Time versus energy

Recently there was a lively discussion over on the Rootsradicals mailing list about energy usage and electric bikes. There was debate about whether it takes more energy to run a bike by electric power or leg power. While the debate was all well and good, it sidesteps the bigger picture. Biking in any form, whether by leg power, electric power, or both, is a far more energy efficient endeavor than driving a car. Depending on how it is calculated, riding a bike is equal to getting anywhere from 200 miles per gallon up to over 1,000 MPG. Even the greenest of electric cars aren't going to approach those numbers anytime soon.

But there is a tradeoff using a bike: time versus energy. The reason bikes take so little energy is because they move slowly. They don't suffer big losses to friction (plus, they are lightweight). But riding a bike takes more time - at least to go long distances (for short intra-city trips, biking can actually be faster).

I started thinking about this tradeoff by monitoring the energy usage on my electric bike. I noticed that when I was in a hurry, I would consume almost twice as much power than when I was taking it easy and going more slowly. Now I've made it into kind of a game, to try to keep my energy usage down, I am also forcing myself to slow down and enjoy the ride more.

But this tradeoff is not just present in biking. It is present in nearly everything we do in "modern" society. Here are some examples:

1. The energy usage of various forms of transportation is directly proportional to speed, i.e.:
Planes > cars > trains > bikes.

2. Washing clothes and dishes - it is both faster and more energy intensive to use the washer/dryer than to do it by hand.

3. Food - it is more energy intensive to buy cheap but fast food, than to grow and cook one's own

US society is one of extremes. On the one end we have people who jetset around in a constant aggravated rush of business. On the other extreme there are the Amish, who exemplify slow and low energy lifestyles.

And then there are all the rest of us in the middle. The question is, how much should we trade down our energy use, at the cost of spending more time on our daily activities?

I think the key is reframing that question. I linked to this article before, but I'll link to it again because it is great - it is all about a mom who formerly led the go-go rushed life, and then due to high gas prices, was forced to slow down while becoming a bit less energy intense.

She discovered that there is increased joy in slowing down. Joy in walking the kids to school, or biking to the grocery store. Many people enjoy gardening, but think it takes "too much time".

Maybe many of us have been convinced that we need to keep moving faster and faster to "keep up with the Joneses". But maybe the higher cost of energy will force us all to slow down (except the super rich). And maybe, seeing our neighbors, friends, and co-workers slow down, we won't feel so guilty about it. About taking time for ourselves, for our families, for some hobbies. Some people have already done this. I have no statistics to back this up, but I believe there is a strong grassroots movement of people doing exactly this. People who are fed up with the go-go buy-buy pace of modern life, who have slowed down, dropped out, semi-retired. Those people did it by choice. Maybe the rest of us will be forced to follow, whether we like it or not, by high energy prices.

But I don't want to make it sound like slowing down is just drudgery. I look forward to my daily bike ride to and from work. It is a time of great enjoyment for me (except on the rare occasion I encounter an intentionally obnoxious driver). I get to look around, see the world, breath the air, hear the birds. I get exercise. I listen to music (not earphones - I have a small stereo on my handlebars). Nowadays, when I get in the car for trips around town, I actually get stressed out, whereas the bike is relaxing, just getting into the rythm of the pedals.

It is hard, though, straddling between wanting to conserve energy and wanting to keep up with all the self-imposed time pressures. Recently, after being aghast at our electric bills (definitely NOT from charging the bikes, that is only $0.03-$0.05 per charge), we realized that the dishwasher was consuming a lot of energy. So we started washing dishes by hand (with water heated by solar). This greatly reduces energy consumption. But it also takes more time. Sometimes it is actually enjoyable - just zoning out, focusing on the present moment, and even listening to music. But other times it is just stressful - because it seems like there are many other things that need to get done.

So how to find the balance? Until it is forced on us by high gas costs, I think the key is one step at a time, avoiding extremes. To me, it is all about doing the little things that are both doable and enjoyable. I'm not about to quit working just so I can farm all my own food. But at the same time, riding the bike every day, hanging the clothes out to dry, and little things like that take some time, but also save a lot of energy.

If everyone did it, there would be a huge impact on energy use and carbon dioxide production.

It is a starting point.

Morgan


My daughter on the way home from dance recital on the Xtracycle:

Taking the train

Here I am in Montana near Glacier National Park, riding on one of the more fuel-efficient modes of transportation: the train. While gliding along and looking at the spectacular scenery, I couldn't help but run some numbers through my head about the efficiency of this mode of transit.

This train is carrying 340 +/- 20 people from Chicago to Seattle, Portland, and points between. So due to my compulsive quantitative bent, I had to figure out how many miles per gallon per person this represents.

My estimate of the fuel usage is about 2,000 gallons, plus or minus 1,000. I got that estimate because I found out the Diesel tanks in the engine are 2,500 gallons, and they topped them off once for the trip (but they certainly weren't empty). Since the train travels a total of about 2,000 miles on its journey, this represents approximately 1 gallon per mile (or mile per gallon for those who like it like that!). After I calculated that number, I talked to one of the personnel, and he said that sounded about right for fuel efficiency.

Ok, so let's say we're in the ballpark. In fact, let's imagine that the fuel usage is

twice

what I estimated, just to be safe. If the train uses 2 gallons per mile, the math is easy. That means it gets 170 miles per gallon per passenger.

Let's figure out how else we could get that kind of mileage. A bicycle would do it, but then, pedaling from Chicago to Washington state takes a while - a lot longer than the train. But the cool thing is, I have my bike with me (a folding bike that I can just carry onto the train free of charge). So I can be fuel efficient for the whole trip.

What about a Prius, the gold standard for green transportation? There are only two ways a Prius could match that mileage. One: drive really slow, like 40 miles per hour, so that the Prius gets 50-60 mpg, and carry 3 passengers and their gear. Well, you could do that, but it would take a lot longer than the train, and be a whole lot less comfortable. The other way is to carry more passengers and drive faster. Driving the prius 70 mph, a loaded prius with bikes on the roof gets at best 35 mpg (I owned one and did cross country trips with it). So, it would require carrying 5 passengers and their gear. Nope, no folding bikes are going to fit in that prius.

Well, for an airplane, fuel efficiency is right out the door. I've seen various estimates, but 30 MPG per passenger would be generous.

Why don't more people use the train in the USA? Well, a couple reasons. The first is that people don't know about it. I told several people that my family and I were doing a train trip who had no idea that there was a train to take a trip in. I guess Amtrak doesn't advertise much.

The second is the train is perceived as slow. Well, it is slower than an airplane. But it is a whole lot more comfortable, you get to see a lot of great scenery, and enjoy the travel. But the real issue is that the US has not invested in high-speed rail like many other countries. If we had a 200mph bullet train like Europe and Japan, it would be possible to go from coast to coast within 12 hours. I've seen people on the internet claim that the US is too spread out for useful train service, except population dense centers. I don't buy that. There are many large cities spread out throughout the US. If connected by high speed rail, these corridors would be used. If we just had three major east-west routes (North, middle, south) and 4-5 North-South routes, it would cover a large portion of the US, with busses acting as the local links to these stops.

While I still use airplane travel for many business trips, if practical train service were available to get me to the destination, I would use that. I like the comfort, the scenery, the ability to relax, and the fuel efficiency of the train. I just wish the US would get its act together and start building a real, large-scale rail system that shows we can once again be leaders in transportation and innovation.

Replacing two car trips per week....

Recently I saw a discussion on another website about peak oil. Someone there was deriding the "environmentalists" who want us "to all use bikes". He was saying "that is not a realistic solution". Perhaps there is no single solution to our current mess of oil dependency. Perhaps, however, if we combine solutions, we will make a dent in this thing.

I came up with the charts below to show what would happen if 1/3 of the USA population replaced

only 2 car trips per week

with a bike trip using an electric assist bike. The bottom line is that this would

save

5.5 billion gallons of gas, prevent the release of 59 million tons of CO2 and save $17 billion dollars, keeping them in American's pockets rather than sending them overseas.

Maybe this is just a drop in the bucket, but 5.5 billions of gas is a mighty big drop. Could 100 million Americans bike an average of 30 miles per week? It doesn't seem like a stretch.

Here is the table on which the calculations are based:

Bike-vs-car-trips

(PDF)