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Readers Questions

Q. 28.06.02
I was just in Iceland and saw the start of their revolution to an H2 economy. The realisation that there is actually no difficulty making H2 if you have geothermal was a form of epiphany for me. There is an inexhaustible supply of geothermal energy all over the world.
Is there a geothermal resource in the UK?
Mark (UK)

A.
Gas thermal energy has been developed in Southampton and supplies heat and power to city centre properties. The City Council are partners in this scheme.
There have been hopes for hot water supplies in the City of Bath, but we don't think anything is currently operational.
The UK government's view is that, after substantial research efforts costing tens of millions of pounds, the results do not justify further investment at present.
Peter

Q. 24.06.02
I am trying to use hydrogen to lift water!
If I invert an airtight container like a gallon jar and place it in a pan of water. Then use electrolysis to separate hydrogen and oxygen from water. Ignite the hydrogen in the airtight container. I feel the result of the combustion will be a partial vacuum in the inverted jar and some water will be drawn up into the jar.
What do you think?
Steven

A.
When you electrolyse the water in the jar, the gases formed (oxygen & hydrogen) will displace the water downwards. When you re-combine the gases by ignition, they will change back to water and the water in the jar will return to fill the jar, but will be at the same level as when you started. The electrical energy put in will show itself as heat; the jar and the water will be warmer.
Peter

Q. 12.06.02
On one of your pages, (http://www.hydrogen.co.uk/h2/solar_pv.htm) you show how all of UK's power could be produced by solar energy, with hydrogen as the energy carrier. Your calculations are interesting but they do not include transportation losses or the extra energy required to prepare the hydrogen for shipment to the UK (via liquid, compressed gas tanks, or compressed gas pipelines). It is quite a distance from North Africa to the UK. I would be interested in seeing the changes to the amount of land that would be required to supply the same 1500 Terawatthours while accounting for transportation energy.
Also, no mention of what the price of electricity would be once the hydrogen is delivered and converted back into electricity. Any guesses? Thank you for your help.
Timothy

A.
Over distances greater than 1000 miles, electrical energy transmission via conversion to hydrogen gas and pipeline transmission is more energy efficient than transmission by HV DC overhead line and much better than AC line transmission.
When the delivered hydrogen is used, near 100% energy recovery is possible because there is full heat recovery from the electricity generation. As a result, the economics at the user end are good. The more significant cost is the cost of the electricity to make the hydrogen. Only when PV costs reduce by factor 10, when mass production as opposed to current batch production of PV panels commences, will the whole economics make sense.
Wind produced electricity - produced on land - is already cheap enough if we could only get planning permission for some big 100+ MW wind farms in the UK.
In answer to your question, the little squares on the map take into account the extra costs you describe.
Peter

Q. 04.06.02
I'm an engineering student and have to write an essay on domestic energy generation and in particular fuel cells. Please could you give me any information on the efficiencies of fuel cells, when used in this context, and the costs of such a project. Also, could you please tell me of any waste products in the manufacture/everyday running/disposal of fuel cells that is potentially harmful to the environment.
Liz (UK)

A.
Fuel cells used in domestic CHP systems can be adjusted to have different efficiencies of electricity production and heat output to suit the heat/power balance required for the home. In winter they can produce more heat, and in the summer, more electricity - which would be useful for driving air conditioning. We suggest you get hold of the books listed in our News section. Some of them will be available in university libraries.
Domestic fuel cells are not really commercial yet but industrial fuel cells of 200 KW output cost about $3000 per KW capacity.
Fuel cells are generally benign and harm the environment far less than traditional energy devices burning fossil fuels.
Peter

Q. 04.06.02
On R4 a few weeks ago I heard an item about domestic CHP systems - as I recall it was, basically, a condensing boiler with a Stirling engine inside, driving a generator. So as well as getting your heating and hot water, you also get electricity.
Do you know anything about these systems, like how advanced are they, are they on the market?
Mike (UK)

A.
The system you describe could be on the market within 18 months. Systems like this are undergoing extensive trials in Europe at present to check their long-term reliability and to discover any unforced problems in extended service in a real domestic-user situation. Similar systems are being developed using fuelcells which combine heat and electricity production in one process.
Peter

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