Sir, Three fundamental issues underlie the looming crisis over the effectiveness and desirability of biofuel projects worldwide.

First, governments have focused solely on the apparent benefits of the liquid fuel itself, rather than considering the full life cycle carbon footprint of its production and delivery to market, as well as other more holistic implications. Flawed decisions were then reinforced by subsidies that distorted the market, and encouraged farmers to embark on projects that will have limited, or even negative, overall benefit to the environment. Finally, these errors have been compounded by newly emerging carbon trading schemes. Fossil-fuel projects and activities are progressing on the basis that their carbon dioxide emissions will be offset by “savings” attributable to biofuel projects elsewhere in the world. The latter are now likely to underperform significantly, with promises unfulfilled, and in the extreme represent the junk bonds of the sub-prime carbon market. The outcome will be still greater emissions into the atmosphere.

Many governments still lack the skills and the mechanisms for thorough evidence-based decision-making, which would help to reduce the risk of such blunders. In the UK we need more rigour throughout the educational system, greater engagement between disciplines, and bold scientific leadership to address what will be increasingly complex issues in the future. Emphasis on the quantitative aspects of science should no longer be an option, but an essential part of our upbringing.

Dr Richard Pike

Chief Executive, Royal Society of Chemistry, London W1

Sir, I would like to point out that the efficiency of producing hydrogen should not be thought about in the old way (letters, April 21, 23). All my life I have measured efficiency in terms of power output divided by the energy of the fossil fuel input, be that petroleum, gas or whatever. But if the energy input is from the wind, then that is free, except, of course, for the capital cost of the wind turbines needed to harvest it. So efficiency should be measured in terms of energy output divided by capital cost of the wind turbines over their lifetime. On that basis, hydrogen could be made quite cheaply.

I have calculated that if all the cars in Britain could be converted to run on fuel cells using hydrogen from electrolysers using electricity obtained only from wind turbines, we would need only 20,000 wind turbines to do that. Britain could do that in 20 years, and then we would not need petroleum imported from politically unstable areas to fuel our cars. We currently have about 20,000 high-voltage pylons in the country, so that puts the number in perspective. Of course, I am not suggesting that wind turbines are the only source of renewable energy; clearly we should also install tidal and wave power, and photovoltaics, but this sum is an indication of what we could do if we put our minds to it.

rob thring

Professor of Fuel Cell Engineering

Loughborough University

Sir, Professor Reuben (letter, April 23) is right to point out that hydrogen should be seen as an energy carrier rather than an energy source, but his view is perhaps more gloomy than is justified.

Electrolytic production of hydrogen does depend on the availability of “clean” electricity and a hydrogen economy based on coal-fired power stations makes little environmental sense. However most “renewable” electricity, wind, tidal, solar, is produced at a time to suit nature and not human demand. Since the actual energy source, wind, wave or sunshine, is free, the energy efficiency of electrolysis is largely irrelevant. If the output of offshore wind farms, for example, were electrolytic hydrogen rather than electricity for the grid, its product would have value independent of at-the-moment demand. Hydrogen, in contrast to electricity, can be stored and drawn down from storage as required.

For hydrogen produced from hydrocarbon, it must be noted that carbon recovery is much more likely to be implemented in large- scale plants than at the exhaust pipe of the car. Yes, the technology is in its infancy but it is the nearest thing we have to the philosopher’s stone in the climate change situation and should be being researched and developed with maximum effort.

Finally, hydrogen fuel cell cars do not have to wait for metal lattice storage technology. Modern, readily available, high-pressure cylinder technology leaves the way open for safe, pressurised hydrogen storage on vehicles.

W. S. Affleck

Watledge, Glos

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