Transport efficiency presentation. 26 January 2017
Over the winter period of 2016-2017 there were a series of presentations about green issues made under the banner of "Ode Aan Gaia" in the art gallery on the top floor of the Vanderveen department store in Assen. In January 2017 I made one of these presentations which was about transport efficiency.
I was drawn to his subject at this time because of the hype which currently surrounds electric vehicles. While electric vehicles are often presented as being a solution to the world's problems, they actually consume just as much energy as non-electric vehicles. The growth in energy usage is the reason why we have a problem with climate change. We can no more drive an electric vehicle with a clean conscience than we can a petrol or diesel powered vehicle.
What's more, all other powered vehicles including public transport have similar emissions per km travelled to private motor vehicles. Even where differences in emissions exist the huge growth in travel has swamped those improvements. The greatest strides in efficiency over the last 60 years have in fact been made by the manufacturers of jet aircraft, which are three times more efficient now than in the 1950s. However the far greater number of flights now results in those aircraft producing 10 times the emissions that were produced by the far smaller number of less efficient aircraft which were flying in the past.
It is similar with all modes. The only way we can reduce our emissions is to use powered modes considerably less and to encourage the use of human-powered transport. Bicycles are the most efficient human-powered vehicles, and the most efficient bicycles are a Dutch product to which the Dutch government has completely failed to offer support.
Below you'll find the slides from that presentation with a summary of the content of the presentation under each slide.
There were also questions and a discussion after the presentation.
Slide 0 - intro
Introductory slide showing a motorway near Assen. While Assen is one of the best cities in the world so far as encouraging cycling as a mode of transport and we can boast about more journeys being made by bike than by car within the city, cars are still used for an enormous number of journeys in the Netherlands as a whole. In fact, cars are used for three quarters of journeys by distance in the Netherlands. The Dutch government encourages car usage by spending more than 10 times as much on infrastructure for motor vehicles as on cycling, and by subsidising driving, especially of electric cars.
A question: "Why not more thought about cycling?"
Unfortunately, even in the Netherlands, and even in cities like Assen which can teach the world many good lessons, progress is not always in a straight line even within cities where there are clashes between motor vehicles and cyclists. This slide shows a particularly unpleasant recent development in the city and the photo drew several comments from audience members who found the experience off-putting or who avoided cycling in that locatione.
The same question, "Why not more thought about cycling?" but with a photo of successful cycling infrastructure on which everyone feels safe.
We have something special in Assen. While there may sometimes be hiccoughs along the way in this country, the Netherlands is rightfully seen as a shining beacon to all other countries. Assen is particularly well placed due to having invested in better than average infrastructure for cycling, even by Dutch standards, for many years. Other countries look to this country and to this city for guidance. The photo shows students and lecturers from Washington University who visited us on a study tour to Assen in 2016.
Unfortunately, in 2017 there are other issues. Cars are seen internationally as "Big Business" and important while cycling is seen as small and unimportant. This is even true in the Netherlands, where cycling receives less than a tenth of the support from government which is given to building roads for cars.
Our self image: We like to think of ourselves as being "green", using low energy light bulbs and using renewable energy to power everything...
Read more about our solar power installation which generates more electricity each year than we use. Note that there are just 16 panels, this being the maximum number we could fit on our roof without some panels being shaded (which reduces their output enormously).
However the reality is something different. The total amount of electricity used by the Dutch population now is more than ten times what it was 50 years ago, long before low energy light bulbs had been invented and before any home had solar panels on the roof. These relatively small positive interventions are not enough to counter the hugely increased number of electrical devices in our homes and at work.
In the Netherlands, around 10% of electricity now comes from renewable sources and around 5% from nuclear power. A quarter of all electricity still comes from burning coal and 60% comes from burning natural gas, which is also a non-renewable fossil fuel energy source and therefore barely better than coal.
We think we're doing well to be "green". The Netherlands now generates more electricity from renewables than was the total consumption in the 1950s. However despite this growth in renewables we've actually gone backwards. Our total usage of electricity has grown so much that even though only a quarter of electricity production in the Netherlands in 2012 was from coal, we now burn four times as much coal to produce electricity as we did in 1950 when all electricity came from coal fueled power stations. Add on the emissions from other sources and it's easy to see that total emissions due to electricity production are now far higher than they were then.
The most practical way to bring down emissions from electricity production is to reduce our electricity consumption.
Have there been efficiency improvements ? Of course. One example is the jet passenger airliner. Boeing marketing from 1958 made the bold claim that a single Boeing 707 passenger jet, an example of the earliest and least efficient passenger jet, could travel many times across the Atlantic to carry as many passengers each year as the Queen Mary ocean liner could while in total burning a tenth as much fuel. While the claim came from the marketing department of Boeing, it was nevertheless absolutely true. Even these first generation jet aircraft were extraordinarily more efficient than passenger ships. What's more, since that time jet airliner technology has moved on and modern airliners are on average 70% more efficient than those early jets. i.e. modern jets can carry three times as many people as older jets while burning the same amount of fuel, or can carry the same number of passengers over the same distance while burning a third of the fuel compared with their predecessors from 1958.
So what's the problem with aircraft ? See the next slide.
Again, the problem is growth. In the time that it took for aircraft efficiency to improve by a factor of three, passsenger numbers and airfreight tonnage have both grown by a factor of approximately 30. The overal result is that our aircraft now produce ten times the emissions now that they did in the 1950s when far smaller numbers of less efficient aircraft were flying.
Just as with electricity, the growth in usage has drowned out all efficiency improvements. The only way to reduce emissions from flying is to fly less.
People have a romantic image of ships. Water transport is often seen as a clean and sustainable alternative to flying, but it should not have that image. There's a reason why ships have enormous chimneys - it's because they produce an enormous amount of pollution.
Modern passenger ships have a more slick appearance, but their weight per passenger has increased enormously. Compare the Queen Mary with the Queen Mary 2. Both carry about the same number of passengers, but the modern ship is longer, wider and taller and weighs twice as much as the old ship. Modern ships offers more luxury to their passengers. For instance, the Queen Mary 2 has far more restaurants and boasts five swimming pools instead of "only" two which were included on the Queen Mary. It also adds a ballroom and also upped the ante by including the first planetarium at sea. While the owners have made some efforts to improve environmental impact over what it might have been, passenger ships simply are not efficient.
While aircraft have been made more efficient over the last 60 years, the same does not apply to passenger ships which remain one of the least efficient modes of transport with amongst the highest emissions. The only way to reduce emissions from passenger ships is to use them less.
Two Minis and a Leaf. The original Morris Mini-Minor from the late 1950s was a very basic car designed for economy while its modern replacement the BMW Mini is far larger, heavier and more powerful. Perhaps a more sensible vehicle to look at as a modern attempt to design an economical car is the Nissan Leaf.
Most people, if asked, will probably make an assumption that the original Mini is inefficient in comparison with newer rivals. There have been quite great improvements in internal combustion engine design since the 1950s, but these improvements have been used not to increase efficiency of cars but to improve comfort, add luxury features and to improve safety. As a result, modern cars are far heavier than older cars. For instance, the original Mini weighed 580 kg, while the lightest of the modern Minis weighs 1050 kg and the Nissan Leaf's use of batteries results in weights varying around 1500 kg.
More weight means that you need more energy to get the vehicle moving and higher rolling resistance once the vehicle is in motion. It also requires more energy from the engine for acceleration and requires heavier braking systems to cope with reducting the speed.
When Autocar magazine tested the original Mini in 1959 they found that it covered 40 miles on a gallon of petrol (64 km on 4.55 l). Burning a litre of petrol results in 2.3 kg of CO2 being released, hence a gallon results in 10.4 kg of CO2 or as it is usually expressed these days, 162.5 g/km.
The modern Mini has a wide ranger of different engines and configurations, some of which manage to improve on the 1959 car but some of which offer rather poorer fuel economy than the 1959 model. While the modern Mini benefits from many years of improvements in engine technology much of this has been squandered on higher performance and more weight. Modern Mini emissions vary between 90 and 180 g/km of CO2, the lower figures being for diesel engined derivatives which are not truly comparable with the original Mini.
The advanced technology of the Nissan Leaf results in only a very slight improvement over the original Mini if that car is powered by the standard Dutch electricity mix. The Leaf requires 12.4 kWh of electricity to cover 64 km, and that results in 155 g/km of CO2 if the car is charged from the Dutch electricity network.
"Clean" electricity is not hypothecated for use only by cars, and if it were then that wouldn't help us because we'd still use the "dirty" electricity somewhere else in our homes or at work.
While aircraft can show genuine improvements in efficiency over the last 60 years, motor cars cannot. There is almost no change at all in how polluting a motor vehicle is per km travelled.
On a full charge, the Nissan Leaf can travel about 160 km. Even "slow" charging requires an enormous amount of electricity. It takes eight hours at 30 A. i.e. 57.6 kWh or roughly equivalent to three days worth of the total output of our domestic solar power installation on one of the best summer days. Charging from a normal electrical outlet is much slower, recharging at a rate of "5 miles per hour". Not many people will put up with waiting 20 hours for a charge before driving 160 km. This represents a huge increase in electricity consumption over even the current levels and it potentially requires a peak consumption after rush-hour which we simply cannot deliver. There is no viable electrical storage technology.
Fast Charging requires a specially installed 500 V 125 A supply. That's roughly equivalent to the output of about 250 normal domestic solar panels at mid-day with full sun in Summer so no normal domestic solar panel array can reduce consumption from the grid by any significant amount while fast charging.
Unfortunately, what has happened is not a trend of reduction of use, but an approximtely 10x increase in the usage of cars. Because CO2 emissions have not improved significantly, a ten-times increase in use means a nearly ten-times increase in emissions due to cars relative to the 1950s, and that would be the case even if we all drove around in the latest electric cars.
For there to have been a reduction in overall emissions relative to the 1950s we must either drive cars which consume a tenth of the energy that they consume now, which is exceedingly unlikely to happen, or to use them ten-times less. Even then we would continue to consume fossil fuels at an unsustainable rate.
There's only one way to reduce CO2 emissions from cars and that's to use them less.
The blue line shows a genuine improvement in safety for modern motor vehicles, at least for the people sitting inside them. However this works against the people outside the cars, who have been made relatively unsafe due to the volume of motor vehicles. That is why separate cycling facilities which improve cyclist safety are more important now than ever.
Your own solar panels ? We have a solar power installation on our roof which generates more electricity each year than our consumption. This is a good thing. The electricity so generated has a far smaller impact on the planet than electricity from most other sources. However look at the sine waves. The blue bars show our generation each month while the red show our consumption. In the summer we produce more electricity than we consume, but that is not the case for the winter. A similar sine wave could also be plotted for daily use with generation only while the sun is shining, but our consumption largely being in the evening after the sun has set when our panels are generating nothing at all.
It is worthwhile to generate electricity in this way, but let's not kid ourselves that the electricity that we generate is the electricity that we use. Everyone wants to take the easy path of claiming to be "green" and claiming that they use only electricity which comes from renewable sources, but that's not the truth. While we generate more electricity than we use, the truth is that our home is still powered mainly by a mixture of coal and natural gas during the evening, just like all Dutch homes. Unless we can admit this we are deceiving ourselves. We are all connected to the same grid.
Note that there is no technology to store electricity on anything even remotely close to the scale that would be required for the whole planet to operate on solar power. The chemicals required to build batteries on that scale simply do not exist in sufficient quantity on our planet. Individuals who think that the electricity that they use all comes from renewable sources are deceiving themselves. Businesses which do the same are also deceiving their customers.
No powered transport is free from emissions of climate changing chemicals, whatever the claims made by their marketing departments. This includes the Dutch railway company who claims that their trains all run on wind power. It's fine that they have signed up for a green tariff, but that doesn't mean their electricity really comes from wind power alone. If the trains were truly powered only by the wind then they could only be run the wind was blowing hard enough to power them, but of course in reality Dutch trains run according to schedules independent of the weather and they do so on same mixture of sources as shown in a previous slide.
Efficiency of different modes of transport. Note that ocean liners already consumed twice as much energy per passenger mile as Concorde, and that pleasure cruisers are even worse than passenger ships.
The graph over-estimates the efficiency of powered modes by always dividing by the maximum passenger capacity. In fact, we know that the average passenger occupancy rate of buses in the UK is around 9 so this figure is off by about a factor of five while the average occupancy of cars is around 1.2 so that figure is out by about a factor of three. Trains also are often full crowded in the peak times but relatively empty at off-peak times. Private cars, motorcycles, trains (especially the more popular faster trains) and buses have very comparable efficiency as seen by how close they are on the vertical axis. Even passenger aircraft have similar consumption per mile.
The graph comes from "Instead of Cars" by Terence Bendixson written in 1977. The outdated units don't matter, only the positions relative to one another on the graph. Since that time, aircraft have become more efficient, cars have remained about the same, and passenger ships have actually become worse because they are now much heavier per passenger due to extra luxuries being onboard. If you've ever tried to run in a swimming pool you'll know that it's hard work even to move at normal walking pace. Imagine how much energy is required to push a hotel, complete with restaurants, cinemas and swimming pools, through the sea at 50 km/h.
Other sources provide very comparable figures. The energy consumption per passenger-mile is almost identical for all powered vehicles, except for taxis which have dramatically higher consumption due to the often travelling with no passengers onboard at all (just the driver travelling to pick up a passenger).
Switching from one transport mode to another but still making the same journey does not reduce emissions. The only way of reducing the energy used, and hence emissions created by an individual is to travel less or to use human-powered machines to make journeys.
Note that the taxi problem of what is otherwise a normal car consuming far more energy per passenger-mile due to making journeys without a passenger is also likely to affect self-driving cars. How does the owner of a self-driving car avoid paying for parking in the centre of the city ? He'll tell the car to drive itself somewhere else, perhaps home, where parking is free of charge and then request the car to return to pick him up and drive him back home. Such cars could also be requested to transport children or goods on one-way journeys without the driver being present which will increase the likelihood of someone using their car in that way, rather than telling a child to transport him or herself by bicycle. For these are related reasons, self-driving cars are likely to dramatically increase the energy consumption of cars..
Back to the Bendixson efficiency graph, but this time highlighting the human powered modes of transport which are the only genuinely zero emission modes. One extra point in red has been added to show the potential of efficient velomobiles driven by human power alone. Why zero emission when we all have to eat ? If you're a human then you still have to eat and to remain healthy you also have to exercise. In practice, human beings who don't walk or cycle tend to eat pretty much the same amount as those who do so there is no saving to be made by not burning off the energy in exercise. The obesity epidemic affects those who are not active more than it affects those who are active.
Of the genuinely green transport modes in the green box, cycling is clearly the winner so far as efficiency is concerned. Not only can a bicycle carry the weight of your luggage for you, but it's easy to travel at four times the speed of walking on a bicycle and by doing so you cover four times the distance in the same time, easily competitive with cars or buses over short distances. This brings many practical every-day journeys within reach without any CO2 emissions due to transport.
The extra efficiency of a streamlined velomobile over a normal bicycle is also obvious to see on this graph. A velomobile can compete very well with motorised vehicles for journey times even over a longer distance than a normal bicycle.
If we want to make transport greener then it is cycling in all its forms should be encouraged above all other modes because it is the most efficient way of using the limited power which we get "for free" from human beings. It is important to make fast cycling attractive in order to maximise the potential of cycling.
The only truly green modes of transport are walking and cycling. While walking is viable only over very short distances, the majority of journeys which people could easily be cycled. The data shows that most journeys are over single digit distances in in London, Toronto and even across the whole of the USA.
So why is it that people don't cycle ? It's mainly due to cycling not being encouraged because cycling on roads simply feels too dangerous. How do we encourage cycling ? Build good quality infrastructure which is so safe to use than even very young children can ride their own bicycles to make their journeys
This is not only good for the planet but also extremely positive for the development of the child.
We should also look at other uses of human power, including making deliveries by bicycle (we set an example by doing this in our own business) and we should encourage the most efficient bicycle designs so that longer journeys can be made at higher speeds while still only using human power.
While all bicycles are amongst the most efficient machines on the planet, the most efficient bicycles in the world are velomobiles. For single-digit distances there is relatively little to gain by using a velomobile, but because these machines enable longer distances to be covered at higher speeds in the same time as a shorter distance can be travelled on a conventional bike, they make human power competitive with CO2 emitting motorized vehicles over longer distances. Velomobiles are a mode of transport which has never enjoyed support from government, even here in the Netherlands. Modern velomobiles are a genuinely Dutch invention which should receive support from the Dutch government. Prominent manufacturers include Alligt, FlevoBike, Inter City Bike, Sinner and Velomobiel.
Given a few sandwiches for power, almost anyone can cycle 160 km in less than eight hours on a normal bicycle. With an efficient bicycle you can do far better than that. Typical journey lengths even for longer regular journeys (work, shops, education etc.) become entirely practical. When cycling, your emissions are 0 g/km of CO2. This is true green clean transport.
1 kWh is approximately as much useful effort as a human can produce per day. With an efficient bicycle you need only about half that energy to travel 160 km (100 miles) in five hours. By comparison, one of the more efficient electric cars, a Nissan Leaf, requires nearly 58 kWh of electricity to travel the same 160 km.
It would take a human being 58 days of hard labour to generate enough electricity to charge a Leaf so that it could be driven 160 km. Of course that's not how we charge such a car, but the electricity consumption is enormous. It takes 20 hours to charge the car from a normal electricity outlet or eight hours from a specially installed 30 A electrical outlet. i.e. by human power alone we can easily beat the speed of an electric vehicle if we include the time spent charging that vehicle.
Use our online cycling speed calculator to work out how far and fast you can cycle with different types of bicycle.
Bicycle shaped pasta ! We've been vegan for more than 20
years. It's not only good for animals and ourselves but
also greatly reduces our impact on the planet.
Optimising a human
A human-being on a bicycle is the most efficient machine on earth. Humans require exercise to be healthy and we have to eat whether or not we exercise. By cycling we make use of the energy from our exercise which is why there is no extra food required to support making normal everyday journeys by human power.
Food does of course have a carbon footprint and we can reduce that to about a third by adopting a vegan diet and removing the inefficiency, wastefullness, and cruelty of meat and dairy production.
This presentation in the form of a blog post
Want to read more ? In September 2017 I wrote a blog post based on this presentation, going into more detail on some issues. Click here to read the blog post.