Toyota negative on batteries because it has more experience than other others on them

Reference ?

I recently read (and posted) about heat driven electrolysis that exceeds 60% energy conversion. The approach also has the substantial advantage of being able to utilize PV/wind at (I'm guessing) close to 100% capacity.

 

I don't think that 60% value means what we are assuming it does. When I last read that link it sounded like it was in reference to thermolysis. Heat the water hot enough and it will break into the component oxygen and hydrogen. That was the research groups 100% benchmark. At the relatively lower temperature, it was 60% because energy in the form of electricity needed to added to the system. It is less electric than room temperature electrolysis, which presumable be at or near 0% on their scale, but the 60% may not account for the heat required to get up to those temperatures.

"The efficiency improvement of high-temperature electrolysis is best appreciated by assuming that the electricity used comes from a heat engine, and then considering the amount of heat energy necessary to produce one kg hydrogen (141.86 megajoules), both in the HTE process itself and also in producing the electricity used. At 100°C, 350 megajoules of thermal energy are required (41% efficient). At 850°C, 225 megajoules are required (64% efficient)." - High-temperature electrolysis - Wikipedia, the free encyclopedia

I presume the 141.86 megajoules is the heat energy needed under thermolysis when the water is at 2500C.

 

Even if electrolysis is less energy efficient, it is easy to do. Takes 5 secs to see it work at home and make your own small H2 sample. Part of the issue with solar/wind is having a place to store the excess generation. H2 can be potentially made in these cases. I don't think we should hold back FCV until solar H2 is economical, rather if FCV "takes off" that route is enabled for the future.

Of course lots of folks hoping that natural gas or other materials can be used to generate H2 on board, so not clear yet we need H2 per se in the long term.

 

I'm not sure what all this gobbly gook means, but ,,,,

Think of it this way. People seem to be claiming you can buy a lot of expensive equipment and land and sell something as cheaply as not doing that, and it doesn't really depend on even getting good utilization of that equipment.

That's like saying you can have bottled water delivered to your house as cheaply as you can pour and filter tap water there. It just doesn't make sense, and even if you recycle the bottles (the equipment after its useful life) it still is going to cost more.

The truth is not only will you have to pay for this other stuff - land, pumps, compressors, electrolyzers, labor, maintenance .... but you have to pay for more electric generation - pv panels or wind turbines. NREL says the cheapest remewable electric generation will come from off peak wind, and this is great, as there is a lot of potential for this on the western and the texas grid, and it's not too expensive - the eastern grid, you know coal states like indiana that fuel cell advocates want to pretend will use renewable hydrogen are not so good. You will find you can build wind .... depending on whose estimate you use for 2.5-8 cents a kwh but you may also need to do grid improvements to get it where your ev or fcv wants to fuel. If you only use the off peak stuff - in California this is between midnight and 6 am. Building the extra wind, say 3x as much as bevs and fuel cells need, and having these things on smart chargers to work harder during heavy wind production is probably pretty economic and lower in cost then burning natural gas in those out of state plants that california is using to hit peak demand.

Now for the utility (I guess california PUC in this case would regulate) to give a cheap price for this wind split, so that they mainly used cheaper off peak, Hydrogen production would require some serious electricity. Say you want a station to be able to fill 300 cars a day, with say 4 kg of hydrogen each (enough to power a mirai for 268 miles), you need to be able to produce 1200 kg a day in those 6 hours. That is 200 kg/hr (actually you'd want it to be higher). If each kg of hydrogen takes 60 kwh to produce that is 12,000 kwh/h or 12 MW of power coming into the station, a lot of power for a small place, pretty easy to do with new lines for a factory. Because of the high power demand NREL is assuming that these hydrogen production sites will be central with grid upgrades done for a production facility that serves many stations and the hydrogen liquified and trucked. This cuts down costs a great deal but increase the amount of energy needed a little. You now need diesel, or natural gas, or hydrogen to power the trucks, and more electricity to liquefy the hydrogen. The cost of the electrolyzer and grid upgrades and liquifier can then be shared by many stations, and the compressors needed at each station also becomes less expensive.

This is not a bad plan for the future if there are a lot of fuel cell cars on the road. NREL estimates that if 15% of the cars were fcv estimates that the stations would need to charge about $8.50/kg not including taxes for the renewable hydrogen. Solar is much more than off peak wind. Solar also has a larger federal subsidy, which makes solar hydrogen hugely expensive to taxpayers, but that may change with future advances. At lower volume though the costs are much higher, and that is california's experimental phase now. They are building a lot of stations that can only produce 100 kg of hydrogen a day = 25 fill ups if each is 4kg, which means once the storage tank is empty it will take an hour to generate enough hydrogen to fill each car. When you look at the low volumes of these stations and likely useful life of equipment it probably costs at least $25/kg of renewable hydrogen about 10x the cost per mile of filling up a plug-in with only federally subsidized green electricity. That makes it a dumb idea to roll out today, but that could probably change in the future. DOE is spending a lot of money to make renewable hydrogen less expensive. Renewables are more money than anyone but a lobbyist would want to spend right now for hydrogen, but that could very well change if enough natural gas powered fuel cell vehicles get on the road.

As to how much less efficient this guy put out a chart of miles for the mirai versus plug-ins using the same amount of renewable electricity. Theoretically at standard tempearture and pressure you could catylitcally electrolyze water at 83% efficiency. If you heat it up say with waste heat from a nuclear reactor it can be over 100% in terms of electricity as it uses the waste heat to power the reaction. Since I doubt we are planning to build nukes to power our cars, lets leave it at say 80%. Chilling and compressing to 10,000 psi takes about 2kwh-7kwh, and the problem is cost, so lets stick with the low end. In a fairly ideal world without having to spend the money on a nuclear reactor we find the best we can do is 1.3 GGE of renewable electricity to prouduce a GGE of 10,000 psi chilled hydrogen. Given the efficiencies of fuel cells versus charging batteries, it means we could probably get to around twice as many solar panels or wind turbines to power fuel cells. Right now we aren't nearly that efficient it takes about 60 kwh of electricity, but its definitely only a engineering problem to get it to 44 kwh. Solving that engineering problem though will not likely reduce the cost of renewable hydrogen very much. The bigger cost drivers are elsewhere.

Hydrogen Fuel Cell Toyota Mirai Energy Efficiency Compared TO BEVs

Just for grins, if it takes 60 kwh to fuel 1 kg of hydrogen, you fill 200 kg per year, wind utilization is 30% and you build 3x as much as you need selling the peak power and using the cheaper off peak wind - 1 million fuel cell vehicles would require you build 13.7 GW of wind. There are 25 GW of wind projects in construction or planning for the ercot texas grid alone, These are typically built under a 10 year contract, but after that the wind farm just operates providing some very cheap night energy. you need to buy the more expensive stuff too to get counted as renewable in texas, but ... there should be a lot of cheap renewable off peak wind electricity in 2030 to power plug-ins or fuel cells but without renewable credit.

 

I still think it does, after re-reading

If anything, the process is more efficient because the electricity can be PV or wind which will be some 2.5x less source energy than that consumed by a heat engine.

 

Car battery charging is about 90% efficient, as is discharging, thus ~80% round trip from wall to wheels. This is what we get today and universally available and cheap...and good improve by a few percent...but not a lot.

Electrolysis 60% (proven today, but only for expensive, high volume)
Compression 90%
Liquefication 90%
Fuel cell 40-60% (you only get the peak after warm up on longer trips)

Net: 20% to 30%, wall to wheels. And this is with expensive equipment, no leakage, no transportation (on site production).

First, this is unproven at any industrial capacity. Second, as I pointed out in your OP and others have said, the "efficiency" number they quote is NOT confirmed to be the actual net overall energy out divided by energy in but rather some academic benchmark.

Mike

 

if more efficient - why do you think the process isn't favored over natural gas
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First you petition the government to loan you money at bellow market rates to build a nuclear reactor so that you can make cheap hydrogen. Then you ask the government for safety waivers because nuclear is so safe you shouldn't have to follow the rules. After 10 years you get approval and break ground on your new nuke that will use waste heat and renewable electricity to make hydrogen. The project takes 9 years to build because of regulation and lawyers so that there are huge cost over runs. You go to the California PUC to get a rate increase which they give you because carbon free electricity and cheap hydrogen is more important than electric rates. Nuclear plants are extremely hot and inefficient at converting heat from the fission reaction to electriicty and the waste heat just like everyone said has now made using electricity from that wind farm over 100% efficient at catalytic high temperature electrolysis. The science and ghg savings are sound, as is the timeframe of taking over 15 years to do this kind of project.

Is the renewable hydrogen more efficient than the current SMR process from natural gas, why yes it is because you used waste energy in the process. Is it cheaper? Well only if you are the government and move the price of the hydrogen to the rate payers of electricity. If you are the government of japan then definitely. Net net though for california they could simply use the money that would have been spent on the project to build wind turbines to offset more natural gas used on the grid than was used to make the hydrogen in a SMR process. They could also use the money to replace the old steam natural gas plants with 50% more efficient ccgt plants. This was the core of the picken's plan before natural gas prices got too cheap to economically do the swap. Doing it requires government regulation or subsidies.

 

But if we make hydrogen during periods of renewable electric surplus, feeding it into a stationary fuel cell, or even CCGT plant, during troughs of renewable power, saves the money of getting it to the cars.

In that case, what are you using to get the water up to the required 850C?

 

No one is holding back solar h2. People are building plants with tax payer money in spite of it being extremely expensive.

H2 is indeed easy to make. The federally subsidized cost of solar is $0.12/kwh-30 cents per kwh. Let's take the low estimate and multimply by the 60 kwh you need for a kg of chilled pressurized hydrogen - that's $7.20 for power alone. Say you have 25% utilization of solar panels and want to make 1 kg/day, that would take a 10 kw panel, you may need a bigger roof if you want to do more. Then you need a big storage tank, a compressor, and a chiller. All of those I'm guessing at very low utilization if you are doing this at home or a 100 kg/day station. I think you need to build one of those to see if you can bring costs down., otherwise why waste the money.

The US last year was 4.4% wind, and less than 1% solar. There is not any excess solar, and very little excess wind to power hydrogen. Der spiegel looked at germany which has a lot more renewables on its grid than the US. They estimated that there would not be much excess renewable electricity there for hydrogen production until at least 2050. Most of the wasted wind in the US is simply waiting for grid upgrades not fuel cell vehicles, but we can build more wind if there is off peak demand.

Leading candidates methane (yes from natural gas, but the oderent is sulfur based, so before odor is put in or renewable biogas, or from hydrogen and electricity) and methanol. Both would lead to cheaper fuel and cheaper infrastructure, but more expensive cars. There is another downside to the fuel cell lobby for these fuels. They aren't that much less efficient in a hybrid then a fuel cell car running on them.

 

you forgot the measly (NIMBY) 5 years of environmental studies & subsequent appeals. yes - just 5 years if they ramrod it through.
Yea, you stole my thunder, it was a leading question

.

 

I meant more efficient than the quoted 64%, which assumes electricity from a heat engine.

Comparing to NG is a different story. I think I have read 90+ percent conversion from NG to hydrogen. In any case the choice to use NG is mostly a "what is cheapest" question. Efficiency plays a part in that question but it is not the entire story. Someone posted above that electrolysis results in Hydrogen that is 3x more expensive than from NG. I doubt it that will turn out to be the case, even before carbon taxation.

Joules

Those numbers look ballpark to me, at least for today. I don't know how much room for improvement they have. The true advantage of hydrogen (although not only hydrogen) is ability to utilize the wind/PV whenever. Plant power capacity will become 50% for PV and close to 100% for wind. It solves the energy storage problem -- which is not a problem today, but it will be when intermittent sources climb well above 50% of the grid power.

 

But the waste heat of from such power plants can be used to heat up the water. Cogen CCGT plants are 90+% efficient at using the fuel. Which is or isn't factored into the efficiency numbers, but likely not, since it was merely an illustrative example of how high temps make the process more efficient, not actual efficiency measurements of an individual process.

Using electric alone, it will take 810kWh to make one kilogram of non compressed hydrogen. For this to work out in an actual plant, you need equipment that can withstand the high heat and pressures, which will raise initial capital and maintenance costs. Otherwise, we could just skip the electrolysis and head right to thermolysis, which would take only 511kWh for that kilogram.

Reforming natural gas is close to high temp electrolysis or thermolysis in process. Some of the NG is used to convert water to steam and heat the process. The NG and water both thermal decompose, and then reform into CO2 and H2. In essence it is thermolysis using a consumed catalyst/reactant to lower water's thermolysis temperature.

 

That would be swift.

Or imagine if the power plant was in the desert and heat pumps could be used.

 

I have a question for you that declare - hydrogen will be made from renewable electricity cheaply, because it doesn't really cost much more and people will pay for it. Let CARB hear your ideas because they seem to be spending a many times more to try to make renewable hydrogen delivered to fuel cell vehciles. DOE is spending about $100M for R&D to try and make renewable hydrogen less expesively.

CARB says auto manufacturers estimate that if there is fueling infrastructure (my guess assume free fuel) have 34,000 fcv on california roads by 2021. If each fcv used 200 kg of hydrogen a year, that is only 7M kg, which you could contract to buy for about $14M if you give the very generous lead time and allow the manufacturer to use SMR. CARB only expects that the $140M it is spending 2014-2021 on top of the federal money which will probably end up being substantial will only build 86 stations which won't be able to deliver that much hydrogen. Please explain to them not us how to build this very expensive infrastructure cheaply. I know the department of energy will give you a grant to set up a pilot plant if you really have some magic method they haven't thought of yet.

 

This is the inescapable reason of why I think H2 will never be the main fuel delivery scheme for future cars. No matter what the best H2 processing efficiency numbers are, this guarantees FCV energy cost will always significantly more than PHEV or EV energy cost.

Since the economic cost of sustainable fuel is a lost cause for FCVs, then the advocacy organizations for FCVs must find some overblown contortion of why FCVs are superior for mainstream use. As those contortions are exposed as overblown (as Tesla routinely does) this economic reality will become inescapable.

However, since H2 can be made from natural gas and most electricity cost is based on fossil fuel generation cost, this fuel cost battle between FCVs and EVs is a lot closer now than what it will be in the future.

 

toyota seems to be more fascinated by range and refill time than anything else.

 

Welcome to the other 97% of America

 

My quick fill PHEV hasn't needed a quick fill since March and I still have 3/4 of a tank to go.

 

exactly. maybe that's their tactic, but we likely won't know for a good 10+ years.