Okay, let's get this out of the way fast... the outcome of this is going to be pretty obvious, it is pretty damn clear that a bike or an electric bike is just going to be cheaper to run in terms of cost and Carbon emissions compared to even the smallest of small cars. Obviously, there will be situations when one is much more useful than the other... after all, I can't imagine going to do a huge food shop or an IKEA run on a bike.... or even just picking up several kids.... unless you have a cargo bike.

However, this isn't the point of this post... I already knew that the outcome on a relative scale... I just wanted to calculate exactly how big the difference was. Now, this post only takes into account the costs of running the two seperate vehicles and not the upfront costs and maintenance... however, to be honest, seeing as we have a pretty small old car and a fancy new bike... the upfront costs are pretty damn similar and the upkeep costs (repair, maintenance and road taxes) are definitely in the favour of the bike!

Rough Carbon Comparison

For this comparison, I will be using a trip that my wife does quite regularly (three times in the week) that we had originally used as the reason for purchasing the electric bike. She wanted to cycle, but the distance was just a touch on the far side to comfortably do on a regular non-assisted bike. She would arrive tired and exhausted, but with the electric assist, it is no problem. It is a one way trip of around 20 kilometres (if you are American... it is probably about 3254.244315684 inches... or whatever sort of funny ancient measure you use... 2343298.76895037 horse steps or 2347632846.27336 snail-hours).

Car

We have a cute little Peugeot 107... better known as a shopping trolley with an engine. It is more than big enough for our uses (although, our family might start to outgrow it...) and in an urban environment it is more than enough for our short trips... and even the occasional trip to neighbouring European countries.

So, it is quite easy to get information about the carbon output of a car... of course, these are in best condition scenarios with the engine warm and running smoothly... but that's okay, we will take the BEST estimate for the car (it will need the help...). Let us give it around 100 grams of Carbon Dioxide per kilometre.

This gives us around 2000 grams of CO2 for our test trip.

Bike

Our Brickers Brisbane e-bike comes with a 600 Whr (or 0.6 kWhr) battery... it was the middle size of battery that it could take... and is rated for around 80-110 kilometres depending on how you drain it. Of course, that capacity drains over time... if it is anything like my laptop, then it is about 70% capacity after a couple of years (that said, I use more charge cycles on my laptop than the bike).

The bike has a top assist speed of up to 25 kph... however, you can easily push it to 28-30 km with a bit of extra muscle oomph! This does leave it a bit slower than a car... but it just means we allocate a bit more time to travel... sometimes... we don't get stuck in traffic jams!

Source: European Environmental Agency

Unfortunately, The Netherlands has one of the HIGHEST Carbon Dioxide intensities for power generation in Europe... at around 505 grams per kWhr in 2016 (America is on a similar order). Well... that is poop... we are on a more specific "green" energy plan, so our personal calculation would be more rosy for the bike... but in the interests of fair play, we will take the worse country-wide figure.

A single one way trip (the test run!) for the bike drains between 20-25 percent of the battery, so lets say 25%. This would make 150 Whrs, or 0.15 kWhr. Multiplying by the Carbon Dioxide intensity for Dutch power production gives us: 0.15 * 505 = 75 grams.

Comparison

I did this calculation several weeks ago... and since then, I've done it many more times.. well, just because it was SOOOO different! Car at 2000 grams and the bike at 75 grams for the SAME 20 km trip. This is even with figures weighted in favour of the car calculation and making assumptions (perfect running conditions, no emissions whilst stopped...) that were also heavily favourable to the car. I kept thinking that I had made a serious mistake... I was expecting a difference but not that much!

Even if you only burnt coal as a your primary electricity source (roughly 1700 grams per kWhr, rough worst case) for your bike.... you would have 255 grams emission!

There is no comparison to made here. In our particular use case (single person trips with up to three bags of cargo and less than 50 kilometres in radius), the bike is hands down the winner in carbon emission running costs... also in electricity costs vs petrol costs!

Conclusion

So, is an electric bike worth the initial outlay of capital? Well, I guess that depends how much you price your currently externalised environmental costs of your pollution from travelling!

If you consider that your pollution emission should be priced at zero, as it has NO immediate and direct personal cost to you... well, then having an electric bike in addition to a car is probably not a good idea... (unless you count the health costs of driving everywhere rather than doing some additional physical exercise!).

However, if you consider that your pollution emission costs are non-zero and are currently not correctly priced in the economy... then it makes sense to reduce as much as possible your own contribution, both in a future preservation way and also in a reduced future expense sort of way. In that case, having an electric bike as an alternative to the car for single person and relatively short radius trips (in our case, up to 30 kilometres or even 45 kilometres is possible) is a viable solution.... and one that is perhaps better than using public transport and definitely better than a second car!

Of course, this is a multi-faceted problem... this isn't the internet with a single cause and single solution! There is the problem of public transport infrastructure already existing, additional impact due to the construction of an electric bike and associated components (most problematic being the battery, however that is quite interestingly addressed in this Neurologica article). It also depends on your own personal use case and geographic location, maybe an electric bike isn't the right fit... but for most urban areas (and some light non-urban) it really works well (wind and inclines are NO problem at all!).