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This is a fantastic effort. The original book was an amazing attempt at napkin-mathing away innumerate arguments.

However, I think that people that read it now can sometimes come away thinking that sustainable energy is pretty difficult, or that heavy nuclear will be the most cost effective way to get rid of carbon in our energy.

Technology trends drastically change the practicality of napkin math that's not even a decade old. It has turned solar from cost ineffective to cost effective. Another decade is going to make storage extremely cheap, as in 2x-10x cheaper. At that point, we will just need to build our solar and wind arrays to capture enough energy at their seasonal minimums.

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The main point that I took away from the book is the phrase that country-scale generation using wind and solar requires country-sized installations. While it's great that the cost of solar is falling rapidly, there's still a theoretical maximum efficiency which we can ever reach. IIRC that's around the 30% mark, and the updates in the OP suggest that for large-scale panels the efficiency has increased from around 10% to around 16%. It discusses other possible but unproven advances which might increase the efficiency more (multi-layer tech, for example). They say: "...companies are now developing multi-layer PV panels that will deliver (although timing remains uncertain) efficiencies greater than 30%". While this is clearly excellent news, it's still only a possible 3x improvement in the future which means we just need installations the size of a smaller country.

Basically, it doesn't matter that the cost has dropped if we simply can't generate enough electricity that way. They discuss the possibility of generating 50% of the UK's total energy needs (not electricity needs) via solar and point out that it's not as ridiculous an idea as it was when Dr McKay wrote the book, but it's clear that we still need some fairly massive increases in technology to get there - e.g. storage, transport, routing. Perhaps they will happen quickly or perhaps they won't, it's very hard to tell at this stage.

tl;dr: I'm really happy to read that solar is improving, but price alone is not the only factor. It's a big one, but it's far from the only one.

Edit: also, in case it wasn't clear - I'd be ecstatic if this data were kept up to date. I was actually wondering about this just yesterday.

Getting around the Shockley-Queisser limit is still very much the subject of active research and not at all impossible.

Solar in rural areas is constrained by available grid connection points. In the UK many areas are already at capacity and would require significant investment to connect. This is a major issue in terms of viability.

Also offshore wind farms can be absolutely vast, which is not practical onshore. The North Sea has the potential to add several GW and achieve economies of scale.

I don't understand why everyone focuses on efficiency. (Okay, it makes sense in the U.K. with their combination of high population density, high latitude, and awful weather, but for large parts of the world it doesn't.) Total watts per dollar (including mounting hardware, cabling etc.) is the figure you should focus on.

MacKay's work makes a complex subject simple, is certainly effective at unit harmonization in a domain (energy) where an array of units can be thrown around without any regards for ease of comparison.

Given technological trends, maybe it makes sense for the next version of this work to be some sort of 'living' document/website, where calculations with changing variables (like efficiency of commercially deployed PV cells) change over time?

> Another decade is going to make storage extremely cheap, as in 2x-10x cheaper.

It might, or it might not; in the mean time people go on using electricity at times when the wind is not blowing and the sun is not shining.

I hear it's getting fashionable to use TCP/IP to coordinate consumption of electricity with power availability from wind/solar

Even when they do not, electrical requirements are going to skyrocket when everybody has to charge their electric car overnight — right now that is when electricity is cheapest, but is almost certain that going to be true in the future.

A personal level, I don't take anybody seriously who talks about about global warming/climate change without mentioning nuclear as the solution, as it cuts down on those who simply want to use it for political purposes.

The environment and energy are political issues. We have to strike a balance between different interests which cannot be fully divorced from subjective debate.

If you do about it that way, everything is a political issue, which is the same as saying you will never ever be able to get anything done period — which is not really helpful.

Yes, we can't get anything done. I had noticed.

Global warming is a moral issue that society disagrees on. That makes it political .

We want to address global warming because it is the right thing to do. There is no physical law that requires us to do those things. Expecting objectivity on a moral question is just not reasonable. Attacking someones character on the basis of one little flaw in their argument is not going to help. People need to believe in the mission, the specifics of the solution are less important.

It is interesting how much society has tried to depoliticize the environment. Politicians love to setup institutions and legal frameworks that let them shrug-off any responsibility or blame. They don't have to deal with the NIMBYs or campaigners, we have an environmental impact assessment instead. Across lots of different fields you see science used as a crutch to avoid any debate on morality. To make real change we have to address that question head on.

I personally wouldn't rush to shut down existing, well run nuclear plants, but don't see a poliferation of current nuclear designs as feasible and the timeline is too short to wait until new models are proven.

In the meantime, solar, wind, efficiency, demand response, a carbon tax, insulation, time of use pricing and a variety of other proven tech could solve the issue if there was the political will to do so.

Can you make a numerate argument that solar is more cost effective than nuclear?

Ok, so I made my comments not about the UK in particular, but at the level of reports from IEA or EIA or Lazard's. At the napkin math level, ignoring baseload (which is nuclear) or dispatchability (which is not really nuclear), PV solar blows away nuclear. But then, so does nearly every energy source. Nobody builds a nuclear plant because its profitable or cost effective.

We need to watch for when solar and wind beat natural gas for electricity generation costs. (And then we need to start watching for power to gas costs....)

> Nobody builds a nuclear plant because its profitable or cost effective.

This just isn't true.

Solar and wind power have failed disastrously in Germany, to the extent that they have to now cut back on wind power and start building coal fired plants, because they were stupid enough to turn off their nuclear facilities.

While I take your point on Germany, it is also true that modern construction of nuclear plants is disastrous financially.

If we're to believe https://www.technologyreview.com/s/601514/germany-runs-up-ag... then the Germans didn't quite "have to [...] start building coal fired plants", but they have trouble stopping people from building more coal fired plants, because that is still economically lucrative.

No. They have to have fossil plants because electricity cannot be stored effectively, except in very mountainous countries with enough hydroelectric dams, like Norway or Costa Rica. Since electricity cannot be stored, it has to be manufactured when required. People require electricity at night or on calm days when the wind is not blowing, and they often don't require as much electricity as can be produced at the right time. Since the Germans turned off their nuclear plants, to make that electricity, they had to build more fossil plants.

So sell the solar generated energy to Norway via the existing DC link and upgrade the link as necessary. Also upgrade the east-west electricity distribution system and sell the energy to neighbours who are in the dark.

And lastly, if electric cars are implemented properly they can be used for peak shedding. See, for instance, https://www.techcentral.co.za/how-electric-cars-could-change..., https://www.citylab.com/transportation/2015/07/bmws-plan-to-..., and https://www.theguardian.com/environment/2017/mar/20/electric....

> Since electricity cannot be stored,

That should be 'Since electricity cannot currently be cost effectively stored," It is a matter of economics not natural law.

> 'Since electricity cannot currently be cost effectively stored," It is a matter of economics not natural law.

What I meant should be obvious to someone who read my entire reply. Selectively quoting part of it and then making a counter-claim using the quote as a strawman argument shows that you are not a person to be taken seriously.

Nuclear all-in costs (about 10-20 cents per kwh) are lower then most sources, and the operating costs beat everything but wind. Big problem is cost overruns.

Are there sources for this which include externalities like mining and producing the fuel?

Okay well on page 164 (https://www.withouthotair.com/c24/page_164.shtml) MacKay writes: "If fast reactors are 60 times more efficient, the same extraction of ocean uranium could deliver 420 kWh per day per person." Granted, this depends on fast breeder reactors and ocean extraction of uranium, but those are both experimentally proven technologies.

Why wouldn't we adopt the only energy source that has been shown to scale to provide the entire world with Western levels of energy for 1,000 years?

Nuclear plants go up in decades, solar and wind generators go up in months.

Here in the UK there's one nuclear power project on the cards - an extra reactor for the existing 'Hinkley Point' power plant.

The problem is the government has had a lot of trouble convincing anyone to build it for them. It's been so difficult, in fact, that they're promising EDF Energy more than double [1] or even triple [2] the present UK wholesale power price, increasing with inflation, guaranteed for 35 years, paid for by tax payers.

I find it difficult to tell my friends that nuclear is cost-effective when it needs such huge, super-long-term government subsidies.

[1] https://www.google.co.uk/search?q=Hinkley+is+the+peak+of+sub... [2] https://www.theguardian.com/uk-news/2016/mar/18/hinkley-poin...

In a traditional power system the price of energy is heavily based on the cost of fuel. Some fuels (like gas) may only be economical when energy prices rise to a particular level.

Nuclear power, solar, and wind are not like that. The fuel is effectively free, and the costs are fixed regardless of demand or energy price. So it makes sense to run the station as much as possible, regardless of how little money the power is sold for. That means that the price would fluctuate depending on the wider market. If the price of gas suddenly drops then nuclear makes less money.

Subsidies let you set the price up front at a level that is "fair" to pay for capital and ongoing costs. You can argue that the price is too high, but the presence of subsidies is difficult to avoid.

The crazy thing about Hinkley is that the subsidy level is actually linked to wider energy prices. The government have a weird incentive to rig the market in favour of Hinkley C. If electricity becomes cheaper then the scheme will seem like a rip off!

Take the money you need to build a nuclear reactor. If it takes 15 years to build, with the same money you could have built a solar panel factory every year, the oldest of which would have built 15 years worth of panels and by the final year you'd be making enough panels to equal the output of the nuclear power plant every year thereafter.

If you focus tightly in on the gloomy and northerly UK then you may think nuclear still has an advantage, but if you treat global warming as a global problem then driving solar down its production curve makes much more sense.

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