Hydrogen powered house

[Joe Blake]

http://www.gizmag.com.au/go/7978/

Looks like something I'd like to have.

Joe

[Rob Beckers]

So, let me get this right: First they convert electricity to hydrogen, and then the hydrogen is either burned (for heating) or converted back to electricity (to power the house). I guess these guys are drunk on hydrogen subsidies. Hard to explain otherwise.

Wouldn't it be nice if politicians stopped tauting hydrogen as the solution to all our energy problems. It's an energy carrier, a storage medium (and not a very good one at that), not a source of energy by itself. We don't have any direct sources of easily available hydrogen on this planet, it has to be made from other materials. Then again, since the 'hydrogen solution' is always just 5 - 10 years away it's perfect for politicians. They can claim to be part of the solution, which just happens to be over the horizon of their next election. Wouldn't it be nice if people were educated enough to see through this spiel.

Maybe I'm getting too much of a cynic... :(

-Rob-

[Paul Bailey]

I guess since I follow the Energy /efficiency scene fairly close. , I have seen this photo over 18 years ago. And as Rob stated where the politicians flow the money seems to go and sometimes vice versa. Yes hydrogen works, it is extremely expensive and not really cost competative with Anything at all. thanks for the posts Joe, whats' up with other renewables down under as I hear its a strong market?? Paul:)

[Rob Beckers]

By the way, I just read that most hydrogen today is made from natural gas. Talk about 'renewable' (or lack thereof)...

-RoB-

[Alan Stevens]

I am glad to see some others that see through the hydrogen myth. It has very low energy density compared to other energy carriers. That house mentioned in the thread would be better storing the off peak electricity in batteries for electrical use and heating water in storage tanks for heating use

Solar hot water for heating and DHW should be used to offset the energy drawn from offsite sources. Also wind and solar PV could be used if cost effective.

As far as a transportation fuel is concerned, a hydrocarbon can't be beat for energy density and ease of refueling. The only issue there is where is the carbon coming from? Since we like within a closed loop carbon cycle, we are creating problems when we add new carbon to the system. If the carbon comes from within the system, then it is an energy carrier, and neutral to the environment.
This distinction gets lost when people only talk about CO2 as the issue.

I may be cynical, but I believe the dumbing down of the environmental issue is a conspiracy of the nuclear lobby. If the only problem is CO2, they don't produce any!

Enough rant for today

[Paul Bailey]

welcome to the group. Thats why conservation in all aspects of energy consumption always wins Hands Down. Paul:)

[Mel Tyree]

The 'Hydrogen House' thread is a half year old. Most people dumped on it (the use of hydrogen) and I tend to agree. On the other hand, why not check out DOE NREL's Wind2H2 site? I would like your opinion!
http://www.nrel.gov/hydrogen/proj_wind_hydrogen.html

(1) I agree that most talk about hydrogen fuel cells is with regard to electric cars and it doesn't help much if you generate H2 from hydrocarbons (fossil fuel) with the aid of electricity (mostly fossil fuel derived OR worse).
(2) But this NREL project is expecting to show that the Turbine to Wheels energy efficiency (Joules(or kWh)/mile driven) is comparable to the energy cost from Well to Wheels (Joules/mile driven) when you include the energy cost to extract, refine, transport, and burn the fuel in an internal combustion engine.

So I have looked into this some. I called NREL and spoke to the guy in charge. He said the efficiency of wind produced kWh to H2+ O2 is 70%. I looked up the typical efficiency of fuel cells (50%)...the rest goes to heat. What I am missing is efficiency of an electric car (kWh/mile) and the energy cost of storing H2 under pressure so you can drive around with it. From the ideal gas law I figured out the pressureXvolume work required to compress H2 to 3000 psi ... it is a large fraction of the covalent bond energy in water! How efficient are air compressors?

I am sure the NREL guy will publish all this but I wonder if anyone in Green Power Talk cyber space has any info to help me fill in the numbers?

[Joe Blake]

The original link seems have temporarily disappeared, but my recollection on reading it was that I'd like to have a "hydrogen house", ie a house which acted as a "home base" that uses (say) a photovoltaic array to generate hydrogen and store it for later conversion to electricity, whether directly into a battery at home or fuel cell in a vehicle.

I agree with Rob's initial comment, and those following. I don't really see hydrogen generation by using non-renewable fuels as being a sane option, but given the increasing efficiency of renewable energy generation systems, I suppose it might come down to a choice of storage media, whether to store the resulting power in a battery OR as hydrogen, or even in another (as yet undiscovered) form.

However, one of the so-far underexplored benefits of use of hydrogen is that, as is often touted by proponents, the "exhaust" gas is nothing but water. Given that lack of clean drinking water is a problem for a considerable number of the world's population (and not just in "third world" countries), for a residence to able to produce at least some of its own water may be a real benefit.

Whilst I have a "water-from-air" condenser, regardless of how much water it produces, when running, it consumes 450 watts of power. Assuming that some method can be discovered to use electrolysis to generate hydrogen from grey, or even black water, I wonder whether that would an efficient means of supplying water to a household, with the heat from the recombination of oxygen and hydrogen being used to co-generate more power?

Just wandering a bit, as it stands, I'm still running the condenser off the grid, but hoping to be able to go over to a PV array. In that situation, I may be able to run the condenser during daylight hours and "store sunlight" in the form of condensed water, for later consumption.

It may seem to be a circuitous route, but if I can do that, then that elides the problem of using possibly expensive technology to generate hydrogen, because the water will be pure, and that would simplify the whole system.

Just speculating out loud. ;)

Joe

[Joe Blake]

... thanks for the posts Joe, whats' up with other renewables down under as I hear its a strong market?? Paul:)

Sorry, Paul,

I must have missed your posting.

Since you wrote this, we've had a Federal election, and the conservatives who quite openly admitted that they didn't believe that the science of climate change proponents was credible, were dumped from office, and have been replaced by a government which has a fairly greenish tinge. Even as I write our Prime Minister is convening what's being called "The 2020 Conference", which is supposed to be a think tank for ideas to be implemented by the year 2020. The environment and renewable energy appears to be high on the agenda, so perhaps by the end of this year, we'll have a clearer view on renewables.

However, government at federal, state and even local levels are starting to take it a bit more seriously and offer various rebates on PV arrays and "smart" power meters. My landlord and I have been talking seriously over the last few months about getting more solar power on our houses, plus rainwater tanks etc.

Just last week (17th Apr) there was a current affairs article on the subject. There was also a companion interview with the Federal Energy Minister, Martin Ferguson.

http://www.abc.net.au/7.30/content/2007/s2220232.htm

http://www.abc.net.au/7.30/content/2007/s2220192.htm

Joe

[Mark Parsons]

What I am missing is efficiency of an electric car (kWh/mile) and the energy cost of storing H2 under pressure so you can drive around with it. From the ideal gas law I figured out the pressureXvolume work required to compress H2 to 3000 psi ... it is a large fraction of the covalent bond energy in water!

Greetings Mel,

I can help slightly with the efficiency of an electric car.
Tesla Roadster specifies 110 Wh/km. http://greenhome.huddler.com/products/tesla-08-roadster-coupe

H2 is NOT going to be our transportation energy carrier under any of the current published concepts.

Regards,
Mark