Wednesday, August 04, 2004

The prospect of a solar hydrogen economy

Hydrogen offers interesting application benefits compared to natural gas and petroleum. But it cannot be found in nature in its pure form. Instead, it must be won through complex processing of fossil fuels or by electrolysis from water. Electrolysis requires electricity, which could be produced from renewable energy sources, but also by nuclear power stations. Its production from fossil fuels causes global warming and is not sustainable. Frequently, the discussion comes back to generating electricity from solar radiation in North Africa, for example in the Sahara. Hydrogen would then be transported to Europe and used here to provide heat, generate electricity and as fuel for vehicles (’solar hydrogen economy’).

The prospects for such a solar hydrogen economy are small. In particular, it makes little sense to convert electricity - the highest quality form of energy - into hydrogen, which is then re-converted into electricity or heat at the point of use. This adds another step in the energy conversion chain with additional costs and above all additional energy losses.

Repeatedly, projects have been presented to produce electricity in the desert, and use this electricity for the production of hydrogen for Europe. They fail because of extremely high costs and technical difficulties, for example the supply of high-purity water in the desert, needed for the electrolysis, or the transport of hydrogen to Europe with reasonable losses. If one would succeed - at a high cost - to produce electricity from solar power in the Sahara, then it would make much more sense to use low loss HVDC (High-Voltage Direct Current) transmission. This would allow direct use of this electricity, rather than through the double conversion via hydrogen.

At best, the use of hydrogen as energy source could offer a meaningful alternative for mobile applications, e.g. motors or fuel cells in passenger cars, provided cheap production and storage facilities are available. The production from natural gas could be defended as a temporary solution, but is not sustainable in the longer term. The production by electrolysis using solar electricity is theoretically conceivable, but might remain limited to special cases for cost reasons (solar electricity will be much too expensive for a long time). Nuclear energy and (outside Europe) hydropower offer the best long-term prospects for the production of electricity needed for electrolysis.


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Saturday, June 26, 2004

How many jobs are created through the use of wind power?

At the end of 2002, 13 800 wind turbines with a combined power rating of 12 000 megawatts (MW) were installed in Germany. If operated all year round they would produce 21.6 billion kilowatt-hours (billion kWh) in a "normal wind year”. That would be about 4 % of the annually electricity generated in Germany (530 to 540 billion kWh). In the last years wind conditions were well below average, i.e. the average base utilization rate of 1 800 full-load hours has not been achieved. In the year 2001, wind contributed 2.2% of generated power (11,5 of altogether 534 billion kWh).

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Wednesday, May 26, 2004

Will the Kyoto Protocol be a victim of supply insecurity? Is OPEC good for the environment? Should environmentalists make the fight against energy poverty their first priority? Christophe Frei from the World Economic Forum raises and discusses these questions in this month's feature contribution, starting from user needs.

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Monday, April 26, 2004

Hydro power - a renewable success story

This month's feature describes hydro-power, the world's currently most used renewable resource. Hydro-power is economically viable for large scale electricity generation. In combination with wind power, it can provide a balanced and emission free electricity system.

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Friday, March 26, 2004

The fossil era - a numbers game

Fossil reserves may last for another 30, 300 or 3,000 years. Current reports indicate that there is plenty of fuel, but it may not be wise to use all, because of risks related to climate change. We live in an age likely to be known to future historians as the fossil era. Fossil fuel usage is a relatively recent phenomenon, that started 150 years ago. Viewed over millennia, the fossil age is only a short bubble in time. The fossil age, historians may say, ran from mid 19th century to somewhere in the 22nd century, and was instrumental in emancipating mankind, enabling the industrial society in its upward swing, but later driven down by environmental considerations and limited fossil reserves.

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