Watch the video but reserve judgment to see how well the scam artist answers questions. After the first question we learn the storage technologies are about 50% efficient. Then we learn that those efficiencies are based on comparing the energy in electricity to the energy in methane.

Some of you all might think my description of scam artist is harsh but pay attention of how they want to pay for it.

@Roger:

Sure there is seasonal variation in energy demand, and nuclear is constant.

In France though, and even more in Germany, demand is highest in the winter, and there is not much of a summer peak due to much lower amounts of air conditioning than in the US.

Solar in contrast that far north peaks heavily in the summer, with the latitude of France getting around 6 times as much sun in the summer than in the winter.

That means that the contribution of renewables is to make the problem you highlight much worse, not better.

To some extent this can be counteracted by the use of wind, which in some areas peaks more or less in the winter, not the summer, but low winds can continue for weeks at a time, so the storage needs of that are horrific.

For nuclear before you start worrying about seasonal variation you could cover diurnal variation relatively easily, since for a flow of 1kw you only need a few kilowatt hours of storage.

The real issue is low demand at nights in the summer..

Encouraging solar makes that much worse, as you either store the power generated by the panels during the day too or throw it away.

It is a heck of a lot easier to bump up the amount of nuclear to cover producing hydrogen for the winter peak than to fool around with renewables which make it harder, not easier.

My remarks apply to France and northern latitudes, not to areas which are further south and where demand peaks heavily in the summer, without a corresponding winter peak.

Even in areas though such as the north-east US where there are peaks both winter and summer solar really contributes nothing if the aim is to near eliminate fossil fuel burn.

This scheme for France though is simply adding several silly ideas together.
They don't make more sense together than they made separately, in fact even less.

This is a way of hiding the vast costs of low capacity renewables delivered when they are least needed, and converted inefficiently for an even more wasteful system.

Perhaps I should mention that I have supported fuel cell vehicles many times on this forum and elsewhere.

That does not excuse producing the hydrogen for them in silly ways, although that is just what Germany plans to do.

This scheme would make Rube Goldberg proud.

They can reuse CO2 sequestered from fossil fueled power plants. They can store the SNG in empty NG wells. They have the wells and pipelines from the past and they have combined cycle gas turbines.

Sure they would like one million EVs on the grid to take the electricity, but they don't have that yet. Some day it might not matter, they will have SO many EVs on a smart grid, storage is NO problem.

I'm surprised that they're suggesting methane as the "gas" part of the proposed "VGV". If one is going for efficiency, it's best to stop at hydrogen, rather than going on to make methane from hydrogen and CO2. Only 50% round trip, but that's a lot better than the ~25% you're looking at with methane.

OTOH, if one doesn't care about efficiency, then there's no reason to limit the synthesis to methane. You have to start with H2 + CO2 -> syngas in any case, and from syngas you can make most any hydrocarbon you want. Methane may be the easiest and most energy efficient, but methanol, ethanol, DME, and Fischer-Tropsch liquids aren't that far behind.

What they should be proposing is establishment a broad synthetic hydrocarbons industry based on hydrogen from surplus electricity of any sort -- excess nuclear or intermittent renewables. It's not really hard to buffer enough hydrogen to absorb even seasonal imbalances between supply and other demand.

Good point, Kit P. The round trip efficiency of VGV will be poor if methane is used as the energy storage medium.

Very good point, Silverthorn, but round-trip efficiency of nearly 100% is still possible using H2 as the storage medium!
If, for example, H2 is used as energy storage medium, for distributed FC-CHP whereby waste heat will be used for winter heating, the efficiency will be very good.

Furthermore, the waste heat of electrolysis can also be
captured and used for hot water heating and other process heat. Hotels, Cafeteria, hospitals, spa, etc use a lot of hot water daily in any season. Electrolyzers can also be distributed where waste heat will be needed. The H2 produced on warmer seasons will be collected via a local H2 piping system to underground storage for use in colder seasons via FC-CHP for distributed generation with very high round trip efficiency.
The round-trip efficiency in this way will be nearing 100%!

This type of energy farming will be very important for human to colonize Mars and beyond. Solar PV's will be used to generate H2 and O2 to be stored for electricity and heat generation at night. Mars is a very cold place! There is no oil nor NG in Mars, and even if such exist, there is no O2 to combust them. The H2 is also needed to make synthetic foods, medicines, and other chemicals to support an entire human and animal population in Mars, in underground communities (to avoid cosmic rays and to maintain adequate air pressure). Re-usable H2-powered hypersonic space planes will be used to transport Mars-bound colonists to space stations in Earth's orbit, then nuclear powered spaceships using electric rockets will transport them to Mars. So, this type of energy farming is the prerequisite technology to support human colonies outside of Earth.

Nulear fuel is very precious energy resource to enable human to travel in deep space and to settle outside of the Earth, and should not be used too much here and now, when solar and wind energy can supply the energy.

"To infinity...and beyond."

“It's not really hard to buffer enough hydrogen ”

Really, do mean store? Just how much experience do have compressing and storing hydrogen?

There is a huge difference a hydrogen molecule with a molecular weight of 2 and methane at 16.

Storing a huge amount is just insane. Even if it can be done in a salt cavern.

@Kit P,
The petroleum refining industry has a lot of experience storing large quantity of H2 in underground caverns, as well as H2 pipeline system for transporting the H2 around. It takes 3x the volume to store energy as H2 as compared with methane at equal pressure, however, NG wells can store enough energy for years, while with H2, only one season's worth of energy will be needed.

However, long-distance transportation of H2 is more expensive than transmission of electricity, so HVDC power lines should be used for regional energy transfer. Thus, local H2 pipeline will be mostly needed, and the cost will be quite manageable.

Nuclear reactor's output can be varied, but for economic reason, should run at maximum power to recoup investment cost. The unused electricity energy can be used to make transportation fuels to reduce carbon footprint and to conserve fossil fuel reserve.

I would understand high temperature thermal nuclear H2 generation but electrolysis and then converting H2 to CH4 looks like wasting energy. In my understanding there will be no any greenhouse reduction at all.

Roger:
I am not against solar.
In fact I have supported it for the past 40 years or so.
I have always had this strange idea that you should use it where it is sunny though!

That is not good enough for solar ideologues, who take a perfectly respectable way of generating power and stick it on a roof in Germany, where it generates almost no power when it is most needed and simply disrupts the economics of providing low carbon power in a sensible way, ie using nuclear at that latitude.

The best and most economic thing Germany could do with its solar arrays is pay to strip them from every roof, ship them to India where it is much sunnier and what is more sunny when power is needed, give them to the Indians and build nuclear plants and EVs themeselves.

They would still make huge savings over the 1 trillion or so Euros they reckon they are going to spend (waste) on renewables.

Your other notion that we need to conserve fuel for nuclear reactors is also ill founded.

At something like $500/kg land based sources of uranium become essentially limitless.
Since there are many designs for reactors which one way or another use fuel around 100 times more efficiency without pushing the envelope of present technology very far the cost of the fuel would still remain tiny.

Of course, at levels way lower than that price uranium from the sea would be perfectly practical to extract, which pushes any concerns about running short of nuclear fuel many, many millions of years into the future.

We could also use thorium. and we have several million years of plenty of fuel for fission reactors to develop fusion.

Solar is fine in hot places, when power is needed roughly when it is available on a yearly basis - nightime storage is not a great problem.
It is especially suitable for off-grid locations.

Nuclear is a much more compact power source, and what you need to power industry, probably even in hot places.

We won't be running out of fuel for it.

What I asked Roger to do was check to see if what he says is true. Roger is very good at repeating theories you have heard for people like Obama who have never produced anything. Nothing Roger says is true. It does not matter how wonderful they sound if engineers can not make it happen.

“Economic growth and stability ”

That is not true anywhere. Spain would be the best example of classic failure. The nuke plant I worked at during start up in Spain is still running providing jobs and value to the community. Finland and South Korea are other examples places that use nuclear power to help achieve stability and economic growth.

“Halting the rise in CO2 level to ensure climate stability. ”

But it does not actually do that. When it works it is too small and it only works 10% of the time.

Rather than debunk each of Roger's theories let state what I have observed. PV and making hot water with solar has been around a very long time. Everyplace that talks about solar only increases the amount of fossil used.

(previous comment vanished)

Why I am supporting solar farming? Very good question.

1. Economic growth and stability: A vast engine for job creation leading to social stability.

So far, countries such as Spain which are pursuing these ideas have massive job losses and social instability.

A steady energy supply thanks to RE at very predictable cost

Has been promised, but never delivered.  The very unsteadiness in supply has required large changes in the rest of the grid, which the RE generators are not asked to pay for; you can see some of the cost-shifting efforts in the article text above.  (Seriously, savings accounts locked up for 30 years?  When the bonds come due and turn out to be worthless, the pols who created this scam will be long dead.)