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A.C. R.
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Davemart, I do not see your point. The cost of noble metals in fuel cells isn't that high. There are fuel cells that use no expensive noble metals and are still ludicrously expensive. The cost are in manufacturing and assembly, fuel cells can't seem to get to the targets enthusiast groups (even entire government agencies) are talking about. The average fuel cell cost is about $8000/kWe based on the total market divided by the total wattage.
ai fin, get real. Here's REAL data from ALL wind farms in an entire windy country, the Republic of Ireland (one of the windiest countries in the world). http://www.withouthotair.com/c26/page_187.shtml That's a LOT of variation, even on an aggregated nation wide level. Lika Mackay said, "we must not kid ourselves". Look at the numbers.
What is more the share of electrolysis in hydrogen production is actually DROPPING: http://www.hydrogenambassadors.com/background/images/background/actual-hydrogen-production.gif From 5% in 2000 to 4% in 2006. The reverse of what Roger is telling us is going on.
As for hydrogen demand being static... that is not true at all! http://ceramics.org/wp-content/uploads/2010/03/hydrogen_growth.jpg Very big growth is going on. Virtually all of the new capacity comes from reformed/cracked fossil fuels. Petrochemical industry is not interested in electrolysis because high power electric infrastructure is not available and too expensive to get up, electrolysers cost more than other options, and electricity is more expensive than natural gas. They will certainly not be interested in coupling an already inferior option to inferior energy sources such as wind. They want reliable hydrogen production, and due to transport issues, preferably close by where its needed. They want 80+ % capacity factor. They are not going to be interested in solar at 10-20% capacity factor to power the electrolyser. They are not going to be interested in wind 15-45% capacity factor. Most industrial areas are not in very high wind speed conditions. So your hydrogen demand is not in the best of wind locations. It is also not in the middle of the desert.
RE is not competitive with fossil fuel. Its unreliability means it competes not with capacity, but with energy, so with fossil fuel prices. A few cents/kWh coal and such. Not competitive at all. When you factor in decreased efficiency of the dirt and gas burners, and increased maintenance cost of that, the economic value of wind and solar is something like 1-2 cents/kWh. Since the price is many times that today, it is not competitive in a raw, strict sense. There are a few exceptions, such as large hydroelectric dams, and to a MUCH lesser extent, geothermal and biomass. They are competitive where they have been competitive for decades, in places that have large reliable hydroelectric resources and less resistance to dam building. This is nothing new. The old renewables are the gold renewables. The new renewables (solar and wind) are pretenders, they are the fool's gold.
Predicting the wind is not the real problem. If you predict with 100% accuracy that the wind of tomorrow will only result in a 5% capacity factor for your wind fleet, then you have a PROBLEM. Even if you get 20/20 vision and a crystal ball, you have to actually go and do something about the lack of wind. There will be mild weather spells for weeks on end sometimes. Burn fossil? Or go nuclear and don't need fossil nor wind in the first place. Those are the options. Like E-P says, the nuclear option is reliably available at night just when the plugins need charging. Wind is not. It may be available on one night, but completely absent on another. Last night here was VERY quiet, not even a breeze. Needless to say solar output was ZERO. Because, uhm, it was nighttime. That means fossil electricity for the plugins charging last night. Plugin hybrids are decent for schedulable demand on the timescale of hours, but not days, not to mention weeks. With solar you have near zero output most of the world in an entire season, better known as "winter". An elementary school child can understand these things. For some reason entire regiments of renewable academics and other impractical people cannot understand it.
If there are benefits with wind, there will be far bigger benefits with nuclear powerplants, that produce excess power far more reliably and consistently than wind. Sadly, it appears the researchers can't mention that. Nuclear energy is still taboo, even in most energy research circles.
I did a check based on fuel cell sales in 2012. The total sales/kWe fuel cells in the world in 2012 gives about $8000/kWe. That's the real fuel cell systems cost based on the current market.
Roger, your reference mentioned a range of up to 1600/kgH2/day, and you used the lowest figure. That is not appropriate since hydrogen is difficult to distribute, the more expensive, smaller scale facilities (closer to point of use) will be used, at $800/kWe. If you use the biggest cheapest facilities your transport and logistics cost to the refuelling station shoots up astronomically. High pressure pipelines or high pressure transport trucks are very very expensive for long distance hydrogen transport. A good reality check is that about 4% of the hydrogen today is generated via electrolysis. The other 96% comes from fossil fuels. Surprisingly even petroleum is a major source of hydrogen, despite its higher cost and emissions than natural gas. If it were attractive to use electrolysers we would be seeing these things all over the world where theres cheap coal and hydro about. We don't see this. We see 4% from electrolysis...
"Please stick to the facts, Tesla engineers are smart enough not to build a car that would destroy itself." That's my point. If the car can take a few minutes of 300 kWe discharging, it should be able to take a few minutes of charging at that rate. Though I do note, that Jeremy Clarkson, the lead presenter of Top Gear UK, driving like a lunatic on his track, managed to break multiple Tesla Sportsters early on. I drive sometimes on the Autobahn in Germany, the high end sedans that the Model S is competing with, are able to work at 200 kW continuously @ 250 kph. Of course the German market is an exception here. But I do think the model S is well engineered and that's why it should be able to take 300 kW of charging for a short time for a 50% charge from say, 30% to 80% SOC. Consumer battery fast chargers are now available for 15 minute fast charge. The story from Technology Review indicates that Tesla feels they can go for a 5 minute 50% fast charge in the future. Fast charging tech is developing rapidly. For Li-ion the limit likely becomes the cooling system capacity to prevent the battery from overheating.
Tesla seems to think they can get a fast charge down to 5 minutes in the long run: http://www.technologyreview.com/news/516876/forget-battery-swapping-tesla-aims-to-charge-electric-cars-in-five-minutes/ 30-40 kWh for a 50% fast charge of a 60-80 kWh pack would need 300-400 kWe charging (actually a fair bit more to account for losses). That's serious.
First let me say that current electrolysers aren't a few hundred/kWe, they are considerably more. But more importantly, it isn't just about capital costs. It is also about staffing costs. Electrolysers are industrial equipment. It needs safety people, maintenance people, logistics people. Lots of people. Those people have to be paid. If the electrolysis rig makes 4x less power because it runs intermittently, it has 4x the staffing cost. 78% efficiency is also not feasible. Large industrial installations get 70% at the moment, smaller ones for a home or small business are in the 50-60% range and have a greatly increased cost/kWe. That means you'll want large scale production, and it means you can't have much cogeneration of hot water. The efficiency is a function of power density. More current means more production at a lower efficiency, so you do that if your power is cheap. If power is expensive you get a lower current and a higher efficiency. But in both cases electrolysis can't compete. The simple truth is that less than 5% of today's hydrogen production is from electrolysis. Even though there are many areas with cheap coal or hydroelectric power. Ripping apart fossil fuels is much more competitive. What I see in industry that electrolysis is NEVER competitive as a rule with virtually no exceptions. It is widely used in aluminium production because there is no alternative process.
Basically, it would mean that if you can't charge for 300 kWe for 10 minutes, then you'll break the car with 10 minutes on a racing track.
Arne: what that means is you'll damage the battery if you drive the Tesla in a sporty fashion most of the time. A little hard to believe. If so Tesla has a problem.
120 kW seems a bit low, the Tesla having about a 300 kWe motor, you could go 240 kWe charging. The charging rate for my laptop is similar to the discharging rate at full power. For fast charging stations, speed is very important. 20 minutes for half a "tank" is quite long compared to <1 minute it takes to fill up a gasoline car completely. Faster charging also means more cars can be charged per station, likely important for the future where a lot of electric cars will be on the road. There's likely a big business case also for intermediate speed charging. Coupled to a restaurant. People could take a bit and relax for an hour or two, the restaurant makes a lot of money. You'd get discount on your charging cost if you order more in the restaurant. Free charging with a full meal.
Roger, running electrolysers at 100% capacity factor is currently more expensive than running steam methane reforming of natural gas. Running the electrolysers at the capacity factors of wind and solar makes it far worse.
Hmm, thinking about that again though... if the LN2 has no market, it could be used to precool incoming air for the ASU to reduce neon/helium production energy consumption... so I guess even then, the LN2 is not "free" energetically... only as free as the inefficiency of the regenerator/recuperator process.
Good points bundy. Nitrogen's lower boiling point indeed means that excess nitrogen production, in an energetic sense at least, does NOT exist. That's interesting. There is a "but" involved, though: ASUs currently produce neon/helium as the lowest boiling fraction, they are quite valuable gasses. If the demand for those gasses goes up (especially helium for helium cooled reactors if we can't get enough from terrestrial sources), the excess liquid nitrogen will be "free" at least energetically. Of course it is still a drop in the bucket on the global transport scheme, so at some point a lot of nitrogen will have to be produced purposfully to these LN2 engines, at which point the ASU energy consumption really hurts this scheme's economics.
They should use ultra high strength maraging steels to make these pistons and other engine parts. Very light, and low contacting areas for friction (because of thinness for strength), are advantages.
A 56 MPG minivan! That's real good value for money. Hydrogen FCVS and plugin hybrid buses would have serious trouble beating that value/$.
For those interested, http://www.hydrogen.energy.gov/pdfs/13005_well_to_wheels_ghg_oil_ldvs.pdf is a study on the well to wheels GhG emissions, even for the 2035 technology case, the coventional hybrid on gasoline (like Prius) does better than HFCV on reformed natural gas.
Also Roger, the fuel cell costs I quoted are NOT years old. They are based on a 2012 order. Real orders, unlike silly DOE spreadsheet predictions that have been wrong for more than a decade. http://energyfromthorium.com/forum/viewtopic.php?f=39&t=4290
Roger, the Gen I and gen II fuel cells have very similar efficiency, except the efficiency band is more narrow (more consistent performance). In terms of average drive efficiency they are still near the 50-55% they were 5-10 years ago.
Roger, sadly you're not right. Almost all hydrogen today is produced from reforming natural gas. If RE makes hydrogen electrolysis attractive, then we should have seen that already in large hydroelectric dams, especially some that have been paid off already and produce ridiculously cheap power. That power is not being used to electrolyse water. Nor is cheap coal electricity being used to make hydrogen. Fuel cells are not profitable without subsidies. Electrolysis is not profitable without subsidies. Wind and solar are not profitable without subsidies. Combining three unprofitable business into one business plan is not a good idea. Fuel cells do not cost $100/kWe. More like $1500-3000/kWe at this moment. Cost come down with mass manufacturing, but not by a large factor (about 2x only).
This graph has well to wheel CO2 emissions per mile for different vehicles: http://www1.eere.energy.gov/vehiclesandfuels/images/facts/fotw686.gif Natural gas battery hybrid electric: 185 grams CO2/mile. Fuel cell battery hybrid electric: 200 grams CO2/mile. This indicates that the fuel cell on reformed natural gas uses more natural gas per mile than the natural gas hybrid electric (by the way, we were wrong; these cars do exist).