World-first home hydrogen battery stores 3x the energy of a Powerwall 2 | Hacker News Reader

World-first home hydrogen battery stores 3x the energy of a Powerwall 2

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39 pointsGaishan24 comments

The unit stores 40 kWh and can generate 5 kW from the fuel cell at an efficient of 62.5% and an additional 5 kW boost from a battery for short intermittent peaks. So it will basically take 5 days to use all of the stored energy with no charging if you are running 40 amps of continuous loads at 120V. That’s pretty good. Not enough for a stove or electric heat but definitely enough for all your lights and appliances and a small air conditioner.

What is great is the 30 year Lifespan vs. 5 years expected from batteries in grid scale storage applications.

80% charging efficiency and 50% round trip efficiency yields 62.5% generating efficiency. To charge 40 kWh at 80% efficiency would take two 10 hour days with 9 three hundred watt panels. But you’d want to power your loads those days too, so probably a 20-25 panel array would be an appropriate size. 25 three hundred watt panels is $8k CAD. On top of the $22k USD for the hydrogen storage. Pretty decent setup for $30k!!

rhodozelia not sure of your math there. 40kwh outputted at 5kw I make eight hours of use at max output? It's winter here so I'd say many households would empty it in less than two days easily. Equally in winter here 4kw of solar panels output about 4kwh's a day. So about two weeks to charge the battery and nothing else... Of course it's summer in Australia so much more solar output but you would be better putting it straight into your AC rather than storing it? Apart from running AC at night? $35000. That said if they can really get it to chug away for 30 years mainantance free unattended I can certainly see useful niches.

you are right it is 5 hours not 5 days!

I wonder how it would compare against Nickle Iron batteries?

https://en.wikipedia.org/wiki/Nickel%E2%80%93iron_battery

I guess the use case might be arguably different - the hydrogen storage could last a week or a month, which the battery would self-discharge.

i own a grid tied 15x325Watt system which gives me around 25 units (25kwh) if electricity in summers. i have thought of a crazy idea of a water battery that would get charged with a solar water heater as well as the solar panels to heat the house in winters...

the USD 22k is wayyyyyyy too expensive

Lol your grid tie systwm comes to 4.8kw if your (15*.375) is correct. We rip around 20kw a day on a AVG house in Aust. My folks shred through 30kw an that's just 2 people.

Given power used to be about $3k a quarter or $12k a year for them...it's only 3 years of bills to cover a 15yr battery. They already got 8kw of solar for 13k too. Not bad at all really, $45k for battery an solar, pays for itself in 4 years if your use is high enough. 11 years of savings before you replace the system.(aus dollars)

sounds good but i paid less than USD 1200 for the panels, inverter, cabling, installation.

Our monthly power consumption is around 300Kwh in summers (no need for air conditioning) and double in winter months (need heavy heating but no electricity due to low supply/heavy snow). that gets to around USD 200-250 for a year. that gives me 22000/250=88 years of no electricity bills to repay this system. Note, my Kwh is USD 0.05

the country is india where due to USD exchange rate which is INR 73:1 USD.

My god I'm jelly of those prices. Aust is 27-32cents a kWh for grid power. About 1$ per watt for solar panels. If you feed back into grid you get paid 16ish cents per kWh.

Oh. We arent paid or anything, just the reading is supposed for a year to year and I have to pay just 10% of my last bill. Say I consume 1000kWh for a year and generate and sell to them 1100kWh, then I still have to pay for 100kWh at same prices.

I could reduce my load on grid by going battery but that is very expensive and with lead acid the ROI doesnt reach as they get depleted in 3 years before any profit is made. Havent looked at lithium as its very expensive..... will see

If the policy for net metering changes in future, I will preemptively buy another 5-10 kWh panels

You have a source on the 5 years life expectancy of battery systems ?

It was relayed to me by a mathematician doing the analysis on sizing a battery system at a solar plant in Hawaii. The trade off between decreases longevity with depth of discharge or increased up front costs for more batteries that don’t get discharged as deeply.

Yeah that seems too low to me, given that a lot of electric vehicles warranty their batteries for 8 years, and those batteries typically undergo more stress in terms of peak charge/discharge and such (and also would be expected to normally last beyond the warranty period - it’s not like they all drop dead after 8 years and one day).

There have been previous articles claiming that the expected cycle in most communities is that users will install panels + batteries first, for savings (of cash or of the environment ;).

At some point, as enough leave the grid, the utility company will install massive environmentally friendly power sources (panels/wind/etc). At that point, it is not only cheaper to get green electric from the utility, it is more green (due to scale).

Battery packs like these have interest for a house, but they are also interesting for a city - like the Tesla packs in Australia et al.

If on the large scale they make sense, they should eventually leapfrog home usage, at which point there will be much less need for home packs and lithium.

One thing to point out is that this kind of system might not be a best choice for a single house with limited solar panel area. At grid scale that is a whole different story. In order to cover our energy needs we will need to build many times more solar than our peek load on the grid. That means lots of times there will be power which nobody wants. Here you don’t care about efficiency (with negative prices you might even favor lower efficiencies). Only thing you care about is how you cover your electric needs then there is cloud cover for a few days and not much wind. Hydrogen seems like a great option at the moment.

nice concept but efficiency is the deal breaker here. One to keep an eye out for improvements.

Doesn't explain how energy will be generated out of hydrogen from its statement of energy restoration

Presuming we're all smart genius ?

It does say that there's a (hydrogen) fuel cell in it to convert the hydrogen back into energy. https://en.wikipedia.org/wiki/Fuel_cell?wprov=sfla1

They also say that it has pretty low efficiency, around maybe 50%.

Yes, 50% seems to be a fair assesment of current PEM fuel cell efficiency. Apparently, the PEM fuel cell itself can get up to 60% efficiency, but there are auxiliary services (cooling, supply and exhaust pumps, etc) that most people don't think about that drive the system down to about 47% reliable output efficiency. That's not bad considering zero GHG emissions, and other benefits such as scalability and power density of the cells, but I'm still hopeful for significant improvements in the next decade (I suspect this may be significant offset in the form of greater H2 storage mass/volume energy density).

We can correct the price or capacity by the efficiency for comparison, but on it's own 50% is not good/bad really. I'd take cheaper per-adjusted-kWh-over-usable-years solution even if it has 10% roundtrip efficiency since I normally get a lot of spare energy from solar.

> You'll want to skip to the minute mark if you don't have a marketing-grade chuck-bucket handy.

Is it a sealed system or do you need to top up water? Routing plumbing to the unit might be challenging in home environment, and I presume it might need treated water to keep its electrodes healthy

I’m not so much concerned about it being an open system but rather that it relies on water as a process fluid. Sure running a geyser for 30+ years is fine if all your losing is thermal efficiency. But in this case we are talking about sticking your neck out for 50% efficiencies.

How long before fouling, pump degradation or just simply water sacristy cripples a system like this? Or simply renders it so inefficient to be superfluous?

Connecting it to plumbing is a big issue and will limit it’s usefulness. Also, energy density doesn’t matter for this use case - it’s just sitting outside your home or garage and there is enough space.

They should make this into a portable unit and sell it as a UPS. Higher storage density is useful here.

You need to top up water: > You connect it to your solar inverter (it has to be a hybrid one) and the mains water (through a purification unit)

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