Electric cars (or electric vehicles, EVs) have different environmental impacts compared to conventional internal combustion engine vehicles (ICEVs). While aspects of their production can induce similar, less or alternative environmental impacts, some models produce little or no tailpipe emissions, and some have the potential to reduce dependence on petroleum and greenhouse gas emissions, depending on the source of electricity used to charge them, and health effects from air pollution. Electric motors are significantly more efficient than internal combustion engines and thus, even accounting for typical power plan efficiencies and distribution losses, less energy is required to operate an EV. Producing batteries for electric cars requires additional resources and energy, so they may have a larger environmental footprint from the production phase. EVs also generate different impacts in their operation and maintenance. EVs are typically heavier and could produce more tire, brake, and road dust, but their regenerative braking could reduce brake particulate pollution. EVs are mechanically simpler, which reduces the use and disposal of engine oil.
Battery electric cars have several environmental benefits over conventional internal combustion engine vehicles (ICEVs), such as:
Plug-in hybrids capture most of these benefits when they are operating in all-electric mode.
Electric cars have some disadvantages, such as:
Like all cars, electric cars give off particulate matter (PM) from road tyre and brake wear, and this contributes to respiratory disease. In the UK alone non-tailpipe PM (from all types of vehicle not just electric) may be responsible for between 7,000 and 8,000 premature deaths a year.
However, lower fueling, operation, and maintenance costs of EVs could induce the rebound effect, thereby releasing more particulates than would be otherwise avoided. In other words, cheaper driving costs serve to encourage more driving, thereby engendering more tire wear. (Other costs, such as congestion and the resulting incentive to pave more land in order to expand the road network, also arise.)
The main advantage that EVs present compared to conventional vehicles is that they can potentially reach zero lifecycle emissions. However, since the electricity currently used to charge electric vehicles across the world does not come from 100% carbon-free sources, today’s EVs still contribute to global greenhouse gas (GHG) emissions. Some studies claim that electric cars emit less greenhouse gas over their lifetime than fossil fuel cars, except possibly in places with a very high proportion of coal-fired electricity, such as Serbia. Others have shown that even in places with diverse generation mixes like PJM (an electricity market in the American mid-Atlantic region), lifecycle GHG emissions from EVs can outweigh those from an equivalent conventional vehicle. The difference in emissions between EVs and ICEVs depends on the distance driven as well as the source of the electricity, because ICEVS typically have a cleaner production stage and electric vehicles typically have a cleaner operational (driving) stage.
In general EVs are cleaner when their electricity comes from renewable energy sources like wind and solar PV, or from low carbon power sources like nuclear energy and hydropower. Electricity generation is also time-sensitive, as certain energy sources are available in higher quantity at different times of the day, even across different seasons in a year. Solar PV electricity is available only during the daytime, and wind generation typically increases with higher wind speeds at night. Large hydropower generation increases in the spring and summer seasons as mountain snow melts. Without large-scale energy storage, nuclear energy is the only main low-carbon power generation that is available at all times. Therefore, charging electric vehicles when there are larger amounts of renewable generation supply to the grid can increase the renewable portion of electrons that power the vehicle and decrease the emissions from driving. Likewise, cleaning up the electric grid by shifting generation from fossil fuel plants to renewable and low-carbon power sources will also make EVs cleaner. This is important since most countries' electricity is generated, at least in part, by burning fossil fuels. The emissions of electrical grids can be expected to improve over time as more low-carbon generation and grid-scale energy storage are deployed. In turn, we can expect that EVs will become cleaner over time.
Another train of thought in measuring the environmental impact of electric vehicles depends on the value of Marginal Emissions Factors (MEFs). Whereas traditionally we attribute to EVs the Average Emissions Factors (AEFs) from all the different types of generation on a grid at a given time, MEFs attribute only the marginal emissions–the emissions from the next unit of power consumed by plugging in an electric vehicle. In most countries, renewable generation never supplies 100% of the electricity demand at a given time. When renewable generation is below total demand, the marginal demand of an EV that plugs into an outlet is almost entirely supplied from fossil generation like coal or natural gas. Attributing the marginal emissions to EVs would greatly increase their environmental impact when compared to average emissions, leading to some disagreement on the true environmental impacts of EVs. Marginal emissions also differ greatly within countries by geographic region, as local energy resource availability and power plants determine the MEFs of charging an EV in that area. Cleaning up the grid by retiring fossil fuel plants and bringing renewable generation online would still make EVs cleaner to operate regardless of whether MEFs or AEFs are used to calculate EV environmental impact. Those who advocate for using the MEFs to calculate the impact of EVs would argue that the power plants on the margin–those plants that increase output to meet next additional unit of demand–are the ones that should be decarbonized first to realize the environmental benefits of a switch to EVs. MEFs also vary by time of day and by season, as electricity demand and resource availability vary.
Researchers in Germany have claimed that, while there is some technical superiority of electric propulsion compared with conventional technology, in many countries the effect of electrification of vehicles' fleet emissions will predominantly be due to regulation rather than technology.[clarification needed]
Many, but not most or all countries are introducing CO
2 average emissions targets across all cars sold by a manufacturer, with financial penalties on manufacturers that fail to meet these targets. Additionally, some governments are introducing Zero Emissions Vehicle (ZEV) mandates, requiring that a certain percentage of new vehicle sales each year be electric or hydrogen fuel cell vehicles. These policies have created an incentive for manufacturers, especially those selling many heavy or high-performance cars, to introduce electric cars and turbocharged cars as a means of reducing average fleet CO
2 emissions. In efforts to lower greenhouse gas emissions from the electric power sector, some states and countries are also introducing clean electricity standards or cap-and-trade systems, which would in turn make operating EVs less emissions-intensive.
Electric cars have several benefits over conventional internal combust engine automobiles, reduction of local air pollution, especially in cities, as they do not emit harmful tailpipe pollutants such as particulates (soot), volatile organic compounds, hydrocarbons, carbon monoxide, ozone, lead, and various oxides of nitrogen. The clean air benefit may only be local because, depending on the source of the electricity used to recharge the batteries, air pollutant emissions may be shifted to the location of the generation plants. This is referred to as the long tailpipe of electric vehicles. The amount of carbon dioxide emitted depends on the emission intensity of the power sources used to charge the vehicle, the efficiency of the said vehicle and the energy wasted in the charging process. For mains electricity the emission intensity varies significantly per country and within a particular country, and on the demand, the availability of renewable sources and the efficiency of the fossil fuel-based generation used at a given time.
Charging a vehicle using renewable energy (e.g., wind power or solar panels) yields very low carbon footprint-only that to produce and install the generation system (see Energy Returned On Energy Invested.) Even on a fossil-fueled grid, it's quite feasible for a household with solar panels to produce enough energy to account for their electric car usage, thus (on average) cancelling out the emissions of charging the vehicle, whether or not the panel directly charges it. Even when using exclusively grid electricity, introducing EVs comes with a major environmental benefits in most (EU) countries, except those relying on old coal fired power plants. So for example the part of electricity, which is produced with renewable energy is (2014) in Norway 99 percent and in Germany 30 percent.
Sales of purely fossil-fuelled cars will end in 2030 and hybrids in 2035, although existing ones will be allowed to remain on some public roads depending on local rules. One estimate in 2020 said that if all fossil-fuelled cars were replaced UK greenhouse gas emissions would fall by 12%. But because UK consumers can select their energy suppliers, the amount of the drop depends on how 'green' their chosen supplier is in providing energy into the grid.
Two thirds of road transport (not just automobiles) particulate matter contamination arise from tire, brake, and road dust, the UK government disclosed in July 2019 and particulate matter pollution was forecast to continue to increase even with electric cars.
|Parts of this engineering (those related to section) need to be updated. Please update this engineering to reflect recent events or newly available information. (December 2020)|
In 2016, the transportation sector overtook the electric power sector as the number one source of annual greenhouse gas emissions in the United States. The US transportation sector was responsible for 1.63 Billion metric tons of carbon dioxide emissions in 2019 alone, with that figure likely to grow with increasing EV sales. Increasing the EV share of the vehicle fleet and cleaning up the power sector are key steps in reducing both the transportation and power sector emissions.
Even within the country, power sector emissions vary by region due to differences in resource availability, state level regulation, and transmission line constraints. In regions where low-carbon energy makes up a large portion of the supply mix–like solar PV in California and large hydropower in the Pacific Northwest–environmental damages from switching to electric vehicles are negative. In fossil-fuel dominant regions like the Midwest and Southeast, the environmental damages from switching to EVs are both large and positive, suggesting that the grid would need to be cleaner in these areas before high EV adoption rates. Studies have shown that at the moment in fossil fuel-heavy regions, it is less environmentally damaging from a lifecycle GHG emissions perspective to drive certain conventional vehicles than it is to drive EVs. When comparing Marginal Emissions Factors, the Western portion of the US grid is the cleanest, followed by ERCOT (Texas), and then the Eastern portion of the US grid. Regardless of region, there are large benefits to electrifying transportation and cleaning up the generation mix across the country.
Power sector emissions have decreased over the past decade, largely due to a shift from coal to natural gas fired power plants across much of the United States. In addition to approximately halving greenhouse gas emissions, burning natural gas instead of coal all but eliminates particulate matter (conventional air pollution). The percentage of renewable generation in the total mix has increased as well, mostly due to new solar and wind installations. Large hydro and nuclear have been stagnant for much of the past decade, and some nuclear reactors are even being decommissioned and taken offline. Of four major greenhouse gases studied, SO2 emissions have shown the largest decline since 2010 while CO2 emissions have shown the least decline. As federal and state governments focus on decreasing GHG emissions with climate policies, these emissions are expected to decline in the coming years, making EVs cleaner along the process.
According to a Union of Concerned Scientists study in 2018:
"Based on data on power plant emissions released in February 2018, driving on electricity is cleaner than gasoline for most drivers in the US. Seventy-five percent of people now live in places where driving on electricity is cleaner than a 50 MPG gasoline car. And based on where people have already bought EVs, electric vehicles now have greenhouse gas emissions equal to an 80 MPG car, much lower than any gasoline-only car available."
Some months in 2019 have seen more than 50% of all generation from renewable sources and is expected to rise further as coal generation is first used only for standby and slowly phased out.
In France, which has many nuclear power plants, CO
2 emissions from electric car use would be about 24 g/km (38.6 g/mi). Because of the stable nuclear production, the timing of charging electric cars has almost no impact on their environmental footprint.
Since Norway and Sweden produce almost its entire electricity with carbon-free sources, CO
2 emissions from driving an electric car are even lower, at about 2 g/km (3.2 g/mi) in Norway and 10 g/km (16.1 g/mi) in Sweden.
Electric cars also have impacts arising from the manufacturing of the vehicle. Since battery packs are heavy, manufacturers work to lighten the rest of the vehicle. As a result, electric car components contain many lightweight materials that require a lot of energy to produce and process, such as aluminium and carbon-fiber-reinforced polymers. Electric motors and batteries add to the energy of electric-car manufacture. There are two kinds of motors used by electric cars: permanent magnet motors (like the one found in the Tesla Model 3), and induction motors (like the one found on the Tesla Model S). Induction motors do not use magnets, but permanent magnet motors do. The magnets found in permanent magnet motors used in electric vehicles contain rare-earth metals which are used to increase the power output of these motors. The mining and processing of metals such as lithium, copper, and nickel requires much energy and it can release toxic compounds. In developing countries with weak legislation and/or enforcement thereof, mineral exploitation can increase risks further. As such, the local population may be exposed to toxic substances through air and groundwater contamination. New battery technologies may be needed to resolve those problems. Li-ion batteries recycling is rarely done in developing and developed countries. In fact, in 2010, only 5% of lithium-ion batteries were actually recycled in the EU.
A 2018 report by ADAC (which looked at vehicles running on various fuels, including gas, diesel, hybrid and electricity) stated that "no powertrain has the best climate balance, and the electric car is not always particularly climate-friendly compared to the internal combustion engine car. At its website, ADAC mentions that a big problem in Germany is the fact that much of the produced electricity comes from coal-fired power plants, and that electric cars are only climate-friendly when equipped with regeneration.
Several reports have found that hybrid electric vehicles, plug-in hybrids and all-electric cars generate more carbon emissions during their production than current conventional vehicles but still have a lower overall carbon footprint over the full life cycle. The initial higher carbon footprint is due mainly to battery production.
In 2017, a report made by IVL Swedish Environmental Research Institute also calculated that the CO
2 emissions of lithium-ion batteries (present in many electric cars today) are in the order of 150–200 kilos of carbon dioxide equivalents per kilowatt-hour battery. Half of the CO
2 emissions (50%) comes from cell manufacturing, whereas mining and refining contributes only a small part of the CO
2 emissions. In practice, emissions in the order of 150–200 kilos of carbon dioxide equivalents per kilowatt-hour means that an electric car with a 100kWh battery will thus have emitted 15–20 tons of carbon dioxide even before the vehicle ignition is turned on. However, Popular Mechanics calculates that even if the 15–20 tons estimate is correct, it would only take 2.4 years of driving for the electric car with a 100kWh battery to recover the greenhouse emissions from the battery manufacturing. Furthermore, two other studies suggest a 100kWh battery would generate about 6-6.4 tons of CO
2 emissions, so significantly less than what the IVL study claims.
However, in December 2019, IVL Swedish Environmental Research Institute updated their 2017 study, reducing their estimate to 61–106 kg CO2-eq per kWh of battery capacity, with potential to go even lower. The new study therefore shows carbon emissions from battery production are 2-3 times less intensive than previously reported, questioning studies that had taken the 2017 figure to prove EV were not better than ICE cars on life-cycle assessments.
Citing the 2019 study:
"The apparent decrease in total GWP [Global Warming Potential] from the 2017 report (150-200kg CO2-eq/kWh battery capacity) to 61-106kg CO2-eq/kWh battery capacity is partly due to that this report includes battery production with nearly fossil free electricity use which is the main reason for the decrease in the lowest value. The lowering of the high value is mainly due to improved efficiency in cell production. Another reason for a decrease is that the emissions from recycling are not included in the new range. They were about 15kg CO2-eq/kWh battery capacity in the 2017 report."
A 2020 study from Eindhoven University of Technology mentioned that the manufacturing emissions of batteries of new electric cars are much smaller than what was assumed in the IVL study (around 75 kg CO2/kwh) and that the lifespan of lithium batteries is also much longer than previously thought (at least 12 years with a mileage of 15000 km annually). As such, they are more ecological than gasoline-powered internal combustion cars. 
Common technology for plug-in hybrids and electric cars is based on the lithium-ion battery and an electric motor which uses rare-earth elements. The demand for lithium and other specific elements (such as neodymium, boron and cobalt) required for the batteries and powertrain is expected to grow significantly due to the future sales increase of plug-in electric vehicles in the mid and long term. While only 7 g (0.25 oz) of lithium carbonate equivalent (LCE) are required in a smartphone and 30 g (1.1 oz) in a tablet computer, electric vehicles and stationary energy storage systems for homes, businesses or industry use much more lithium in their batteries. (As of 2016) a hybrid electric passenger car might use 5 kg (11 lb) of LCE, while one of Tesla's high performance electric cars could use as much as 80 kg (180 lb).
The main deposits of lithium are found in China and throughout the Andes mountain chain in South America. In 2008 Chile was the leading lithium metal producer with almost 30%, followed by China, Argentina , and Australia . Lithium recovered from brine, such as in Nevada and Cornwall, is much more environmentally friendly.
Nearly half the world's known reserves are located in Bolivia, and according to the US Geological Survey, Bolivia's Salar de Uyuni desert has 5.4 million tons of lithium. Other important reserves are located in Chile , China , and Brazil . Since 2006 the Bolivian government have nationalized oil and gas projects and is keeping a tight control over mining its lithium reserves. Already the Japan ese and South Korea n governments, as well as companies from these two countries and France , have offered technical assistance to develop Bolivia's lithium reserves and are seeking to gain access to the lithium resources through a mining and industrialization model suitable to Bolivian interests.
According to a 2011 study conducted at Lawrence Berkeley National Laboratory and the University of California Berkeley, the currently estimated reserve base of lithium should not be a limiting factor for large-scale battery production for electric vehicles, as the study estimated that on the order of 1 billion 40 kWh Li-based batteries (about 10 kg of lithium per car) could be built with current reserves, as estimated by the U.S. Geological Survey. Another 2011 study by researchers from the University of Michigan and Ford Motor Company found that there are sufficient lithium resources to support global demand until 2100, including the lithium required for the potential widespread use of hybrid electric, plug-in hybrid electric and battery electric vehicles. The study estimated global lithium reserves at 39 million tons, and total demand for lithium during the 90-year period analyzed at 12–20 million tons, depending on the scenarios regarding economic growth and recycling rates.
A 2016 study by Bloomberg New Energy Finance (BNEF) found that availability of lithium and other finite materials used in the battery packs will not be a limiting factor for the adoption of electric vehicles. BNEF estimated that battery packs will require less than 1% of the known reserves of lithium, nickel, manganese, and copper through 2030, and 4% of the world's cobalt. After 2030, the study states that new battery chemistries will probably shift to other source materials, making packs lighter, smaller, and cheaper.
According to a 2020 study balancing lithium supply and demand for the rest of the century needs good recycling systems, vehicle-to-grid integration, and lower lithium intensity of transportation.
China has 48% of the world's reserves of rare-earth elements, the United States has 13%, and Russia, Australia, and Canada have significant deposits. Until the 1980s, the U.S. led the world in rare-earth production, but since the mid-1990s China has controlled the world market for these elements. The mines in Bayan Obo near Baotou, Inner Mongolia, are currently the largest source of rare-earth metals and are 80% of China's production. In 2010 China accounted for 97% of the global production of 17 rare-earth elements. Since 2006 the Chinese government has been imposing export quotas reducing supply at a rate of 5% to 10% a year.
Prices of several rare-earth elements increased sharply by mid-2010 as China imposed a 40% export reduction, citing environmental concerns as the reason for the export restrictions. These quotas have been interpreted as an attempt to control the supply of rare-earths. However, the high prices have provided an incentive to begin or reactivate several rare-earth mining projects around the world, including the United States, Australia, Vietnam, and Kazakhstan.
In September 2010, China temporarily blocked all exports of rare-earths to Japan in the midst of a diplomatic dispute between the two countries. These minerals are used in hybrid cars and other products such wind turbines and guided missiles, thereby augmenting the worries about the dependence on Chinese rare-earth elements and the need for geographic diversity of supply. A December 2010 report published by the US DoE found that the American economy vulnerable to rare-earth shortages and estimates that it could take 15 years to overcome dependence on Chinese supplies. China raised export taxes for some rare-earths from 15 to 25%, and also extended taxes to exports of some rare-earth alloys that were not taxed before. The Chinese government also announced further reductions on its export quotas for the first months of 2011, which represent a 35% reduction in tonnage as compared to exports during the first half of 2010.
In order to avoid its dependence on rare-earth minerals, Toyota Motor Corporation announced in January 2011 that it is developing an alternative motor for future hybrid and electric cars that does not need rare-earth materials. Toyota engineers in Japan and the U.S. are developing an induction motor that is lighter and more efficient than the magnet-type motor used in the Prius, which uses two rare-earths in its motor magnets. Other popular hybrids and plug-in electric cars in the market that use these rare-earth elements are the Nissan Leaf, the Chevrolet Volt and Honda Insight. For its second generation RAV4 EV due in 2012, Toyota is using an induction motor supplied by Tesla Motors that does not require rare-earth materials. The Tesla Roadster and the Tesla Model S use a similar motor.
Battery electric vehicles have lower maintenance costs compared to internal combustion vehicles, since electronic systems break down much less often than the mechanical systems in conventional vehicles, and the fewer mechanical systems on board last longer due to the better use of the electric engine. Electric cars do not require oil changes and other routine maintenance checks.
Internal combustion engines are relatively inefficient at converting on-board fuel energy to propulsion as most of the energy is wasted as heat, and the rest while the engine is idling. Electric motors, on the other hand, are more efficient at converting stored energy into driving a vehicle. Electric drive vehicles do not consume energy while at rest or coasting, and modern plug-in cars can capture and reuse as much as one fifth of the energy normally lost during braking through regenerative braking. Typically, conventional gasoline engines effectively use only 15% of the fuel energy content to move the vehicle or to power accessories, and diesel engines can reach on-board efficiencies of 20%, while electric drive vehicles typically have on-board efficiencies of around 80%.