Jean-Marc Jancovici

Investing in renewable energy doesn't mean that you'll drastically reduce your CO² emissions.

You have to take into account the capacity factor of what you install https://jancovici.com/wp-content/uploads/2017/11/load-factor.jpg

You need to install 3 to 4 times more windmill and solar panel to approach the same output. You also need to install huge way to store your electricity (mostly using damns, hard to get in places where you don't have mountains such as NL) and you need to invest the double into the electricity infrastructure to transport this electricity (your windmill will produce most of the time at 10-20% of it capacity, but the day it produces 90% you still have to transport it, therefore your grid need to be oversized for the average usage).

Solar panels are mostly coming from China and need to be changed each 20-30 years (they are loosing efficiency after a few decades). Windmills need to be changed each 20 years (lots of mechanical stress involved), and are mostly impossible to recycle (https://www.livingcircular.veolia.com/en/industry/how-can-wind-turbine-blades-be-recycled). Also, to install windmills you need to put a lot of concrete in the fields as a base, concrete that is emitting also a lot of CO² to produce.

As a result you'll still have a non-controlled electricity production, where prices will vary a lot and where maintenance costs will stay really high decades after decades. It's not only about investing, it's also about maintaining something that…

Interesting counterpoint, thanks.

> A "raw" solar panel in China costs about 25 cents / W, and each watt should produce about 45kWh over its lifetime (5W per day for 25 years).

I imagine that you're making assumptions on having sufficient luminosity all year round, right? So perhaps that depends on where on Earth you are.

According to Jancovici [1], in most of Europe, solar panels produce about 100 kWh/m²/year, assuming that they are oriented correctly (I don't know if e.g. the necessity of cleaning them up is factored in). From the same source, in terms of energy used to build the panel (is shipping included?), it takes 1 to 4 years to reimburse that energy but that's under the assumption that all the energy from the panel can be used. In practice, solar panel installations produce energy at a rhythm that depends on nature, which means that for many uses, the electricity needs to be stored somewhere if we want to actually use it at a different rhythm, e.g. when you're actually at home/in the office/etc.

Unfortunately, storing electricity at scale with current-tech is energy-expensive (both to build the batteries and because of energy loss during storage), e.g. storing it as hydrogen has a yield of ~30%, couldn't find the yield of other technologies of batteries including the energy cost of building/shipping/disposing of the battery. So, in the worst case, these 100 kWh/m2/year turn into ~30 kWh/m2/year, which means 3 to 12 years for recouping energy cost.

So, by this…

Did you check my links? "Collapse" may have several definitions; generally for a complex society or ecosystem it's a rapid simplification, reduction of exchanges and population.

Here is our situation: as you may have heard, every year around August we reach the "Overshoot day". That means that we use more resources (even renewable ones) than the Earth can produce (its carrying capacity), i.e. we're actually "mining" renewables resources such as oceans, soil, forests, etc. That means that the quantity of renewable resources globally available tends to go down while our resource usage still goes up.

At some point, our resource usage WILL fall down UNDER the line of globally available renewable resources. The longer we wait, the LOWER we will need to back down.

See https://www.sustainable.soltechdesigns.com/over-carry.html for a relatively detailed explanation and real-life examples.

Also I don't really get where you're going with your fossil fuels example. We switched from renewables to fossil fuels back in the 18 and 19th centuries because they're so much denser, easier to use and powerful than renewables. They enabled the "great acceleration" by providing almost limitless energy, and doing without them is a tremendous, unprecedented effort.

Human history is about getting better energy sources: our ancestors got bigger brains by eating meat (more energy). Then they invented fire (more energy) to make their food more digestible (more energy). Later on they invented…

I believe you’re a little confused.

> But [nuclear] takes the most time, cost hilarious amounts of money

Depending exactly what you mean, this is either very true, or dead wrong. It is true that a single nuke plant costs gigantic amounts of time, money, and resources. But it also deliver significant power, typically 1GW (sometimes a bit less, generally more). Windmills are vastly cheaper, but typical ratings are around 1MW, and that’s a maximum, not an average, and if you need to control energy output you’ll need a buffer (batteries, flywheels, dams…).

To replace a single nuke plant, you’ll probably need something like 2000 windmills, and energy storage to match. Or less if you’re okay with temporary power shortages (a harsh but valid political choice).

Now which is cheaper? One nuke plant? Or 1-2K windmills? All those windmills will need a lot of concrete, for which we’re destroying quite a few beaches (desert sand does not work unfortunately). You’ll also need quite a bit more rare earth materials to get that thousand dynamos to work. And eventually you’ll need to transport all that in a world without oil (one reason renewable energy is cheap is because transport is still cheap, thanks to oil).

> We need technology which is cheap, deployable before it is too late to reduce our emissions and accessible for every country on this planet.

Agreed.

> if you really care about the environment and are not merely one of those people who blindly recite Michael…

Let's not forget that:

- CO2 emissions of Germany is still 5 times more than a comparable (similar GDP/flatness/weather) than France for electricity production [1];

- Electricity production is roughly a third of all final energy and CO2 emissions come mainly from coal and fuel [2]. Two threats for which Germany has done very little for now.

- Germany is spending around 2 billions of dollars [3] for renewable energies, whereas it would have cost more than 50x less with nuclear, allowing to spend the rest of this investment into building insulation and thermal renewable energies.

- PV investments were computed from past market prices, not with the negative price obtained with non controllable source of energy [3]. Germany is only at the beginning of energy subsidies.

Investing in photovoltaics is politically efficient, not environmentally efficient. Please let's stop to focus on renewable electricity. Let's start focusing on carbon-less solutions. The hard problem is about coal and fuel.

The situation could not be more urgent, since conventional oil has reached its peak. Not removing our dependency on oil is strongly damaging for our economies. Focusing on non controllable sources of energy is just accelerating the damages. Please see https://jancovici.com/en/ for more convincing arguments :)

[1] - https://electricitymap.tmrow.co

[2] - https://en.wikipedia.org/wiki/World_energy_consumption#Energy_supply,_consumption_and_electricity

[3] -…

> I keep seeing justifications like that and it makes me want to puke

This kind of justification is _indeed_ a bit cynical and morbid. I suspect it is a way to respond to the sometimes overly emotional argument from nuclear opponents.

I don't think it helps having a cool-headed debate on this complicated topic.

However, I do think mentionning that all form of electricy productions have risk trade-offs, and illustrating it with the insane number of casualties caused by other sources of energy production is relevant. (Eg: https://www.statista.com/statistics/494425/death-rate-worldwide-by-energy-source/)

But a bit of "tact" is warranted.

> First of all: The total number of victims is unknown and it is still rising. Even for Chernobyl.

The total number of victims from the direct events (explosion, short term exposure) is largely "known" (although the Soviet numbers might not be trustworthy, if you want to go this direction.)

The long-term numbers are of course harder to estimate. Again, it's going to sound morbid; but, to know if it's "still rising", you have to determine if someone who dies from a cancer 34 years after the event died because of the event.

I'm in no way qualified to say so.

I have to revert to the same method I use when I don't know stuff: I find scientists to trust.

In this case, the UN organization that has to investigate such things does not see a massive hidden mortality, as I understand it.…