A Hydrogen Economy
Fuel Cells Are Not Magic Bullets...
Nothing less than the fate of the planet is at stake... No place on the planet can remain an island of affluence in a sea of misery.
- Maurice Strong
Interchange between the I-5 and I-10 freeways, Los Angeles, US (N 34°02' - W 118°16')
Los Angeles, in Southern California, is the second-largest city in the United States in population and area. Los Angeles is a shipping, industrial, communication, and financial centre for the western United States and much of the Pacific Basin, and the motion-picture capital of the nation, if not the world. The Los Angeles metropolitan area encompasses 34,000 square miles (88,000km2) and is connected by a freeway system, which is increasingly unable to accommodate the growing traffic. The tremendous number of vehicles, coupled with the geographic position of the city, creates unhealthily high levels of smog (not to mention road rage). A light-rail system and bus transportation do little to alleviate the highway congestion. One-quarter of the energy produced globally is absorbed by the transport sector. Transportation accounts for half of world petroleum consumption, which has expanded 7-fold in 50 years. This sector is responsible for nearly ¼ of carbon dioxide emissions and is thus among the chief sources of greenhouse gas emissions, which lead in turn to global warming. It is possible, however, that the petroleum era may be coming to a close, succeeded by the age of hydrogen, a clean fuel extracted from water, which can be used in engines equipped with a fuel-driven battery.
Source: yannarthusbertrand.com from Earth from Above by the incomparable photographer Yann Arthus-Bertrand
This is wrong. A common mistake when talking about energy use is to confuse energy with ways of storing energy. Most energy on earth came, originally, from the sun. If we want to perform a task (like, say, travel from San Diego to Los Angeles) we need to use energy, which gives us two options - we can use solar energy which has already been stored, or we can use solar energy currently striking the earth.
The latter option is, effectively, useless. Most things we want to do require a large amount of energy over a small amount of time - the sun provides a very small amount of energy over long periods of time. A car which ran directly on solar power would move far too slowly, and even then, only on sunny days.
The only practical answer is to use energy which has already been stored, and the most common forms of stored energy are fossil fuels (the petroleum mentioned in the quote), which release their stored solar power when burnt. The power is still from the sun, but by mining and burning a lump of coal, we get access to a nice big chunk of solar power, all in one go, which tends to be pretty useful.
Now, the author thinks we should stop using the solar power stored in petroleum, and start using the solar power stored in hydrogen. There's just one tiny problem with that.
There is no solar power stored in hydrogen.
Hydrogen isn't really an energy source, it's an energy medium.
See, the neat thing about coal is that we have coal mines. Your average coal mine has a lot of coal in it, and if you want some, it's pretty easy to just go grab some. The problem with hydrogen is that there aren't any hydrogen mines. In fact, there isn't any hydrogen either - or at least not useful hydrogen. Potential energy tends to "leak". Things which are hot (that is, have heat energy) tend to cool off. Things which are raised above the ground (that is, have gravitational potential energy) tend to fall. Things which have chemical potential energy tend to oxidise (that is, burn, rust, explode, corrode, et cetera). At some point in the past, we had lots of free hydrogen floating around (which had a lot of potential energy), but these days it's mostly in water (which has pretty much no potential energy), and hydrogen likes staying attached to oxygen as part of a water molecule. If you really want some hydrogen, the obvious way would be to apply an electric current across the water, which splits the water molecules into hydrogen molecules and oxygen molecules. At some later point you can then oxidise the hydrogen and oxygen (burn them), which gives you your original water back, plus some (but NOT all) of the energy you originally used to split the water.
So, if you want to run a car around, we currently take some solar power stored in oil, burn the oil, and use that energy to move the car. The author proposes taking some solar power stored in hydrogen, burning the hydrogen, and using that energy to move the car. But as mentioned previously, there isn't any solar power stored in hydrogen. The first thing you have to do is store some energy in hydrogen (which you'd normally do by applying a current across some water). The problem is, where do you get the solar power? All the problems and issues mentioned previously apply. Hydrogen fuel cells are nothing more or less than glorified batteries, and where do you get the hydrogen? You've got to use energy to split water. And where do you get that energy? Well, from solar power, and we're right back to square one.
Now, fuel cells are cool, and fuel cells have a lot going for them, but ALL they are is a variant on batteries. It shouldn't be more than another year or two and your laptop may run off a fuel cell - which should give longer life than your current lithium ion battery, but both the fuel cell and the lithium ion batter are charged by power coming out of your wall. Around here (in New Jersey), that's pretty much coal or nuclear. (In New Zealand, it will likely be hydro or natural gas.) Where you live, it might be coal, natural gas, nuclear, wind, solar, hydro - but for most people, it's coal, or some other fossil fuel, and for most of the remainder, its nuclear. Even when you end up with fuel cells in your car, all you're doing is moving the point that the fossil fuels are burnt from your engine to the power plant.
Of course, power plants tend to be more efficient than car engines, so there will be some savings - perhaps as much as 10%, but probably not any more than that. What fuel cells will not, and can not do is create power themselves. Fuel cells merely store it, and, some day, may store it very well and efficiently, but they have to have something to store. There will be no "age of hydrogen" ever, because hydrogen is not a fuel source. As for the "age of petroleum", well, perhaps it will end someday, but when it does, it won't be because of hydrogen, but because of things like very cheap and efficient solar panels (if we ever manage to solve the sizable engineering challenges), cheap and safe nuclear power (if we ever manage to solve the very sizable engineering challenges), or best of all, core taps - drilling giant bore holes to the core, dropping water down it, then running a turbine off the resulting high pressure steam (if we ever manage to solve the very very sizable engineering challenges).
Mind you, if we ever DID get cheap solar panels, fuel cells might prove to be an ideal way of storing energy for use during the night. But then again, maybe not. By the time we have cheap solar panels, perhaps we'll all be using loops of room-temperature superconductors to store energy, which should work much better than fuel cells, if we could just solve the sizable ... et cetera and so on.)
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Nothing too amazing. It's logically equivalent to a solar panel generating electricity which is then run through a tank of water to generate hydrogen. At BEST, a square metre of these cells will capture somewhat less than 100% of the solar energy which strikes that square metre of the earth's surface, and the resulting hydrogen, when burnt, will produce somewhat less energy than was captured.
As always, there is no free lunch, and I note the article seems to mostly just quote the scientists involved, who are probably less than objective. Assuming there IS, in actual fact, a revolutionary breakthrough, what it will boil down to is:
Anyhow, time for a reality check. Let's see - a "7-metre squared" array powers one car for one year. I interpret "7-metre squared" to mean an array 7 metres on a side. That would be 49 square metres.
In the southwest, energy density from the sun is 7.573 billion joules per square metre per year. How much will they be capturing? Less than 100%, so that puts an upper ceiling on power - a maximum of 371.1 billion joules. A gallon of gasoline contains 130 million joules. In other words, their solar cells will, at an impossible 100% efficiency rate, capture the equivalent of 2,689 gallons of gasoline.
Since the article helpfully says the car will drive 11,000 miles in that year, we see that the car will be getting about 4 miles per gallon. Sounds reasonable - real cars do better, but remember we were assuming 100% efficient solar cells. In reality, it's lower, probably WAY lower. At the moment, 10% would be a good number for current technology to achieve, and that yields a miles per gallon (mpg) rating of 39. And, hey, guess what? That's EXACTLY the mpg rating of a Mercedes A-class. Okay, so it looks like we're talking about some 10% efficient photo cells here - not bad, but not revolutionary. Forty-nine square metres per car sounds okay then.
Now, for reference, the total gasoline consumption in the US is 130.7 billion gallons. That makes 18.03 x 10^18 joules, which you could get from, oh, 2.5 billion square metres of 100%-efficient solar cells, or from 25 billion square metres of 10%-efficient. Call it 2,500 square kilometres of impossibly efficient cells (about the size of Delaware), or 25,000 square kilometres of the ones they seem to be developing. That's about the size of West Virginia. For comparison, New Jersey is about 8,000 square kilometres, and California is about 163,000 square kilometres. Texas is 260,000 square kilometres.
Yes, that's right - we're talking about paving over 1/10th of Texas with expensive manufactured goods. The mind boggles. (Oh, and how long do you suppose they last? If we assume 10 years, and each is 1 square metre, then, on average, you'll need to replace 80 solar cells EVERY SECOND. Yeah.)
Upshot - they're not doing anything special with regards to efficiency. What MIGHT be cool is if these things were cheap - that could help. But, naturally, that's the area the article completely ignores. Typical. Without some estimation as to the cost of an acre of solar cells, there's no way of working out the actual energy cost.
The article quotes one of the researchers talking about $3 a kilogram of hydrogen. I'd take that with a grain of salt, but at face value, that's $3 for 140 million joules. At that rate, 1 billion joules costs $21. Non-OPEC countries have oil production costs of maybe $15 a barrel. At 6.1 billion joules per barrel, that works out to $2.50 for 1 billion joules. Saudi Arabia has marginal production costs of, perhaps, $1.50 per barrel, or $1.50 for 6.1 billion joules. At that rate, 1 billion joules costs about $0.25.
But don't forget, those oil prices don't include the costs of refining and transporting, nor carbon emissions and other environmental damage. Then again, those hydrogen costs don't count the fairly stunning infrastructure costs needed for hydrogen use in the US - pipelines, distribution stations, hydrogen burning cars, and so on. Now you see why the Saudi Arabia receives quite a bit more money every year than solar cell researchers. :-)
Nothing magic here. But if they're cheap, they may still be viable for the future.
Um, sorry, that sorta ended up longer than I intended. I'm pretty sure my numbers are right, but there could be an error, or just an incorrect value. Google is great at turning up information, but the net is full of bad data.
Why a Hydrogen Economy Doesn't Make Sense
by Lisa Zyga
This chart compares the useful transport energy requirements for a vehicle powered from a hydrogen process (left) versus electricity (right). Image Credit: Ulf Bossel.
In a recent study, fuel cell expert Ulf Bossel explains that a hydrogen economy is a wasteful economy. The large amount of energy required to isolate hydrogen from natural compounds (water, natural gas, biomass), package the light gas by compression or liquefaction, transfer the energy carrier to the user, plus the energy lost when it is converted to useful electricity with fuel cells, leaves around 25% for practical use - an unacceptable value to run an economy in a sustainable future. Only niche applications like submarines and spacecraft might use hydrogen.
"More energy is needed to isolate hydrogen from natural compounds than can ever be recovered from its use," Bossel explains. "Therefore, making the new chemical energy carrier form natural gas would not make sense, as it would increase the gas consumption and the emission of CO2. Instead, the dwindling fossil fuel reserves must be replaced by energy from renewable sources." While scientists from around the world have been piecing together the technology, Bossel has taken a broader look at how realistic the use of hydrogen for carrying energy would be. His overall energy analysis of a hydrogen economy demonstrates that high energy losses inevitably resulting from the laws of physics mean that a hydrogen economy will never make sense. "The advantages of hydrogen praised by journalists (non-toxic, burns to water, abundance of hydrogen in the universe, et cetera) are misleading, because the production of hydrogen depends on the availability of energy and water, both of which are increasingly rare and may become political issues, as much as oil and natural gas are today," says Bossel.
"There is a lot of money in the field now," he continues. "I think that it was a mistake to start with a ‘Presidential Initiative’ rather with a thorough analysis like this one. Huge sums of money were committed too soon, and now even good scientists prostitute themselves to obtain research money for their students or laboratories - otherwise, they risk being fired. But the laws of physics are eternal and cannot be changed with additional research, venture capital or majority votes." Even though many scientists, including Bossel, predict that the technology to establish a hydrogen economy is within reach, its implementation will never make economic sense, Bossel argues. "In the market place, hydrogen would have to compete with its own source of energy, that is with ("green") electricity from the grid," he says. "For this reason, creating a new energy carrier is a no-win solution. We have to solve an energy problem not an energy carrier problem."
A wasteful Process
In his study, Bossel analyses a variety of methods for synthesizing, storing and delivering hydrogen, since no single method has yet proven superior. To start, hydrogen is not naturally occurring, but must be synthesized. "Ultimately, hydrogen has to be made from renewable electricity by electrolysis of water in the beginning," Bossel explains, "and then its energy content is converted back to electricity with fuel cells when it’s recombined with oxygen to water. Separating hydrogen from water by electrolysis requires massive amounts of electrical energy and substantial amounts of water."
Also, hydrogen is not a source of energy, but only a carrier of energy. As a carrier, it plays a role similar to that of water in a hydraulic heating system or electrons in a copper wire. When delivering hydrogen, whether by truck or pipeline, the energy costs are several times that for established energy carriers like natural gas or gasoline. Even the most efficient fuel cells cannot recover these losses, Bossel found. For comparison, the "wind-to-wheel" efficiency is at least three times greater for electric cars than for hydrogen fuel cell vehicles.
Another headache is storage. When storing liquid hydrogen, some gas must be allowed to evaporate for safety reasons — meaning that after two weeks, a car would lose half of its fuel, even when not being driven. Also, Bossel found that the output-input efficiency cannot be much above 30%, while advanced batteries have a cycle efficiency of above 80%. In every situation, Bossel found, the energy input outweighs the energy delivered by a factor of three to four. "About four renewable power plants have to be erected to deliver the output of one plant to stationary or mobile consumers via hydrogen and fuel cells," he writes. "Three of these plants generate energy to cover the parasitic losses of the hydrogen economy while only one of them is producing useful energy."
This fact, he shows, cannot be changed with improvements in technology. Rather, the one-quarter efficiency is based on necessary processes of a hydrogen economy and the properties of hydrogen itself, for example, its low density and extremely low boiling point, which increase the energy cost of compression or liquefaction and the investment costs of storage.
The Alternative: An Electron Economy
Economically, the wasteful hydrogen process translates to electricity from hydrogen and fuel cells costing at least four times as much as electricity from the grid. In fact, electricity would be much more efficiently used if it were sent directly to the appliances instead. If the original electricity could be directly supplied by wires, as much as 90% could be used in applications. "The two key issues of a secure and sustainable energy future are harvesting energy from renewable sources and finding the highest energy efficiency from source to service," he says. "Among these possibilities, biomethane [which is already being used to fuel cars in some areas] is an important, but only limited part of the energy equation. Electricity from renewable sources will play the dominant role."
To Bossel, this means focusing on the establishment of an efficient "electron economy." In an electron economy, most energy would be distributed with highest efficiency by electricity and the shortest route in an existing infrastructure could be taken. The efficiency of an electron economy is not affected by any wasteful conversions from physical to chemical and from chemical to physical energy. In contrast, a hydrogen economy is based on two such conversions (electrolysis and fuel cells or hydrogen engines). "An electron economy can offer the shortest, most efficient and most economical way of transporting the sustainable ‘green’ energy to the consumer," he says. "With the exception of biomass and some solar or geothermal heat, wind, water, solar, geothermal, heat from waste incineration, etc. become available as electricity. Electricity could provide power for cars, comfortable temperature in buildings, heat, light, communication, et cetera In a sustainable energy future, electricity will become the prime energy carrier. We now have to focus our research on electricity storage, electric cars and the modernisation of the existing electricity infrastructure."
Citation: Bossel, Ulf. "Does a Hydrogen Economy Make Sense?" Proceedings of the IEEE. Vol. 94, No. 10, October 2006.
Source: physorg.com 11 December 2006 © 2006 Physorg.com
Ode on the Car
Sir - An ideal government, you say, would not hand out subsidies to the middle class. You are right of course, but predictably missing from your list of middleclass tax beneficiaries are car drivers. Like many others, you have a blind spot when it comes to the car. "Free choice and the popular vote will keep the car rolling on" you swoon. There is nothing freely chosen about the way our taxes are used to construct and maintain miles of roads and the rest of the car's hideous infrastructure. It is our taxes that pay for the hospitals that patch up millions of the car's living victims, and for the military required to ensure continued supply of its fuel.
I never voted for this insane technology, which even in America, the most car-ridden society of all, is accessible only to 59% of the population. Despite what you say, we are not all motorists, and for many who are, it is because subsidised car driving has made any other way of getting around expensive or dangerous. Free choice never came into it.
Source: The Economist 19 October 1999 Letters to the Editor
To Ronnie Horesh: you reside in one of the few cities in the Western world where you can comfortably live without a vehicle. Some 39% of residents either use the cable car, buses or trains, or walk or bike as their primary method into the city on most weekdays. In addition, 12% of Wellington companies surveyed said they had significantly increased the number of staff telecommuting.
Russia has one car for every 6 people - and 50% of those vehicles are 10 years old or more.
Australian Inventor Makes Engine That Runs off Air
Melbourne, Australia - An Australian inventor claims to have made the world's first commercially-viable motor vehicle powered by compressed air. The vehicle is being tried out by contractors in Melbourne's parks and gardens over the next 12 months as an alternative to conventional diesel or petrol engines. The engine's designer, Angelo Di Pietro from Melbourne company Engineair, said the engine produced no pollutants and had only two moving parts, increasing its efficiency over conventional designs. Di Pietro said it used compressed air to drive a rotary engine, abandoning the pistons and cylinders seen in regular designs.
The vehicle being tested in Melbourne has reached 50 kilometres an hour (31 miles an hour) in the workshop and had proved more efficient than battery-powered golf carts. Di Pietro said the engine's potential was immense and he claimed to have attracted interest from the United States, China, the Netherlands and Britain.
Source: story.news.yahoo.com AFP Thursday 26 August 2004 photo credit also AFP
1973 Envisions 1983 - Where Are the Monorails?
Why Didn't Mass Transit Appeal More?
An overly optimistic view of the future that was from the 1973 Cleveland Electric Illuminating Company Annual Report
Is This a Solution?
Giant Microwave Turns Plastic Back to Oil
by Catherine Brahic
A US company is taking plastics recycling to another level - turning them back into the oil they were made from, and gas. All that is needed, claims Global Resource Corporation (GRC), is a finely tuned microwave and - hey presto! - a mix of materials that were made from oil can be reduced back to oil and combustible gas (and a few leftovers). Key to GRC’s process is a machine that uses 1,200 different frequencies within the microwave range, which act on specific hydrocarbon materials. As the material is zapped at the appropriate wavelength, part of the hydrocarbons that make up the plastic and rubber in the material are broken down into diesel oil and combustible gas.
GRC's machine is called the Hawk-10. Its smaller incarnations look just like an industrial microwave with bits of machinery attached to it. Larger versions resemble a concrete mixer. "Anything that has a hydrocarbon base will be affected by our process," says Jerry Meddick, director of business development at GRC, based in New Jersey. "We release those hydrocarbon molecules from the material and it then becomes gas and oil." Whatever does not have a hydrocarbon base is left behind, minus any water it contained as this gets evaporated in the microwave.
"Take a piece of copper wiring," says Meddick. "It is encased in plastic - a kind of hydrocarbon material. We release all the hydrocarbons, which strips the casing off the wire." Not only does the process produce fuel in the form of oil and gas, it also makes it easier to extract the copper wire for recycling. Similarly, running 9.1 kilograms of ground-up tyres through the Hawk-10 produces 4.54 litres of diesel oil, 1.42 cubic metres of combustible gas, 1 kg of steel and 3.40 kg of carbon black, Meddick says.
Gershow Recycling, a scrap metal company based in New York, US, has just said it will be the first to buy a Hawk-10. Gershow collects metal products, shreds them and turns them into usable pure metals. Most of its scrap comes from old cars, but for every ton of steel that the company recovers, between 226 kg and 318 kg of "autofluff" is produced.
Autofluff is the stuff that is left over after a car has been shredded and the steel extracted. It contains plastics, rubber, wood, paper, fabrics, glass, sand, dirt, and various bits of metal. GRC says its Hawk-10 can extract enough oil and gas from the left-over fluff to run the Hawk-10 itself and a number of other machines used by Gershow. Because it makes extracting reusable metal more efficient and evaporates water from autofluff, the Hawk-10 should also reduce the amount of end material that needs to be deposited in landfill sites.
Source: environment.newscientist.com 26 June 2007 photo credit Global Resource Corporation
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