domingo, 20 de noviembre de 2016

The future of electric mobility (I) Electro-gas stations or electro-stables?

(versión española en:

A few months ago, before the summer, I had the opportunity to participate in a meeting on the future of cities in Graz (Austria), one of those macro-congresses organized to design an urban future being both sustainable and profitable for large industry . An important part of the presentations (approximately 1/4 of them) was devoted to urban mobility. I participated in a session on urban cycling with a presentation whose central thesis was that speed of execution is important for the success of cycling networks. There were more interesting interventions on mobility on foot and by bicycle, but most sessions on mobility were devoted to electric mobility, more specifically to electric vehicles (cars and buses) powered by batteries.

This summer, watching the Tour de France on TV, I stumbled upon some amazing images. A group of cyclists were riding escaped from the platoon and a motorcycle of the organization filmed the bicycles with an infrared camera. The commentator informed us that the subject of such filming was to verify that the bicycles did not have a battery and an electric support motor. In the most common models, the battery and motor are housed in the frame tube (under the seat post), but there are other possibilities. And the UCI is concerned about this possible "electric doping."

The reflections of this post have as origin my impressions in Graz and after the quoted images. But when I started to write them I realized that they would occupy a larger space than reasonable in a blog post, so I decided to divide their exposition in two parts. The first, contained in this post, deals with the economic limits of the most conventional idea of electric mobility: the electric car powered by batteries. 

The electric car seems to have become the "great white hope" of car industry, given the growing awareness of society about the environmental drawbacks of a mobility based on the internal combustion engine. It is not only that oil is depleting, nor the increasingly evident climate change associated with the irresponsible consumption of fossil fuels. It is that society is increasingly asking why it is necessary to live among such devices that produce smoke and all kind of polluting gases. Personally, I am convinced that, in a few years, people will look back and will not be able to understand how, at the beginning of the 21st century, did can we live among cars propelled by oil. Just as now we wonder how, not many years ago, we were able to live between the cigar smokes in bars, buses, elevators and classrooms.

However, it is not clear if the electric car is the solution to the problems generated by the predominance of the oil propelled car in urban mobility. The environmental groups have insisted that the electric car per se is not a solution to climate change, because without deep changes in the production of electricity, its generalization would only transfer the emissions from the cars themselves to the power plants. Moreover, the groups that defend a healthier and more efficient mobility model in cities have insisted that the electric car would not solve the serious problems of traffic accidents, abusive occupation of urban space, traffic congestion and sedentary lifestyle that the predominance of the private car entails.

All this being rigorously true, I think the main reason for which electric car will not become generalized is economic: The technology of battery-powered electric cars is far from offering a mass-consumption product comparable to the conventional petrol car. Here are some reasons:

A conventional car has a power-to-weigth ratio much higher than any electric car. It will take decades to get (if finlly attained) batteries with an energy density comparable to that of oil at a reasonable cost. The energy density is just the accumulated energy per kg of weight. Gasoline and diesel have an energy density of approximately 12 kwh per kg (10 kwh per liter), while lithium batteries used in electric cars (including modern Tesla batteries) have an energy density of 0.5 kw-h per kg, at the best. This means that for storing the energy accumulated in any gas tank of, say, 50 liters (with an energy content of approximately 500 kw-h), a battery of at least one ton (1,000 kg) would be required. Even considering that the electric motor is three times more efficient than the gasoline engine, the difference is abysmal. Based on these data, some have defined electric cars as "wheeled batteries".

But if serious is the problem of the accumulation of energy, much more serious is the problem of refueling that energy. We have being painted a future in which gas stations are replaced by electro-gas stations, in which hundreds of thousands of electric cars recharge their batteries in a matter of minutes. Nothing further from any reasonable reality. The difficulty lies not only in the need to replace millions of gas stations by electro-gas stations, but above all in the need to completely redesign the electrical network to meet the needs of such electro-gas stations. Following with the above example, to recharge a single electric car with the same energy (500 kw-h) and in the same time period that a 50-liter fuel tank would be filled (say 1 minute), a power supply able to provide 30,000 Kw (500x60) would be required. If you want to recharge 10 cars simultaneously, then you would need a 300,000 Kw (300 Mw) installation. As a comparison, a typical domestic installation is usually sized to supply a maximum power of 3 to 6 Kw. Another comparison: a nuclear power plant typically provides 1 Gw (1,000 Mw), ie it would give power for 3 (sic) electro-gas stations able of simultaneously charging 10 electric cars in one minute. Note that the problem mentioned can not be avoided by improving battery technology. In fact, it is intrinsic to the energy vector used (electricity). Moreover, we are assuming the availability of batteries capable of accumulating hundreds of kw-h of energy in a minute, something quite remote from reality at the moment. 

The figures from the previous example, derived from elementary arithmetic calculations, are scary and illustrates how far from reality is the idea of a world populated by electro-gas stations, offering to electric cars a service similar to that current gas stations offer to cars with internal combustion engines. It could be objected that electric motors are more efficient and therefore require less energy, that normally drivers do not fill the entire tank at the gas stations and could tolerate charging times of several minutes for their vehicles. Well, divide by 10, or even by 100, the figures from the previous example. Yet they are still creepy and show how far from reality is the hypothesis of a world populated by electro-gas stations.

Obviously it is possible to recharge electric cars more slowly at home. For example at night. This is a very popular hypothesis among the electric generation industry, since its realization would help to smooth the electric demand curve. To charge an electric car in the garage of a house with the energy equivalent to 10 liters of gasoline or diesel, ie 100 kw-h, in 10 hours, would require a power supply system sized to provide at least 100 / 10 = 10 kw. This is, of course, a much more reasonable hypothesis, although in any case it supposes to triple or quadruple the capacity of a typical system of home supply. And doing it massively in a city could imply to change the entire power supply system of such city.

But the important thing from an economic point of view is that, if we choose this slow charging system, we are giving up one of the advantages that led to the success of the oil propelled car: its unlimited availability over time. Unlike, for example, the riding horses, which they replaced with success, the gasoline cars do not have "dead times". They do not need to stop for long periods of time to rest, sleep and feed themselves. Neither do they need special spaces (stables) for such rest periods. Unlike a riding horse, a conventional car does not need to be stored, between each use, of more than a space of about 10 square meters on the public thoroughfare. This is one of the main reasons why the average urbanite can now own a car, while he did never could own a riding horse. Therefore, a world populated by electric cars, rather than a world populated by electro-gas stations, would be a world populated by electro-stables.

Owning an electro-stable can be an affordable task - to a certain extent, since we have seen that it implies to increase notably the power of the electric supply system - for the owners of a detached house with garage. The problem is compounded for the neighbors of a block of flats with a common garage, which would have to undertake substantial changes in their electricity supply system, which, moreover, would only benefit to the owners of electric cars. For people living on blocks of flats without a garage, to possess an electro-stable can become a real nightmare. Of course, many of the current owners of a gasoline or diesel car would not even consider this possibility.

Along with the problem of having an electro-stable, own or shared, inevitably associated to the ownership of an electric car, a similar problem will appear in hotel industry. Just as the old inns had to have stables for their customers 'horses, the new hotels would have to have electro-stables for their customers' electric cars. The availability of appropriate charging systems for electric vehicles in a hotel of, say, 100 rooms, would not be trivial.

In long-distance trips is where electric cars show their greatest weaknesses over their gasoline competitors. Randomly planned trips are over. Now a careful planning is needed, from electro-stable to electro-stable, under penalty of ending parked on the road aboard an useless gadget (for this, the electric car is worse than a horse, which can always graze and make its needs on the field). And on territories where there is not an adequate network of electro-stables it is impossible to travel: it is not enough with filling the tank and also load some additional gasoline cans.

On the other hand, the costs of disposal and recycling the electric car necessarily include the costs associated to the batteries, which in any conscious economy would mean additional costs for the electric car. There are also serious problems associated to the mining of the materials needed for such batteries, for example lithium. But I will not go into these problems that are already covered in other texts easy to find in Internet. I feel that what was said suffices to show that the electric car, as a good for consumption, can not be compared to their fossil fuel competitor. And that this is not because its technology is still developing, but due to intrinsic aspects linked to the change of energy vector: From petroleum derivates to electricity.

Is it possible to think of a process of massive substitution of the current oil cars for the new electric cars? It seems obvious that not, except at the cost of a notably contraction of the car market. In other words, if the oil becomes depleted or becomes more expensive than a certain threshold, it would be plaussible that many consumers (the wealthier ones) will buy electric cars. But many others (possibly many more) will simply give up the car (which would not be so bad, incidentally), given the difficulties, the higher cost and the worst service that the electric car would offer them.

Another possibility is that this shift from the petrol car to the electric car would be forced by public institutions, by means of rules (for example, prohibiting oil cars from circulating in cities), taxes (for example, raising taxes on gasoline and gasoil) or incentives and subsidies of all kind that favor the electric car. Of course, it would be fine to limit the use of cars in cities. But only for gasoline cars? Does the electric car not produce congestion, abusive occupation of public space, traffic accidents...? Higher taxes to oil would also be fine in order to moderate the pollution produced by conventional cars.  But does it not pollute the electric car in countries where most of the electricity is of fossil or nuclear origin? As for subsidies and economic incentives to the electric car,  which are usually quite generous Are not there other more urgent social needs?

In any case, even assuming that these actions from governments were successful (which is not currently the case) the only result would likely be a contraction of the car market, since many people would simply give up the car (which would be fine of course). In such case, in addition, since the electric car is specially unappropriate for long-distance trips, the perverse effect might be that consumers with higher purchasing power would choose to have two cars, a electric car for the city and a conventional car for long distance trips. A scenario undoubtedly appealing for the automobile industry, but of dubious usefulness for the environment.

It remains to be examined the mixed strategy, which seems to be increasingly successful in recent times, which is to promote the plug-in hybrid car as a transition to the only-electric car. However, as any user of a hybrid car knows, hybrid cars behave as conventional cars on interurban roads,  being only more efficient than conventional cars in cities. As for their "plug-in" characteristics, the advantages we have detailed of the conventional refueling versus the electric one, make it possible to expect that the percentage of electrical energy consumed would be quite low compared to the total. Hybrid cars are, in fact, gasoline cars whose competitive advantages over conventional cars are limited to urban areas, where there are other alternatives more desirable and competitive as we will see in the next entry. The announced transition from hybrid cars to total electrification is more than doubtful.

I will end here with this entry, hoping to have demonstrated that the future of the electric car powered by batteries as an object of great consumption, comparable to the current car of gasoline or diesel, is quite doubtful. And that this is so for reasons that do not always have to do with the poor development of the technology. In fact, the most powerful reasons have to do with the very essence of the electric car and its dependence on the electric power supply system.

Does this mean that electric mobility, or more precisely autonomous electric mobility on battery-powered vehicles has no future? The answer in the next entry, which I will headline as: "The future of electric mobility (II) Tons or kilograms?"

Until then

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