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2 internautes sur 2 ont trouvé ce commentaire utile :
3.0étoiles sur 5
The Hydrogen Economy - Hard facts, Janv. 13 2004
Jeremiah Rifkin's book "The Hydrogen Economy" does not give what its title promises.
Most of the book is devoted to historical, political, social considerations, most of which I find well written and even convincing, but which have nothing to do with hydrogen.
However, to me as an engineer, his recourse to thermodynamics to explain the fall of past civilizations appears ludicrous and unnecessary - there is no need to appeal to thermodynamics to make us understand that our world will collapse if it will run short of reasonably cheap energy.
Whether the production of liquid fuels and natural gas will peak within the time frames advocated by Rifkin, or at some other time, there is no doubt in my mind that it will peak, and that well before that time the world must start to convert to renewable energies (assuming that energy from nuclear fusion is still far away from being harnessed).
However Rifkin sees everything easy and cheap. In his chapter on Reglobalization from the Bottom up he advocates the installation of fuel cells in every household or neighbourhood or community, but he seems to forget that "upstream" of each fuel cell there must be a power generator (wind turbine or photo-voltaic cell), electrolytic cells to produce hydrogen and a hydrogen storage facility. Scale economies will certainly reduce the cost of these commodities, but in my mind it is difficult to think that with their combined cost, and the energy losses that will be incurred at each step (electricity to hydrogen gas, hydrogen gas to stored hydrogen, hydrogen to electricity) electricity generation will be cheaper than present day cost from fuel or gas fired power plants.
Also the numbers are staggering. Rifkin writes "Providing these 100 million (per year) new users with an average per capita consumption of electricity equivalent to what US consumers enjoyed in 195 would require the creation of 10 million megawatts of new electricity capacity globally by 2005". Should this capacity have to be provided entirely by renewable sources, as a rough order of magnitude this would require the installation of either:
- From 300 to 500 million 300 KW capacity wind turbines, or
- from 1 to 1.5 million square kilometres of photovoltaic cells
All the above seems to me quite sobering. Particularly the shift to renewable energy sources does not give many hopes to be a way "to lift billions of people out of poverty". Therefore I cannot be as optimistic as Rifkin does - however I share with him the conviction that the shift to these sources is inevitable, and that the world must brace itself to meet the challenges and sacrifices that it will entail. The sooner, the better.
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4.0étoiles sur 5
The Hydrogen Economy, Jui 9 2004
Par Un client
I bought this book thinking that it would be somewhat different from what it actually is. This is more of an oil-history book until the last two chapters. The first seven chapters slowly build up to doomsday-esque scenarios. While they may never come true, it is certainly instructive to think about them because if we do nothing then they will come true. We need some scaring so that we can kick the H2 research into overdrive before it really is too late.
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4.0étoiles sur 5
The Future of Energy, Mars 14 2004
Jeremy Rifkin's book _The Hydrogen Economy_ explains the current fossil-fuel economy and how it got to where it is today and how it's going to be replaced. One interesting aspect of our modern system Rifkin points out is that with the advent of fossil-fuels current farmers put in more energy into producing their crops then they get out of them. This fact points to a larger point that Rifkin makes in the book. The energy balance of a civilization must be maintained for that civilization to survive as such. When a civilization can no longer take in enough energy the civilization will collapse. Rifkin also argues that the more energy a civilization can get and use the more powerful the civilization will be. I'm don't think that energy alone is what makes a civilization more powerful but it is an integral part of power. With fossil fuels our civilization uses more energy faster then any civilization in history. Rifkin also points out that as civilizations mature more and more energy is needed to maintain a civilization and that civilizations have much more difficult energy problems growing and developing more infrastructure.
The book points out several problems with the current system. One problem or potential problem is the threat from Islamic Fundamentalists. This threat could come in the form of sabotage of oil and other fossil fuel infrastructure. The threat could also come from the outright revolt and overthrow of regimes friendly to the US and are major producers of oil. If an Islamic Fundamentalist regime took control of Saudi Arabia for example they could cut the world off from the oil there or raise the price enough to hurt the world economy significantly. Another problem with the current energy system pointed out in the book is the dwindling of oil in the world. This seems to be the biggest problem. As oil becomes scarcer the price will rise. This will create major problems for our society and the world.
The solution to these and other energy problems including global warming is hydrogen. Rifkin explains how hydrogen can be used to store energy generated by non-polluting renewable systems. The ability to store energy generated from renewable sources is essential if these systems are going to replace fossil fuel energy regimes. Hydrogen according to Rifkin will also give people control over their own energy. Hydrogen will allow people to become less or non-reliant on the current centralized energy system.
This book is easy to read and can be understood by everybody even if you have a minimal background in the sciences. The book doesn't get very technical and doesn't try to explain the technical aspects of a switch to hydrogen, which is a good thing for people like me who don't have much of a background in the sciences. Rifkin spends much of the book explaining how fossil fuels changed society and how the switch to hydrogen will change society again.
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