What’s the greenest car of all?

Published May 7, 2021, 10:11 AM

by Eric R. Tipan

Counting carbon from factory to tailpipe

What makes a vehicle green? For a vehicle to be considered ‘green’ it has to be fuel efficient, pollute less, and most critical of all, be efficiently-made. It’s easy to say but tough to do for machines that were initially conceived in the steam era.

Over the centuries, the hard work and R & D of some automakers has yielded models whose emissions per kilometer is equivalent to the energy consumed streaming one episode of ‘The Falcon and the Winter Soldier.’ Imagine that.

New energy vehicles

As more and more of these ‘new energy vehicles’ (NEV) come in, I’m sure you’d like to know which one is actually the ‘greenest’ of them all: electric, fuel cell, hybrids, or plug-in hybrids.

Finding out which among the four won’t be as easy as looking at what comes out of the tailpipe though. To truly know the environmental impact of each NEV, we have to take into consideration the entire manufacturing process, including the components it uses, and even how the energy it needs is generated.

First, let’s explain what NEVs are. Electric vehicles (EVs) use battery-powered electric motor/s. Fuel cell vehicles (FCVs) generate energy from compressed hydrogen to power the motor and, in certain models, recharge batteries. Hybrids use an internal combustion engine (ICE) that charges battery-powered electric motor/s. Plug-in hybrids have an ICE that can charge battery-powered electric motor/s but with an option to charge from a regular wall outlet.

Global warming potential

The Graduate School of Engineering of Osaka University did a study that details the Global Warming Potential (GWP) of passenger vehicle production, which is composed of greenhouse gas emissions, acidification, eutrophication, and carcinogen emissions.

Pure EVs and FCVs have the highest GWP because making one has a greenhouse gas generation equivalent of 5,791-kg of CO2. Hybrids (and plug-in hybrids) only cost the environment an average of 4,650-kg of CO2 per unit, while conventional vehicles are the lowest at only 4,166-kg of CO2 for each.

While these discrepancies are just between 10% and 28%, it can actually go as high as 70% depending on the size of the vehicle and range.

Internals of a battery electric vehicle.

The electrical drive components contribute some 960-kg of CO2 but it’s really the batteries that do the biggest damage. It gets even worse depending on the type of battery. Nickel metal hydride releases more CO2 compared to lithium-ion because it needs more mass to carry the same energy capacity.

As per the Swedish Environment Institute, “for each kilowatt-hour storage capacity in the battery, emissions of 150 to 200 kilograms of carbon dioxide equivalent are generated.” As an example, producing the Nissan Leaf’s 40 kWh (kilowatt hour) battery puts out 7,000 tons of CO2 emissions while making Tesla’s 100 kWh battery releases 17,500 tons of CO2. This is why it becomes utterly important to only buy an NEV with just the right battery size for your needs.

To put some perspective on that, the International Civil Aviation Organization has calculated that the carbon footprint of a person returning from Stockholm, Sweden to New York, USA by plane has just a little over 600 kilograms of CO2 or just 0.66 tons.

For most high-power battery EVs, it would take them more than 100,000 kilometers to reach lower total emissions (from production to daily use) than a conventional vehicle. And that’s even if you lived in Costa Rica, which produces 95% of its electricity from renewable sources, which means all EVs there are charged with clean energy.

Only as good as the source

Another very important factor to consider when going ‘green’ is knowing how electricity is produced in the country you’re in. Remember, NEVs are only as good for the planet as the electricity used to charge them.

Vehicle and battery production emission numbers will vary depending on the country where they’re made. Countries using zero-carbon nuclear and hydropower will obviously have an eco-friendlier manufacturing process while nations that still depend on oil and coal will see very high CO2 outputs.

The Philippines’ most heavily-used energy source is coal — which is a fossil fuel — and is the world’s largest contributor of greenhouse gas emissions. 42.62 percent of all our electrical energy demand is satisfied by 32 coal-fired power plants across the country.

Despite being strategically positioned in the Pacific Ring of Fire, we haven’t been able to harness geothermal power to its fullest, only getting about 600 GWh (gigawatt hours) more now than we did in 2003. This is just a fraction of our total 106,041 GWh consumption as a country. To make matter worse, 25 more coal-fired plants are set to be put up by 2030 to keep up with domestic energy demand.

This means that charging an EV or plug-in hybrid in the PH can be just as bad (or even worse) than fueling it with gasoline (or diesel) because the electricity drawn from our grid produces 915 grams of CO2 emissions per kWh.

Internals of hydrogen fuel cell vehicle.

If you’re thinking hydrogen is the solution because it is the most abundant element in the world, think again. Over 90 percent of the hydrogen needed to power a vehicle, heat homes, and provide electricity is produced using the steam methane reforming process. After desulfurization, reforming, high-temperature shift, and pressure swing absorption, for every kilo of hydrogen produced, we get 9.3 kilos of CO2 emissions.

By comparison, from well to tank, it only takes 720 grams of CO2 to produce one liter of gasoline, and 640 grams of CO2 to produce one liter of diesel.

Right for the country

Bottomline, being environmentally-friendly isn’t just about how little CO2 your vehicle emits, because the end never justifies the means. Equally important is knowing how much CO2 it took to make it and how much more it will take to keep charging its batteries.

To answer our question, based on all parameters, a hybrid would be the greenest vehicle for the Filipino. It has lower manufacturing emissions and it doesn’t need to be charged using our non-renewable energy sources. It can charge itself by running its petrol engine. That may still produce emissions, but it’s far less over its production and lifetime than an electric vehicle plugged to our grid.