Energy Efficiency in Transporation

According to the United States Environmental Protection Agency (EPA), transportation accounts for a whopping 28% of greenhouse gas emissions in the United States and 90% of that is petroleum based as of 2018. I live in an urban area, so I like to think I am doing my part by doing things like taking the train or bus and cycling and walking to many of the places I go. Before, I never really looked into how much more efficient it is, so I decided to look into it. For simplification, I will use two terms to primarily get my point across: miles per gallon equivalent (I’ll be using US gallons, which are roughly 3.78 litres) and kcal (what most Americans typically just call “Calories”) per kilometre travelled. I’ll express them as mpge (or mpg when appropriate) and kcal/km. For multi-passenger vehicles (like buses, trains, and planes), there’ll be an alternate measurement that shows what it uses per person. I’ll go through each and talk about the energy usage of each. Most of these will end up being a rough estimate to give a range.

Energy in Gasoline

So, a typical US gallon of gasoline contains roughly 31000 kcal (Calories). For comparison’s sake, that is roughly:

  • 80 McDoubles
  • 55 boxes of Kraft Mac & Cheese
  • 620 Gogurts
  • 196 cups of cooked oatmeal
  • 41 slices of Costco cheese pizza

I also want to point out that it is unsafe to drink gasoline, so chugging a litre of it won’t give you this energy

Walking

For those who are able to walk, it is a relatively efficient form of movement. Someone walking can expect to burn roughly 60 calories for every kilometre walked. This would translate to roughly 360mpge. I was pretty surprised to find out how efficient walking is as a mode of transportation. Eating a single Oreo cookie wuold have enough energy to walk a kilometre. Walking at various speeds and jogging appear to use roughly the same amount of calories for the same distance travelled. This pattern seems to change once you get into higher speeds and especially when you reach sprinting speeds and more energy per unit of distance travelled.

Bicycling

I enjoy a good bike ride and love using it as a way to get somewhere. Assumign I am leisurely riding and not going for speed records, I usually don’t feel tired at all after cycling. Well, it turns out there’s a reason for that. On flat ground, cycling uses about half the energy of walking and you can expect to use up 30 calories for 1 kilometre travelled (720mpge). This changes a lot when going up steep gradients and decreases by similar amounts when going downhill.

Cycling Abroad

One thing I noticed when I was in the Netherlands was that cycling just seemed to be a way of life. It didn’t seem like it was something someone takes up and ventures to do on the road. You just kinda have a bike and use it to get around. In most of the United States, it would be hard to navigate on a bicycle without knowing exactly what you are doing. Everywhere I went in the Netherlands, you could hop on a bicycle and just figure out how to get there while on the bike. Even in the densest of urban cores in the US, that would be no easy feast as seemingly just about everywhere, you’d be surrounded in a sea of cars and have to struggle to make turns.

Potential Cycling Improvements in the United States

My biggest issue with cycling in the U.S. is that for a novice, very few places feel like they are safe. In the Netherlands, I felt like I could let a 6 year old navigate in the streets without worrying about safety, but even a grown adult in the U.S. would feel unsafe cycling in most parts. Most cities I’ve been to have no cohesiveness or comprehenisvie rules in their planes. Bike lanes seem to appear and disappear and change in type within blocks of one another. The vast majority of roads make it feel as though cycling is an afterthought and any riding a bicycle is left to feel like a second class citizen on the streets. This leads to people using cars to get to places that are short distances away from each other. Distances that in other places, the car would be a last thought. Given some improvements, I think far more people would bike around as a mode of transportation. People at town hall meetings often say that they don’t see people using the cycle lanes available, but that is often because you often can barely use the existing ones without already knowing where you’re going and will often feel endangered by cars on the road. Cars also take up a fair bit of space, so twenty people on bikes passing by doesn’t look like there’s nearly as many people as twenty cars passing by.

I’m getting a little carried away with the improvements that can be made to make cycling better on a page about energy efficiency, but I think I’ll eventurally write something about this.

Car

The automobile is the default mode of getting aroudn in the vast majority of the United States. It is actually a pretty inefficient mode of transportation when only carrying one person, which is often the case.

Petrol/Gasoline Cars

A car that gets 60mpg (Toyota Prius) will use about about 342 calories per kilometre travelled. A Honda CR-V, which gets roughly 30mpg will use about 684 calories per kilometre travelled. This puts the Prius at roughly 5 times less efficient than walking if there’s a single passenger in the car. It even lags behind 5 people walking vs. 5 people packed in the car. It’s even worse when compared to a bicycle at 10 times less efficient for a single passenger and that’s with a Prius. A person on a bicycle compared to a single-passenger CR-V is 23 times less efficient. These aren’t even including the energy required to extract and transport gasoline for individual use, which I will get into in a later segment.

Electric Cars

Electric Cars are often heralded as the saviour for the environment, and while much. much better than gasoline powered cars, they are still less efficient than other forms of transportation. A Nissan Leaf will get you about 160 calories per kilometre (120mpge). With 5 passengers in it, the Leaf actually beats out walking in terms of direct energy usage at 32 calories per kilometre per person but still falls behind cycling. There are inherent inefficiencies in energy production and movement that should be accounted for and I will go over those in a later segment.

Bus

Buses are often large and heavy and their efficiency shows as much.

Diesel

Most fossil fuel buses are powered by diesel and a 15 metre long bus that gets 8mpge with diesel will use about 2800 calories to move one kilometre. This on initial sounds bad, but when you consider that during rush hour, a bus will typically have quite a number of passengers, the numbers look much better. In that bus with 40 seats is at seated capacity, it will use about 70 calories per person to move one kilometre, which is relatively decent. At an additional 40 person standing capacity for that same bus, the per passenger efficiency drops to 35 calories per person per kilometre.

Electric

An electric bus gives you many of the benefits of electric cars’ energy usage improvements, but now in electric bus form. A Proterra Catalyst 40’ E2 bus will use around 1050 calories per kilometre travelled. With its seating capacity of 40, this gives us 26 calories per kilometre travelled. Assuming an additional 40 for standing capacity, that would bring it down to 13 calories per kilometre.

Bus Summary

Buses can be surprisingly efficient when used, but the full capacities are likely just a reflection of expected rush hour capacity. Mid-day and nightly capacity will likely hover around half of seating capacity or even lower, which for the bus still gives us efficiencies over single occupancy vehicles. For the diesel bus, a 5 person occupancy already puts it ahead of a single occupancy CR-V and at 9 people it beats the Prius. For the electric bus, only 2 people are needed for it to beat the energy usage of a single occupancy CR-V and 4 people will have it beat a single occupancy Prius. It would take a capacity of 9 for the electric bus to beat a single occupancy Nissan Leaf.

Rail

When I was younger, I remember seeing CSX (freight train company) commercials stating that they could move one ton of freight 500 miles on a single gallon of fuel. I had a hard time believing that because at the time a Toyota Camry would move about 25 miles on that same amount of fuel.

When I got older, I decided to look into that number and discovered that it was true. The reason why it’s true is that the rail-train combination is extremely efficient at moving things. This is due to the low friction between the train wheels and the rails (metal to metal).

The German Intercity Express high speed trains use roughly 24000 calories per kilometre travelled. Their capacity ranges from 500-850, so if there is a train with 600 passengers, it will use about 40 calories per passenger per kilometre, which is on the extremely low end, and translates to roughly 560mpge per passenger. At full capacity, this number drops to 28.

I couldn’t find any true numbers for intracity transit such as Metros/Subways and Trams, but if I ever do find them, I’ll come back and update this article.

Energy Production

Energy production isn’t free: both in terms of costs and energy transfer. It takes energy to make energy and this is one of the reasons that oil/natural gas fracking is only feasible at certain prices is that it takes a lot of energy to get that energy.

Gasoline

Gasoline requires quite some energy to get from the ground to the station pump. If the petrol pumped into a car in Manitoba, Canada is coming from Saudi Arabia, it had to be:

  • Pumped
  • Refined
  • Shipped to a port city in Canada
  • Transported to Manitoba This entire process means that there was a significant amount of energy put into getting that petrol into that car. Enough that it’s a little misleading to only use the fuel efficiency for measuring greenhouse gas emissions and energy required to move that car.

One extremely good thing about gasoline is that it is extremely energy dense. This is a big part of the reason it has been used for so much. Airplanes will likely continue using fossil fuels for the forseeable future as batteries are far too heavy for a flying object to make good use of them, especially since the weight of the battery remains constant throughout the journey unlike the plane getting lighter after the jet fuel is burned.

Electricity

In the developed world, we are used to flipping a lightswitch and having everything work. Anyone who has spent time in a developing country or parts of developed countries without as built out infrastructure are used to the electric grid failing on them. It takes energy to run the electric grid and with all electricty, there will be loss during the transfer of it. There is only so much that can be kept. This means that for every bit of energy in a smartphone, electric car, or electric bus, there was a bit of energy lost in that transfer.

Human Powered Movement

One of the greatest things about human powered movement like walking and bicycling is that it uses the energy that people already use. Some would bring up the point that you would have to eat more, but the amount more that you eat doesn’t take as much to produce as the amount in electricity or fossil fuels would be. The thing is that everybody ends up consuming energy to live no matter what, so that is a built in and consuming your extra calories in the form of a low emission/energy food source would decrease overall energy usage by quite a bit. If you do any low impact cardio at the gym, being able to bike or walk to your daily activities would build that in a fair bit. Walking to the train and getting to work before was a built in 300 calories for me per day and getting in more built in exercise would ensure that society as a whole can improve cardiovascular health and lungs would likely do better from lower transportation and energy generation related emissions.

Environment

Overall, the built environment prioritizing development that makes it difficult to use means of transportation that would save energy negatively impacts our environment. Within the U.S., the average person living in Manhattan likely uses far less energy on average from having to heat/cool smaller spaces and walking, cycling, and taking the train to get places saves quite a bit of energy and causes less land to have to be buiilt upon to house and serve people. There’s a lot more on the topic of how changing the built environment to prioritize alternate modes of transportation would help the environment that I plan to write about and this page will serve as some of my base material off of which to go.

Wishlist (to find out)

I’m curious about some forms of transportation:

  • Heelys
  • Gliding
  • Piggybacking