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There was obsession over hydrogen fuel cells. Ballard developed a practical hydrogen fuel cell for cars, and got funding from major car manufacturers. They built one prototype vehicle, and tried to drive it from Vancouver to Calgary. Once it got high in the Rocky Mountains, lower air pressure meant insufficient oxygen for the fuel cell. It stalled, had to be towed back. Ballard promised to continue to work on it, but we haven't heard much since then. They have built city transit buses run on hydrogen.
One issue with hydrogen is storage. Hydrogen leaks through most materials, you really need metal. Traditional storage is a heavy metal pressure tank. The tank weighs more than the fuel. Years ago I suggested a fibreglass shell to contain pressure, and a bladder of aluminized Mylar. The aluminum would contain hydrogen. Don't use that tank for long term storage, but should be fine for a vehicle fuel tank. Furthermore, researchers found carbon fibre batting can increase hydrogen storage mass for a given pressure. Hydrogen binds loosely to carbon. The lightest, most efficient carbon is carbon nanofibres. Problem at that time was no one knew how to make carbon nanofibres longer than 1/10 mm, or how to make them economically. Now they can make continuous ribbons of carbon nanofibre. Those ribbons can be mass manufactured, and cut to produce batting.
But batteries are getting better. We may already be past the the point where rechargeable batteries outperform hydrogen fuel cells. Not sure how to calculate that. Realize the most practical means to produce hydrogen is electrolysis of water. In a hydrogen economy, each vehicle fuel station would have it's own electrolysis device, store hydrogen on-site and sell to cars. Stations would have city water supply and high power electric service. Some stations could have an on-site well to completely eliminate the water bill. In East Saint Paul, a suburb north-east of Winnipeg, every home has their own well. It's a modern well, a large diameter pipe driven into the ground. At the end is a heavy steel spike, followed by a thin stainless steel mesh to keep rocks/gravel/sand out, but let water in. An immersion pump is an electric water pump buried with the pipe, below the frost line so it doesn't freeze in winter. A horizontal pipe underground, again beneath the frost line, connects the pipe to the house basement. It requires good quality water. In East Saint Paul the water tastes good, but Springfield is a suburb further east, they have hard water with iron and calcium that requires a water softener. Headingley is a town west of Winnipeg, they can't use well water because their ground water is too salty. A fuel station would have to ensure well water is compatible with their electrolysis device. If not, it's city water. So what does that do to the cost of hydrogen?
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The cost of water is a minor part of this. The water must be purified at some expense depending on its quality (we aren't talking about potable quality water, we have to avoid fouling the electrolysers). After that it can be sent to the electrolysis cells after mixing with a concentrate of the electrolyte and some additives. As the cells consume water, more of the cleaned-up water can be added to maintain levels and chemical concentrations, but there will always be some blowdown to be made up and from time to time the cells must be taken offline and emptied for servicing then refilled.
The major costs are in capital servicing and electrical power. Hydrogen is not easy to store, so long term storage is not really an option. By-product Oxygen and Deuterated water may help with sales, in addition to hydrogen.
For long term storage, conversion to methane or methanol is probably a good option and these can be reformed to Hydrogen when the need arises.
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It's been decades, but I used hydrogen gas in ordinary 220 cu ft welding bottles. If you let it sit around for weeks, it leaks right through the steel. If you use it fast, you never see the leak. It's slow. It's quite real, but it's not catastrophically fast for hydrogen-powered vehicles.
It's just very heavy for the energy you can store within. In that sense, batteries are just as good as bottles of hydrogen gas, actually. But it has real applications that justify its use, such as welding. That's why it's out there in those bottles.
As for a source of water to electrolyze, how about one that needs no electrolytes? What's wrong with used frack brine? It's about 5-10 times as saline as sea water, and ought to conduct electricity like a bandit between electrodes.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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If you electrolyse pure brine you get Chlorine rather than Oxygen. I suppose that a mixed brine will decompose in the order of electronegativity of its ions. So Bromine before Chlorine and Iodine before Bromine.
You still get Hydrogen, unless you use a mercury electrode which will dissolve the sodium. The resulting amalgam can be separated and reacted with water to make caustic soda. At this point the Hydrogen is released from the water. The mercury goes back to the electrolysis cell to regenerate the amalgam. Industrial production of caustic used this process for many years. They might have dropped it now due to concerns about mercury traces.
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Frack brine will have all sorts of heavy metal contaminants in it, as well as the diesel they don't want to admit is the carrier of the sand, when emulsified with a suitable detergent. Some of these contaminants will be radioactive, too.
I just wanted to use some of it for something else useful, before putting it down that disposal well. We really ought to get something more than a mild earthquake from that.
But, at only 10 times the salinity of sea water, won't it still behave like sea water and electrolyze? Mostly to hydrogen and oxygen? I dunno, chemistry isn't one of my strong suits, excepting combustion, which for me was school-of-hard-knocks stuff.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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It would electrolyse and probably foul your electrodes and other equipment and fill the clean up train and the cells with toxic sludge (which you will then have to find a home for). Also the products would probably be impure and in need of separation/purification. Each brine would need to be characterised. Each field would give different salts and different concentrations.
If your brine contains saleable elements, the sludge concentrate might have some value allowing you to pass on the disposal problem.
Generally, for Hydrogen production by electrolysis a sulphuric acid solution is used..
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The mere fact that we're fracking and converting coal to oil now should be taken as a crystal clear indication that we're running out of easily obtainable petroleum products. That is the best reason I can think of to move away from fossil fuels at best possible speed. All arguments about saving the environment are distant seconds, to "Hey, bubba, there ain't no gas left!" Unfortunately, the pricing of oil and gas has never been tied to the scarcity or difficulty with which the commodity in question has been provided. If it was, then efforts to improve efficiency would've been seriously ramped up many moons ago.
I think fuel cells are a technological dead end. It's a scientifically interesting form of internal combustion engine technology that lacks the design life and operating characteristics of rechargeable batteries and the power-to-weight ratio of modern intermittent internal combustion engines. A fuel cell's only claim to fame is better fuel economy for a given level of output than traditional intermittent combustion engines. The price paid for the fuel economy is a delicate limited operating life system reliant upon expensive precious metals, too heavy and bulky for small mobile applications, that uses expensive specialty fuels that aren't obtainable in an input energy efficient manner.
Ultimately, chemical reaction technologies will be too expensive, too limited by their operating environment, and too energy intensive to use for mobile applications. The future of mobile energy storage belongs to solid state super capacitors that can withstand millions of charge / discharge cycles and operate in temperature extremes that would kill or greatly diminish the capacity of chemical batteries. Unlike batteries of any description, very near to 100% of the energy used to charge them comes out when they're discharged and complete depletion of a capacitor's charge has no deleterious effects on its ability to take a charge during subsequent recharging cycles.
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For energy storage, its hard to beat a tank of diesel fuel. It isn't particularly difficult to make it from coal- the South Africans did it for many years, maybe they still do- or from natural gas, using the Fischer Tropsch process. There is no shortage of coal, and the current depression of the oil price (and therefore of most other fuels) is a result of production of shale fracking gas and coal seam gas in the US and elsewhere. It really is the environmental consideration that is driving the rise of renewables, helped along by government tax breaks and lax regulation regarding waste disposal.
Last edited by elderflower (2018-04-30 04:56:48)
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But when you look at the price graphs and see the huge reductions in the price of solar, wind and battery storage, I think ultimately (probably within the next 20-30 years) renewable energy is going to be the cheaper option just about everywhere. Wind and solar can already win in open bidding competition in some parts of the world, although not for base load yet.
For energy storage, its hard to beat a tank of diesel fuel. It isn't particularly difficult to make it from coal- the South Africans did it for many years, maybe they still do- or from natural gas, using the Fischer Tropsch process. There is no shortage of coal, and the current depression of the oil price (and therefore of most other fuels) is a result of production of shale fracking gas and coal seam gas in the US and elsewhere. It really is the environmental consideration that is driving the rise of renewables, helped along by government tax breaks and lax regulation regarding waste disposal.
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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Yes, and that causes problems for the plants that provide baseload power. They have to keep operating to make sure the grid doesn't fail, but they're being undercut on sunny and windy days by renewables, making it unprofitable to provide that service. Can wind and solar compete on a level playing field, where they have to provide constant power, rather than opportunistically providing it when they have it?
Use what is abundant and build to last
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I would say they are getting there in some places.
https://www.renewableenergyworld.com/ar … rices.html
The solar plus storage system beats diesel on price - although it's probably not full baseload yet.
The price for wind plus storage in Colorado in a bidding round was actually at 2.1 cents per KwH - cheaper than old coal plants.
https://thinkprogress.org/colorado-wind … 82b91a543/
Haven't seen what is meant by "storage". I doubt it's full storage. But I think this shows the renewable energy providers are increasingly able to smooth out their supply.
Yes, and that causes problems for the plants that provide baseload power. They have to keep operating to make sure the grid doesn't fail, but they're being undercut on sunny and windy days by renewables, making it unprofitable to provide that service. Can wind and solar compete on a level playing field, where they have to provide constant power, rather than opportunistically providing it when they have it?
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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The playing field is level when the renewables have subsidies.
That is because the fossil fuel and related industries all have subsidies of one type or another.
Coal's biggest subsidy is not having to fully clean up all the messes made digging it up. For the power plant industry, a big subsidy for coal plants is not having to fully clean up the messes made with waste coal ash. Some of the superfund sites are proof of this.
Oil and to a lesser extent gas, get the same not-cleaning-up-the mess subsidies (albeit nowhere near as extensive as coal), plus the depletion allowance.
I'm not saying this is all bad: having subsidies helped pay for turning a tertiary recovery method (fracking) into a cost-effective recovery means today. But that outcome also is a warning: all the "easy" oil and gas is gone.
So, the smart person keeps the subsidies on the renewables, and as a policy matter, works on better electricity storage, for the day when the renewables must take over from fully-depleted fossil. That's sometime in the next few coming decades.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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That is because the fossil fuel and related industries all have subsidies of one type or another.
Coal's biggest subsidy is not having to fully clean up all the messes made digging it up.
Really? Verify that. In 1995/'96 I worked for the electric utility in Alberta. 90% of all power for southern and central Alberta came from 2 coal burning power plants. They made a big deal of "remediation". They harvested coal by open-pit strip mining, but once all the coal was gone from one area, they would cover it with the "overburden" they had removed to start mining. That means soil stripped off is put back. Then they would plant trees. Their marketing division made a big deal of this. Restoring the natural environment after mining is complete is called "remediation".
Ontario today offers a deal to farmers, home owners, and businessmen. If they pay for construction of a windmill or solar array, the electric utility will sign a contract to buy all the power they produce and at a fixed rate. It's a long term contract, so business can focus on producing power. Many in Ontario have complained that the rate paid for power produced by green technology is so high it's really a subsidy. Electric rates in Ontario have skyrocketed, they now have the highest electric rates on the continent while Manitoba (the neighbouring province) has the lowest rates on the continent. Ontario has the largest population of any province in Canada, and by far the most manufacturing. They have long since dammed every river that could be dammed for power. They even dammed Niagara Falls, only letting 20% of river water flow over the falls at night, rising to 40% during the day when tourists are watching. In winter, it drops further. Power from the dam is used by both New York State, and Ontario. Reduced flow has slowed erosion of the falls. But the point is extreme electric rates are a major issue for the provincial election; they're in the midst of an election campaign right now, election day will be June 7. Of course there's more to it: they replaced a 3,800 megawatt coal-burning power plant with natural gas, and they screwed it up. They started construction, built the foundations, changed their mind and paid tens of millions of dollars in cancellation fees, then did it again and paid more to complete the natural-gas burning power plant. Conservative candidates blame the current high electric cost to wind and solar, but simple miss-management has more to do with it.
So look to the fiasco in Ontario before talking about subsidy to green energy.
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