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“Project Volt Gas Volt” proposes long-term financing plan to support widespread implementation of power-to-gas systems

Project Volt Gas Volt is based on a long-term financing plan and the use of existing technologies for the large-scale conversion of surplus renewable electricity to methane, with subsequent reuse. Diagram: Isabelle Plat. Click to enlarge.

Corinne Lepage, Member of the European Parliament (and former French Minister of the Environment) and Professor Robert Bell, Brooklyn University, City University of New York, are proposing Project Volt Gas Volt (VGV) as a technology pathway for using renewable energy to “keep the lights on” on the broadest scale without disruption, together with a long-term financing proposal for the project. Although they are targeting an initial implementation France, they see it as broadly applicable.

Project VGV uses surplus electricity generated by renewable and nuclear sources to produce hydrogen via electrolysis. The hydrogen is combined with CO2 to produce methane, which is pumped into and stored in the existing natural gas grid and used like natural gas for use in power generation, transportation, or other thermal and industrial uses. The concept is the same embodied in Audi’s e-gas project (earlier post), to which the VGV proposal makes continued reference.

ETOGAS in the energy system. Source: SolarFuel. Click to enlarge.

ETOGAS (formerly SolarFuel) in Stuttgart, Germany, has built a 250 KW demonstration plant for this method. Audi, along with ETOGAS, is building the first commercial-scale demonstration plant (6.3 MW). (Earlier post.)

If generated in sufficient quantities, the synthetic natural gas produced by the e-gas or VGV processes could replace the present-day uses of natural gas and perhaps ultimately most fossil fuels, Lepage and Bell argue. Stored methane could become the “battery” for renewable energy, simultaneously making hydraulic fracturing obsolete, they proposed.

Further, they note, France is unique in that its nuclear plants cannot use all the electricity they could generate, for lack of demand. If this potential production supplied the Volt Gas Volt plants, the nuclear plants could operate at nearly 100% capacity. This would help speed up the return on investment in VGV for the development costs of the energy transition. In other words, they suggest, nuclear power could thus help subsidize the transition while allowing for a reduction in the number of plants in operation.

Dr. Hermann Pengg, head of project management e-fuels, Audi, giving a talk on energy conversion and storage using Power-to-Gas at ASPO 2012.

Financing Project VGV: the Green Redemption Fund. Lepage and Bell propose establishing a 30-year “Green Redemption Fund” in France to support VGV. The fund would also encompass an industrial development plan. Its board of directors, the private investment instruments it sets up, and the necessary tax changes should ideally be approved by referendum and could be annulled only by another referendum, the goal being to build the necessary level of confidence, they suggest. Creation of the fund should be a condition for assuring the project’s sustainability.

There would be a commitment to lock up the investments for a period of 30 years. This commitment is made as a guarantee that the necessary amounts will be paid over time, for the sole purpose of ensuring the energy transition via a cross-generational initiative.

The following different types of financing could co-exist, they proposed:

  • A share of the “nuclear rent” paid by all French citizens and that must be invested in France (since the nuclear risk cannot be insured, these payments will be the nuclear industry’s guarantee of its conversion).

  • An annual contribution of at least €1 billion from the oil and gas industries in the form of a reallocation of public subsidies paid until now to the oil sector—which total €19 billion according to the Court of Auditors—with the rest allocated to debt reduction. Gas produced by the VGV system would be bought on this basis. Initially, synthetic methane produced by the VGV system will be more expensive than fossil gas, but ultimately will be less costly.

  • The allocation of emissions allowances and the carbon tax, once it is in place. A carbon tax levied directly on fossil fuels could be calculated on the BTU equivalent of the oil needed to produce a tonne of CO2. Based on the Rocard-Juppé plan, which comes to around €10 per barrel of oil equivalent, this tax would generate around €8 to €10 billion a year in France alone, and more than €100 billion if applied to the Europe of 27. This would also be the basis of the calculation of the carbon tariff on imported goods and services produced using fossil fuels.

  • Individual savings accounts blocked by the holder in return for an exemption from inheritance taxes. Several solutions are possible, provided these funds are locked up for 30 years and earmarked for the younger generations. Capital and interest could be blocked for 30 years and the transmission to heirs would offer attractive conditions.

  • Private green funds could help finance a global fund. All funds will have to be invested in green energy and that all profits will be re-invested in green energy. This could create a magnet effect and draw capital into France, they suggest.

  • Lepage and Bell suggest a debate should be launched to encourage allocation of the wealth tax to the fund.

  • The Green Redemption Fund could use COFACE-type mechanisms to secure the receivables of wind farms and solar installations. This use could multiply tenfold the amount of private financing of renewable energy installations.

  • The Green Redemption Fund must have investment capacities, the duo insisted—perhaps similar to REITs, for example, the American equivalent of FPI, to invest either in real estate (land or buildings) or in real estate mortgages. In the United States, this investment vehicle now covers gas pipelines and photovoltaic installations.

  • The Green Redemption Fund could also acquire strategic companies (national and foreign) to enable France to catch up from its delay in renewable energy.




Alternatively you could simply use France's nuclear plants to power much of the light vehicle fleet with off-peak charging, so they would no longer have less than full utilisation.

More fake renewables fake economics.

Kit P

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 Pham

It's not so simple. There is a tremendous seasonal variation in energy utilization, yet nuclear energy output is very constant. Some means of seasonal-scale of energy storage is needed, and this is one possibility.

This is the first step for now, making synthetic methane. When the H2 pipeline system and cavernous storage system is fully implemented, H2 alone can be used for local H2-FC-CHP to further imcrease the round-trip efficiency, since the waste heat of the FC can be used for heating in colder seasons, and for FCV as well. Lower cost and higher efficiency will result when H2 can be directly used, without requiring conversion to methane.



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.

Roger Pham

You've made many good points, but I don't understand why you're against solar energy farming, or why you're against converting nuclear energy to transportation fuel, as this VGV scheme is accomplishing.

Look at the whole issue of RE as energy farming. With farming, you sow the seeds, cultivate the soil, and collect solar energy to grow the crop. Solar PV energy storage is the same thing, with the advantage of 10-100x higher collection efficiency than photosynthesis, meaning much less land utilization. You can't farm on a small house's roof or on a parking lot, but you can put PV panels on houses and parking lots and lands already developed, or waste desert lands, to collect solar energy, so sparing any new arable land required for solar energy collection.

Human started with hunter-gatherer behavior for food foraging in small tribal scale, moving up to large-scale agriculture to support vast civilizations. Yet, we are still in the primitive stage of hunter-gatherer with respect to energy collection, using preformed fossil fuels made hundreds of millions of years ago. It is about time that we move toward large-scale energy farming to solve many problems associated with energy hunting-gathering behavior.

Nick Lyons

This scheme would make Rube Goldberg proud.


This approach has the goals of reducing CO2 and storing excess renewable electricity as fuel for ICE vehicles.

It's economics depend on presently generated, but un-stored/unused electricity and excess CO2 levels/fines(?).

In any case, Audi supports this approach.

It's not like Audi is demanding $40 billion taxpayer euros to become non-bankrupt and do the research.

It could be that Audi and Dr. Hermann Pengg, head of project management e-fuels, are more correct than some US utility/auto scam artists.


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.


This opens another avenue or method to store large e-energy surpluses.

We have similar problems with large mismatch between seasonal water availability (50,000+ mega-watt) and e-power consumption + exports. A high percentage of the over abundant water in sprig and fall is not used because it corresponds to low power consumption periods (21,000 to 24,000 mega-watt).

The mismatch may increase with the arrival of another 4,000 to 10,000 mega-watt of wind power in the next 5 to 10 years.

Locally, almost 80% object to NG & Oil fracking but very few would object to storing and exporting surplus e-energy.


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.


To recover 25% of wasted energy is not as good as 50% or 75% but it could be a starting point towards 75+%?

Roger Pham

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."

Kit P

“It's not so simple ”

Actually it is. We can make all the power society needs with nuclear power.

“yet nuclear energy output is very constant ”

That is not correct. All light water reactors are designed to load follow which is exactly what they do in France and every navy nuke ship.

One of the nuclear physics properties of LWR is negative temperature coefficient of reactivity. What that means in practical terms is that reactor power follows turbine demand.
“I don't understand why you're against solar energy farming, ”

Better question is why are you for solar farming?. Have you done any serious study? Have you ever bothered to check to see if those great sounding projects actually work.

While it might sound contradictory, we should build wind farms and solar systems at the capacity of industry. However, plans on 100% renewable energy should wait until it is actually practical. Scam artist with power point presentation are not the people that will make it happen.

Kit P

“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

“yet nuclear energy output is very constant ”

That is not correct. All light water reactors are designed to load follow which is exactly what they do in France and every navy nuke ship.

One of the nuclear physics properties of LWR is negative temperature coefficient of reactivity. What that means in practical terms is that reactor power follows turbine demand.

Roger Pham

@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.

Roger Pham

@Kit P,
Why I am supporting solar farming? Very good question.

1. Economic growth and stability: A vast engine for job creation leading to social stability. A steady energy supply thanks to RE at very predictable cost will lead to confidence in business investment and further enhancing business positive feedback loops. Can you predict with certainty the prices of oil and NG in the next 5-10 years? Yet, the price of RE is very predictable, and can only get cheaper and cheaper and more plentiful!

2. Job creation and social stability as above

3. Halting the rise in CO2 level to ensure climate stability. Even though many people are not certain regarding GW and the ensuing consequences, the risk still exists, and it is good to buy insurance against GW and climate change & disruption. Just like when you buy health insurance and home insurance and life insurance, you can't predit that these personal catastrophies will happen to you within a year or two, but it is good to buy insurance!

4. Local enery security: Remember when the NG pipeline from Eastern Europe to Western Europe was shut off temporarily and the West was shivering? With local H2 storage, these can be prevented.

5. Preventing pollution fron oil spills and from NG fracking.

6. Conserving nuclear fuel for future deep space travel.

7. Solar farming to support 10x-100x the level of world population as now: Photosynthesis as a means of solar farming can support only ~10 billion worldwide, due to the inherent inefficiency. However, with energy gathering efficieny 100x higher, the world can support 100 1000 billion population instead of the 10 billion people that will strain the limit of photosynthesis. We will no longer need to grow food, but merely need to synthesize food from solar energy making H2 and incorporating carbon and nitrogen and sulfur into H2 and turning these into basic foodstocks. The basic powder food ingredients can be printed out using 3-D printers, as NASA is experimenting with now, for human deep space travel. The advantage is that your future synthetic food will be pure and free from the pollutions that natural foods is affected today, eg. insecticides, herbicides, arsenic, carcinogens, hormones...

8. Water can be purified from solar energy via multi-effect distiller at very high efficiency and absolute purity for human consumption only...No longer any needs to waste rain water for irrigation of food crops...No need to waste vast tracts of lands for farming...More lands for vast urban sprawls, natural parks and wildlife preservation etc...Cars will run on H2 and battery to traverse the vast urban sprawls without any pollution...batteries will be recycled. No more oil spills.

Thus, with solar farming, the earth can support 100-1000 billion population before the real need for a massive exodust to Mars and Titan, etc from over us a few centuries to perfect our space travel technologies!


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.


P.S. Audi (VW) scraped their e-tron programs - both a1 and R8 and now trying atract attention to extremely crazy ideas.


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.


"to support an entire human and animal population in Mars, in underground communities"


Why bother going to Mars? You can do that right here.

One good thing about doing this on Earth rather than on Mars is that the 99% of humans who would go insane from living in a hole in the ground can go outside occasionally for some fresh air.

Have you considered underwater colonies?

Kit P

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.


I am forced to agree with DaveMart and also Kit P's first comment.

Storing energy for winter use can be as simple as a district heating system using a large pile of earth for thermal storage; the heat losses become very small as the size increases, and the system is nearly as cheap as the dirt from which it's made.

Conversion to hydrogen remains expensive, and methanation is inherently lossy; there's simply no way to avoid that, and any overhead associated with capturing or storing CO2 must be added.  As always, hydrogen is a solution in search of a problem.  If you need something with carbon, start with something that has carbon.

There are a host of uses for "excess" nuclear generation, and the reliable nightly/weekend nature of surpluses makes more "dump load" applications economic.  Instead of cutting the fleet down, France should be looking to expand it.

Nulear fuel is very precious energy resource to enable human to travel in deep space and to settle outside of the Earth

There is no shortage of uranium.  While precious, it is anything but scarce; using fast-breeder reactors, the energy content of the U/Th in an average ton of granite is more than a ton of coal.

All light water reactors are designed to load follow

Which does not make it a good idea.  Changing power output causes thermal cycling, and the need to alter neutron flux means adding and removing boron with the consequent production of contaminated ion-exchange media.  With large, predictable surpluses at marginal cost well under 1¢/kWh, it makes more sense to find cheap dump loads to consume them instead of spending money and creating nuclear waste to create scarcity.


(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.)


Clean e-energy sources mix (Hydro + Solar + Wind + Geothermal and eventually + clean Nuke with well managed waste) may be the best approach for the next 50 ++ years or so.

The world should restrain from burning Coal, Petroleum Coal, NG, Oil and similar products to generate electricity. Existing plants should be progressively phased out.

By 2050 or so, the world could design and mass produce cleaner nuclear power plants to generate a higher percentage of the electricity required.

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