Different types of vehicles can impact the environment in different ways.
In this guide, we look at the potential impact of electric, gasoline/petrol, hybrid and hydrogen cars.
Summary – Which Type Of Car Is Best For The Environment?
To answer this question, first you have to answer what environmental indicator/s you’re defining ‘best’ by.
The main eco measurements tracked for vehicles are:
- greenhouse gas emissions (CO2 in particular)
- and also 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 potential eco impacts of cars such as water footprint, waste footprint, resource depletion, and so on.
You also have to consider that there’s an eco footprint not only at the car use stage (when fuel is burnt, or when electricity is used), but during manufacturing, sourcing or materials, sending in the car to scrap as waste or for recycling, and so on.
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.
As an interesting note – some reports say that if we want to address both greenhouse gas emissions and air pollution effectively, then doing so in stationary power generation (at power plants and for electricity production) might provide a better and more effective return on investment than the transport sector.
So, which type of car is best for the environment? …
According to a few different sets of data, for greenhouse gas emissions:
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 renewables or clean energy (like 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
… these generalizations will change though over time as car technology and electricity grids change worldwide
To add some data to this:
In the US, 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. In Sweden, which has one of the world’s cleanest grids – the reduction could be up to 85% (thehill.com)
In Australia – an electric car emits about half the CO2 emissions per kilometer driven compared to an average passenger car, and this goes to one third less emissions when taking car manufacture into account. Fuel efficient hybrids beat both cars right now over a 10 year period. But, as Australia’s electricity grid gets cleaner, electric cars will probably pull in front over the long term. For this to happen, grid power/electricity emissions have to half from present levels (solarquotes.com.au)
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. 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, like greenhouse emissions, is significantly impacted by how clean the electricity grid of a city is. The trends might be the same 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 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.
According to politico.com, for air pollution:
Some sources indicate that if electricity mixes are only 30% renewable by 2030 in the US, then air pollution would actually be lower if all electric vehicles were replaced by gasoline cars
In this same scenario, electric vehicles would only lead to a net greenhouse gas emission reduction of one half of 1% through to 2050 [a change that is insignificant and will have no impact on the climate]
Eco friendliness really differs by
- individual city
- car type
- car brand/model
- And, other specific factors
We might also separate greenhouse gas emission calculations, and individual air pollutant emission calculations for each type of car.
But, 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 for example in the long term over a 30 + year time frame and beyond.
We might also consider – what is a sustainable limit for greenhouse gas emissions, and also each type of air pollutant, per individual car on the road? We would eventually need to extend that out to other types of transport like 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.
The total amount of emissions and air pollution matters perhaps more than efficiency rates, 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. So, total cars on the road and total distance travelled matters. Population sizes matter here, as well as other macro factors.
Other specific variables and assumptions to consider or be aware of in any calculation might include:
Fuel efficiency per mile (or kilometre) of the car
The brand and model of car (along with it’s size)
Total number of cars on the road now
Total number of miles travelled per day
Emission rates (of GHGs, and individual air pollutants)
Future forecasts of how many cars will be on the road and in use, and what types of cars they will be
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. Increased efficiency in electricity production and consumption is also a big variable, as well as advancements in the different types of energy (renewables, nuclear, and so on)
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. Other technology advancements forecasts may be taken into account too
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
Other notes to consider might be:
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 sources 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)
Electric cars can continue to get cleaner after they’ve been bought as their energy source gets cleaner, whereas gasoline/petrol and hybrid cars are locked in once they are manufactured and bought
The economics of cars has to be taken into account – how heavily do we subsidize them? 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?
On subsidies – there can be a range of subsidies that might be offered for electric cars 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
Electric cars have some future challenges such as new charging infrastructure on highways, improved battery manufacturing and retooling of existing car plants. Also, what do we do in the future with electric car batteries?
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
Electric cars have room for future improvement – in particular with batteries, charging and autonomous driving
Different car types might have different conflicts of interest in terms of the sides putting information out on them – 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
Lastly, we might consider that there’s other ways other than transport to lessen emissions or environmental impact. Cutting consumption rate, or looking for improvements in other sectors such as stationary electricity generation, industry, and buildings and home dwellings may help. Look at things such as population growth and city living/planning may also help.
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 by following the resource link in the resources list at the bottom of this guide.
- Electric cars are better for the environment than traditional gasoline models
- [Cleaner energy grids in the future will reinforce this, and many places except Southeast Asia are starting to green their electricity supply]
- [A good tracking metric of this can be how many coal plants are closing, and the total number of coal plants decreasing]
- … carbon dioxide emissions from battery-powered vehicles were about 40 percent lower than for internal combustion engines last year [in 2018]. The difference was biggest in Britain and the U.K., which have large renewables industries. It still held in China, which is more reliant on coal to make electricity
- … When an internal combustion vehicle rolls off the line its emissions per km are set, but for an EV they keep falling every year as the grid gets cleaner
- 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
- [EVs are better for the planet]
- Oil and gas companies [have put out hit pieces on EVs]
- [Some say EVs] do not really reduce emissions but shift them from the exhaust pipe to the electricity plant.
- With a theoretical all coal electricity grid, [EVs] 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 U.S. car that gets 29 miles per gallon has total emissions of about 400 grams of carbon dioxide per mile …
- Today an electric vehicle using an average mix of U.S. power generation sources — coal, natural gas, nuclear and renewables — emits roughly 300 grams per mile, or 25 percent less. With more nuclear or renewable carbon free electricity, net emissions can fall to 100 grams per mile or less — and that’s including upstream emissions used in the manufacturing of solar panels, wind turbines and the vehicles themselves. This would mean cutting emissions from ground transportation by 75 percent.
- On some of the world’s cleanest grids, such as Sweden, a full transition to electric vehicles could reduce these emissions by up to 85 percent.
- Future challenges for electric cars are new charging infrastructure on highways, battery manufacturing and retooling of existing car plants
- Electrification … is starting to influence aviation as well …
- Technology development underway on improved batteries and autonomous vehicles will make future electric vehicles even better, safer, and more efficient. Coupled with increased renewable generation, greenhouse gas and pollutant emissions will decline dramatically.
- There’s subsidies given to electric cars [in some places] … [for the initial purchase of the car, but also for rebates on chargers, and other benefits]
- [Subsidies come from taxes]
- States … have mandates of how many electric cars they want on the roads by a certain year
- But there’s debate as to whether electric cars are that much better for GHG emissions and air pollution
- Some estimations predict adoption of electric vehicles nationwide [in the US] will likely increase air pollution compared with new internal combustion vehicles
- 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.
- EVs can only be as clean as the electrical grid. Natural gas is biggest energy source, followed by coal. Even with large increases in wind and solar generation, the EIA projects that the nation’s 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
- As for greenhouse-gas emissions … electric vehicles will reduce them compared to new internal combustion vehicles. But based on the EIA’s projection of the number of new electric vehicles, the net reduction in CO2emissions between 2018 and 2050 would be only about one-half of one percent of total forecast U.S. energy-related carbon emissions. Such a small change will have no impact whatsoever on climate, and thus have no economic benefit.
- [these numbers are through to 2050 though – not beyond]
- It’s worth noting that in states like California, electricity rates are rising – so running a car becomes more expensive. This may only increase as more people need to use electricity infrastructure and power to charge their cars
- It’s mainly wealthy people that can afford EVs. Those who can’t afford them (ratepayers), still have to pay for infrastructure associated with EVs
- Zero emission credits boost the bottom line of EV manufacturers – [worth noting from a conflict of interest stand point]
- 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 at the moment what beats both conventional petrol powered cars and electric vehicles charged from the grid is a fuel-efficient hybrid. … [especially on] total emissions over an average lifespan of 10+ years.
- [a cleaner grid will mean] electric cars will eventually beat hybrids on total emissions
- … [for Conventional internal combustion vehicles,] around 81% of the emissions [come] directly from burning the petrol, 13% from extraction and transportation, and around 6% from refining
- Different conventional internal combustion cars burn a different amount of fuel per kilometre. A small, low performance, petrol powered car can result in less emissions than an electric car such as the Nissan Leaf charged with today’s grid power.
- Hybrid electric vehicle – the most fuel efficient Prius results in only 31% as much CO2 emissions as the average passenger car, which comes to around 107 grams per kilometer driven.
- Electric vehicle – each kilometer driven in the Leaf will result in approximately 164 grams of CO2 emissions when it is charged with grid electricity. This comes to around 2.5 tonnes less CO2 per year than the average petrol burning passenger vehicle.
- … the Tesla S will result in around 182 grams of CO2 emissions per kilometer driven when charged from the grid. So an electric sports car only uses around 11% more energy per kilometer than the Leaf while a conventional sports car like the Ferrari 430 results in about 75% more CO2 emissions per kilometer than the average petrol powered passenger car.
- Per kilometer – hybrids win over electric and conventional cars [per kilometer drive] – … an electric car like the Leaf results in less than half the emissions of an average petrol powered car per kilometer driven when charged from the grid, while a fuel efficient hybrid results in less than one-third.
- Cradle to grave comparison – total cradle-to-grave emissions of Nissan Leaf would be 63% that of the average petrol passenger car with the same lifespan
- Over a 12 year lifespan comparing total CO2 emissions – hybrid wins again, followed by electric, and then conventional
- In the example above … [it was] assumed the grid will remain as dirty as it is now for 12 years but, fortunately, that is not going to be the case. Over the past 10 years the amount of CO2 emitted per kilowatt-hour of grid electricity consumed has fallen by around 11% and this will accelerate as Australia’s aging coal power plants are shut down and replaced with renewable energy
- Battery manufacture will become more cleaner too
- 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. Electric will eventually beat hybrids – but it will take time. Hybrids don’t seem to have much more room for improvement
- Some states have their electricity grid attached to other states (who’s grid can be dirtier)
- [Air pollution and health costs -] … air pollution from cars could be killing more people than car crashes and could be costing Australia over $10 billion a year. If we assume the amount is $10 billion, then with around 1.2 million cars sold in the country each year we could spend $8,000 ensuring each new car sold is electric and the country could still come out ahead overall on cost. Toxic vehicle pollution would be greatly reduced if fuel-efficient hybrids were used, but would not be eliminated.
- So fuel efficient hybrids and electric cars with a solar set up are both good
- It seems to depend on the country
How Might Hybrid Cars Be Better Or Worse For The Environment?
We’ve already discussed this above in the solarquotes.com.au excerpt.
Are Conventional Gasoline/Petrol Cars Better Or Worse For The Environment?
Refer to the summary section above.
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.
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, and, 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
More information on the eco friendliness of hydrogen cars …
- [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 has the edge: The production of conventional cars is less harmful for the environment.
- [Electric cars are also more eco friendly than hydrogen cars right now]
- … electricity is needed to generate hydrogen, which the car tanks up on. Electricity is then produced from hydrogen again in the car. This double conversion significantly reduces the efficiency level.
- [hydrogen cars have] far greater range and can be re-fueled more rapidly [than electric cars, and this is a benefit]
- [we have to consider that fuel cells at the moment use platinum – which is an expensive and increasingly rare metal – alternatives may have to be researched and developed]
- … the fuel cell could be a key future technology – especially when surplus electricity from wind power and solar energy is stored temporarily in the form of hydrogen and thus becomes accessible for household heating or mobility.
- Currently, wind farms are simply switched off when there is too much electricity on the market and the eco-energy goes to waste.
- … tungsten carbide could be an example of a future alternative to the platinum currently required for hydrogen fuel cells
- [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]
- [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]
- [it’s probably even better to introduce hydrogen as a fuel source to ships, trains and large trucks before passenger vehicles like small to medium cars]
- [hydrogen would need] … extensive hydrogen distribution infrastructure which would be required for refueling automobiles. Such an infrastructure could easily cost as much as $5,000 per vehicle or more
- The environmental and health benefits are also seen at the source of hydrogen production if derived from low- or zero-emission sources, such as solar, wind, and nuclear energy and fossil fuels with advanced emission controls and carbon sequestration
- … gaseous hydrogen produces fewer GHGs than liquid hydrogen in most cases
- … gaseous hydrogen produced from grid electrolysis creates 33% fewer GHG emissions
- [but this depends on estimates made about electrolysis efficiency and how clan the energy is that is used to produce hydrogen]
A further summary of the benefits and consideration for hydrogen fuel cells can be read at https://afdc.energy.gov/fuels/hydrogen_benefits.html
TheConversation.com writes about the efficiency of hydrogen cell vehicles and other types of vehicles:
- Low energy efficiency is already a major problem for petrol and diesel vehicles.
- Typically, only 20% of the overall well-to-wheel energy is actually used to power these vehicles. The other 80% is lost through oil extraction, refinement, transport, evaporation, and engine heat.
- … battery electric vehicles have significantly lower energy losses compared to other vehicle technologies.
- Interestingly, however, the well-to-wheel losses of hydrogen fuel cell vehicles were found to be almost as high as fossil fuel vehicles.
- [battery electric will probably always be cheaper to run than hydrogen vehicles because of their higher energy efficiency – potential savings of about $2000 a year]
- [both battery electric and hydrogen] technologies face different challenges in terms of infrastructure, consumer acceptance, grid impacts, technology maturity and reliability, and driving range (the volume needed for sufficient hydrogen compared with the battery energy density for electric vehicles).
- [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]
- [but, both battery electric and hydrogen fuel cell energy efficient technology can be developed over the long term in not only the transport sector, but all sectors.]
Read more at http://theconversation.com/why-battery-powered-vehicles-stack-up-better-than-hydrogen-106844
- [with any hydrogen production system – you have to be careful of any hydrogen that could potentially escape into the atmosphere]
- [some estimates say] in reality around 10-20% of the hydrogen would escape into the atmosphere
A further description of how hydrogen fuel cell technology and cars currently work can be found at https://www.eesi.org/topics/hydrogen-fuel-cells/description