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Is Personal Mobility Device eco-friendly?

These few years, Personal Mobility Device (P.M.Ds) like e-scooters, unicycles and hoverboards are become increasingly common on the streets of Singapore. They look set to be the new trend in commuting. Besides the convenience and affordability (compared to years ago, their prices have dropped to the acceptable range) of these P.M.Ds, a lot of sellers are touting these as environmentally friendly. But is it?

Is Personal Mobility Device like e-scooters and e-unicycles really eco-friendly? First, of course, we are comparing it to cars. There is no contest if we are comparing P.M.Ds to bicycles or walking. (and by that, I mean bicycles and walking wins hands-down. Bicycles and walking are definitely more eco-friendly than P.M.Ds. They are just much more tiring as well)

Turns out the answer is….

Read on judge for yourself;

Fact: Personal Mobility Device uses electricity (obviously…) and convert it to motion. The process of conversion is completely clean, producing ZERO emissions. That means that no harmful polluting gases associated with cars’ combustion engines like CO2 or Nitrogen Oxides are emitted. (And yes, this is so even if you use ultra hi-grade petroleum. If you are wondering why this is so, ask in the comments, I’ll be happy to answer) It is worth noting that P.M.D.s (good ones at least) happen to be very silent as well, so no noise pollution as well, which anybody living next to main roads can appreciate.

Also fact: Electricity needs to be produced. If the electricity is produced in power plants by burning fossil fuels, then those harmful polluting gases will also be emitted in the process of generating electricity.

So it turns out that whether P.M.D.s are really eco-friendly or not, depends on how we generate the electricity. And how does Singapore generates its electricity?

According to the Singapore Energy Statistic 2015 report released by EMA ( Energy Market Authority, for full report, go to (in case you’re wondering why I didn’t link it, yes, its because I don’t know how to)

SES2015_Final_website_2mb4 (2)

Basically, it is saying that ~96.2% of the Singapore’s electricity is generated by fossil fuels (Natural gas and Petroleum) and only 3.7% is from clean sources like Solar cells. Now it seems as though Singapore’s generation of electricity would also produce a lot of harmful emissions since its mostly by burning of fossil fuels. But actually it is not, because we can see that 95.5% of it is from Natural Gas and it can be clearly seen that Singapore is moving away from generating electricity from Petroleum Products. This is significant because Natural Gas is cleaner than Petroleum Products. According to (i know it is obviously a natural gas company and there is a chance its figures is biased, but don’t worry, I have checked with its listed sources like EIA, DOE, the figures checks out), burning natural gas produces 28% less CO2, with significant reduction in other pollutants like Nitrogen oxides and Sulfur Dioxide as well. (Carbon Monoxide amounts is slightly higher though)

Basically, even if we account for the carbon emitted in the process of generating that electricity in our power grid, cars still emits 3x to 3000x more CO2 than P.M.D.s (based on calculations on between a medium sized car travelling 20km and a unicycle which use 0.144kWh for 20km.)

Wait… there is another consideration factor, EFFICIENCY.

With cars, you are using a 1500kg vehicle (that’s the weight of an empty average sized car) to move a less than 100kg person around. Whereas, with P.M.D.s, the heaviest model of P.M.D. is less than 15kg.

Now, its slightly troublesome to measure the separate efficiencies of electricity-to-mechanical machines and combustion engines, since they use different units and different models can vary greatly. But it is not a stretch to assume they have the same or similar machine efficiency on average.

This means that it will take ~10 times more energy to transport a person around with a car than with a P.M.D..

So, is P.M.D.s eco-friendly? Or is the author purposely avoiding comparing P.M.D.s with bicycles and walking?