Clack et al paper criticizing Jacobson was published in the journal PNAS, which was the same journal where Jacobson had published his paper. Jacobson sued not only the authors of the paper but PNAS itself, alleging that the Clack paper was so full of errors that PNAS was legally at fault for agreeing to publish it. It should be noted that if the Clack paper had been anywhere near as bad as Jacobson claimed, PNAS could have retracted it (which probably would have persuaded Jacobson to drop them from the list of defendants in the lawsuit), but they did no such thing.

Note that the court never made a decision either way on the technical merits of the case. The decision the court made was that it was inappropriate for that type of decision to be made by any court. PNAS similarly failed to take sides -- it could have retracted any of the papers, and they had a financial incentive to retract the Clack paper when Jacobson was suing them for publishing it, but they just left the papers from both sides up.

Here is a YouTube video with some other critics of Jacobson (24 minutes). They estimate that a nuclear zero-carbon grid would cost a fraction of the cost of the Jacobson plan.

Jacobson has many other critics.

Most observers agree, possibly even Jacobson agrees, that the closer the wind/solar portion of electricity on the grid gets to 100%, the more expensive the whole solution becomes.

Jacobson seems to assume that nearly every building will have heat pumps installed. Generally, installing heat pumps involves digging up the land next to the building, which is hugely expensive and just not feasible in very dense cities, with tall buildings surrounded by little or no vacand land.

Along those lines Jacobson assumes that we will somehow use a lot less energy in the future than we do now. Energy conservation is all fine and good, but it's only going to happen if energy is considerably more expensive than it is now, and that is the world Jacobson wants to lead us to, while a nuclear future could give us abundant, cheap energy.

Jacobson plans to add many turbines to existing dams, many times more turbines than are on them now, and when a lot of energy is needed, run all the turbines on the dam. This means that the flow downriver from the dam will be many times more water than the river has ever carried and the rivers will overflow their banks and we will have massive flooding. To guard against this we will have to build dikes all along the river banks for the whole distance the river flows from the dam to the ocean, and it's not clear that Jacobson has taken this expense into consideration.

Many of the dams that Jacobson wants to add turbines to are irrigation dams that don't currently have any turbines at all. Our existing dams have obligations to move water in certain directions at certain times, and it's not clear that they can continue to meet all those obligations while providing adequate energy backup for the grid.

Jacobson assumes a sustained buildout of his infrastructure, at a per unit of GDP basis, of 16 times that of the German Energiewende, or 6 times that of 2011, Germany's peak year.

A Harvard Study in 2018 (after Jacobson's paper was published) found that the amount of land required for wind power would be 5 to 20 times what was previously thought. They also found that large-scale wind farms, if built, would significantly warm the Earth.

There is a new technology being explored called Underground Pumped Hydro Storage (UPHS). I've never heard Jacobson mention it, but it could make his plan much more viable.

The idea is that you blast two caverns into the rock underground at different altitudes and pump water back and forth between them as a means of energy storage. The main problem with pumped hydro storage on the surface is that there are very few suitable locations for it. UPHS could be done in many places.

If UPHS works, it could increase the amount of hydro backup available to the Jacobson plan by an order of magnitude, possibly multiple orders of magnitude. In addition, our existing dams tend to be concentrated in certain parts of the country like the Pacific Northwest, while UPHS facilities could be situated all over the country, thus requiring a less extensive grid in order to be viable.

UPHS could make renewables without nuclear work. Probably not cheaper than fossil fuels, but cheap enough to be acceptable at least to the rich world.