The renewable energy hydrogen car: the future?

[dedeleco]

The topical on McPhy storage by magnesium hydride (wolves I did not do it ...), will announce a yield of 97%

http://www.lejournaldesfluides.com/actu ... se-solide/

yes with the storage of the heat of storage of H2 in MgH, if not less than the formic acid

Presented in the form of modular reservoirs in which hydrogen combines on magnesium hydride pellets, the system developed, based on work by the Néel / CNRS Institute, is reversible. It charges and discharges like a battery. Other advantages: it allows a volume density much higher than liquid (cryogenics) or gaseous (very high pressure) storage and works at low pressure, which facilitates its use and restores 97% of the energy of the stored hydrogen.

To achieve these results, it was first necessary to accelerate the charging and discharging time of the magnesium pellets in hydrogen, thanks to a special preparation of the magnesium powders in nanostructured crystallites and additives. Then, it was necessary to allow the intense exchange of heat generated during the contact between magnesium and hydrogen within the tank. Finally, the problem was to store this heat produced in a phase change material (fusion / solidification) to restore it in good time for the emptying of hydrogen from the tank.

So it is a complex system of implementation.

It is not certain that concentrated solar thermal panels which store heat directly in phase change materials (or even quite simply in large volumes of free earth at 400 ° C in solar geothermal energy similar to a low temperature volcano ) to restore it to thermal machines giving electricity do not have a much better overall yield than current photovoltaics, as Carnot predicts at more than 300 ° C.

[Leo Maximus]

... Solar H² is the winning combo.

And the H2 wind? it does not exist ?

It doesn't exist here, of course, but the Germans have been investing billions of euros in it for several years.

Keywords "windkraft" and "wasserstoff"

Ditto for the Japanese taken by the throat from Fukushima.

[dedeleco]

The Japanese are relaunching volcanic geothermal energy which they have with very strong potential which works at night without sun and recharged by concentrated sun !!

http://www3.nhk.or.jp/daily/english/20120410_01.html

[Leo Maximus]

The Japanese are relaunching volcanic geothermal energy which they have with very strong potential which works at night without sun and recharged by concentrated sun !!

http://www3.nhk.or.jp/daily/english/20120410_01.html

They have energy under their feet and the industrialists (Toshiba, Hitachi, Fuji, Sumitomo, Mitsubishi, and the others) who built geothermal power plants in Iceland, USA, Philippines, Mexico, ... Everything you need , what.

Will they be able to get rid of the nuclear lobby? The production of enriched uranium has restarted at the Rokkasho-Mura plant! To do what ?

[Fakir]

... Solar H² is the winning combo.

And the H2 wind? it does not exist ?
.

Of course. Just that for solar, I have the study which shows that it is cheaper than nuclear.

[Fakir]

yes with the storage of the heat of storage of H2 in MgH, if not less than the formic acid

The article refers to the energy consumed to store H².

Presented in the form of modular reservoirs in which hydrogen combines on magnesium hydride pellets, the system developed, based on work by the Néel / CNRS Institute, is reversible. It charges and discharges like a battery. Other advantages: it allows a volume density much higher than liquid (cryogenics) or gaseous (very high pressure) storage and works at low pressure, which facilitates its use and restores 97% of the energy of the stored hydrogen.

Today there are 4 main storage techniques: http: //fr.wikipedia.org/wiki/Stockage_d'hydrog%C3%A8ne
H² filling at 1 bar: 90 g/ M3 which consumes almost nothing 99% efficiency (must ride with a hot air balloon ...)
Storage at 700 bar: 42 kg / M3 90% yield
Liquid storage at -253 ° C: 71 kg / M3 65% yield (expensive!)
McPhy storage is revolutionary because it stores 10 kg / m100 at 3 bar for a yield of 93%.

Formic acid stores 53 kg / M3 with a yield of 60%.

[Leo Maximus]

... Solar H² is the winning combo.

And the H2 wind? it does not exist ?
.

Of course. Just that for solar, I have the study which shows that it is cheaper than nuclear.

There are several PV installations in Japan where solar electricity is stored in batteries for the night. The capacity is a few MWh. It is mainly in the southern islands of the archipelago.

In Okinawa (Japan), there are around XNUMX electric Nissan Leaf vehicles that run exclusively on solar electricity.

I will collect info on this. The Japanese are not late, do not believe.

[Pierre-Yves]

hydrogen has many qualities, but you also have to keep a cool head! Here are some things to think about.

performance. If we are talking about renewable energy, we must start from electricity. So we have the chain: electricity -> electrolysis -> storage (compression or liquefaction or storage in MgH, ...) -> transport -> conversion into electricity by a heat pump. By pure generosity putting a yield of 80% at each of these stages, the final yield is 40% (in fact, much less).
With lithium batteries, the chain is reduced to: electricity -> batteries -> electricity; and the yield is greater than 80%. Hydrogen therefore leads to energy waste!

energy density. If we now compare to diesel,
- for H2: 100kg / m3 at 33kWh / kg = 3300 kWh / m3
- for diesel: 855kg / m3 at 11,64kWh / kg = 9952,2 kWh / m3, i.e. three times more.

To have the same autonomy as with diesel, storage will be 3 times larger. And I'm not talking about the weight or the danger of carrying around an explosive gas.

Obviously, lithium batteries, which are still only 0,150kWh / kg, lag far behind. But, as for H2, research is progressing and this energy capacity can still be multiplied by 10 or 20: lithium-oxygen reaches 2 or 3 kWh / kg. With such energy densities, we approach the performance of diesel which must be burned in an internal combustion engine with a lousy average yield.

As for the automobile, as has been said many times on this forum, 3/4 of the needs can be covered by light cars with a range of around XNUMX km ... Small cars with lithium batteries are well placed!

PS. That I can store 100kg / m3 in MgH against only 71kg / m3 with liquid hydrogen leaves me a little perplexed. liquid H2, they are only small molecules all tight against each other, however ...

[Fakir]

hydrogen has many qualities, but you also have to keep a cool head! Here are some things to think about.
performance. If we are talking about renewable energy, we must start from electricity. So we have the chain: electricity -> electrolysis -> storage (compression or liquefaction or storage in MgH, ...) -> transport -> conversion into electricity by a heat pump. By pure generosity putting a yield of 80% at each of these stages, the final yield is 40% (in fact, much less).
With lithium batteries, the chain is reduced to: electricity -> batteries -> electricity; and the yield is greater than 80%. Hydrogen therefore leads to energy waste!

In fact, the energy chain of H² has a lower yield than that of accumulators.
80% Electrolysis 93% McPhy storage 60% heat pump and 95% efficiency of the electric car
Or 42%
For the accumulator 70% for charge-discharge and 95% efficiency of the electric car, i.e. 67%
The efficiency of the gasoline energy chain is around 10% ...

energy density. If we now compare to diesel,
- for H2: 100kg / m3 at 33kWh / kg = 3300 kWh / m3
- for diesel: 855kg / m3 at 11,64kWh / kg = 9952,2 kWh / m3, i.e. three times more.
To have the same autonomy as with diesel, storage will be 3 times larger. And I'm not talking about the weight or the danger of carrying around an explosive gas.

Admittedly H² has a less interesting volume energy than gasoline, 3 times less. However, the heat pump has a performance 4 to 6 times more efficient than an internal combustion engine.

Obviously, lithium batteries, which are still only 0,150kWh / kg, lag far behind. But, as for H2, research is progressing and this energy capacity can still be multiplied by 10 or 20: lithium-oxygen reaches 2 or 3 kWh / kg. With such energy densities, we approach the performance of diesel which must be burned in an internal combustion engine with a lousy average yield.

It is clearly a solution for tomorrow. Today there is H²

As for the automobile, as has been said many times on this forum, 3/4 of the needs can be covered by light cars with a range of around XNUMX km ... Small cars with lithium batteries are well placed!

This is true, but it is the last ¼ that conditions the purchase. The Nissan Leaf is now on the market at € 30000. This car with 160 km of autonomy and especially an 8 hour recharge is not finished in my opinion. Especially that every 5 years, you have to reinvest qqs thousands of euros to change the batteries.
I do not understand the reasons for the absence of a hybrid vehicle with a battery for the first 50 km rechargeable!

PS. That I can store 100kg / m3 in MgH against only 71kg / m3 with liquid hydrogen leaves me a little perplexed. liquid H2, they are only small molecules all tight against each other, however ...

Carbon hydride is even more efficient, oops we call it gasoline ^^

[chatelot16]

Carbon hydride is even more efficient, oops we call it gasoline ^^

that's it you understood

instead of looking for hydrogen storage means which are dead weight as much to link it to carbon which is also an energy carrier and not a dead weight to transport

hydrogen alone is too gaseous
coal alone is too solid
miracle the 2 together it's liquid!

all the dream mode of using raw heat to separate oxygen and hydrogen: it works almost except that it inevitably recombines by cooling

another carbon miracle: if we heat water vapor in the presence of carbon, oxygen makes CO and hydrogen is not lost: it is the solar gasifier which mixes the energy of carbon and solar thermal energy to make CO and H2 mixture called synthesis gas and fischer tropsh base

without solar heating the gasifier consumes much more coal and makes less hydrogen

it is not a simple hypothesis: it is the gas with water which was used in industry, except that without solar heating the gasifier alternately works with air to raise the temperature, and with steam or it cools ... while it walks in the air it only makes CO diluted by the nitrogen of the air ... while it walks in the water it makes CO and H2 without nitrogen

the solar gasifier will make pure CO and H2 without nitrogen as long as there is sun