Water good idea: Solar-powered home stores energy as hydrogen
Although solar panels can be used to power a home with clean energy, demand for power fluctuates during the day and excess power is often also produced. A new development in Chiang Mai, Thailand, reportedly solves these problems. It converts excess power to hydrogen and stores it for use later.
There are four family homes in the Phi Suea House development, as well as several other purpose-built buildings. According to project developer CNX Construction, the homes will be the first in the world to run on solar-powered hydrogen storage.
To achieve this, there will eventually be 114 kW of photovoltaic panels generating around 441 kWh of electricity a day, a partial excess of which will be stored in two 2,000-Ah lead-acid battery banks. Electrolyzers will then convert additional excess power into hydrogen gas by applying an electrical current to water. The hydrogen will then be stored until it is needed, typically at night, at which point it will be changed back into electricity via fuel cells.
CNX says the system is the most effective and ecologically-friendly way to store the energy produced. In addition, the process is entirely clean, with oxygen and water being its only by-products.
When fully up and running, the system will reportedly be able to produce hydrogen at a maximum rate of 2,000 l (440 gal) every hour and will be able to store up to 90,000 l (19,800 gal). The daily demand for electricity will be in the region of 200 kWh and the fuel cells will be able to produce 120 kWh at full storage, easily covering the estimated 80 kWh that will be required overnight.
To ensure the efficiency of the houses, they will have solar hot water panels installed, meaning that no electricity will be be required for heating water. In addition, the houses will have double glazing, thick walls, natural ventilation, efficient fans to reduce air conditioning use, plus large windows and lower-power LED lamps to minimize the energy required for lighting.
The development has been being tested with a reduced load since March. CNX tells Gizmag it will be fully operational by the end of January.
The video below explains the energy system employed by the Phi Suea House.
Sources: Phi Suea House, CNX Construction
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A side issue: "around 441 kWh". Haurrrph! The adjective "around" means "don't pay attention to more than one significant digit".
I also think Lithium Ion batteries have now passed deep cycle lead acid as the overall cheaper option for nightly use. Deep cycle lead acid banks can't be discharged under 50% without greatly reducing the total number of cycles and Lithium Ion batteries support several more cycles even if discharged much more deeply (~80%). This is in addition to being about 3x the density (and nearly 6x if counting the need to double deep cycle lead acid capacity).
The battery banks are 2,000 Ah each. There are 2 but 4,000 Ah of storage is needed for 2,000 Ah of capacity because its lead acid. Assuming 12 volts that's basically 24 KwH of useful battery storage.
The Tesla Powerwall packs are $3500/10KwH and 3 of them would take up far less space than all of their lead acid banks.
From the photos it looks like the 120 kWh hydrogen system also offers far better energy density than the lead acid battery banks which is interesting too. Hydrogen offers lower total efficiency than batteries because of high losses through electrolysis but you could compensate for it by throwing in extra panels.
I don't know how much maintenance is involved with the hydrogen system but that's part of what's learned through experiments like this. For a lot of people a lower maintenance system that requires additional panels might be more suitable that a room for of lead acid batteries that have to be regularly topped off and replaced every few years.
Also, I found a lead acid vs lithium ion comparison article here that has some useful data: http://www.altenergymag.com/content.php?post_type=1884
The article is from 2012 and lithium ion is now about half as expensive.
Nothing really new here.
You writing doesn't take into account 2 major flaws that would drive the cost down, improve reliability, improve the environment (big time).
The 2 major flaws will be addressed by in US technology research.
Proof has been done and prototype valuated concepts.
But still, you are on the right track for energy and all technology that can get us off hydrocarbons will be welcome.
And that's what I don't like a lot of this junk, PV panels are decent but once you factor in costs of battery and replacement and all the heavy metals and chemicals associated with their production you might as well get a good geothermal unit, solar hot water heater and tap into the grid for the remaining. My dad pays about $35 bucks for utils on a 5k square foot home.