Thoughts on the Energy (and Carbon) Saving Potential for Personal Mobility

How to deal with your car problems?


Peter Wurmsdobler

3 years ago | 13 min read

This story is about the energy and carbon saving potential in personal mobility, not as a scientific piece of work but merely as a collection of thoughts about what I, as an individual, or my family, could do given our mobility requirements. Despite calls that such contributions (or savings actually) are futile, I do believe that an individual can contribute to an incremental change in global behaviour in the same way as an individual vote counts in a democratic system to trigger a direction change of a larger community following complex system and market dynamics. In this sense, the article also touches on what local or national governments could do to support these efforts creating a virtuous cycle.

There are plenty of publications containing statistics on energy usage and carbon dioxide emissions, and most importantly, advice on the potential of reducing energy expenditure and carbon footprint in general and for transport in particular. My favourite book is “Renewable Energy — Without the Hot Air” by the late David MacKay; its data may be a bit out dated these days but its approach and message remain nevertheless quite relevant. Other easily accessible sources are The Burning Question, How Bad are Bananas and There is no Plant B by Mike Berners-Lee. Depending on the statistics used, transport accounts for a third of the global energy consumption, of which a portion is used for personal mobility.

Of course the saving potential depends on the mobility requirements themselves; since this is a personal account, I will only look into a few cases relevant for me or my family in the city we live in, e.g. commute to work, grocery shopping, family outing, etc. For every mobility case the decision sequence in the diagram above ought to be exercised with the mobility options in increasing energy expenditure: none, feet, bicycle, buses, trains, car. As a result we obtain on one side of the scale: avoidance is the best saving; on the other side, an individually owned vehicle as the last resort when all more energy efficient alternatives have been exhausted. The objective is to always use the means of transport with the smallest footprint, most likely to be a form of shared transport, leading to the obsolescence of individual car ownership.

The Potential of Zero — the Trivial Solution

In mathematics the zero solution to equations of various sorts is often called the trivial solution. In a similar vain, zero or no mobility, or staying at home, might be a solution, too. As with any energy expenditure, energy you do not spend does not have to be produced, like heat not escaping from a well insulated home does not have to be replaced. Therefore, whenever I think that I need to go to somewhere, I ought to ask myself whether this mobility request should be rejected. Perhaps we should not get in the car at the drop of a hat and drive off to do something that could be postponed and coalesced with another activity? Imagine if there was a more visible cost or carbon tag associated with every use of a car fitted with a coin operated meter? Then we would quite often refrain from moving, avoid transport and stay at home.

A compelling reason to use any form of mobility is to get to work, for most people at least. Well, I feel privileged to work for a Cambridge start-up company that embraces many collaborative tools the market has to offer, and also operates across multiple sites in the UK; the physical presence in the office is desired but not always required. Quite a few colleagues choose to work from home on one or two days a week, and some choose to come into the office only occasionally. It is all a matter of available network bandwidth and perceived latency. While the video conferencing tools a couple of years ago were not conducive to productive remote work, the recent bandwidth increase made it possible to share screens, see and hear your peers at a decent resolution with merely noticeable latency.

In general, the saving potential depends a bit on the job at hand and may only apply to a portion of the working population. Given modern collaborative tools and high speed networks these days, however, I think that there is quite some energy saving potential in remote work. The savings would be offset by the embodied energy in all network and other communications equipment as well as potential energy expenditure the heat/cool the home (only if it is not well insulated). If a portion of the country’s workforce can work remotely for a portion of the time, the theoretical gain is the product of both factors which may well be in the order of 10% or more. A reduction worth having. It needs, however, a significant investment in network infrastructure, but I reckon the net gain is positive.

Take a Walk on the Side-Walk, not

Many years ago I went to College Station, TX, for a conference. After checking in at a hotel, I asked the lady at the reception: “What is the best way to walk to the town centre and would you have a map, please?” As European I had assumed that a) every town has a historic centre, and b) you can get there on foot. The response was a surprised: “You cannot walk there, it is too dangerous and too far”. When I insisted that I would want to walk, because it is only a mile or so away, the lady gave me her phone number adding kindly, “if you are in trouble, call me and I will pick you up”. Shortly after I realised what she meant. There are no side-walks, the city was built with individually owned cars in mind and I had to walk next to wide multi-lane roads. Drivers must have wondered what idiot that must be.

Later, when working in Charlotte, NC, I realised that the infrastructure available and the premises of a society are related; it felt like some sort of small city centre made up of a few shiny sky scrapers in the middle as a hub, with many shopping malls, industrial estates and sub-urban areas as satellites around. A society built on the premise of individual car ownership to realise personal mobility constructs industrial/commercial estates for producing goods and earning money, shopping malls for buying goods and spending money, housing estates for dwelling and consuming goods, and a road network of between all of them; vice versa this infrastructure re-enforces the aforementioned premise. Such a society does not cater for pedestrians nor provide side-walks.

Perhaps it is time to think about alternatives and, among other premises of the consumer society, letting individual car-ownership go. It is ecologically not viable; there are even not enough resources in the world to allow all current vehicles to be replaced with electric equivalents. Consequently, alternative town planning is needed that makes individual car ownership obsolete by bringing the places of life such as houses, schools, offices, etc closer together, all in walk-able distance. A recent talk on Art in Real Life: Architecture and Public Space at the Tate Modern presented alternative concepts. For example, having more but smaller convenience stores well distributed in an area, in combination with delivery services for larger or repetitive grocery shopping? And I would say, as long as these kind of mobility targets are within half a mile or perhaps one kilometre away, walking should be the first means of transport taken into consideration; I really ought to heed my own advice. Beyond that, perhaps the bike as the next option.

I Want to Ride my Bicycle

There are many occasions when my family or myself need to go for a short distance, e.g. to go to the cinema as a family, or perhaps take my son to some classes one or two miles away. In many of these cases we ought to take the bicycle. Alas, quite often we don’t and take the car. Why is that? While I am not worried myself to cycle on busy roads as an adult, it is simply not safe to do so with a child in the city of Cambridge, UK. There are not enough cycle lanes, and sometimes even worse, there are some for a short stretch only to end all of a sudden. Among other collections, there used to be one in the Guardian, the Readers’ worst cycle lanes. Over the past decade the city did invest in a better cycle path network, but I think the critical mass has not been reached to start a virtuous cycle that makes the bicycle the choice number one for urban mobility.

As many other city dwellers, I need to get to work. In my case, I happen to work in Cambridge, UK, and I happen to live at a distance to work which takes 12 minutes to bridge on a comfortable bicycle ride. There is not much energy to be saved as cycling is quite energy efficient, apart from the embodied energy in the bicycle which I have had for 10 years and intend to keep for a long time, unless it gets stolen. And cycling to work spares me a gym membership, too, as I get my daily exercise for free, with little additional energy spent through my physical work. In fact, I would be prepared, as I have done in the past, to accept up to 30 minutes bike ride one way; at a comfortable 20km/h his would give me a 10km radius which already covers quite a surface, nearly all of Cambridge. If I lived farther away, however, what would my options be? Perhaps take an e-bike or other forms of micro-mobility which would extend my range to perhaps 20 kilometers or more. If I lived even farther away or the weather was really terrible, what would my options be? Perhaps take a bus?

On the Buses

When I first started work in Cambridge, I had to take the bus from the Science Park to the Railway station because I did not have a bicycle yet. At the bus stop a sign said “a bus every 10 minutes”. What I realised is that this might well be true for the mean value; but the sign did not mention the standard deviation which was more about one hour. So quite often I waited for a long time only to see 3 buses arrive in a row. As I did not have any other means of locomotion at the time I had to put up with it. This experience made me think, how come that in a city of smart people there is no smart transport network?

These days, I do have a bicycle and I do use it for most journeys, but I also own a car. When we go to town as a family we still take the car; I feel guilty but I can explain. Taking a bus adds time to the journey both due to the unpredictable and quite large worst case waiting period for a bus to arrive. In addition, taking the bus as a family is prohibitively expensive, such that it is cheaper to take the car and pay for quite a few hours hour parking in town. This should not be an invitation to further increase the parking fees. Rather, it is a sign that public transport as a shared and energy efficient mode of mobility does not work. Due to the aforementioned factors, a negative feedback loop is in operation: more cars result in buses being stuck, buses become a less attractive mode of transport, people not using buses, they in turn being less available and more expensive, people taking their cars…

As a Continental European, the whole problem seems to be related to belief that public transport should be a business which to me is a contradiction in terms. A public service cannot be a business that creates revenue for its shareholders; it is a service for all stakeholders of society. It is true, it does have a cost, it necessitates a significant investment, but it also produces returns in many forms, monetary and non-monetary. For example, the city of Vienna, Austria, affords an excellent public transport service for only 1 Euro a day per person. This is certainly one contributing factor to Vienna being placed in the top ranks for quality of life in global surveys.

As for Cambridge, if public transport was seen as a public service, a city of smart people could conceive an alternative that actually does work as a service. For instance, given that Cambridge has a medieval city centre, it does not make sense to use large double decker buses, all trying to run in convoluted ways through the city. Rather I could imagine a network of smaller, electric buses running in a denser, adaptive network, at much higher frequency, not at a fixed rate, but an adaptive frequency which is fed by a real-time customer requests, information feeds from CCTV, traffic model predictions, you name it. If as a customer I can lodge my request in advance and expect that a small bus will be at the bus stop, the mean waiting time would be much smaller. That combined with attractive prices would result in a virtuous circle: uptake in usage, fewer cars, buses getting through, etc.

A critic might say that this is not affordable, think of the capital expenditure and operating cost of a larger fleet of smaller buses with more drivers on the pay roll (In due course most of these buses may well be autonomous). I haven’t done the numbers, and I am sure they are large. But think of the benefits to society, to the quality of life, the long term returns which are difficult to quantify, and last but not least, a decrease in car-miles and consequently a reduction in energy expenditure and carbon emissions. I am sure an economist could come up with a business case with the desired result, either way actually. The result desired depends on the political will.

Long distance journeys

Once you go beyond a city on long distance journeys taking the bike or a bus is not really an option. Trains would be an excellent means of shared transport as the amount of energy needed per passenger mile is very small. However, again I have to admit, that we as a family in the UK tend to take the car. Why is that again? Well, taking the train as a family is simply financially not very attractive. I wonder, if the cost of any means of transport reflects the cost of the energy to build and run that means of transport, why does train transport not work out to be significantly cheaper, or conversely using an individually owned car more expensive? You would think that the transport costs are commensurate with the energy costs involved in building and running the system, i.e. train & tracks versus cars & roads?

It is perhaps a very contentious topic that has been covered by many news papers in the past; just google “fossil fuel subsidies”. Markets have always been distorted by subsidies which were politically motivated, with some vested interests where those who make the policies are those who benefit. The problem is exacerbated by the belief that a national infrastructure that ought to serve the nation is deemed to be run as business to serve shareholders; to me national infrastructure should be considered as a service that constitutes the backbone of said nation and needs to produce value for all stakeholders. I do admit that this is my personal position influenced by my upbringing in a country that used to have and still has excellent public transport service, Austria. If, in an ideal world, there were no market failures and most environmental externalities converted to costs, the transport services should converge to the means with the least energy and carbon footprint. But alas, there are no economies without market failures; this leads me to conclude that train infrastructure ought to be in public hand.

Night on Earth: Taxis

There is not too much to be said here. If where you need to go is too far to walk, to cycle and there is no bus, or there are other circumstance that require you not to share a means of transport, there is always a taxi service. Friends of our neighbours once won a car, but sold it immediately and put the money in a bank account as taxi money. When they are not walking, cycling or taking the train, they use that account to pay for a taxi; and they have been doing it for a long time. Provided that you walk or cycle where you can, and provided that there was a decent public transport network, I guess doing the numbers would quickly reveal that owning and running a car is more expensive than taking a taxi on all remaining occasions. And if it doesn’t?

Last Resort: the Personal Car

If you want to save energy and reduce carbon emissions: first, question the need for locomotion and unleash the potential of not using any form of mobility. Second, consider walking or cycling; you can cover quite a lot of ground on a bicycle, e-bike or other form of micro-mobility; if there is a cycling infrastructure problem, talk to your MP or local government representative. Third, Consider using shared forms of transport, i.e. bus, tram, trains, etc. I reckon shared forms of transport offer the biggest gain in energy saving and carbon emissions; if again there is a public transport infrastructure service problem, talk to your MP or local government representative.

A mobility infrastructure embracing the combination of walking and public means of transport should cover most of urban mobility requirements. An individually owned vehicle should then be the last resort when all more energy efficient alternatives have been exhausted. The obsolescence of individual car ownership would free up a lot of resources, space and energy which can only improve the quality of life and the state of the planet. As a consequence it would be possible in the long run to convert many of these shared transport services into autonomous ones running in the freed up but dedicated space.

Ceterum censeo: under no circumstances succumb to buying an SUV.


Created by

Peter Wurmsdobler

Contributes to the technological foundations for the self-driving revolution at Five, UK. Interested in sustainable economies and renewable energy.







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