By Tuan Nguyen
Posting in Energy
Researchers have demonstrated an innovative "self-powered" method of producing hydrogen that may revive interest in fuel cell technology.
If a new technology pans out, the fading notion that hydrogen will someday supplant fossil fuels may be on the verge of a comeback.
There was a time in the early 90's when the fuel cell was touted as the clean energy technology of the future. The only byproduct was water and it also packed a whole lot more energy than electric car batteries. For instance, nine pounds of the stuff was enough to enable a vehicle to go 150 miles. However, methods to generate hydrogen were in and of themselves energy intensive. And ultimately, the concept of needing energy to produce energy was problematic enough to make it a dealbreaker for many green investors.
But now researchers at Penn state have demonstrated an innovative "self-powered" process of producing hydrogen that, if scalable, can revive interest in fuel cell technology.
What enables the technique to work is the clever integration of bacteria, seawater and fresh water. In 2009, researchers discovered that special bacteria called microbial electrolysis cells can break down matter in wastewater to release hydrogen, though it still needed a slight jolt of electricity to get the process going.
They eventually turned to a separate process known as reverse-electrodialysis or RED, which is similar to desalination, except run in reverse. The logic goes something like this: extracting the salt from seawater requires quite a bit of energy, so bringing the two back together would release energy that can be used to give the little bugs a kick start.
"If you think about desalinating water, it takes energy, Bruce E. Logan, a professor of environmental engineering, told the BBC. "If you have a freshwater and saltwater interface, that can add energy. We realized that just a little bit of that energy could make this process go on its own."
Logan's cells were between 58 and 64 percent efficient and produced between 0.8 to 1.6 cubic meters of hydrogen for every cubic meter of liquid run through the cell each day. The researchers estimated that only about 1 percent of the energy produced in the cell was needed to pump water through the system.
The findings were published in this week's issue of the Proceedings of the National Academy of Sciences.
So far, this approach has only been demonstrated successfully in the lab. To scale up this technology, the researchers proposed running seawater and river water through a stack of alternating cathode and anode exchange membranes.
"This system could produce hydrogen anyplace that there is wastewater near sea water. It uses no grid electricity and is completely carbon neutral," Logan said. "It is an inexhaustible source of energy."
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Sep 21, 2011
I'm not so interested in science. But I like reading this article. Somehow, I got important details and informations. - http://www.appliedergonomics.com/
Ground all non-military, jet-powered aircraft. Air temperatures will drop from 2Â°-5Â°C within 5 days. Proof? Analyze US air temperatures during the the three weeks surrounding the September 11th terrorists attacks in 2001. This information should be readily available from NOAA.
You can create a warm base for your early seedlings, by putting manure and some easily rotted plant material under the compost where you sow the seeds, and glass over them. It's called a warm or cold frame. This process for "making hydrogen" is clever in its way, but it's limited by the amount of vegetation you can provide to feed the bacteria. The first and second laws of thermodynamics say that the energy content of your "free hydrogen" cannot exceed what you'd get from drying and burning that vegetation.
For instance, to make ethanol from monosaccharide sugars, you use yeast. As far as this discussion goes, it's near enough a bacterium. Converting sugar to alcohol releases carbon dioxide, at a rate of one molecule for every two carbon atoms in the ethanol. So one third of the carbon is what supplies the energy the yeast uses. In due course, by my calculations, the energy will ultimately derive from thorium or uranium in nuclear breeder reactors. A ton of fissile isotope can do the work of about a million tons of coal.
The funny thing is, there is already a limitless supply of hydrogen already available to us in the form of water. When you electrolyze water and separate the components, you can then run it on a closed-loop so that power from the battery/alternator can then run the electrolysis process. You can literally run cars on water at this point, but that's not what Big Oil or Big Auto would have you believe.
Hydrogen as a fuel has an excellent energy density per mass, roughly 33.3kWH/kg. But hydrogen at standard temperature and pressure is a gas. As a result, it has an energy density of 0.53kWH/L In comparison, diesel fuel has an energy density of 11.6kWH/kg and 9.7kWH/L. Gasoline is a little lower on both accounts. So in order to get enough hydrogen at standard temperature and pressure to do what we're doing with diesel or gasoline, we would be driving dirigibles instead of cars. The solution to this is to, of course, compress the hydrogen for storage, with optimum results being the production of liquid hydrogen. Even pressurised hydrogen gas is too dangerous a commodity for the average car owner. Liquid hydrogen would be even worse! Also, I think it was Stanford Univeristy that found that hydrogen caused its containment systems to become brittle. This is not to say that H2 doesn't have any uses, but those uses will need to be industrial, not consumer. So for everyone else, you might as well forget the hydrogen economy dream. H2 just isn't practical for the average Joe and never will be.
Just another pie-in-the-sky idea that can't be scaled up. Lots of processes can be used to get the H2, but none is commercially viable, hence reforming methane to extract H2. The only idea I know of that could do it involve NIMBY nuclear reactors, and isn't going to be approved in my lifetime, if ever.
There are a couple of things wrong with the process as it is presented. The first is that it still uses waste plant material to create acetic acid. While we have a certain amount of that already, to really create lots of hydrogen we will need to grow it. That means land and that means fresh water, neither of which we have in the quantities to replace much of the electric power we use. It's why ethanol doesn't work. But since this process produces CO2, the only way to not produce net CO2 is to capture it first with vegetation. Also, while it's a fun science experiment to use the voltage difference between fresh and salt water, the question is why? Since it apparently doesn't need a lot of energy but just voltage, you can get the voltage from many places. You can even take some of the hydrogen output to feed a fuel cell to create the voltage. Modern power plants do that all the time. Once they're generating they use their own output to run cooling pumps, equipment, etc. Nuclear power plants even use up to 25% of their own power for operations just to keep the plant running. Mixing salty water with fresh won't work in the country's interior, and transporting hydrogen from the coasts to the interior is an unnecessary cost.
The hydrogen is generated in the nature by many fermentative bacteria in anaerobic conditions. This production is having a positive net energy balance, and it could exploit the biomass resources, also wastes, for the fuel manufacturing. Therefore, it would be highly advantagoeous to investigate the potential that is in the microbiological applications for future energy alternatives. This road would be completely sustainable! Elias Hakalehto, Adjunct Professor in Biotechnical Microbe Analytics, University of Eastern Finland
Dear Follow in g+ I would like to introduce to you a very interesting and important subject and I want your support and collaborations. Hello All My subject will be about that the humanity have passed its infancy, childhood and adolescence and now the humanity are in the maturation stage and we must push this mature humanity farther to the full maturation, and to enhance the awareness of unity and the feeling of responsibility . Part One Do you think my friends that the global worming was due to the carbon dioxide and alike only? The answer is NO. Why? Because there is a very dramatic factor that we create but we do not understand its effects, and not aware of it. And that is the urbanization of the area where it should be green and this will tern this area that was a carbon dioxide consumer and an oxygen and humidity producer to a new type of desert + carbon dioxide
If you study the graphic model of the process, you will see that any CO(2) that gets "generated" is CO(2) that was taken away by the original plant sources that produced the waste the bacteria ultimately digest. The contribution of CO(2) by this process is net zero. The biggest problem in getting people to understand anything about the natural, technological, or political realities that impact us all is fragmented, short-circuited thinking. This kind of thinking produces huge political problems for the whole population because it is currently the dominant mode of thought in the general public.
The figure shows that CO2 is generated in the process, and I was wondering how much. If it's significant, this could obviously be another potential problem. Judging from the previous comment, perhaps you could do a follow-up article that addresses some of the issues brought up.....
Let's get it right...too much information on "new" that's not new, incomplete, and just lacking credibility. "Green" has gone to the news media's head. Get real.
Not only is the picture of an old technology, its also the wrong technology. This new microbial cell uses osmotic pressure as a power source, the idea was taken from the experimental Norwegian osmotic interface generator that uses an osmotic pump. Basically anywhere you can put an enclosed volume of salty water next to one of less salty (waste or fresh) water separated by a special membrane, you will get a pressure differential from Osmosis, the passage of water molecules through a membrane that allows them and nothing bigger to pass. (Artificial sausage skin is such a membrane, I remember being shown this process in school 30-odd years ago...) This pressure is used to pump the water into a completely different process, that has nothing to do with the dead MFC tech that you linked to on Wikipedia. Also, it has nothing to do with the piezo-electric generator California is considering for the road surfaces. Thats a total non-starter as well... Imagine a world where we buy electricity to power our devices, and food to power our bodies, but our power companies harvest the kinetic energy we produce from food to generate the electricity to sell to us. Not the best deal unless you are a power company, right? Theres green and theres green, but I'm so not wet behind the ears.
I suspect that, even on a very large scale, that the energy taken 'out' as we capture fresh water from rivers and combine it with salt water near the ocean will be 'small' compared to the entire system, nonetheless, we are taking it. I wonder, over time, if there would be consequences, particularly at those river months where we are 'premixing' the two waters before putting them back into the ocean.
The trade-off for grounding a commercial airliner is about a hundred cars making extended trips. It's a negative net outcome. 2-5C? That kind of wild claim is debunked all the time. Do everyone a favor and educate yourself. You're obviously on the web; there's a lot of good material out there you can learn from (and bad examples to learn from, too). Don't stop trying, though. Remember Edison failed hundreds of times before his successes. Persistence can pay off.
are both fossil fuels that are normally gasses and are used as fuels. They are stored in a compressed form and rarely cause problems. Why do you claim the pressurized H2 is too dangerous for widespread use? What evidence do you have? I recall a video demonstration from many years ago. Three cylinders were filled with the equivalent (fuel energy content) quantities of gasoline, propane and H2. From behind cover, each cylinder was pierced by an armour piercing sniper round. The gasoline exploded and produced a large fire. The propane tank exploded, leaving a small crater and no tank fragments. The H2 tank had a small bullet hole and an invisible flame from burning H2 (H2 leaking from the hole) above the tank. The flame was detected using a wooden splint, which ignited when passed through the flame. H2 cannot combust without O2. Remember the damage to the WTC towers from two airliners almost fully loaded with fuel? The highjackings were performed before the flights had finished climbing. This was an important part of the terrorists plan to maximize the fuel load in the attacks.
How is energy lost? The salt water and waste water are ultimately going to mix any way you slice it, so why waste that? We can use it. It's no different in principle from sunlight falling on solar cells instead of the ground below. Even if it were true that energy were somehow lost from the ocean (although the water got there via rivers after solar evaporation from the ocean, so it's really solar energy), how much greater the loss when we burn fossil fuels representing limited stores of solar energy garnered over millions of years. For whatever reason, some of the comments here fail to recognize that almost any form if not all forms of energy we use are ultimately solar energy. It's just that using forms of solar that are short cycles instead of millions of years and that are inherently balanced in terms of our current global conditions don't unleash carbon dioxide from the past to upset our current balance, such as it may be. (See the second paragraph of my comment in reply to the worry that CO(2) gets generated when in fact it is net zero for the whole process.)
The waste or used water could go through a natural filtration device before going back to get levels back to the previous levels of saline content so basically adding the same water over and over again I woulkd suspect. This is a very very interesting development as I do see hydrogen as a great possibility of energy. Just have to figure out safe containage in vehicles as it is very explosive.
Rephrased from Wikipedia: 1) Although the energy/weight of LH2 is around twice that of other fuels, its energy/volume is remarkably low. [This is problematic for passenger vehicles smaller than a bus.] 2) Note that LH2 liquifies near absolute zero. Therefore, it requires cryogenic storage technology such as special thermally insulated containers and requires special handling common to all cryogenic fuels. This is similar to, but more severe than liquid oxygen. Even with thermally insulated containers it is difficult to keep such a low temperature, and the hydrogen will gradually leak away (typically at a rate of 1% per day). It also shares many of the same safety issues as other forms of hydrogen, as well as being cold enough to liquefy (and possibly solidify) atmospheric oxygen which can be an explosion hazard.
Electro spinning see the company cella energy; it is a very interesting idea for safe transportation of hydrogen fuels