Different types of vehicles can impact the environment in different ways.
In this guide, we look at the potential environmental impact of electric, gasoline/petrol, hybrid and hydrogen cars.
Summary – Which Type Of Car Is Best For The Environment?
Firstly, the environmental indicators that are defining ‘best’ have to be identified.
The main eco indicators tracked and measured for vehicles are generally:
– Greenhouse gas emissions
CO2 is the main greenhouse gas that gets measured and tracked
– Air pollutant emissions
There’s different individual air pollutants that can be measured, but carbon monoxide and nitrogen oxide are common pollutants from vehicles
But, there’s other indicators to consider too, such as water footprint, waste footprint, resource depletion, and so on.
Different Stages Of A Car’s Lifecycle
Consideration should also be made for the eco footprint not only at the car use stage (when fuel is burnt, or when electricity is used), but also during manufacturing, sourcing or materials, sending in the car to scrap as waste or for recycling, and so on.
So, different stages of a car’s lifecycle have an impact.
Focus Of This Guide
In this guide, we will mainly be focussing on greenhouse gas emissions and air pollution at the car usage stage, as that’s where about 80% of the environmental impact might occur, according to various reports.
So, Which Type Of Car Is Best For The Environment?
It depends on whether carbon emissions, or air pollutant are being measured as an indicator.
But, in general:
Right now, hybrid cars might be some of the most fuel efficient cars, and be the most eco friendly cars across most cities and towns where they are used.
Electric cars vary in their eco friendliness.
Electric cars can be more eco friendly when they are smaller, and also source their power from an energy grid using more clean energy (such as solar, wind, nuclear, etc).
Electric cars can be less eco friendly when they are larger, and also source their power from an energy grid using more dirty forms of energy (such as fossil fuels)
For hydrogen fuel cell cars, it’s a similar story – it depends what energy sources are used for hydrogen production as to how eco friendly the fuel is.
Some reports say some hydrogen vehicles could emit less, and also use less energy than conventional cars, even on fuel obtained from natural gas as an energy source.
However, cost can be an issue for hydrogen cars right now.
Conventional cars may be less eco friendly than very fuel efficient hybrid cars, and electric cars that source their energy from cleaner energy sources.
But, fuel efficient conventional cars may be more eco friendly than electric cars using dirtier energy sources.
In the future (over time), as energy grids get cleaner, and technology develops, alternate fuel vehicles may continue to get more eco friendly in some ways compared to conventional vehicles.
If power grids can continue to get cleaner, clean energy can become more widely available, and electric car technology can get better and advance further – electric cars might be the most eco friendly option over a longer term 30 + year time frame and beyond (according to some reports)
So, electric cars can also continue to get cleaner after they’ve been bought as their energy source gets cleaner, whereas the emissions of conventional cars are locked in once they are manufactured and bought (as they can’t change along with the energy grid)
According to some reports, conventional internal combustion engine gasoline/petrol cars have decreased emissions and increased fuel efficiency significantly over the last 50 years or so (today’s vehicles emit only about 1% of the pollution than they did in the 1960s), but internal combustion engine cars might have far less potential to continue this trend year on year into the future compared to electric cars (some reports indicate for example that electric cars might be able to improve 10% annually, compared to 1 to 3% for conventional gasoline/petrol cars and hybrids.
Different Variables Ultimately Impact The Environmental Impact Of Different Vehicles
The above comments are only generalisations.
Eco friendliness really differs by key variables such as the:
– Individual city or town (and their energy mix, planning and layout, etc)
– Car type
– Car brand and individual model, along with it’s size
– Features and performance of the car
– Fuel efficiency per mile (or kilometre) of the car
– Emission rates (of GHGs, and individual air pollutants) of individual cars (usually has to be tested and confirmed for each car)
– Operation and use of the car by the individual driver
– Energy source used for fuel or power
– Efficiency of the energy conversion process from energy source to vehicle (one report we reference in guide below suggests that EVs may have good energy conversion, whilst conventional cars and hydrogen fuel cell cars may have worse energy conversion efficiency)
Total Measurements That Impact Transport Overall As A Sector
Apart from assessing the eco footprint of individual cars, the total impact of transport overall as a sector can also be measured and assessed.
Some factors relevant to total impact might include:
– Total number of vehicles in use
– Total amount of miles, or, total distance travelled by all vehicles per year
– Total amount of emissions and air pollution by all vehicles per year (matters perhaps more than efficiency rates and other metrics, because if we consider a carbon budget for example, there’s only a total tonnage of CO2 that can be emitted before a certain level of warming
– Future forecasts of how many cars will be on the road and in use, and what types of cars they will be
– How much power electric cars might be able to get from off grid energy sources such as ‘at home’ solar panels, or even solar panels on car roofs
– Future forecasts of the specific energy mix (particularly the share of renewables vs coal) in a specific city, by what specific year.
How much cleaner a power grid can get is a big variable, along with home much renewable and clean energy is actually available in a specific city.
– Future forecasts for efficiency of electricity production and consumption
Increased efficiency in electricity production and consumption is also a big variable
– Future forecasts like how much more fuel efficient different types of cars can get
Or, how much they can lower their emissions annually up until a certain year i.e. the potential each type of car has to become more eco friendly.
– Technology advancements
Advancements in the different types of energy (renewables, nuclear, and so on)
Other technology advancements forecasts may be taken into account too
Other indirect factors might include:
– Population size and population growth
– City design, development and planning
What Is The Sustainable Emissions & Air Pollutant Limit For Each Vehicle On The Road?
An interesting consideration once the eco impact of each type of vehicle is known, is:
– What is a sustainable limit for greenhouse gas emissions, and also each type of air pollutant, per individual car on the road?
This might set a goal or target for emission rates for vehicles.
Other Types Of Transport Other Than Cars
The eco impact of other types of transport might be considered too, such as trucks, buses, ships, planes, and so on.
We would need to include private transport, but also transport such as freight, commercial road and air transport, and so on in those calculations.
We actually put together a separate guide for the CO2 emissions of different types of transport here.
Environmental Impact Of Transport vs Stationary Power Generation
As another interesting note, some reports say that if we want to address both greenhouse gas emissions and air pollution effectively, we might focus on how we can do so with stationary power generation (at power plants and for electricity production) rather than transport.
Stationary power generation might provide a better and more effective return on investment than the transport sector according to some reports.
[It’s probably far cheaper to try to decrease air pollution and emissions from stationary energy sources like fossil fuel power plants, and to introduce better air pollutant rules and inspections, than try to do the same through hydrogen fuel cell technology in cars]
Other Practical Considerations To Be Taken Into Account With Vehicles
At the bottom of this guide, we outline some practical considerations
Greenhouse Gas Emissions Of Different Types Of Cars
The most fuel efficient hybrids might emit the least emissions right now.
Smaller electric cars (compared to larger sizes or sports versions of electric cars) on a cleaner power grid with a higher share of clean energy (like renewables and nuclear) might be second in terms of emissions
Standard electric cars running on a mostly natural gas power grid might emit less than gasoline/petrol cars
The newest and most fuel efficient gasoline/petrol cars might emit less than electric cars running on a mostly coal power grid
Electric cars (especially larger models) running on a majority coal power grid, might emit the same or more emissions than most other cars right now
What can be observed below, is that different geographic location run different energy sources for their energy grids, which impacts emissions.
In the instance of the US, politico.com mentions that if clean energy doesn’t make up a certain % of electricity production in the future, the impact of emission reductions might be insignificant.
To add some data to this section from different reports …
thehill.com mentions that:
‘[EV’s running on an] all coal electricity grid … would emit more greenhouse gases than today’s gasoline cars.
With natural gas electrics fare much better, and with renewable electricity better yet.
… the average new car (that gets 29 mils per gallon) might emit 400 grams of CO2 per mile, whilst a new electric vehicle using an average US coal, natural gas, nuclear and renewable mix for it’s energy/electricity supply, might emit 300 grams.
A new electric car on mostly renewable energy and nuclear might emit 100 grams (per mile) – a 75% reduction [and that’s including] upstream emissions used in the manufacturing of solar panels, wind turbines and the vehicles themselves.
politico.com mentions that in the future in the US:
[In a scenario where] the [US’] electric generating mix [is] 30% renewable by 2030 … … electric vehicles would only lead to a net greenhouse gas emission reduction of one half of 1% through to 2050 … based on the EIA’s projection of the number of new electric vehicles …
Such a small change will have no impact whatsoever on climate, and thus have no economic benefit.
… carbon dioxide emissions from battery-powered vehicles were about 40 percent lower than for internal combustion engines [in 2018].
The difference was biggest in Britain and the U.K., which have large renewables industries.
In Sweden, which has one of the world’s cleanest grids – the reduction [from average cars to electric cars] could be up to 85% (thehill.com)
When charged from the grid an electric car will result in around half the CO2 emissions per kilometer driven than the average Australian passenger car.
When the greater emissions resulting from its manufacture are taken into account, EVs emit around one-third less per kilometer.
[But, fuel efficient hybrids beat both cars right now over a 10 year average lifespan period, and also a 12 year lifespan]
But, as Australia’s electricity grid gets cleaner, electric cars will [get cleaner, and have an opportunity to beat hybrids, and this is especially the case if hybrids don’t have much more room for improvement]
For a grid charged electric car to beat a current fuel-efficient hybrid on total emissions including manufacture, the amount of CO2 emitted by grid generation would have to fall by almost half.
In their guide, solarquotes.com.au also provides emissions data on vehicles with differing sizes, performance levels, and that run on different energy systems, such as the Nissan Leaf, a Prius, a Tesla S, and a Ferrari 430
This data is based on a typical Australian electricity grid, but obviously is depends specifically on the energy mix of an individual State, or the energy mix of another State if the State imports most of their electricity
Hydrogen Cars Specifically
There’s not as much data on hydrogen cars, but, considering they currently use a methane source like natural gas to produce the hydrogen, it’s unlikely they are as eco friendly as the most fuel efficient hybrids or mostly renewable/clean energy fed electric cars.
However, they may be more eco friendly from an emissions and energy use perspective than a standard internal combustion vehicle according to one report.
How the hydrogen is made is a big variable, because the actual electrolysis process from the fuel cell only produces electricity, heat and water vapor.
The energy conversion efficiency and cost effectiveness of hydrogen cars should also be considered.
One estimation from wikipedia.org on hydrogen cars and GHG emissions:
… per mile traveled, a fuel cell electric vehicle running on compressed gaseous hydrogen produced from natural gas could use about 40% less energy and emit 45% less greenhouse gasses than an internal combustion vehicle
Air Pollution Of Different Types Of Cars
Air pollution, like greenhouse emissions, is significantly impacted by how clean the electricity grid of a city is.
The trends with air pollutants might be the same as they are with GHG emissions too.
Electric cars fed mostly by clean energy might pollute the least, followed by the most fuel efficient hybrids.
Smaller cars might pollute less than larger more fuel intensive cars too.
Internal combustion engine gasoline cars, and electric cars fed mostly off of fossil fuels (in particular coal), might emit more air pollutants.
Hydrogen cars might depend on how the hydrogen is produced i.e. from what base energy source.
Again, if clean energy doesn’t make up a certain % of total electricity production in the future, EVs might have a negative or negligible impact on decreasing air pollution.
New internal combustion engine vehicles are far more cleaner and efficient than old ones.
Today’s vehicles emit only about 1% of the pollution than they did in the 1960s, and new innovations continue to improve those engines’ efficiency and cleanliness.
According to politico.com, EV’s may increase air pollution in the US in the future, depending on the energy mix used:
Some estimations predict adoption of electric vehicles nationwide [in the US] will likely increase air pollution compared with new internal combustion vehicles
Even with large increases in wind and solar generation, the EIA projects that the [US’] electric generating mix will be just 30% renewable by 2030.
… if the EIA’s projected number of electric vehicles were replaced with new internal combustion vehicles, air pollution would actually decrease—and this holds true even if you include the emissions from oil refineries that manufacture gasoline
Are Electric Cars Better Or Worse For The Environment?
Below we’ve paraphrased and outlined some important information from different sources.
You can read the full resource guides by following the resource links in the resources list at the bottom of this guide.
Something that is interesting to note is that some reports indicate that EV’s may in some instances move their emissions footprint from the car usage stage to the electricity generation stage.
Electric cars are better for the environment than traditional gasoline models (bloomberg.com)
[Battery electric vehicles are probably the best technology to pursue and develop over the next few decades if we want to decrease GHG emissions as fast as possible] (theconversation.com)
[EVs are better for the planet, however, some say that EVs] do not really reduce emissions but shift them from the exhaust pipe to the electricity plant (thehill.com)
… there’s debate as to whether electric cars are that much better for GHG emissions and air pollution
EVs can only be as clean as the electrical grid.
In The Future
While technological improvements will see related emissions from combustion engines falling by about 1.9 percent a year through to 2040, pollution from electric vehicles will fall anywhere from 3 percent and 10 percent annually.
That’s largely because of grid decarbonization but also reduced electricity consumption
Managing EV Battery Waste
Something else to consider with EVs in the future is effectively managing EV batteries – reusing them, recovering materials from them, and managing them as waste.
How Might Hybrid Cars Be Better Or Worse For The Environment?
We’ve already discussed this above in referencing the solarquotes.com.au guide.
However, as a summary of the potential sustainability of hybrid cars:
In general, hybrids might provide a more fuel efficient and more eco friendly option to petroleum or diesel only cars in the short term – they generally produce less pollution and greenhouse gases overall usually
Right now, some hybrids may even be more eco friendly than some electric cars – especially the small to medium size hybrids
Electric vehicles (with batteries and electric motors) and possibly hydrogen fuel cell vehicles may become more eco friendly in the long term though as electricity grids get cleaner
Hybrids could be good vehicle to help transition to those vehicle types (until EV technology advances, and until energy mixes become more clean worldwide)
Are Conventional Gasoline/Petrol Cars Better Or Worse For The Environment?
We’ve discussed potential answers to this question elsewhere in this guide.
Are Hydrogen Cars Worse Or Better For The Environment?
Right now – it’s difficult to say
They might be worse for the environment than electric cars, conventional gasoline/petrol cars, and hybrid cars in some ways.
There are two main reasons for this:
1) They rely on mainly natural gas at the moment (which is a fossil fuel) to produce the hydrogen that is used in the car’s fuel cell for energy/fuel
2) Their energy efficiency (because there’s various steps of energy conversion required to deliver energy to the car) is not as good as other cars
However, hydrogen fuel cell vehicles might have a lot of potential in the future to be one of the most eco friendly vehicle types when they can utilise cleaner energy (sun and wind for example) to produce the hydrogen to go in the fuel cells, and when they become more efficient with energy conversion
Something else to note about hydrogen fuel cell cars is that they probably aren’t a very cost effective way right now to reduce air pollution and greenhouse gas emissions, compared to other car types
The environmental and health benefits [of hydrogen vehicles might be better when hydrogen production come from low emission sources, and less from fossil fuels, unless they have] advanced emission controls and carbon sequestration
[afdc.energy.gov goes on to describe how gaseous hydrogen might produce fewer emissions than liquid hydrogen, and also discusses how grid electrolysis might be more sustainable, in addition to how electrolysis efficiency plays a role]
cmu.edu explains: [Hydrogen might have a role in reducing our impact on the environment and with greenhouse gas emissions many years from now, but, right now we have many other options which are more cost-effective]
[You have to] analyze the [full lifecycle of a fuel cell]
[The results are pretty clear…] Fuel cells for cars are only ecologically sound if they are able to run on hydrogen from renewable energy sources.
It doesn’t make any sense to draw electricity from the … power grid, use it to produce hydrogen via hydro-electrolysis and fuel cars with it; the CO2 emissions per kilowatt hour of electricity would be far too high using this method.
At present, industrial hydrogen is predominantly obtained directly from natural gas. However, the fuel cell does not really have any environmental advantages with this kind of fuel, either.
A car with a combustion engine currently … is less harmful for the environment [and electric cars are also more eco friendly than hydrogen cars right now]
Hydrogen Escaping Into Atmosphere
[Some estimates say that] in reality around 10-20% of the hydrogen [in a hydrogen production system] would escape into the atmosphere (physicsworld.com)
Other Considerations For Different Vehicles
Efficiency is an important factor in the efficient use of resources.
Electric vehicles may have some of the best efficiency, with conventional fuel vehicles and hydrogen fuel cell vehicles behind them.
theconversation.com writes about the efficiency of different types of vehicles.
What they mention is that (paraphrased):
Petrol and diesel vehicles can have issues with low energy efficiency, with about 80% of energy lost though ‘through oil extraction, refinement, transport, evaporation, and engine heat’
Battery electric vehicles have lower energy loss than that
Hydrogen fuel cell vehicles have wheel to wheel losses that are almost as high as fossil fuel vehicles
… electricity is needed to generate hydrogen, which the car tanks up on [and] Electricity is then produced from hydrogen again in the car.
This double conversion significantly reduces the efficiency level [of hydrogen fuel cell vehicles]
Practical Considerations For Different Cars
– Economics of cars
Do we subsidize them, and how much do we subsidize them?
What do subsidies include? – There can be a range of subsidies that might be offered for electric cars and alternate energy vehicles, such as rebates, tax credits (on purchasing cost), free use of public charging stations (funded by ratepayers and taxpayers), preferential access to carpool lanes, and so on
Will they end up being affordable for everyone to purchase and maintain (get serviced, repair, replace parts, and so on)?
Will electricity be affordable into the future?
Can we afford additional infrastructure, power capacity, and charging equipment?
– How fast can new car production be scaled?
Some reports say that clean car production can’t scale fast enough to meet carbon budgets, just as one example
– Various alternative energy vehicles have their own practical challenges
For example, electric cars, hybrid cars, and hydrogen fuel cell cars may all have their own set of practical challenges to consider.
– There can be conflicts of interest between groups in favor of electric cars and cleaner energy vehicles, and other groups
Fossil fuel companies perhaps might not being in favor of electric cars and power grids continually getting cleaner, but, on the other side you perhaps have electric car companies who benefit from subsidies, tax breaks, and so on
For example, thehill.com mentions that ‘Oil and gas companies [have put out hit pieces on EVs]’