Comments by "Engineering the weird guy" (@engineeringtheweirdguy2103) on "Two Bit da Vinci"
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@seanhardman1964 hydrogen will do little to encourage desalination. Because desalination built to supply hydrogen, will go to hydrogen. It won’t be utilised else where especially if used in vehicles.
Energy storage is well and dandy but you need to look at the applications. Renewables suffer from 2 problems. Intermittency and curtailment. To overcome both 2 strategies are usually adopted in conjunction with one another. 1. Is diversification. I.e not putting all your eggs in the same basket. You distribute your solar and wind farms over different places significantly spread apart. If it’s cloudy in California, it’s probably sunny in Arizona. If there is no wind in Texas, there’s a good chance it’s windy in Colorado for example. You also diversify the types of renewables. Having wind, solar, geothermal, etc all working together. 2. Is energy storage. Unlike what most people thing this isn’t to store days worth of energy, and it isn’t a backup, it’s to capacitate the energy fluctuations in renewables. For example, if demand is 200MW and wind is producing 212MW, you put 12MW into a battery, when they’re under producing 188MW later on, you put 12MW back into the grid from the battery. This prevents curtailment. Which is when renewables like wind and solar produce too much or too little, they are usually shut down and all that energy is wasted. Batteries allow them to continue making energy for longer as well as providing rapid frequency response which is another issue.
The problem with hydrogen however is that you lose 55% of your energy doing that. So for the purpose of capacitation it’s not really applicable to the job. If you’re over producing 12MW let’s say for one hour and you put that into hydrogen, when you’re later under producing 12MW, you only have 5.4 MWh to put back into the grid. It’s not applicable. Hydrogen storage might be applicable to things like hospitals and critical industries located in disaster prone areas such as near earthquake zones. Allowing them to keep running if the power fails. Such a use case would be well suited to that.
As for vehicles, Battery electrics offer better efficiency which means less capital projects to infrastructure to meet the energy needs. They’re better performing, have significantly less cost of operation, better handling and better safety, all with more practicality and comfort. For domestic passenger vehicles. Hydrogen just won’t make sense to consumers. You have a hydrogen car and an equivalent battery electric but the battery electric for the same price and size a faster, better handling, cheaper to run, will last longer, is a safer vehicle and has more cabin and storage space to boot. Hydrogen isn’t applicable here. It doesn’t have an edge.
Especially considering developing a charging infrastructure is significantly faster and cheaper than developing a hydrogen infrastructure for refuelling.
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@seanhardman1964 you don’t need to pump lithium. It isn’t a fuel, you don’t need it for every mile you drive. You just need a couple of kilograms per car. And despite what people say about it, there is plenty of it. Additionally most of the water used in lithium processing is brine. Not fresh water. It’s what they extract the lithium from. It’s also why it’s almost exclusively found in arid regions. You can drink brine and you can’t use it for agriculture.
And you’re talking about a VG or VPP’s (Virtual Grids and Virtual Power Plants) which is a little more complicated than whacking in the biggest batteries you can find. Once again, a 40kWh battery like the lavo isn’t suited to this task due to its power memory issues. As I said before. Hydrogen isn’t a catch all, it has a niche use case like all technologies. And most pertinent to this topic, is that domestic passenger vehicles, isn’t one of those niche use cases.
You could technically run a BEV with an array of super capacitors which have zero degradation, basically unlimited life and can charge and discharge as fast or as slow as you wanted to. So you could charge your EV in minutes and be able to throw down incredible power to the wheels and never need a new battery. Sounds great right?! Until you realise that it would only get you 25 miles even if you stacked the car to the roof with them because they don’t hold a lot of energy.
However they do have their use cases for rapid short discharges. Like power normalising, circuit memory and even in EV’s as a buffer where a few of them are charged with energy continuously, and when rapid acceleration is needed, they output the short Burst of high power output for the acceleration. A power output that would normally damage the lithium batteries.
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@seanhardman1964 because the efficiency matters. Hydrogen isn’t going to play as big a role as you think it is. It’s not as suitable for a lot of applications as lithium or other methods.
I’m not against renewables. I’m for renewables. But if you have storage that has fast turn over cycles like almost all grid size storage bar pumped hydro, losing 55% of that energy is costly. So is the speed at which hydrogen can be generated and stored at that scale. Slow response times make for a fragile grid. Wasting 55% of that energy is also a big no no, it means you have to produce 80% more energy for the same outcome. Which is saying a lot because renewables like wind and solar have curtailment losses of 10-30%. So using hydrogen as stabilising storage for renewables reliability is a fools errand. Couple that with slow response time and it can’t be used to shore up the grid either.
What grid scale hydrogen storage CAN achieve is low cycle storage. That means backup power for hospitals, army bases, critical industries, etc.
I’ve already explained this. Renewables aren’t bad, hydrogen isn’t bad, it just has its good use cases, and very poor use cases. Just because people invest money in it doesn’t make it a good idea. In the 1930’s and 1940’s people put money into radioactive water filters because they thought the radiation was good for you. Didn’t mean it was a smart idea. A lot of money was put into rotary engines for aircraft, and into blimps. Even look at Mazda’s rotary engine. Great idea, worked fantastic, lots of money invested in it, but had limited use cases and was ultimately canned. Likewise for the opposite. In south Australia they installed the first grid scale lithium batteries. Politicians from the federal government and the opposition criticised that moving saying it was a stupid waste of money. Now it’s SA most valuable grid asset and almost every other state is installing grid scale energy include 2 massing 500kWh lithium batteries into Victoria.
Some things have their use cases. Some things are better suited to better jobs. Unfortunately hydrogen, despite being a very clever technology, has very limited use cases. Not for grid storage, or home storage, not for renewables storage to avoid curtailment and not for grid stability and certainly not for domestic vehicles.
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@seanhardman1964 ok, so firstly I want to start off saying that I have always specifically said hydrogen was ill suited to domestic passenger vehicles. meaning vehicles you and me drive. I agree that large industrial vehicles like excavators, trucking and aircraft would be better suited to hydrogen. But it's just not suited to domestic passenger vehicles. Because most domestic uses of vehicles, people like you and me, dont need to regularly haul large car long distances, we also on average only have to travel around 70 miles for work.
Hydrogen is not well suited for domestic vehicles in comparison to BEV's which are far better suited. BEV's offer better safety, performance, handling, practicality, space, convenience and operation costs when compared to hydrogen. Its just not a competition for consumers when you start comparing the vehicles and its not something thats going to be fixed by technology. its due to physical limitations to do with hydrogen which I will get into detail about in another comment if you want to read it but wont bore you here because this will also be a long comment. I will also defend my thoughts about the economy of scale in that comment as well but suffice to say that its not that I dont think it wont reduce prices, its that I dont think it will make it cheaper than BEV's per mile.
(im going to do the next part in km, because they're my native units. I use miles because everyone on here always seems to be American).
You started talking about the cost of mining and producing lithium and other parts of BEV's compared to hydrogen vehicles. Whilst I cant comment in any competency about the overall environmental impacts, the efficiency I can talk about. These are sunk costs of energy to create the vehicles. Once off for the life of the vehicle. So far I have been talking about operating costs, whats need, ongoing, to operate the vehicles. It is estimated that the energy requirements to manufacture a vehicle is around 2,670 kWh. So how does that stack up to operational costs. Well we know that hydrogen, mostly due to the second law of thermodynamics, isnt very efficient. of the electrical energy provided to make the hydrogen, at best around 30% of that energy actually makes it to the wheels. Meanwhile for BEV's, that number is around 80% or more. So if we assume two identical vehicles in terms of weight, aerodynamics, rolling resistance, and both use the same electrical motor, but one is a BEV and the other is a Hydrogen Fuel Cell vehicle, then they should both need the same energy to drive per mile input to the motor. Lets assume a requirement of a Tesla model 3 at 0.13 kWh/km over the average yearly distance travelled for a US citizen at 22,000 km. That means the motor would need to consume 2,860 kWh of electricity to travel that distance on average. So, knowing how much energy is lost due to inefficiencies, we know that the BEV's would need to draw 3,575 kWh of electricity from the grid, whilst the Hydrogen vehicle would need to draw 9,533 kWh of electricity from the grid. Thats a difference of 5,958 kWh of electricity per year.
Now lets look at the manufacturing costs. it is assumed that the manufacturing costs of a vehicles is around 300 gallons worth of petrol. Petrol having an energy density of 8.9 kwh of energy per gallon means that it takes 2,670 kWh of energy to make the cars.
Now I know you think thats not an issue because renewables are green. but it is an issue. Because you have to built MORE renewables. Building anything has its environmental costs in sourcing materials, land usage, and economic costs. Making a grid 3 times larger so you can drive a vehicle that is slower, less safe, less practical and far more costly per mile to operate doesnt seem like the most efficient solution.
There is also another aspect with manufacturing costs to do with hydrogen. And that is that it doesnt last as long. Modern EV's will last between 30-40 years of driving on their batteries. Much to peoples disbelief the last longer than ICE vehicles despite what they hear from friends. Hydrogen vehicles however come off the assembly line with an expiration date printed on them. for no more than 10 years from manufacture. So you also have to take into account that you would have to make 3-4 times more hydrogen vehicles for every persons lifetime than BEV's. that means mining the metals, making the batteries, getting the fuel cells.
I'm not saying that hydrogen vehicles dont work. Im not even saying they dont work well. Im saying they're not suitable for domestic vehicles when compared to BEV's.
As for hydrogen production rate vs battery charging rate. Batteries actually win that one. Hydrogen by electrolysis is slow. So is electricity production via fuel cell. As i mentioned before. Hydrogen has slow response compared to Batteries.
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@seanhardman1964 Now for outlining hydrogen vs BEV vehicle suitability's.
For alot of this I will be directly comparing the Toyota FCEV Mirai to the Tesla Model 3 as they are both mid sized sedans, the Mirai is about 1 inch taller, 1 inch wider which is not very significant for aerodynamics but the Mirai has the advantage on space because its 11 inches longer. The mirai also weighs around 100kg more than the model 3. So lets get to it.
Hydrogen vehicles are slow. very slow. The mirai having a 0-60 of 9.2s whilst the model 3 does it in 3.2s. They both operate on electric motors, their weight is very similar and their aerodynamic coefficients aren't very dissimilar either. Hydrogen is slow because of the limitations for the fuel cells. The fuel cell is very slow at making energy. As water is produced on one side, it effectly blocks new air from reaching the fuel cell catalytic area to produce more water and generate more electricity. also coupled with the fact that air is only around 20% oxygen, it cannot produce energy very quickly. It is also directly proportional to the surface area of the catalyser. The mirai's entire engine bay, instead of being used as storage like the telsa, is taken up by the fuel cell in an attempt to maximise its catalytic surface area.
Even then, the flow rate of energy is only just enough to allow the Mirai to cruise and does not provide enough energy to adequately accelerate the vehicle. As such they put around 1.6 kWh of lithium batteries on board. The batteries absorb what little excess energy there is, and output it to the electric motor.
What this means is that if you want the car to go faster you have to do 2 things. 1.) take up space to expand that catalytic surface area or install another fuel cell. 2.) have larger battery storage to allow for a larger power output to the motor.
The physical limitation to hydrogens performance is the Fuel cell and its catalytic surface area. Hydrogens first super car, the Hyperion, has 3 fuel cells on board and replaces the batteries with an array of super capacitors. But you can see from the car how large it is but how little space there is due to the attempts to maximise the catalytic surface area.
now onto space, or practicality. The model 3, has a skateboard battery design. This allows alot of cabin space, alot of boot space with the model 3 have one of the largest boots in its size class as well as allow for the front engine bay to become another boot (called a "frunk"). The Mirai has not "frunk", it has a smaller boot than a Totyota Yarris in a size class well below that of midsized sedan. infact the Yarris has a larger boot by a whole 100L of space. The cabin space is also so small that you can actually fold the rear seats down to try to expand the boot area into the cabin. Something the model 3 can do.
So why so little space despite being a physically larger car than the model 3? This is because hydrogen, whilst has alot of energy per kg. takes up a LARGE amount of space. Hydrogen in the Mirai is compressed to 700 bar. thats 32 times the pressure LPG is stored at in those metal BBQ gas bottles. Its highly compressed. its also incredibly light. Such that the Mirai can travel 400 miles on its takes which equates to around 5.6kg of hydrogen. However 5.6kg of hydrogen at 700 bar also equates to 147L of space. Thats right, the mirai has the largest fuel tank volume of any mid sized or large sedan in history. At 147L. That takes up alot of space. Infact it takes a larger portion of where a tradition fuel tank would go. It also takes up the entire volume where a transmission would normally go meaning you have the centre console bump which rear passengers stuck in the middle hate, as well as the under side of the front of the vehicle. it has 3 tanks. 3. Ontop of those thanks they need to put the batteries somewhere, so they do it in the boot making it significantly smaller. Then they have to put the fuel cell somewhere and thats your "frunk" space completely gone.
hydrogen drive trains take up alot of space. thats why you always see hydrogen advertised for energy DENSITY not volumetric energy density.
That means the vehicles are far less practical than BEV's. BEV's offer more space and better storage and a more comfortable car for passengers, especially adults. Once again its a physical limitation of hydrogen and technology wont help here.
Now we get to handling. Since the base of the vehicle is entirely taken up by fuel tanks, it already had a higher centre of gravity than a BEV with their skateboard battery pack design. Then ontop of that you're putting the fuel cell and batteries ontop. This means that with a higher centre of gravity and higher overall weight, the vehicle will not handle as well as a BEV. Straight and simple. This is again a physical limitation, technology wont help here.
Then there is safety. BEV's are excellent for safety. They have extra crumple zones at the front, rear and sides thanks to the battery pack design, allowing for additional crumple zones increasing survivability. They also have an extraordinarily low centre of mass, which significantly reduces the likelihood of roll over in an accident which also increase survivability. Hydrogen on the other hand, does not have the crumple zones at the front or back or sides. infact the entire drive train only weight around 100kg, fuel tanks included. So where does the rest of the weight come from? chassis reinforcement to protect the fuel tanks containing explosive gasses at 700 bar. The fuel tanks are incredibly safe as long as they dont critically fail. they can handle punctures and heat. Not being torn open in an extreme collision though. with a stiffened chassis to protect the fuel tanks this means less crumple zone to absorb energy which means less survivability.
also it has a higher centre of gravity meaning its more likely to roll over compared to a BEV.
These are physical limitation. Technology could help here but doubtful.
Lastly, cost of operation. This is the cost spent on fuel. Now hydrogen vehicles arent efficient with their energy. You need approximately 3 times more electrical energy per mile than a BEV. This isnt a small amount. Since BEV's. the price of electricity is the only consideration, off the batt we know that hydrogen will always be at least 3 times more expensive per mile than BEV's and that economy of scale wont fix that problem. power companies have already reached scale. The price of electricity per kWh can be assumed to be the same for either the BEV or hydrogen. They will never be cheaper. Not as long as you are converting energy into hydrogen and then hydrogen into electricity. there will always be an upper limit to efficiency thanks to the second law of thermodynamics, it will never be as efficient or more efficient than a BEV. simple as that.
But thats not the only cost. We have to add the cost of water, cost of transportation, Then there is the facility which creates the hydrogen, their overhead costs, maintenance, admin, staff and then finally a profit markup so over all those costs, they still make a profit on their product. Their product is purchased by fuel stations who have their own capital costs, overheads, staffing etc. They have to buy the hydrogen at the cost for the hydrogen plants to make a profit, cover their own costs then add a profit margin ontop of all that to supply the customer with fuel.
This makes it VERY expensive. economy of scale will help a little here but again, it will still never be cheaper than BEV's. they will always be well over 3 times more expensive per miles to operate. thats a physical limitation of their efficient, and again, why the efficiency matters.
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@seanhardman1964 So to review. If someone is in the market for a green car even ignoring infrastructure issues, they have the choice between the Mirai and the Model 3 for example, similar vehicles, similar size similar market. the Tesla has better cargo and cabin space, better acceleration, better handling, better safety and is significantly cheaper per mile to operate. So what does the Mirai have going for it?
The Mirai can be refuelled. which seems good on face value except that you dont get hydrogen to the home. but you do get electricity. When you average daily commute is around 70 miles and the model 3 has a range of 325 miles, it becomes trivial to just plug in when you get home. The average person spends approximately 16-17 hours per year driving to and from, and getting fuel. But with a BEV charging from home thats zero. That means every morning you wake up with effectively a full tank every morning for 0 time out of your day. Sure you do a long trip maybe once or twice a year but with supercharging networks it means you only spend around an extra 1.5 hours for a 1,000 mile road trip each way. Still much better than the 16-17 hours every year to get fuel. This means the BEV is more convenient.
Ok, so in the domestic vehicle market, refuelling isnt really and advantage, what about range?
well the Tesla model 3 has a range of 325 miles, and the Mirai has a range of 400 miles. So for all the significant lack of acceleration, cargo and cabin space, the much higher cost per mile, the compromised safety and worse handling, and 147L of fuel tanks, you only get an extra 75 miles over the Tesla model 3. All whilst considering your daily needs would rarely punch you over 100-150 miles on a battery that can go 325 miles or a tank that can go 400 miles.
The advantage there doesn't out weigh the disadvantages there. not even close.
the the better option for consumers then is clear. The Battery Electric takes every category except for range, but the added rage of hydrogen is barely worth the consideration.
Hydrogen vehicles arent very well suited to the domestic vehicle market. Not in comparison to BEVs.
and to be clear again. Im not saying hydrogen isnt suited to trucking where range and refuelling times are a much greater consideration, or to industrial equipment or air travel etc etc. I'm saying for vehicles you and me drive, there would only ever be 1 reason someone would logically go with hydrogen over Battery electric for their daily driver. That would be that you live somewhere, where you cant charge your car. On the street parking for example. People with driveways, car ports, garages, even apartment multi level carparks can be fitting with charging stations as long as you can convince your super which is getting easier and easier and they become more and more popular. But not everyone will be able to charge from home and those people would likely need hydrogen vehicles. But they would be getting an inferior vehicle and is going to cost them more.
As I keep saying, Hydrogen has its use cases. But its not suited to every application, its not even suited to alot of applications. Grid scale storage isnt a good use case for hydrogen just as domestic passenger vehicles isnt a good use case for hydrogen. There are better options. Thats not to say hydrogen cant be used or isnt going to be used for some situations, like when you cant charge from home. But the majority domestic vehicles wont be hydrogen. similarly, the majority of grid scale storage wont be hydrogen. use cases like hospital backup power would be a good example of where hydrogen would excel. grid storage for grid stability and renewables stabilizing is not a good use case for hydrogen. Power plants are not a good use case for hydrogen, home storage is not a good use case for hydrogen unless the way the grid is regulated is literally entirely changed as we know it. Lithium home storage is much easier to integrate into existing a future grid technologies.
You have to look at the use cases without bias. sure it would be neat to have a one stop energy solution that solves all our grid problems, renewable problems and transport problems. But it doesnt work like that. nothing works like that, nothing ever has.
The power grid has dozens of types of generation depending on what the application and requirements are, balanced on cost and effectiveness (which is how efficient it is which relates to how profitable it is). Even cars arent a one stop. There are diesel and petrol cars, which have different uses and trade offs, there are V engines, Boxer Engines, Straight Engines, Rotary Engines, all with different use cases, and trade offs between benefits and detriments.
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