Hydrogen Home Storage. Could this be a game changer? 

I live in Australia. We invested in roof top solar like millions of other Australians. Unfortunately governments on the left and right have overseen the price we get for our solar energy from energy companies plummet. It’s ironic that Australia is now wasting vast amounts of renewable energy because governments on both sides of politics can’t work together to capture this energy. While I’m a fan of renewables, the fact is they don’t provide enough baseline power, in-particular during the night when most homes use most of their power.

The energy ministery of my country (Chile), has started to invest a lot in green hydrogen at the north, not sure how it will develop in the next years

it is indeed the HydroCarbons attempt to remain relevant and a financial force in Canada as evidenced by the Alberta Politicians statements that hydrogen technology will move forward to ensure jobs and a future for Canadas Oil and Gas Industries regardless of cost or viability.

This is the first application of the hydrogen cycle that has an overall efficiency that I find palatable.

Thank you for everything you research for us. I'm on a fixed income and severely tight budget, and although I can't afford to financially donate, I spread the word about your channel all the time. Keeping us informed about changes that will overwhelm us over the next 20 years will be paramount, hopefully you'll be here to explain it all as we progress in an honest, easily comprehensive way. 💖

"It takes more energy input from the fossil fuels than you get out. You can't make this up." All hydrogen production requires more energy put in than you get out. There is absolute no way around this law of physics.

As I've come to expect from your videos, this was yet another very interesting and exciting development in the green energy industry. Enjoy your week holiday!

Home storage is a good idea even without windmills or solar panels as they can make the home independent for the times where there is neither wind nor sunshine to rely on or in the worst case a blackout.

Without knowing which metal is hydrated, it's hard to know if this is just trading one problem for another one down the road.

*The devil is the details* , competitive vs battery? hardly : -The warranty of 10 years and 30 years lifespan /20.000 cycles is on the *metal hydride only* , basically the "sponge" inside the tanks , the least expensive part , you do however need to consider parts that will die first and require maintenance like : the fuel cell ( *very* expensive) has a lifespan of 30.000h, that's 3.5 years always on but they say on "normal" usage it should last around 10 years but then it means basically turning it completely off for 2/3 of the day not producing H2 or electricity (basically an expensive backup generator) . then you have the water filtration system , I can't tell the lifespan but as for any water filtration systems, it does require frequent, periodic maintenance . Also the "small" 5kWh battery is tasked to be discharged to 1C (5kW) than the typical 0.5 discharge rate of battery storage systems that will result in a shorter lifespan (stated as 10-15 years vs around 20-25 of battery storage systems) in fact on their website they state : " An annual maintenance will likely be recommended by a qualified technician to undertake the general inspection and replacement of any consumables like filters, coolant levels and electrolyser fluids etc. which is dependent on environmental factors and usage patterns " AKA : you will need our technicians to inspect and replace stuff every year on you expenses or you'll lose the warranty and get the filtration stuffed up and the fuel cell seized (degraded by element poisoning ) within one year . I can't understand of LAVO can claim their system roundtrip efficiency is "way above 50%" when they use Nestack fuel cell and their best efficiency conversion of H2 to electricity is 56% , so if you take a 20% loss of the electrolyzer you have in the best case scenario a round trip efficiency of 45% and this without taking account of the AC/DC inverter , battery ,hydride sponge and the water filtration system losses . Now let's compare with battery systems : 1x LAVO : 30.000 austrialian $ onboard energy=40kWh , max output 5kW , energy useable after DC/AC = *20kWh* (i'm generous), generate noise, maintenance required ,consumable parts , requires a good amount of space and it's heavy 560kg with the tanks included . 2x Powerwall : 26.600 AU$ onboard energy=27kWh max peak power 14kW , energy useable after the DC/AC inverter= *25.6kWh* , virtually silent, no maintenance required ,take less space , and weight less than half of a LAVO system .

The metal sponge is the way Acetylene is stored.

We've been using acetylene dissolved in a carrier to make it safe and manageable, for 100 years. This is probably just the first of many hydrogen storage systems using this principle.

2 Thinks! First, my wife has chemical sensitivities so I made a hydrogen cook stove (Hindenberg I with modified natural gas range) and we cooked with H2 for years. The off-grid PV system electrolyzed water and stored H2 gas in an inverted barrel in a larger water filled barrel using only the pressure from the alkaline electrolyzers. We also purchased bottled H2 gas. Results are the chef-preferred "cooking with gas" but with no CO, CO2 pollution. Second, consider "H2 gas blending with CH4" at the home / business. Solar electrolysis H2 combining with natural gas at 10-20% H2 blend can be easily used in all gas appliances with no modifications. Reduced carbon and uses renewable energy to displace fossil fuel for distributed solar fuel at the point of use in residential, commercial and even industrial processes.

Interestingly pretty much all of the state governments in Australia are at odds with the federal government in regards to carbon targets🙄

Hydrogen storage in metal hydrides has been around for decades, I've even seen a large system personally in use at my university about a decade ago, feeding PEM fuel cells. This Lavo unit is just a sexy commercial version of very well established tech. The more important question is, why if it's been around for so long, has it not been widely implemented? Probably because fuel cells are generally considered as being too expensive to be practical at the moment, however, if they do become more mainstream, then hydrogen storage in metal hydrides would probably be the preferred choice imho.

So each module stores 10 kWh, and they are removable. So if the modules can be made cheaply enough, an outhouse could store a winter's worth of a Passivhaus-standard energy needs. Bit of a fiddle having to keep changing them but IMHO it's a move in the right direction.

Thanks, good video. I agree with your conclusion. More competetion will lower the costs while improving the designs. Green is improving at an astronomical pace. Yeah!!!

whatever system they develop you can rest assured that either it will have a limited life (then you have to buy another) or they will make parts that have to replace, but what they will not allow you to have is a lifelong maintenance free system. Check out the new Hydrogen powered JCB that even gets its H2 from abroad in on-site storage tanks (excellent carbon footprint I must say) I have repeatedly asked them why their new engine is not HOD (Hydrogen On Demand) but have been ignored!

This could lead to a real EXPLOSION in home storage.. ;)

So let's use hydrazine, N2H4, instead...and pass it through a graphene filter...

I wonder they had considered using the heat from the electroliser as past of the domestic water heating. That would raise the operating efficiency.

i don't get why people are so focussed on how hydrogen is produced, but ignore the environmental impact of producing batteries

This isn’t new technology and it’s awesome to see it being pursued commercially finally.

Let's put solar panels on every home, business and covered parking rooftop and switch to electric vehicles making nearly everything we do solar powered while completely decentralizing our power supply and empowering everyone as power generation owners. Solar power is CHEAPER and electric vehicles are soon to be CHEAPER to make and already are considerably CHEAPER to maintain and operate, especially if charged from your own solar power. A 3-5 year ROI (return on investment) for a solar array that will generate power for decades is a no-brainer and the panels can even be made locally too. #EndFossilFuels #SwitchToSolar #SwitchToElectric

Excellent - such a valuable and clear video. Very much appreciated, as someone who pays quite a lot of attention to Scott Morrison's massive climate policy vacuum.

Too much intro - too much back ground . Please get to the revolutionary product, then tell what YOU want.

I would like some follow-up videos to the New tech you've brought up over the years. New stuff is cool to hear about, but viability is only proven over time and I find it incredibly hard to check up on these things.

The waste heat from the conversion could be used for heating water and the house using a heat pump.

Brilliant concept open up a very healthy contest in storage intuitive and inventive product is wait will save humanity dispute politics

For me, I'd prefer not to have an explosive gas in my home, especially for the new largely underground infrastructure I have in mind. Hydrogen is just too wasteful, renewable energy directly to batteries makes more sense to me. Could even be home sized gravity batteries.

Metal hydrides for storing hydrogen have been a known technology since the late 80's

Exceptional news, while your calculation on the unit featured (designed for commercial or industrial?) may be off as they could have one at a half the size for 20 kWh per hour & also have the price to be $15,000 (to Tesla's $13,300 & 13.5 kWh)... If the argument is it's sufficient for a home unit, & more than one Tesla powerwall would be needed : it's still a good investment argument... I just wonder if one could fuel a Mirai or a fuel cell lawnmower, at home, while they're at it. - Or vent heat - or provide water for showering or what not...

If it's patented it's the opposite of "held close to the chest" - in fact, it's then public information

This is not the first time you discuss a technology kept secret by its sellers. To me that's shady as hell. Why does it have to be secret, is it not enough that we have very restrictive IP laws? Or is it magic?

So, I might be wrong here, but in addition to being more than double the cost of a tesla power wall, wouldn't you also need to double your solar capacity in order to make up for the 50% efficiency rate? I think that needs to be considered as part of the total cost of ownership for a system like Lavo, since it's roughly 50% less efficient than the battery.

Can't understand why you wouldn't want to cook on hydrogen gas.

Andrew Forrester a Iron Ore mining magnate, has expressed his interest into "green" hydrogen. Also making "green" steel. He is not waiting for govanostra. His company is Fortescue Metals.

7:18 50% is actually really high? A typical PEM electrolyzer is up to 80% efficieny, but fuel cells are only 60% efficient. On top of that with pressurized storage you would lose another 5% of your total energy bringing your best case efficiency up to 45% but in practice this number is closer to 40%. My biggest fear is that the capacity of this machine is marginal and the up front and/or maintenance costs are too high.

11:07 small mistake. You can't pressurise hydrogen to liquify it at "normal" temperatures. It's critical point is 32K.

There is only a small tiny problem. Hydrogen does not exists in nature. Therefore it needs to be produced. Which we come to another tiny little problem, According to latest findings it is very expensive to produce, then additional money is needed to store it at very low temperature, and yet another problem is to transport it at low temperatures, and after is all said and done it needs an electric motor for its power to materialize. Why go through the whole complex and costly spiel, when we have in nature already an inexhaustible source of energy in our perennial Sun. The only thing we need to do is gather its power with solar panels coupled with accumulator to store excessive energy for use when the Sun is absent, and use other renewable sources as back up, and we solved the problem permanently and at costs we can easily afford.For over a century the Hydrogen miracle from time to time resurface, it is studied again and put back in the shelves again for the basic reasons known to every one.

FYI, as an Australian I would like to declare that ScoMo is an absolute Womble.

Cooking on hydrogen. Lets make this a saying.

"Cooking on gas is one thing, Hydrogen, not so much" How does that make a difference lol! I'd rather cook on Hydrogen any day over propane lol! Hydrogen is Clean!

The latest from Australia is the power industry wants to penalize people that have PV systems at certain times of the day for putting power into the grid. This is on top of having a difference of up to 30 cents per kilowatt for PV as against power from the grid (for example 11 cents for a PV kilowatt and then charging 37-38 cents per kilowatt in return to the same customer).

I think the low round-trip charge / discharge (in)efficiency won’t compensate for the high claimed cycle count. It’s a physical limit and can’t be improved much whereas cycle improvements in Li technology and further price falls will continue to improve it.

0:22 Why would you not cook with hydrogen? Coal gas is 50 % hydrogen, plus a few other components. That was the standard in many British homes until the 1970s. The entire gas infrastucture was switched first from coal gas (mainly hydrogen and methane) to natural gas (mainly methane) and it can be converted back to hydrogen when it becomes feasable.

Thank you for your thoughts and knowledge. You mentioned that in Australia we can utilise millions of panels. Recently we have heard that people will be charged for uploading their excess power to the grid. I wonder if you could please investigate this recent change, thank you.

it is truly unfortunate that lithium is pulled from the dictatorship of Bolivia and sent to another dictatorship, China, to make lithium batteries.

It would be really interesting if those hydride units are easy to remove when full and, say, stick in your car, or sell to someone who needs more energy.

U.K. based AFC energy has been powering the new Extreme E Grand Prix series unsung Hydrogen

The perfect home hydrogen fuel cell would get its water for electrolysis from rain water barrels, use excess solar power to convert the rain water to H2. The hydrogen fuel cell can power the house at night and warm the house during winter and run AC units during the summer. The fuel cell’s water byproduct is undrinkable without processing; you can either use that water to keep radiated heat pipes full, or filter/mineralize/soften the water for drinking. For me, I’d like to use a CO2 scrubber to turn the fuel cell’s water to soda water. Unlimited vodka club.

No, this is definitely not a game changer. It is more of a toy for the environmentally concious. The millions and millions of ordinary people need something that is simple, affordable and works.

I love your videos. Happy Easter!

fuel cells ruin it for me, just burn the hydrogen for heat ? Stirling engine ?

Have you considered making a video on the environmental impact of NFTs?

It still amazes me that the vast majority of houses in the UK are not fitted out with solar. I do realise that we just can't dispose of fossil fuels overnight in favour of electric as the amount of job losses would probably cripple the British economy, but I do think we should be progressing a lot faster than we are at present.

"Electricity at low prices" LMAO. Prices and profits won't drop until energy companies (same for other utilities) are no longer privately owned. Maybe if Australia went on the 'green' production H2 use they could desalinate seawaterand regreen the interior.

Sure, why not. A fellow in New Jersey has been running his home and a car on hydrogen made from his PV system for at least 15 years. Always seems to have an excess of power. Has ground sourced heating.

3:55 This looks like real progress to me. I have no doubt that, ten years ago, Morrison would have simply said "There is no credible energy transiton plan," and simply omitted the rest.

Metalhydride storage of hydrogen is well known and widely used in modern German submarines for instance.

TLDW: Unlikely edit: glad you addressed the link to fossil fuel companies

lithium iron phosphate (LFP) cells have very high cycle rates. The ones I am using are rated at 10,000+ cycles. They are very safe, they are non flammable. They weigh a bit more than the cells used in a Tesla Powerwall but since they are going to sit in place for decades their extra weight is not a problem. The materials used in LFP cells are much less expensive than the chemistry Tesla is currently using in Powerwalls. I am very skeptical of this hydrogen fuel cell approach. It's much more complicated than a simple battery solution so I expect higher prices and more maintenance issues. And I'd need to see some reliable cost and efficiency data. Tesla has changed the storage world with their new dry rolled, tabless 4680 cells. If the cell is LFP it's likely the cost of storage will drop below $50/kWh. With a 10,000 cycle life that works out to $0.005 US per kWh cycle. Almost nothing. The efficiency of a LFP battery exceeds 90%. As far as I can tell hydrogen fuel cells are, at best, 60% efficient. Additional energy will be used in purifying the water, extracting the hydrogen, and forcing into the storage material. This 'store it in a brick' fuel cell system might be less than 40% efficient. Sounds like an idea with no future.

4:13 Mark Z. Jacobson used as a source to "comprehensively debunk" anything is an oxymoron. His work is highly contested despite his tendency to sue anyone who disagrees with him.

What about converting the methane gasses coming out of landfill sites to hydrogen?

"RedFlow" 😂 I mean, I get it, redox flow -> RedFlow, but it just evokes menstruation imagery ^^

Not cooking with hydrogen? Well come to Germany! In many parts of the country they are mixing 10% hydrogen in with the natural gas supply. There are plans to up it to 20% next year. Burnt your pancakes? Well, that's hydrogen cooking! It burns them faster than you can get the maple syrup ouit of the cupboard!

It's always been a reality. But the tank you need is impracticably large. This is amazing.

For the price I'd rather be buying lithium. The main selling point should be long term storage which they don't seem to be promoting with only 40KWh. The tank size should be up to 1MWh at least to store the summer surplus to be used it in winter.

Lavo could make sense today in a hybrid commercial system today where you use hydrogen and lithium ion. There is a portion of your storage that will need to cycle at a far higher rate so hydrogen can be used for that while the lithium ion can be used more for the medium term storage. Kind of like cache and RAM memory on a computer.

The US PBS program Scientific American Frontiers S14 E3 'Future Car' discussed this same metal in the back in 2004.

I am hopeful for the technologies but skeptical because of the link to fossil fuels. Great video :>

What would be awesome is a hybrid system, a BIG Hydrogen "cell" like 100kwhr and a 20kwhr LiFEPO4 (just safer, and fine for home use/solar). You can then try to have enough renewable power input (PV / Wind) to mildly cycle the lithium pack daily and at not to high of "C" rates but then use the hydrogen as dump load for extra energy to then use in low energy input days. Should be able to get large numbers of "days of autonomy" from a system that way. Very long lifespan, self sufficient possibilities too, getting the best out of each technology.

Love the cycle life. Hopefully they can get round trip efficiency up and cost down. . . .

How about H2 powered ships? Ain't that a thing? :)

I would think they could get the price down with economies of scale. However, I hope whatever metal they use is not an expensive one, e.g., platinum, which is used in Plug Power’s PEM fuel cells.

Lavo should pursue being a viable solution of capturing and storing solar / wind energy to be able to release it on-demand as a replacement of Peaker Plants. Total lifetime output of 800,000 kWh is much better than the 40,500 kWh of the Tesla Powerwall 2.0.

I want to go like grandpa quietly in my sleep; not like the kids kicking and screaming in the back seat of the car

BUT WHERE DO YOU GET THE HYDROGEN FROM???? Electrolysis??? Why not just put the energy in a battery without the 30+% loss??? #dumbideasarestilldumb #facepalm #RIPHUMANS

You can also use process heat from nuclear powerplants to create hydrogen using thermochemical processes to produce carbon-free hydrogen as you would with renewables only more reliable.

Shouldn't the terms be dirty hydrogen and gray hydrogen, not gray and blue respectively?

Thank you for your ever so comprehensive video and information 🙏 love, from Portugal

Brilliant round up on hydrogen. A must view for all politicians. Love the Australian hydrogen battery setup for home use. But if possible being able to cook on hydrogen gas would make me happy. I much prefer gas to electricity for exotic cooking. A clean burning gas flame like hydrogen would seem a perfect solution. Maybe the hydrogen battery guys could pipe a little hydrogen into a burner on my kitchen worktop? Sizzle. Sizzle. Ummm.

Awesome content 👍👍

You really need to start thinking of large industrial arrays of solar and grid solar. Especially in places like Australia and US where we have huge amounts of empty sunny low cost, unused land for such installations. Britons and Europeans assume solar on rooftops is the standard way to go. But, places like US and Australia can build twice the kWh of solar for the money with industrial sized projects plugged directly into the grid. Same for energy storage.

One would be wasting their time waiting for fossil fuel companies to do any meaningful development. They’re mostly interested in the profit of natural resources THEY OWN, which really just taints the spirit of true development. I vote YES to the development of GREEN hydrogen.

I'm an Aussie and I'd love to see the world have a transition plan to renewables. Having said that, I'd like to clarify a point made in this clip. It's important to understand that Australia is THE biggest exporter of coal, in the world. Accounting for 30% of the worlds coal. Therefore whilst someone could make an economic case for Australia to produce cheap renewable energy for it's domestic market, it doesn't want to discourage the world from using coal because it will devastate our huge export revenue stream. This is an important factor and an aspect that people rarely mention in their analysis of our policies.

Silly silly silly 😊😊 they still wanna burn stuff . Like he basically stated .THE LAW OF CONSERVATION OF ENERGY . THE BIGGEST BURNER IS IN THE SKY .

very interesting! Can you research ballard and it's H2 tech? They say they're most advanced in fuel cell tech. Is it true?

On my 9kw solar array, I’m on course to produce a massive excess of electrical power during the summer months, even when electric car driving is taken into account. There’s only 3 dark months of the year where my panel electricity production is significantly short of my electrical demand. Battery storage is great for daytime to nighttime shifts in electricity. But this hydrogen concept seems to have the potential to expand its storage capabilities cheaply. That would enable seasonal shifts in surplus electricity, in spite of the inefficiency compared to batteries. I’m reckoning that 1MWh of storage would do it. No need for a bigger electrolyser or fuel cell, but there’s certainly a need for larger metal hydride capacity.

LIVO Vs Powerwall Volume is about 6.5 times ((1680 x 1240 x 400)/(1150x753x147)) and weight is 1.7 times (196/114). Also, LIVO needs a water inlet, which needs to be conserved. It has Electrolyzer. Both need regular maintenance. Max. system pressure 35 bar is another concern at Home! However, it is a good idea.

Ask ourselves this...IF THE PEOPLE WHO DESIGN COMPUTER SYSTEMS , SMARTPHONES and now TESLAS used the same mentality as THE HYDROGEN NEANDERTHALS . JUST WHAT KIND OF TEXTING WOULD WE BE DOING ? WAIT I GOT IT . SMOKE SIGNALS 🤣🤣🤣

A much better idea for powering one's electricity needs is to be connected to the grid which supplies 24/7/365 electricity. In the UK, the CCC's plans for the electricity generation sector, is to get us to net-zero by 2050 from 80 % of our electricity being generated by wind and solar power plants (WASPPs). But because these technologies are stuck with the INTERMITTENCY PROBLEM, the plan is to transform intermittent electricity to dispatchable 24/7/365 electricity using green hydrogen manufactured by electrolysis, by taking 'surplus' electricity from WASPPs when their generation exceeds demand. What they neglect to do is explain how staggeringly complex this is and how massively expensive it is too. Considering only the total capital investment required and (to transform intermittent electricity to 24/7/365 electricity) the cost of fuel - that's right: the cost of green hydrogen fuel - would run up an annual 'bill' (starting now) of £31.83 billion per year, every year, FOREVER! By contrast, the capital investment and fuel cost for Rolls Royce's advanced nuclear power plants (NPPs) to generate the same amount of electricity each year is £8.41 billion per year. Rolls-Royce will be in production by 2030. Through installing at a rate of 9 or 10 units each year, by 2050, 182 NPPs would be operational at a cost, including fuel, of £25.23 billion per year, which is 20% below the perpetual WASPP alternative. But then there would be a 40 years investment hiatus before further investment is needed; hence the £8.41 billion per year equivalence. Down at the money-source level, your typical UK household, £31.83 billion (for the WASPP recommendation) spread across the 27.8 million UK households will, one way or another, ‘insinuate’ £1,145 each year into each and every energy bill. The advanced NPP solution would cost £303 per year. The route the UK Government is being urged to take by the CCC, National Grid, Greenpeace, FoE, etc., in pursuit of these ridiculous intermittent WASPP technologies is insane. But burgeoning developments in advanced NPPs will start sucking commercial investment out of WASPPs before the end of this decade and the WASPPs built over the next 10 years might be the last we will see of them. colin-megson.medium.com/by-2050-the-cccs-sixth-carbon-budget-calls-for-635-twh-year-of-despatchable-electricity-from-d1cac83a213

Actually steam reformation of methane produces hydrogen and carbon MONOXIDE not dioxide. Slight difference.

Sounds "explosive."

Investing $23,000 USD just in energy storages means that your electricity monthly bill HAS to be BIG, in order to justify it.... (mine it's less than $10USD per month....)

I've wanted a system for my house for over 10 years.. WATER, WATER, WATER. Send ME one Please ?!?!?!? Already have solar panels for the hydroponic garden and battery for night time watering. My Company has installed Hydrogen backup systems for the Power Company in SE USA to help keep there communications up at Cell Towers

$35k for 40 kwhr - not inc installation (needs power and water) or the output inverter. Is now discounted to $29k, but I expect $35k total installed cost. Due to the potential of a hydrogen leak, cannot be installed inside. There are several other gotchas ; 5kw maximum charge and discharge is not enough for most homes. What if you have the ac on, and you want to boil the kettle ? The Lavo has only been tested with a 3kw inverter output so far, and 3kw certainly isnt enought for most people. The Tesla Powerwall 2 is typically $11 to $13k installed. The PW2 13.2 kwh, 5kw max charge and discharge, 7kw 10sec discharge. 3x PW2s can be daisy chained for the same money as the Lava, ie, 15kw discharge. The manufacturer stated round trip efficiently is 90%. Tesla also have a neat integrated pv inverter available for offgrid. The Lavo round trip efficientcy ? Lavo claim 50% !. The maximum theoretical H to E fuel cell conversion efficiency is 63% Typical H to E fuel cell conversion efficiency is 50%. Then there are the 'charge' losses. I doubt the Lavo round trip efficiency is nearly as good as 50%. Maybe all that lost heat energy can be used for underfloor heating in winter ? Will require a much larger solar pv system. This link: LAVO’s Australian Made Hydrogen Battery: Incredible Engineering. Tough Sell. www.solarquotes.com.au/blog/lavo-hydrogen-battery-review/ "... Another option would be to load up on Century lead-acid batteries. They will be more energy efficient ... "

Well! I doubt the claim of 50% "round-trip" efficiency, for the following reasons: - I assume they start from DC from PV panels, and not from AC from the grid, hence avoiding the 5% loss of that conversion.... However, I would be surprised if the voltage did not have to be adjusted to suit the hydroliser. I shall use an arbitrary 2% loss. - I neglect the water-pumping duty... - An industrial-size, high-temperature electrolyser can get an efficiency in the 70+%. But a home-scale one should be challenged reaching 60%. - Then, if my understanding is correct, the hydrogen is adsorbed, in the form of metal hydride, by compressing it. This compression is probably not to very high levels, and the losses thereby limited, but the compression will still reduce the efficiency by a couple of %. - To desorb the hydrogen, I wouldn't be surprise that you have to apply to those canisters a partial vacuum. A vacuum pump also consumes power, say another couple of %. - Then, the hydrogen is combined with the oxygen of air (which must be purified, hence a small pumping loss, which I neglect) in a fuel cell. This FC has around 50% efficiency. - The various losses of efficiency above are emitted in the form of heat. There must be therefore a cooling system. Say 1% loss for an air-cooled cooling system. - Finally, the DC power from the FC must be converted to AC to be used within the home, hence another (and final!) loss of 5%. Therefore, the round-trip efficiency of the system should be more like 0.98x0.70x0.98x0.98x0.50x0.99x0.95 = ~31%, then the 50% claimed!!!! Unless the company has found some thermodynamic tricks, which are not in my book! BTW, the round-trip efficiency of storage batteries is not 95%, but: 0.95 (conversion AC/DC) x 0.95 (ohmic losses within the battery) x 0.95 (conversion loss DC/AC) = ~86% (starting from grid power), a bit more from DC from a PV installation. Still, the difference in efficiencies between the two system is stunning! Hydrogen, as a short-term (overnight) storage system is a non-starter. For long-term storage (weeks, or even seasonal), the jury is still out. Last but not least: a storage battery "à la" Powerwall, is solid-state. It will last decades, with some but limited (and pretty well known) storage-capacity losses, but NO maintenance. The hydrogen system has several motors, several rotating devices (pumps, compressor), and will therefore not escape not insignificant maintenance costs over decades of lifetime... say 1-2% per year of the initial purchase price. The performances of the electrolyser and FC will also degrade with time, as the electrodes of the electrolyser, and the catalyst (platinum) of the FC get progressively contaminated by impurities from less than perfectly pure water and air. If, or rather when, those have to be changed, expect a sizable bill! One last thought: the speed of reaction of such power-storage devices to a grid failure: the battery will react in a few milliseconds, you will just notice, if it happens at night, a flickering of the lights. The hydrogen system will take tens of seconds to a couple of minutes to come to power. No big problem... but you will, for sure, have to restart your internet connection!

Very interesting, as ever, though, in my opinion, not quite as sound as usual. No matter what you do, the fundamental physical properties of Hydrogen mean that you are currently working from a maximum of 35% electricity to electricity. The best projected figure is something like 45%, less than half of that of the National Grid. Metal hydrides are proven ways of storing hydrogen but can never have high gravimetric efficiency. That with the highest Hydrogen content is Beryllium, at 18% w/w, though I assume that there are problems using it as it never features in research reports where complex hydrides (mostly involving Tin) predominate. Tin hydride itself contains just 3% Hydrogen. A friend who worked on the experimental, Hydrogen fuel cell-powered narrowboat Ross Barlow (2007) says that its (complex metal) system achieved 1-2% w/w. The (no doubt correct) claims about relative lifetimes of "hydrogen batteries" and the Tesla Powerwall is fine but supercapacitors will do the job better (99+% efficiency), cheaper and for longer (a million cycles). No contest in my book. Hydrogen may well be necessary for applications which can't be satisfied in other ways, such as HGV's, trains and large ships, and might be OK for localised gas grids, but is always going to come second to direct and stored electricity in less demanding applications such as grid-connected homes and cars.

Thank you for this excellent presentation of the evolution of Hydrogen for energy. Soon (I hope) you will present us with a user-friendly-economic-green-energy system for the home.