Efficiency of transport on gasoline, batteries and hydrogen
In this article, I would like to show in detail how much each technology is more or less effective solely in terms of energy costs for movement. It does not affect the economic or other component of the cost of transport production on such a drive, service, infrastructure and much more.
So, let's start with gasoline. What do we know? One liter has a weight of ~ 750g. and about 10kWh of stored energy. But how much energy does it take to get 1 liter of gasoline in the vehicle’s tank? We omit such things as transportation, storage, etc., we discuss only production and processing. The average EROI ( energy return on investment - the ratio of energy received to spent, energy profitability. Source Wikipedia ) oil production and refining into gasoline is 5, i.e. we give the 5th part, namely 20%. This means that about 2 kWh of energy will be spent for every liter of gasoline. But it also has about 10 kWh of stored energy, it seems to be profitable, but taking into account the efficiency of the internal combustion engine, transmission, etc. the total efficiency if it will be the same 20% it will already be good. It turns out some kind of insanity, at first we spent 2 kWh of energy for extraction and processing, then we used only 2 kWh for movement, and the rest was lost in the form of heat to the atmosphere ... It will be even more interesting when we compare the consumption of two models, one with a gasoline ICE and the other with batteries .
For example, Ford Focus. In the gasoline version, the actual consumption will be about 7l / 100km, and in the electric version about 14kWh / 100km from the battery (not from the network, we will return to this). What we ultimately have:
But with electric vehicles you need to be precise to the last detail, I don’t touch on the environmental part in this article, but we also need to talk about it in the case of EM. Namely, the charger (charger) also has losses for recharging the EM from the network. The average efficiency of the charger and high-voltage battery (VVB) is about 90%. Those. with a flow rate of 14kWh / 100km from the network, you need about 15.5kWh for a 100km run. In winter, of course, even more, because consumption grows significantly due to electric stoves, although many EMs use a heat pump, consumption may be more than 20kWh / 100km from the network, but cars in ICE also consume more fuel in winter ...
But can this end? No! Electricity transmission in the network also has losses, it is very difficult to determine them, but it is worth saying about it. In different cases, we have several transformations of electricity to high voltage for transmitting it over long distances, then lowering the voltage for the end user. I dare not express any even average figures with losses, but I will show one picture that shows that the losses on overhead lines of power lines are ~ 64%, i.e. almost 2/3 of all losses. Those. the farther the power station is from the consumer, the decently the greater the natural loss ...
The average statistical loss schedule of a typical power company. Source asutpp.ru
Local energy softens this indicator, and if it is still a renewable energy source (RES) it is even better, but about the environment another time. It turns out with an electric car it is very difficult to say how much energy was spent on moving, but if we put aside losses on the transmission of electricity, just as we did not take into account the additional costs of transporting oil and gasoline, we get the conclusion mentioned above: “EM will pass approximately the same distance on the same amount of energy that was expended to produce X liters of gasoline for an ICE car. ”
If for a moment we get distracted and recall how long the EM charge and the mileage on a single charge do not always suit everyone, but how fast and far everything is on a car with ICE, you want to figure out if a hydrogen car can solve all the problems?
I am considering a car using hydrogen fuel cells (FCs), where hydrogen is mixed with oxygen in a fuel cell and the resulting electricity is used to move using an electric motor, I do not take the option of injecting hydrogen into an internal combustion engine as a car with HBO (methane) as an example.
If it’s very short, then a car on a fuel cell: it can quickly refuel (although there are not many refueling so far), a “full tank” in ~ 5 minutes and has a decent power reserve of about 400-500 km. Although for example expensive Tesla and not only also have a power reserve of 400-500km (400km models since 2012), but at best they charge at 120km in 5 minutes, but cars on fuel cells are also not cheap. Sorry for my retreat.
But how effective are cars on fuel cells. On average, the real consumption per 100 km is in the limit of 1 kg of hydrogen per 100 km. And what is 1 kg of hydrogen? First, let's talk about the fact that on average for 1 kg of hydrogen in a tank, a car needs to spend, according to information from different sources, about 50 kWh of energy. If this is so, then it is 2-3 times less efficient than moving on a BEV, an electric car with batteries, because a car on a fuel cell is essentially an electric car, in which, by the way, there is also a small buffer VVB.
Let’s check if it’s as much as 50 kWh of energy per 1 kg of hydrogen. Because one liter of hydrogen weighs 0.09 g, then in 1 kg of hydrogen we have about 11.111 liters. For example, to produce 1000 liters of hydrogen by electrolysis of water on an industrial scale, about 4 kWh of energy is needed, we get 44.444 kWh for 11.111 liters. But in order to put more than 11 thousand liters of gas into a tank of reasonable size, hydrogen is liquefied by multi-stage cooling, which is also energy-intensive! So 50kWh for 1kg of hydrogen seems to be true.
Maybe then the approximate consumption of 1kg / 100km is overstated, but in fact it is much lower? We check. During the reaction of hydrogen with oxygen, about 3 kWh of energy is released when using 1000 l of hydrogen. The efficiency of modern fuel cells, unfortunately, is about 50%, which means that out of 1 kg or 11.111 liters of hydrogen instead of 33.33 kWh of potential energy, only half is “captured”, i.e. ~ 16.67kWh. Those. there are losses, it is also necessary to decently cool. There are losses on the charge of the buffered VVB and as a result we get about the consumption of the same Ford on batteries ... Physics cannot be fooled and the consumption of 1 kg of hydrogen per 100 km is also similar to the truth. For all types of cars there are long reviews, tests, measurements and the consumption of gasoline / electricity / hydrogen is no secret.
As you can see, there is nothing ideal today:
Let us now think a little about the future prospects.
ICE is already squeezed in its potential to the maximum, the efficiency of the electric motor and its control (controller) are at a fairly high level, 90-95% and the improvement of the efficiency will not lead to a noticeable improvement in energy efficiency. For example, the Tesla Model S electric car, when switching to a different type of engine and materials for the controller, achieved a small increase in mileage on a single charge with the same battery capacity, i.e. slightly reduced consumption, I think there’s nowhere to improve further and further improvements will be in the field of battery chemistry. But the car on the fuel cell still has potential. Firstly, a reduction in the cost of hydrogen production from 4ex to 3kh kWh per 1000l. Secondly, raising the efficiency of the fuel cell, for example, to at least 75%, then at the output we get from about 39 kWh of costs per 1 kg of hydrogen (34 kWh for electrolysis + about 5 kWh for liquefaction), on which it will be possible to travel already 150 km, i.e. with a flow rate of 26kWh / 100km today instead of 50kWh / 100km today.
In addition to all this, the world every day more and more needs effective and affordable energy storage technology, but this topic is for another article.
Thank you for attention.
So, let's start with gasoline. What do we know? One liter has a weight of ~ 750g. and about 10kWh of stored energy. But how much energy does it take to get 1 liter of gasoline in the vehicle’s tank? We omit such things as transportation, storage, etc., we discuss only production and processing. The average EROI ( energy return on investment - the ratio of energy received to spent, energy profitability. Source Wikipedia ) oil production and refining into gasoline is 5, i.e. we give the 5th part, namely 20%. This means that about 2 kWh of energy will be spent for every liter of gasoline. But it also has about 10 kWh of stored energy, it seems to be profitable, but taking into account the efficiency of the internal combustion engine, transmission, etc. the total efficiency if it will be the same 20% it will already be good. It turns out some kind of insanity, at first we spent 2 kWh of energy for extraction and processing, then we used only 2 kWh for movement, and the rest was lost in the form of heat to the atmosphere ... It will be even more interesting when we compare the consumption of two models, one with a gasoline ICE and the other with batteries .
For example, Ford Focus. In the gasoline version, the actual consumption will be about 7l / 100km, and in the electric version about 14kWh / 100km from the battery (not from the network, we will return to this). What we ultimately have:
- the gasoline Ford has not yet driven a meter, but for 7 liters of gasoline in the tank, it has already been spent from 14 kWh of energy;
- electric Ford on the same amount of energy will travel about 100km!
But with electric vehicles you need to be precise to the last detail, I don’t touch on the environmental part in this article, but we also need to talk about it in the case of EM. Namely, the charger (charger) also has losses for recharging the EM from the network. The average efficiency of the charger and high-voltage battery (VVB) is about 90%. Those. with a flow rate of 14kWh / 100km from the network, you need about 15.5kWh for a 100km run. In winter, of course, even more, because consumption grows significantly due to electric stoves, although many EMs use a heat pump, consumption may be more than 20kWh / 100km from the network, but cars in ICE also consume more fuel in winter ...
But can this end? No! Electricity transmission in the network also has losses, it is very difficult to determine them, but it is worth saying about it. In different cases, we have several transformations of electricity to high voltage for transmitting it over long distances, then lowering the voltage for the end user. I dare not express any even average figures with losses, but I will show one picture that shows that the losses on overhead lines of power lines are ~ 64%, i.e. almost 2/3 of all losses. Those. the farther the power station is from the consumer, the decently the greater the natural loss ...
The average statistical loss schedule of a typical power company. Source asutpp.ru
Local energy softens this indicator, and if it is still a renewable energy source (RES) it is even better, but about the environment another time. It turns out with an electric car it is very difficult to say how much energy was spent on moving, but if we put aside losses on the transmission of electricity, just as we did not take into account the additional costs of transporting oil and gasoline, we get the conclusion mentioned above: “EM will pass approximately the same distance on the same amount of energy that was expended to produce X liters of gasoline for an ICE car. ”
If for a moment we get distracted and recall how long the EM charge and the mileage on a single charge do not always suit everyone, but how fast and far everything is on a car with ICE, you want to figure out if a hydrogen car can solve all the problems?
I am considering a car using hydrogen fuel cells (FCs), where hydrogen is mixed with oxygen in a fuel cell and the resulting electricity is used to move using an electric motor, I do not take the option of injecting hydrogen into an internal combustion engine as a car with HBO (methane) as an example.
If it’s very short, then a car on a fuel cell: it can quickly refuel (although there are not many refueling so far), a “full tank” in ~ 5 minutes and has a decent power reserve of about 400-500 km. Although for example expensive Tesla and not only also have a power reserve of 400-500km (400km models since 2012), but at best they charge at 120km in 5 minutes, but cars on fuel cells are also not cheap. Sorry for my retreat.
But how effective are cars on fuel cells. On average, the real consumption per 100 km is in the limit of 1 kg of hydrogen per 100 km. And what is 1 kg of hydrogen? First, let's talk about the fact that on average for 1 kg of hydrogen in a tank, a car needs to spend, according to information from different sources, about 50 kWh of energy. If this is so, then it is 2-3 times less efficient than moving on a BEV, an electric car with batteries, because a car on a fuel cell is essentially an electric car, in which, by the way, there is also a small buffer VVB.
Let’s check if it’s as much as 50 kWh of energy per 1 kg of hydrogen. Because one liter of hydrogen weighs 0.09 g, then in 1 kg of hydrogen we have about 11.111 liters. For example, to produce 1000 liters of hydrogen by electrolysis of water on an industrial scale, about 4 kWh of energy is needed, we get 44.444 kWh for 11.111 liters. But in order to put more than 11 thousand liters of gas into a tank of reasonable size, hydrogen is liquefied by multi-stage cooling, which is also energy-intensive! So 50kWh for 1kg of hydrogen seems to be true.
Maybe then the approximate consumption of 1kg / 100km is overstated, but in fact it is much lower? We check. During the reaction of hydrogen with oxygen, about 3 kWh of energy is released when using 1000 l of hydrogen. The efficiency of modern fuel cells, unfortunately, is about 50%, which means that out of 1 kg or 11.111 liters of hydrogen instead of 33.33 kWh of potential energy, only half is “captured”, i.e. ~ 16.67kWh. Those. there are losses, it is also necessary to decently cool. There are losses on the charge of the buffered VVB and as a result we get about the consumption of the same Ford on batteries ... Physics cannot be fooled and the consumption of 1 kg of hydrogen per 100 km is also similar to the truth. For all types of cars there are long reviews, tests, measurements and the consumption of gasoline / electricity / hydrogen is no secret.
As you can see, there is nothing ideal today:
- the car on the internal combustion engine remains the most convenient, but the most inefficient;
- a battery-powered car is the most efficient, but not the most convenient;
- a fuel cell vehicle is almost as comfortable as a gas vehicle, if there were as many hydrogen gas stations, but somewhere in the middle in terms of efficiency.
Let us now think a little about the future prospects.
ICE is already squeezed in its potential to the maximum, the efficiency of the electric motor and its control (controller) are at a fairly high level, 90-95% and the improvement of the efficiency will not lead to a noticeable improvement in energy efficiency. For example, the Tesla Model S electric car, when switching to a different type of engine and materials for the controller, achieved a small increase in mileage on a single charge with the same battery capacity, i.e. slightly reduced consumption, I think there’s nowhere to improve further and further improvements will be in the field of battery chemistry. But the car on the fuel cell still has potential. Firstly, a reduction in the cost of hydrogen production from 4ex to 3kh kWh per 1000l. Secondly, raising the efficiency of the fuel cell, for example, to at least 75%, then at the output we get from about 39 kWh of costs per 1 kg of hydrogen (34 kWh for electrolysis + about 5 kWh for liquefaction), on which it will be possible to travel already 150 km, i.e. with a flow rate of 26kWh / 100km today instead of 50kWh / 100km today.
In addition to all this, the world every day more and more needs effective and affordable energy storage technology, but this topic is for another article.
Thank you for attention.
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