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Last Updated: Monday, 19 November 2007, 23:21 GMT
Powering up for a hydrogen economy
Keith Guy
Keith Guy

Sooner or later the world is going to have to make the switch away from fossil fuels, says Keith Guy. In this week's Green Room, he explains what needs to be done to make the vision of a global hydrogen economy a reality.

Traffic (Getty Images)
It has been a long journey for hydrogen technology

An increasing global population, rising standards of living and more industrial production mean the amount of energy the world consumes could rise by 50-60% over the next 25 years.

Today, the biggest forms of energy are fossil fuels - oil, gas, coal. But that is set to change in the future for at least two reasons:

  • "easy" oil and gas sources are declining
  • emissions of greenhouse gases related to fossil fuels are rising to unacceptable levels

But what are the alternatives and can they ever become a reality?

Hydrogen is already providing a growing alternative energy source for transportation in several countries, including the US and Japan.

In a bold move, Iceland has set itself the challenge of becoming the world's first hydrogen economy, with the aim of the fuel supporting all its energy needs by 2050.

Blue Lagoon, Iceland (Image: Tom Sandars)
Iceland's landscape makes hydrogen power a feasible option

This means the total elimination of fossil fuels and should result in cutting the country's greenhouse emissions by up to 50%.

However, one could argue that Iceland's natural energy resources, its waterfalls and hot springs, give it an unnatural advantage over less well-endowed countries.

Making the switch

So what progress can other countries hope to achieve and what do they need to make the hydrogen economy a reality?

Let's start with a look at what advances the world is currently making.

The most obvious step that we are beginning to see is the introduction and take-up of fuel-cell powered vehicles.

President Bush inspects a hydrogen fuel station (Getty Images)
Hydrogen is a very light gas making it far more difficult to work with than gasoline

Although there may be an intermediate stage with onboard gasoline reformers, these cars offer immediate benefits - they are about twice as efficient as current fossil fuel transport and can significantly reduce air pollution in cities.

Since the first hydrogen filling station was set up in 2000 in Dearborn, US, we have seen a steadily growing number opening up to meet the increased demand, especially in the US, Japan, Germany and Iceland.

Many buses in Iceland are already converted to use hydrogen and are refuelled by a filling station on the outskirts of its capital, Reykjavik. There are also plans to convert the country's entire fishing fleet.

Breaking down barriers

Unfortunately, whilst moves towards an increased use of hydrogen are starting to gather speed, as things stand this growth is restricted by a number of constraints at the political, commercial, technical and social levels.

Safety concerns are still widespread, with the spectre of the Hindenburg accident still in the minds of many.

Fuel cell bus (Image: BBC)
Hydrogen-powered vehicles help cut pollution in cities

The public perception of the dangers around hydrogen's transportation and distribution need to be addressed if we're to see widespread use in the future.

At a practical level, there are real issues in terms of how we store and transport hydrogen. Hydrogen is a very light gas making it far more difficult to work with than gasoline.

From an economic point of view, the costs of switching over to hydrogen-based technologies are high. In the US for example, the investment required to convert existing gasoline stations to provide hydrogen to vehicle drivers will run into billions of dollars.

While fuel cells may be getting cheaper, they are still more expensive than conventional engines.

The cost of producing the actual hydrogen itself is high, although the good news is that economies of scale do exist.

As the supply increases, the costs will start to come down. It is expected that the same will apply to the associated costs of storage, transport and vehicle design.

What we'll also need to see is a move from natural gas-based hydrogen, which is being used during the market development phase, to industrial-level hydrogen production using renewable resources on an economic basis.

This will require further development, both in the public and private sector, if we're to see any significant progress.

There is a real political need for a common worldwide approach if we are to see the transition to a hydrogen economy.

National and international government organisations must get behind the technology and provide the support for research, and ultimately the commercialisation of hydrogen, if we are to succeed in developing a viable and green alternative to fossil fuels.

The hydrogen economy is developing but more must be done if we're to see real progress in the medium to long term; only then will it cease to be a theory and become a reality.

Professor Keith Guy is a Chem Envoy for the Institution of Chemical Engineers (IChemE)

The Green Room is a series of opinion pieces on environmental topics running weekly on the BBC News website

Do you agree with Keith Guy? Is hydrogen a viable alternative to fossil fuels? What needs to be done for a global hydrogen economy to become a reality? Or are the costs too high to make it a viable option?

Even if you are fully committed to a zero-carbon future, Hydrogen as a technology looks like a blind alley. The fundamental problem is that Hydrogen must be produced from other sources of energy, such as solar power. In this sense, it isn't really a fuel - it's an energy storage technology. It doesn't look particularly good as a storage technology. The efficiency of the "Hydrogen cycle" doesn't look good (a high proportion of the original energy is wasted in creating and then using the Hydrogen). And Hydrogen is troublesome to store and to transport. Other avenues are going to prove more fruitful. Biofuels, particularly second generation ones made from crop by-products such as straw, are a better solution for much transportation use. Meanwhile improved battery technology is a better way of storing electrical power. Combining the two in a hybrid car is a good option, where short journeys can be done entirely using the battery.
Mike Edwards, Romsey, UK

The whole green energy situation could be solved or sped up if we were to admit to ourselves how wasteful we are as a society when it comes to energy. Renewable resources cannot match the amount of energy we currently use. We need an energy diet. We need to look at the amount of energy we can produce cleanly and learn to live on that, instead of trying to match or replace fossil fuels. As a species we are successful because of our adaptability to different environments, we now have a low fuel environment so lets adapt.
john, London

Hydrogen is definitely what is needed. However, I feel that the industry has hampered the introduction of hydrogen with the focus on fuel cell technology. This is complex and difficult to engineer, whereas the simple replacement of petrol with hydrogen as a fuel is much easier, requiring adjustments to ignition timing, a fluid for cylinder lubrication, and safe storage of the hydrogen. All of these challenges have already been solved - hydrogen can be stored in the form of chemical compounds that release hydrogen gas when heated, and can then be re-used. This could be implemented right now. As for the generation of hydrogen, there is research under way into novel means of producing hydrogen by electrolysis using pused current drives that can be many times more efficient that normal electrolysis using DC. Homes could have mini hydrogen generation stations, using a mixture of renewable and non-renewable energy sources to produce the hydrogen. Hydrogen isn't just the way forwards, it could be implemented right now if there was the political and, more importantly, the industry will to do so.
Neil Kiley, Preston, UK

Perhaps we should call it the pie in the sky economy.......In fact I have devised a way to power the world from floating pies (blackcurrent works best)...there are a couple of problems though...The pies take a lot of energy to produce, are difficult to transport and have a relatively short shelf life......Not to worry there a re economies of scal to be had and we can bake them using energy from renewable sources......."Hmmmmm tasty"
Dave, Darlington UK

In view of the magnitude of the problem I think to speed acceptance a system of pricing energy in relation to its environmental cost is required. Hydrogen as a potential low polluter and low generator of CO2 might rate as the base cost; other more damaging fuels that cost 'less' to produce would be taxed so that they are not cheaper than clean fuels. Don't forget that there is also the question of reducing energy use by greater efficiency and prevention of waste. Interest in saving electricity would increase considerably if it was more expensive! Jim
Jim Thorne, London

Hydrogen is an energy storage medium, not an energy source. At this point the creation, storage, and use of hydrogen is less efficient than batteries for storing energy, especially at the densities needed for powering transport. The most efficient means of obtaining hydrogen at this point uses natural gas as the source and results in green house gas emissions.
Albert, Kensington, MD, USA

The expression "hydrogen economy" suggests that there is plenty of free hydrogen around and the only task is to learn to utilize it. In fact, there is nothing further from the truth than that: There is no free hydrogen around (1), to generate it is polluting (2), energy consuming (3) and dangerous (4). So what is the "hydrogen economy" than?
Tibor, Neuss, Germany

Hydrogen storage mediums are the way forward. However it is going to require that people cease to be afraid of nuclear fission power and fusion power. There is no way a hydrogen economy of any scale would be powered by renewable energy. The sooner environmentalists realise that the entire world is not going to take a step back technologically to save the lesser mottled badgerbird the better. Fortunately, once we are using hydrogen as a resource, our civilization's power output can increase considerably with little to no net effect upon the planet.
Nicky, Manchester

Why not just give up the car? human beings lived fine without them for 99.9% of human history
Mark, Hitchin, UK

The hydrogen hoax: the total CO2 emission will actually increase as long as the hydrogen will be generated by liquid, tar-sand, shale, or coal-derived petroleum - as the coal and oil lobby will make it happen - and not from geothermal, wind, wave or nuclear power.
H. Deweerd, Waltham, MA, USA

Bio fuels are a crime against humanity. While people starve how dare we use land to grow fuel. We MUST also end our addiction to hydrocarbon fossil fuels. In my opinion we need to utilise all the alternatives, wind, wave and nuclear. What is more we need to do this now. Otherwise future generations will curse us all and rightly so!
byegad, Durham

If you use Nuclear to generate the Hydrogen, then you have your win-win scenario, where no greenhouse gases are released.
Doug Bauman, Pittsburgh, PA, USA

There is a lot of bad info here. Turning electricity into hydrogen then back into electricity is at best probably 50% efficient althought there has been work in labs that gone either side of this figure (93% to 37.5%). However storing energy as hydrogen is very cheep, doesn't use anywhere near the resources it takes to make bateries and can be done in the home with very simple technology. We already have an energy grid for electricity into almost every home (UK). What this means is that you could power the average family car for less than 5p a mile at current energy prices, probably a lot less. Compare that to most cars today. Fuel cells are extremely simple units, the expensive part is the exotic elements used in maufacture of the plates. Like the issue of fuel cell life expectency, this will be overcome with volume and time. The issue would therefore be one of clean generation of electricity in the first place and there is so much more that could be done across the world. You don't need to use energy so efficiently when it is collected and renewable rather than mined and burned.
Dan, Norwich

Yes, I belive that Hydrogen is a great alternative but since Hydrogen is so flamable what the heck happens when you crash!!
Callum Lee, Barnsley, UK

Whyle I agree that hydrogen is not a energy source but petrol is not better. It seems that people forget that to make a litre of petrol or gasoline we need. 1 To exract oil from underground using electricity. 2) Transportation of oil in very polluting oil tanker. 3) refining the oil in petrolor gasoline at the refinery and this step require elettricity. 4) Transporting the refine petrol or gasoline to the petrol station.( Again pollution in trasnportation) 5) Finally when we put petrol in our car we add some pollution of our own. I don't think that hydrogen that could be produced at a Hydrogen station using electrolisis will be more polluting.
Guido, Perth

Among all of the discussions I have read about hydrogen so far there has been no mention of the fact that water vapour, a by-product of burning hydrogen, is the most potent greenhouse gas by far. Don't we need to consider the consequences of pumping billions of tons of water vapour into the atmosphere?
Andrew Haigh, Noosa, QLD, Australia

Why are we forgetting the immense power of hydro electricity? There are moves by some indian car makers like REVA to bring electric cars in the market. Electricity produced from hydro does not emit any greenhouse gases. My country has a potential of producing 83,000 Mega watts of electricity while due to lack of capital we are just producing 600 Mega watts, why don't developed nations look to countries like us? Besides, hydrogen, hydroelectricity will help in controlling greenhouse gases effect.
Sandeep Jalan, Kathmandu, Nepal

The one problem I see with hydrogen supply is that we do not even have enough renewable energy (hydroelectric, solar, wind)to generate electricity for every city in the world. A good part of these rely on fossil fuels. Where then are we going to get enough renewable energy to supply electricity needs AND create enough hydrogen to power all the cars in the world?
Hector Castaneda, San Salvador, El Salvador

Hydrogen would need to be transported under very high pressure, in the thousands of PSI, this will need to be done in big ol' tanker trucks which will need to be specially constructed to transport hydrogen and nothing else due to the problems of hydrogen escaping. There will have to be a large increase in the numbers of these fuel trucks as they will have a smaller carrying capacity than your typical fuel truck. Consider the number of accidents involving fuel trucks at their present levels, then increase that factor as the number of fuel trucks increases. Also, these fuel stations would need to be specially constructed, you can't just stick a hose in existing underground fuel tanks and away you go. Also consider the fact that creating a pipeline system would have to be specially constructed and require continual replacement as the seals corroded and the rate of hydrogen loss increased, this replacement would occur more frequently than does with the natural gas pipeline network. So, factor in the problems of energy generation, production, transportation, storage, replacement of facilities, that hydrogen self ignities when released under pressure and you may start to wonder why it is reasonable to see hydrogen as a likely source of anything other than grief. Save it for the future when we've tackled some more pressing problems.
Chris, UK

The only readily available sources of energy that are flexible enough to underpin a whole new way of working that doesn't involve fossil fuels are SUNLIGHT and PEOPLE (c). This is the bootstrap principle. Sunlight creates food; people eat food. People dig ore/chop wood, heat and shape crude energy gatherers e.g. windmills. Windmills allow easier digging and more accurate shaping of less crude energy gatherers. Eventually we reach sophisticated use of energy WITHOUT recourse to fossil fuels. Waterfalls and fast-flowing rivers are also good. Back to the Industrial Revolution!
Paul O'Brien, Plymouth, England

The logic of the author is seriously flawed - using his own facts. Hydrogen just moves the problem from the streets to the power station - its even more looney than the bio fuels campaign where Palm Oil is produced by clearing Indonesian Rain Forest creating net net even more greenhouse gases. Unless politicians stop creating false markets, price carbon and award huge incentives to countries with rain forests to realise the true value of that rain forest by protecting them, then its all over. I doubt the politicians can pull this off, all we can do is organise the public and exert pressure on the people who are supposed to represent us and get them to stop talking about it and start building towards a huge sea change in energy sourcing and distribution. It does not get more serious than this and full credit to the BBC for stimulating the debate of our lives.
Ian, London, UK

H2 is no good because of the difficulty of storage. Better to use ethanol or methanol or something similar. This can be made in a number of ways including part of a closed carbon cycle by using electricity to split CO2 (as someone else said). There is no problem with storage and distribution. Electric cars for short journeys may also be a contender but by using batteries and not fuel cells which need H2. Either way it gets us off the oil hook and we can finely tell Saudi to FO next time they want a bribe.
malcolm, lancaster

Yes, Hydrogen works and could easily be used on its own or via fuel cells but there are vast practical problems in storage and supply and the laws of physics may prevent a solution to them. It is not viable to store and transport it as a gas because it uses too much volume and to store it as liquid requires keeping it cool, which uses enormous energy, or it is kept cool by evaporation, that is by some of the liquid hydrogen constantly boiling way and in a couple of weeks a stored tank full of liquid hydrogen would have boiled away 70% of its volume. Notwithstanding that, if we can solve these problems for storing hydrogen then we will be able to utilise the excess night capacity of power stations on standby which goes to waste because we cannot store electricity.
Keith Budden, Rayleigh, Essex

How do you create the hydrogen? What is the energy source for turning water into hydrogen? If it is gas, oil or coal, then CO2 emission will not fall. Why not convert cars to electricity instead? It has the same environmental benefits of hydrogen. Hydrogen fuel cells just stores engrgy like a battery, it does not create it. It is not the solution to transports energy needs.
rhodri, London

Where is Keith planning to get the Hydrogen from? If we ever get nuclear fusion to work then you could use that to split water - but with the almost unlimited energy that fusion could provide we could presumably "make" petrol, diesel and methane by splitting water and CO2 - which could then be transported and used with no changes to the existing infrastructure...
David Legge, Falkirk

The big problem with all renewable energy sources like wind generators and photo-electric cells is that they do not provide a continuous supply and we have no effective way to store electrical energy on a large scale. From a practical standpoint existing wind generators are virtually useless. Load balancing with wind generators is a nightmare since you have no idea from minute to minute what they can provide. They are only built to win browny points. Electrolysis of sea water to produce hydrogen is a good way of overcoming the energy storage problem. Generators could be located largely at sea overcoming many aesthetic objections. We already have the technology to pipe gas from sea storage to land. While setting up a distribution network to allow the hydrogen to be used in homes or cars would take time, adapting gas fired power stations and other gas fired industrial processes to run on hydrogen should be relatively easy. Large scale industrial use of hydrogen instead of natural gas should be the quickest and cheapest change. Once that infrastructure is in place it can be gradually extended to domestic uses.
Warwick Gibbons, Crete, Greece

I agree with Keith that the future of mobile energy storage has to be Hydrogen. Bio fuels may have there limited uses but they cannot replace more than a fraction of our transport needs if we want to eat as well as get from A to B. However Hydrogen is an energy store, not an energy source, and if NOT produced from fossil fuels needs significantly more energy to produce than it will store. We will need to get this energy from somewhere and a rough back-of-the-envelope calculation, assuming we generate the Hydrogen we'll need in the UK from electricity, show we'll need around twice the current generating capacity of the UK to produce it. Its thought to be just about possible to replace around 40% of our current electrical generating capacity with renewables, maybe even 60% at a push. But this is still only going to be 15-20% of what we will need, the rest will have to come from Nuclear and Clean-Coal. I do wish the different sides of the CO2 neutral sources would stop flaying at each other. None can be the final solution, we'll need them all and it is not an eithor or. Building more nuclear reactors does not mean we build less wind and wave farm, and neither should the reverse be true., We need all the CO2 neutral sources we can get our hands on.
Stephen Cooper, Letchworth G. C. Hertfordshire

Hydrogen will never be a complete solution as its EROI (Energy Return On Investment) is so low compared to oil fuels. Currently vitually all hydrogen is produced as a by-product of refining oils. Battery run vehicles will be a better solution.
Robin Lavender, Wells, England.

Hydrogen is merely a "battery" for carrying energy. Producing it requires energy, most of which will come from fossil fuels anyway--notably electricity from coal-burning power stations. This means that, currently, hydrogen-powered vehicles creates MORE pollution than conventional gas-powered vehicles. So until the industry can also produce the hydrogen in a clean manner, there's really no point to making hydrogen cars.
Chris C, Salt Lake City, UT, USA

Hydrogen as a fuel should not even be considered if it is produced from a reforming process in a refinery. This is a highly inefficient form of energy production which would render the fuel a very long way from being non-CO2 producing. Any writer who would even consider this as an environmental option should not be taken seriously as they clearly know nothing... And in this case I feel ashamed as the writer is a Chemical Engineer - like me... If it's going to be done it has to be by electrolysis which is VERY energy intensive. I don't think we have the energy available to cope.
Steve, UK

Totally agree. One of the most abundant "green" resources available on this planet and we are only just starting to see its potential. Given that we knew existing fuels were always going to run out or become too expensive to extract why has it taken so long to develop the potential of hydrogen. When you also consider we have know the harm done to the environment by fossil fuels for at least a decade you would have thought hydrogen technology would be in common use by now. As regards the cost of change, whatever new energy economy we switch over to it was always going to cost billions if not trillions. So, yes, lets make it a reality.
Dave H., Bristol UK

Please, please, please. Can somebody do the proper energy equation. Hydrogen is very clean and efficient BUT it takes more energy to produce it than you get out of it. If we take that energy into condsideration then it is a very poor choice. Energy has to come from somewhere you can't just conjur it up out of thin air.
Robin Sinton, Newcastle upon Tyne UK

By stockpiling hydrogen emulating the production of hydrocarbons by natural means then over time "clean" hydrogen would be viable. Instead of conversion of conventional fuels which is expensive you can convert gravity directly to the gas and store it for future use. I've proven it but you can't tell 'em.
Pennyworth, Derby, UK

In terms of renewable energy, hydrogen is a storage mechanism for energy, just like a battery. If it is to be used as a renewable it needs to be "created" from water. To do this electricity is needed. This is why it is a storage medium. Without renewable energy generation the hydrogen, the hydrogen cannot be considered clean. That said, if hydrogens storage problems can be sorted and mass produced, then it may become the best and cleanest portable energy medium.
Mark Williams, Billingshurst ,UK

Hydrogen is not a 'primary' fuel. It requires energy to extract hydrogen from water or other sources. Hydrogen may be useful as a means of storing and transporting energy, but in itself it does nothing to move us away from fossil fuels. We need alternative sources of energy (solar, wind, nuclear) on a massive scale. When we have them there may be a place for hydrogen.
Mike Ayres, Bodmin

Yes we NEED to switch from GAS to HYDROGEN Powered Cars,TRains trucks, ect...we need to expand our wind,water=wave powered citys...we should be all over this in a HUGE WAY!!!INVEST & EXPANDING EVEN MORE!!!i mean pure water as pollution???sounds like a win-win situation to me!!!
james jc gough, sudbury ont Canada

Keith, Your comment on the Hindenburg are misleading to those who are not aware that it was the coating on the ship that lead to the disaster and the deaths on the ground were from that flamming debree. Point taken on the Hydrogen in the ship but this is akin to saying "People are concerned about a hydrogen Bomb". Differn form of hydrogen as you know. Keep the fuel cell/hyrdrogen articals in the front of the world.
Chris, valdez, Alaska

First. As hydrogen being energy STORAGE compared to fossil fuels being energy SOURCE it can not be their alternative. Hydrogen is clean as clean is the energy stored in it. As long as there is not an enormous spare capacity of renewable energy hydrogen will be made from coal, natural gas and nuclear power. Second. Fuel cell car is not hydrogen car - it is electric car with battery and using the fuel cell to full the battery when it is drained. Plug-in electric car with small and efficient diesel generator running on biodiesel is much more viable and cheap alternative than plug-in electric car with fuel cell. It is not very correct to lie to the people that hydrogen economy is a solution to our current energy problems. It will come (if it come) WHEN we deal with the problems not before that.
Dimitar Mirchev, Sofia, Bulgaria

Hydrogen is not a green fuel, it is just a 'carrier of energy'. The hydrogen still has to be made, either with fossil or renewable fuels. Iceland is a special case as they have massive amounts of geo-thermal energy to tap into. Most places in the world don't. Instead of building a hydrogen economy why not by-pass it altogether and use renewable energy directly? People already have electricity sockets, so suppling cleanly made electricity to power electric cars seems a much better and cheaper option.
R. Smith, Japan

You do not go into the amount of energy needed to make the hydrogen. What is the amount of energy needed to replace one gallon of gasoline with an equivalent amount of hydrogen? I think you'll find it takes electrical energy equivalent to two gallons of gasoline or perhaps more. Where will you get all that electrical power? Moreover, inexpensive, durable fuel cell technology is still confined to the lab, if it exists at all, and with existing hydrogen storage technology, a hydrogen car has a cruising range no better than the Tesla electric car. Finally, there is the fact that hydrogen leaks; it is the smallest of all molecules. Its only saving grace is that it goes up after leaking out of whatever it has escaped from, so if it diffuses through the roof, it won't accumulate in explosive quantities. Unfortunately, it is very definitely a greenhouse gas, so the more of that gets into the atmosphere, the worse our problems will be. I'm inclined to think that most of the enthusia! sm about hydrogen was cooked up by oil and auto companies, because they know that our present level of technology, it is an invitation to boondoggle. Frankly, I'm more hopeful about the hydrogen in lithium batteries. I think battery-powered electrical vehicles have a fighting chance of becoming practical.
John Silver, Port Angeles, Washington

No, not unless the hydrogen can be generated in sufficient quantity without using fossil fuels. It can't be mined, so like electricity it's only an energy transport medium. The most feasible, if unpalatable, option available at present is nuclear-generated electricity, which then begs the question - why not just use the electricity directly?
Michael Poole, Sanda, Japan

Things will change and the use of fossil fuels will be a thing of the past. Or we can continue down the same road and watch our futures dissapear! It's up to the Politicians and the News Media to start making changes otherwise it will be to little to late! As for myself i will continue driving my S550 mercedes and my F450 truck and polute with the best of them until the Politicians & the News Media decide to change things. Our future is up to them.
michael , las vegas nv.

Not just viable, the next best alternative. I see only two options with the capacity to replace oil and natural gas, hydrogen and nuclear fusion. Solar cells, used to create electricity used to separate hydrogen and oxygen seems the best alternative.
Roger Bates, Beaverton, OR, USA

A hydrogen economy would prevent CO2 emissions from cars and buses themselves but in the long run the hydrogen has to be produced from the electrolysis of water. This itself uses vast amounts of electricity which with the current methods of generation (In countries without large renewable resources such as the UK) is still very carbon intensive. Generating electricity renewably is a far greater technological and economic barrier than a hydrogen infrastructure. Until we develop new, cleaner methods of energy generation a hydrogen economy serves only to move the problem from our streets to the polluting power stations.
Jamie, Oxford

The technology necessary to make the switch has been around for 3 decades and more. The public perception of hydrogen is not an issue. People want their cars to start and their lights to switch on. They don't CARE where the power comes from so long as it won't , kill innocent kids in war, bankrupt the family or destroy the planet. The reason the world hasn't switched over yet is very mundane. The common man does not have the choice to make it happen. Those in economic and political power do.
Mark Pinheiro, Edison, New Jersey U.S.

Hydrogen really is the answer along with advances in the generation and storage of electricity. Even if fusion technology doesn't work out, hydrogen production is an easily transferable way to store excess generation capacity from renewable energy for later use. I like the fact that it is less dangerous than current petroleum or alcohol fuels because it doesn't contain the carbon which reflects heat back when it burns. I'm also not against its use in airships as it has greater lift potential and is cheaper to produce than helium. Airships would have less of a carbon footprint than aircraft in use today and could be used to haul both cargo and people alike. A little bravery is going to be needed if global warming is to be defeated.
Dale Lanan, Longmont, Colorado USA

I suppose its come to the time to ask whether we as the human race want a good life or a long life. How much is the next generation worth? Or do we as a species all end up like the fat guy in the meaning of life (monty python)? Its choice time people.......
Udo, Melbourne Australia

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