viernes, 2 de diciembre de 2016

The Pasanen Report

(Versión española aquí)

Anyone who has a friend who is in favor of the theory of "vehicular cycling" knows the Pasanen Report, either by its name "The risks of cycling", or as "the report that proves that cycle paths are more dangerous than the carriageway ". The Pasanen Report was written in 2001 by Eero Pasanen, an engineer from the Helsinki Transport Department and a black novels author. Its main thesis is that "it is safer (for cyclists) to ride along carriageway, between cars, than through ours (refers to Helsinki) bi-directional cycle paths". After complaining that "it is hard to imagine that our present two-way cycling network could be rebuilt", Pasanen adds "But in those countries and cities which are just beginning to build their cycling facilities, two-way cycle paths should be avoided in urban street networks."

It is not surprising that supporters of vehicular cycling, which state that cycle paths are more dangerous than the carriageway, and should therefore be discarded, have the Pasanen Report amongst its texts of reference.

But does this report resists a critical analysis? The bulk of his argument is summarized in the attached figure, which compares the cyclist accidents that occurred in different scenarios:

The figure compares the total length of cycling trips on different ways (in blue) with the number of accidents recorded on those ways (in yellow), all in percentages. Apparently, the image shows that the percentage of cycling accidents on the cycle paths along the streets of Helsinki is higher than their share of the total of cycling trips. From where Pasanen deduces that it is more probable to suffer an accident while circulating on a cycle path than while circulating on the carriageway. 

A first methodological criticism to the Pasanen Report and its conclusions is that it is what is referred in social sciences as a "cross-sectional study", that is, a study that compares events taking place simultanesously. However, this is not the most appropriate method for the present purpose. In fact, it can be assumed that bicycle paths were built on the most dangerous avenues, in order to reduce their danger for cyclists. So, we do not know if the supposed higher danger of bicycle paths is simply due to the higher danger of the street itself. It would have been much better to do a "longitudinal study", comparing the accident rate on a particular route before and after building the cycle path. In this way, it would be possible to know with certainty its effect on cycling accident rate, irrespective of uncontrollable factors, such as the danger of the street itself (due, for instance, to a higher or lower traffic density).

But the main criticism refers to the classification of roads and, in particular, to the distinction between "separated" and "not separated" cycle paths. If we consider all the cycle paths together, we see that the total length of the bicycle trips on them is 45 + 26 = 71%, while the total number of accidents is 56 + 8 = 64%, and the comparison is favorable. The "separated" cycle paths account for 26% of the length of the bicycle trips and only for 8% of accidents. Therefore, to "rebuild" the Helsinki cycling network, improving their safety, does not seem as difficult as Pasanen claims: It would suffice to separate the bicycle paths from the carriageway by some physical elements, such as bollards or curbs.

Eero Pasanen also worried in his report about the competition that cycling does to public transport, a competition that is also seasonal in Helsinki (there are many more cyclists in summer than in winter). It is a specific problem of cities with an extreme climate, such as Helsinki. But it has nothing to do with the thesis of the dangerousness of the cycle paths relative to the carriageway, which Pasanen wields as the core of his argument.

The Pasanen Report dates from 2001 and does not seem to have had too much influence on the city's mobility policy. Helsinki is preparing to organize the Velo-city Conference in 2019, and plans to reach 17% cycling mobility by 2025.

jueves, 1 de diciembre de 2016

The future of electric mobility (II) Tonnes or kilograms?

(Spanish version here)

At the beginning of my previous entry on this subject I related an image of the Tour de France in which a motorbiker of the organization records with an infrared camera to some cyclists escaped from the peloton. The motorbiker was looking for possible batteries and electric motors that would help the cyclists to continue their adventure. It is not science fiction: a cyclist develops a power of only a few hundred watts and some hundreds more provided at key moments (on a ramp, for example) can to turn any mediocre cyclist into a superclass at the height of Indurain or Eddy Merckx. The current technology of batteries and electric motors allows to do so and it is not easy to detect, given the small dimensions of the batteries and the motors involved.

Does this mean that the future of electric mobility is the electric doping of cyclists? Of course not. But the above example is relevant because it shows what can be done by applying modern electric technology to a bicycle. Which can lead us to analyze the possible applications of this technology to a conventional bicycle.

Let's first calculate the weight of a lithium battery with an energy density similar to modern Tesla batteries of 0.5 kw-h per kg able to meet the needs of a cyclist riding an electric bicycle at 25 km / h, with an energy consumption of 250 watts, which is the legal limit for a pedelec (1). For an autonomy of 100 km (that would be traveled, at 25 km/h, in 4 hours), we would need an energy of 4x250 = 1,000 w-h = 1 kw-h. So if the energy density is 0.5 kw-h, the Tesla battery would weigh about 2 kg. A very accessible weight for your bicycle transport.

What power would we need to charge the battery? If we want to charge it in a minute (assuming the battery will withstand such a load, which with the current technology is impossible) we would need 60 kw of power, which is much more than any domestic installation can withstand. But if we settle for charging it in an hour, we only need 1 kw of power, of course. That is, we need what any domestic electric heater spends (2). So, while we still can not power our electric bike with electro-gas stations, at least we can say that the electro-stables we need are everywhere: any domestic plug is enough to "graze" our electric bicycle in a reasonable time.

In fact, all the above considerations (and many similar ones) can be made simply from the comparison between the power developed by a car (in the order of tens of thousands of watts) and a bicycle (of the order of hundreds watts), ie 100 times less. What makes thet a "slow" recharge of an electric bicycle can be done in 10 times less time and with a power 10 times less than the "slow" recharge of an electric car.

In addition, the use of the electric bicycle, which we must not forget that it is an assisted pedaling vehicle. Therefore, it requires some physical effort on the part of its driver. Thus, the pedelec need its own driver also doing from time to time stops to replenish forces. That is to say, the need to "graze" (electrically, it is understood) from time to time the electric bicycle, runs in parallel with the own needs to replenish forces of its driver. In a country with a minimally developed electrical infrastructure, both needs can be covered simultaneously almost anywhere (including the user's own home) without special electrical power or parking space needs.

So, we can conclude that although it is practically impossible to replace a conventional gasoline car with an electric one without drastically reducing its performance and/or facing problems of quite improbable solution (see my previous entry), with the electric bicycle just the opposite happens: Replacing a conventional bicycle for an electric bicycle means to significantly increase its performance, without creating problems whose solution entail relevant inconveniences.

So, unlike the electric car, the electric bicycle may already be a commodity of mass consumption. In fact it already is, and it is enough to go outside and take a look to be convinced of it. For those of us who, like me, believe that things do not happen by chance, there is no better confirmation of what has been exposed so far than the undoubted success of the electric bicycle around the world. In Western Europe and the US more than one million electric bicycles a year are sold, but that is nothing compared to China, with a fleet of more than 100 million (sic) electric bicycles and an annual output that exceeds 20 million (3). Conversely, global sales of electric cars are not expected to exceed 500,000 units this year.

Together with pedelecs and e-bikes, electric scooters, segways and "electric wheels" are undergoing a major boost as consumer goods. They all have the common denominator of being low-consumption vehicles (a few hundred watts at most) designed for personal transport. In fact, if we stop to look a little, many of the "electric cars" that we see for our cities and that are counted as such in the statistics, like the Renault Twizy, are actually four-wheel electric mopeds, that can be driven with a moped license.

Personally I feel that the commercial success of all these e-bikes, mini-electric cars, segways, etc., is due more to the little social consideration that physical exercise has as a daily activity in our motorized societies (4) than to its actual advantages. In any case, all these new and successful vehicles, including pedelecs, are personal transport vehicles of low weight and power (compared to a conventional car), low speed, etc. These characteristics completely alienate them from the ideal of the "electric car" (as a substitute for the conventional gasoline car). This allows them to take advantage of all the potential of emerging technologies in the fields of new materials (light and resistant), miniaturized electric motors , batteries, etc. Without facing the insoluble problems (because of their fundamental and not merely technological nature) that are faced when we attempt to replicate, based on electricity, the performances of a conventional gasoline car. In fact, this is what has almost always happened in the history of technological development: new technologies rarely replace old ones, but overlap with them, generating new paradigms.

Thus, these new electric vehicles, light and for personal urban transport, do not replace the conventional car, but rather appear as a new type of mobility, essentially urban. This new electric mobility could replace, improving their performance or even making it possible to generalize (for example in cities with large slopes), the urban mobility by bicycle, wherever it exists. This is something that even advertising, that great indicator of social trends, teaches us, as can be seen in the attached image, which corresponds to an advertisement of the aforementioned Renault Twizy.

This emergent electric mobility, personal and urban, will have positive and negative aspects. It will all depend on how it is run, whether towards a model that tries to replicate the conventional mobility of gasoline cars (mini-electric cars seem to be the paradigm in that sense) or towards a model inspired by active mobility, whose paradigm would be the pedelcs. Europe, partly due to the early pressure of groups such as cycling associations, seems to be heading in the second direction, encouraging pedelcs. Albeit, unfortunately, simultneously promoting the mirage of replacing conventional gasoline cars and buses by their electric counterparts, which get the lion's share of aids and investments.

The irruption of this new electric mobility will also have important repercussions in the regulatory field, similar to the one that had the irruption of gasoline mopeds in Holland in the years 70 and that caused not a few debates. For example, where should segways, e-bikes, or electric scooters should circulate? By the road or by the pedestrian zones? By bicycle paths? These issues are already here and depending on how they were solved reality will move in one direction or another. In principle, the position of cycling associations is that only those gadgets which - like the pedelecs - are an aid to active mobility, but do not replace it - such as e-bikes - can be equated with bicycles and should share the same regulation.

In any case, I am increasingly convinced that the future of autonomous (ie powered by batteries) electric mobility will go in the direction of the development of a new personal mobility of urban scope, whose first babbling we are already seeing. It would be good for us to prepare ourselves for it and at the same time stop pursuing the mirage of replacing our old and polluting gasoline cars with brand-new electric cars with equal benefits.


(1)  According to European legislation, an electric bicycle is an assisted pedaling vehicle (without accelerator: the engine starts when pedaling is detected and stops when it stops) with a maximum power of 250 and a maximum speed of 25 km/h. Above these performances, the vehicle is considered to be an electric motorcycle.

(2) Incidentally, using electricity to warm up (eitherour food or our feets on a stove) is very bad business, as the efficiency of the electrical system is only 1/3, which means that to produce 1 kw-h of thermal energy, we need (and pay) 3 kw-h of primary energy.

(3) This is due, in part, to the fall in sales of mopeds as a result of the restrictions on their circulation that have been imposed due to the increasing pollution of cities. It must be said anyway that most Chinese "electric bicycles" are, in fact, e-bikes or low-power electric mopeds, without pedals and equipped with an accelerator. They are therefore not pedelecs and, therefore, there are not electric bicycles in accordance with European legislation.

(4) Intensely motorized societies maintain a love / hate relationship with physical exercise. On the one hand, as an activity linked to everyday tasks - such as work, daily displacement, etc. - is considered as an indicator of low social status. On the other hand, physical exercise is sacralized as an expiatory ritual of the sedentary way of life that motorization and automation of daily life imposes on us.

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