The Truth about Hydrogen 

As the world battles to eliminate fossil fuels from our energy diet, electric cars
The last few years have seen an incredible boom.
Last year, more than one million electric cars were sold worldwide.
Nissan Leafs, Tesla and other electric vehicles now number more than three million worldwide.
And while there are many brands of electric cars to choose from, there are only two options for powering electric vehicles: fuel cell or battery.
Both produce electricity to drive electric motors, eliminating the pollution and inefficiencies of fossil fuel powered internal combustion engines.
Both hydrogen and electricity for batteries can be produced from low or zero carbon sources, including renewable energy such as solar and wind, and are therefore both pursued by car manufacturers and researchers as a potential future for electric vehicles. Used to be.
However, a great debate is being waged by supporters of each technology.
Elon Musk called the hydrogen fuel cell technology "incredibly dumb", claiming they are more of a marketing ploy for vehicle manufacturers than a long-term solution.
Conversely, Japan has announced its intention to become the world's first hydrogen society, together with the Government of Japan and the auto industry, to introduce 160 hydrogen stations and 40,000 fuel cell vehicles by March 2021.
So which is really better?
At first glance, hydrogen seems a very clever way to power a car.
Compressed hydrogen has a specific energy (aka energy per unit mass) of about 40,000 watt-hours per kilogram.
The best lithium-ion batteries only have a specific energy of 278 W / kg, but are mostly around 167 W / kg.
This is 236 times the energy per kg for hydrogen.
And due to its energy density and lightweight nature, compressed hydrogen and fuel cells can power cars for extended range without adding much weight, as we saw in our last video to include technology in the aviation industry as a There is a huge road block.
Designers of electric vehicles are caught in a catch 22 with energy density and range.
Each additional kilogram of weight to increase the range requires additional structural weight, heavier brakes, a higher torque motor, and more batteries to be carried around this extra mass, reducing this weight. Limits how a battery-powered vehicle can travel up to new technology. May help reduce battery weight.
For hydrogen fuel cell vehicles, this weight compounding is not an issue.
Additionally, the hydrogen fuel cell vehicle can be re-fueled within 5 minutes, where battery-powered electric vehicles, such as the Tesla Model S, take more than 3 hours to fully recharge.
When looking at the range and refueling time hydrogen can be offered, you can see why some car manufacturers are investing in this technology.
On its face.
Hydrogen is a clear winner, but it lags behind when we begin to consider the end-to-end production process.
While batteries and hydrogen fuel cells are both forms of power storage, costs vary greatly.
Charging the Tesla Model 3 with a fully 75 kilowatt-hour battery costs between $ 10-12 depending on where you live.
With a range of 500 kilometers, it is between 2 and 2.4 percent per kilometer.
A great price.
Befor 4day , I visited a petrol station that introduced a hydrogen pump, fed by its own on-site production facility.
Which used off-peak electricity to produce hydrogen.
Hydrogen from this station cost $ 85 to fill a 5 kg tank of Toyota Miris, which had a range of 480 kilometers.
It is 17.7 percent per kilometer, 8 times the price.
And the problem here is, more energy is needed to produce hydrogen.
Dig deeper into the production process to understand the economic feasibility of hydrogen.
Before any hydrogen vehicle can hit the road, you must first produce hydrogen, but hydrogen is not a readily available energy source.
Even though hydrogen is the most abundant element in the universe, it is usually stored in water, hydrocarbons, such as methane, and other organic materials.
One challenge of using hydrogen as an energy storage mechanism comes from being able to efficiently extract it from these compounds.
In the US, the majority of hydrogen is produced through a process known as steam reforming.
Steam reforming is the process of combining high temperature steam with natural gas to extract hydrogen.
While steam reforming is the most common method of producing industrial hydrogen, it requires a good deal of heat and is wildly inefficient.
Hydrogen produced by steam reforming actually has less energy than natural gas that began with steam reforming.
While hydrogen fuel cells themselves do not cause pollution, it does.
So if we want to capture the future scenario with as little carbon emissions as possible.
Another method of producing hydrogen is electrolysis - separating hydrogen from water using an electric current.
While the power required for this process can be provided from renewable sources, it also requires more energy input than steam reforming.
When you do electrolysis, you lose 30% of the original energy from the renewable.
So we are sitting at 70% energy efficiency from hydrogen fuel cells. If conventional electrolysis is used, the car starts its engine before it.
A more efficient method of producing hydrogen is polymer exchange membrane electrolysis.
Using this method, the energy efficiency can reach 80%, with the added benefit of being produced on site, which we will get in a moment.
But it is still a 20% loss of energy from renewable energy.
Some experts say that the efficiency of PEM electrolysis is expected to reach 82–86% before 2030, which is a great improvement, but the battery charging efficiency at 99% is still well lacking. [1] A 19% difference in production costs does not explain the difference in costs, so we are losing energy.
The next hurdle in getting a hydrogen fuel cell vehicle on the road is the transport and storage of pure hydrogen.
If we assume that hydrogen is generated at the site, as if it were for this petrol station, we eliminate an energy sink, but the cost of storage is simply problematic.
Hydrogen is an extremely low density as a gas and liquid, and so to obtain sufficient energy density, we have to increase its actual density.
We can do this in two ways.
We can compress hydrogen at 790 times atmospheric pressure, but it takes energy, about 13% of the total energy content of hydrogen.
Alternatively we can convert hydrogen into liquid, cryogenically.
The advantage of hydrogen liquefaction is that a cryogenic hydrogen tank is much lighter than a tank that can hold pressurized hydrogen.
But again, the physical properties of hydrogen mean that hydrogen is harder to liquefy than either. Gases other than helium.
Hydrogen is reduced to 40% by lowering its temperature with an efficiency loss of 40%, once you factor in the extra weight of the refrigerator and the refrigeration itself.
Therefore pressure at 13% energy loss is a better option.
Once hydrogen is produced and compressed with liquid or gas, a viable hydrogen infrastructure requires that hydrogen be transported from where it can be transported to the end-use point, such as That vehicle refueling station.
Where hydrogen is produced, it can have a large impact on cost and the best method of distribution.
For example, a large, centrally located hydrogen production facility can produce hydrogen at a lower cost because it is producing more, but it costs more to deliver hydrogen because the point of use is farther away.
In comparison, distributed production facilities produce hydrogen on site, so delivery costs are relatively low, but the cost of producing hydrogen is likely to be higher because the volume of production is lower.
While some small-scale, on-site hydrogen production facilities are being installed on refueling pumps, 
Until this infrastructure is broadened, we have to assume that most of the hydrogen is being transported by truck or pipeline, where we know energy losses can range from 10% to 40%. In comparison, assuming that the electricity we use. To charge the battery as a whole comes from renewable resources (such as solar or wind), we just have to consider the loss of transmission in the grid.
The United States grid is used as a reference for typical grid losses, with the average loss being only 5%.
Therefore in the best case for hydrogen, using the most efficient means of production and transport, we lose 20% of the energy during PEM electrolysis, and a loss of about 13%, 33% for compression and storage.
In other systems, it may be 56%.
For battery power, up to this point, we have lost only 6% for grid and recharging. Bringing our best case efficiency to 27% and our worst case to 50%.
The next stage of powering electric vehicles is what is called tank to wheel conversion efficiency.
For hydrogen fuel cell vehicles, once the hydrogen is in the tank, it will have to be converted back to electricity again.
This is done through a fuel cell, which essentially acts like a PEM electrolyzer, but in reverse.
In a PEM fuel cell, hydrogen gas flows through the anode into channels, where a catalyst causes the hydrogen molecules to separate into protons and electrons. Once again the membrane only allows protons to pass through it, while electrons flow through an external circuit to the cathode. This flow of electrons is the electricity used to drive electric motors to vehicles.

If the fuel cell is powered with pure hydrogen, it has the potential to be up to about 60% efficient, with most of the waste energy lost to heat.
Like hydrogen fuel cells, batteries also come with inefficiencies and energy losses.
The grid provides AC current while the battery stores the charge in DC.
So to convert AC to DC we need a charger.
Its peak charger efficiency is around 92%, using the Tesla Model S as an example. The Tesla Model S runs on AC motors; Therefore, to convert AC current to DC battery into AC current, an inverter must be used with an efficiency of about 90%. Additionally, lithium-ion batteries may lose energy due to leakage.
A good estimate of the charging efficiency of lithium ion batteries is 90%.
All these factors achieved an efficiency of around 75% overall. However, hydrogen fuel cell vehicles also have some of these similar inefficiencies.
DC current is required for any type of electrolysis, and therefore a rectifier will be needed to convert the AC current from grid to DC.
The conversion efficiency here is 92%.
We have to convert the DC current produced by the fuel cell to AC to power the motor through the inverter with an efficiency of 90%. Finally, the efficiency of the motor must be considered for both fuel cell and battery-powered vehicles.
Currently, this is around 90–95% for both of them, which is surprising when you consider that the efficiency of an internal combustion engine running on petrol is only around 20–30%. If we combine all these inefficiencies and compare current generation batteries, then the best and worst case of current gen hydrogen.
We can see how they measure up.
Even with the BEST case scenario.
Considering no transport due to onsite production, and assuming very high electrolysis efficiency of 80%, and high fuel cell efficiency of 80%, hydrogen still emits less than half the efficiency.
Worst case is worse than this.
So while you can go ahead with a fill-up of hydrogen in your fuel cell vehicle over a battery-powered electric vehicle, the cost required to deliver that is because of the astronomical form of charging the battery. Energy loss and capabilities will exceed.
Based on our worst case scenario, we would expect the cost per kilometer for hydrogen to be about 3.5 times higher, but as we saw earlier it is 8 times the actual price.
Additional costs of production unrelated to capacity are clearly in play.
The cost of construction of the facility is one and the profit the station will benefit from the sale is another.
For now, these inefficiencies and costs are driving the market, where most of the investment and research is going into battery-powered electric vehicles.

So which win?
The same renewable resources are used to power them, assuming both are equally green compared to internal combustion engines.
Fuel cells allow time and long range for rapid filling; A big advantage.
But battery-powered vehicles can hold in range as long as there are enough hydrogen stations to make fuel cell vehicles viable.
While fuel cells are efficient relative to combustion engines, they are not as efficient as batteries.
They may make more sense for operations disconnected from the grid.
The use of hydrogen for planes can actually mean a lot, but once again there is a topic for another article.
For now, battery-powered electric vehicles seem to be the sensible choice going forward in the quest for pollution-free consumer transportation.
As battery-powered cars become more common, we also begin to see self-driving cars as the norm.




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