Several articles and studies have been done recently regarding whether electric vehicles (EV’s) are really green. Are gas cars better for the environment? If we could switch to battery electric vehicles, should we?
In reviewing this question, there are three areas that I feel merit review:
- Energy efficiency
- Greenhouse gas (GHG) emissions
- Cost comparison
Each is worth looking at independently. So I’ll look at each in a separate post, this being the second.
GREENHOUSE GASES AND EMISSIONS
So with this second article, we’ll take a look at greenhouse gases.
The internal combustion engine generates a lot of toxic gases. There are definitive links between auto exhaust and asthma as well as cancer. There are also links between high levels of air pollution and heart attacks. Several studies have linked auto exhaust, especially diesel exhaust, to autism, Alzheimer’s and dementia, though I will point out that these studies do not necessarily show a cause and effect relationship. There are a lot of factors that have improved the quality of the exhaust from an internal combustion engine through the years. These include catalytic converters, filters, fuel injection, and other methods. Through the years, auto manufacturers have reduced the amount of poisonous emissions from gas burning engines dramatically. So much so that suicides by carbon monoxide poisoning from running a car in the garage have pretty much been eliminated and the number of accidental deaths from someone running the engine to make the heater work in a snowed-in vehicle is a rare occurrence. Even so, the nature of the internal combustion engine is that hazardous emissions, while they can be reduced, cannot be eliminated.
Electric Vehicles have no emissions at all at the point of operation. There are no gases generated at the point of use. Batteries are sealed and generally have a gel rather than a liquid core, so there are no harmful fumes. Recent breakthroughs in solid-state batteries may eliminate any liquid or out-gassing risk for battery electric vehicles. While there are no emissions generated at the point of use, the source of power used to generate the electricity may generate gasses. The generation of electricity is where an electric vehicle might not be green. On the other hand, the polluting power plant is probably not in your garage, backyard, or neighborhood, so the quality of the air one personally breathes will probably be improved by trading the gas burner for an electric vehicle. The gas burning car’s exhaust will always be a few yards away from your nose when you drive, though the electric power plant is probably miles away.
Each source of energy used to generate electricity has its own total GHG emission levels. To keep the analysis simple, I’ve chosen four sources for power and will compare GHG equivalents, which converts various pollutants into CO2 equivalent factors. First and last are Coal and Solar, which represent the worst and best GHG emissions for commonly used sources of energy. I’ve used grid mix emission numbers for comparison in the second and third positions. The US grid mix is used for the average. Those who live in high coal using states will have an emission level somewhere between the coal and US grid mix level. Since most EVs being driven today are in California, I’ve also included the CA grid mix, which is significantly cleaner than the US grid mix.
EMISSIONS AT POINT OF USE
Unlike the prior article, where it made sense to show the Pump/Plug-to-Wheel (PTW) efficiency, because EVs have zero emissions, there’s no point in putting up a chart comparing PTW of gas to EV vehicles. The gas cars give off toxic gases at the point of use, the EVs don’t.
EMISSIONS IN GENERATION
The chart below shows the well-to-wheels (WTW) emissions using the GREET application to generate our numbers. For the gas cars, I’ve compared a fuel-efficient 35mpg vehicle with a Nissan Leaf and BMW i3, the next comparison is between a luxury sedan/average car (both get the same MPG on average and generate similar emissions in the model) and the Tesla. The last comparison is the most apples to apples comparison, the RAV4 2 wheel drive gas burner vs. the RAV4 EV.
Total GHG emissions for Gas and Electric Vehicles of similar classes with multiple forms of generation
Note: The GHG emissions from solar (.027 g/mile) have been exaggerated in order to display on the chart.
Using grid power and especially solar power, the electric vehicles are significantly less polluting than gas burning vehicles. Only when comparing pure coal generated electricity against gas cars does the balance shift. While it is true that when using coal, the WTW emissions of an EV can be as much as 20% more than a comparable gas burning vehicle, when powered by solar generated electricity the balance shifts in favor of the electric vehicle by more than 10,000 to 1 (3-400 g/mile vs. 0.027 g/mile = 11,000-14,000 to 1).
It can be argued that coal plants are favored when generating marginal electric power. For example, a grid running at night has a single EV plugged in and is forced to generate more electricity. The additional electricity will probably come from a coal plant. Under this marginal analysis, the EV uses coal, which is the dirtier alternative, thus EVs are dirtier. However, marginal analysis only works when there are small quantities of EVs. There were over 119,000 plug-in vehicles sold in the US last year and that is a number large enough that marginal analysis breaks down. With enough EVs on the road, the power companies will need to keep more efficient plants on line or build new plants. The power companies would build more efficient and less polluting power plants to generate the electricity needed to meet the new baseline power requirements caused by the EV usage. Which means it’s fair to compare the EVs using the average grid power mix rather than marginal power.
EMISSIONS IN VEHICLE PRODUCTION
If one stopped the analysis at generation and Operation, EV’s are the clear winners. However, making batteries uses a lot of power and can generate a lot of GHG emissions. It’s pretty difficult to analyze the GHG emissions during production; firm numbers are not available. Even if they were, a change in the supply chain can dramatically impact emissions. The Leaf is built at an energy star compliant factory in an area with higher than average coal mix in the electric grid, is it a cleaner or dirtier factory because of it, or is it a wash? The BMW i3 is built at plants that are primarily powered by low emissions electricity such as solar and hydroelectric. These clean energy sources reduce the GHG emissions for the vehicle production, but how much does that reduce the emissions generated in building the battery? To generate an answer that is reasonable, but is really just an educated guess, I’ll go back to the Argonne National Lab and use an average number based on the weight of the batteries installed. A 2010 report on battery life-cycle costs gives an average of 12.5 kg CO2/kg of battery. Adding the other pollutants generated creating the battery gives a total average GHG CO2 equivalent of 13.0 kg/kg of battery. Multiplying by the weight of the battery gives ~2800 kg GHG for the battery of a Leaf, ~3000 kg for a BMW i3, ~7200 for a Tesla, and ~4900 for a RAV4. These numbers are probably high because EV battery producers have been working to reduce the emission profile of batteries. How much has been reduced is up for debate, so we’ll run with these numbers and just remember that the numbers are probably on the high side.
From the chart, you can see that the GHG emissions from production of a gas car are somewhere between one half to one quarter the amount of GHG emissions from building an electric vehicle. The EV doesn’t look as good from an emissions point now, however, the one year operating GHG emissions of a gas car are almost twice that of the production emissions. What’s the best way to make sense of this information? Perhaps a good way is too look at the point in time where driving an EV equals the same emissions as driving a gas car. Here are several charts comparing emissions over time. The calculations below assume 12,000 miles per year of driving. Please note that the emissions from the operation of a solar vehicle have been exaggerated greatly in order to display something on the chart.
FUEL EFFICIENT CAR vs LEAF and BMW i3
The source of the generation power makes all the difference. EV’s powered by coal start out with an emissions disadvantage and never recover the emissions deficit. EVs that use US grid electricity or CA grid electricity will make up the deficit within 2 years and when solar energy is used to generate the electricity, the deficit is made up for in less than one year. Does the same ratio hold true with the larger EVs?
TESLA AND RAV4 vs GAS CARS
These charts are similar to the more fuel-efficient vehicles above, but the larger battery packs mean a larger emission deficit to overcome and more time required to reach parity with the gas burning vehicle. As with the smaller vehicles, using straight coal to generate electricity means that the EV never recovers from the emissions deficit and actually creates more emissions than the gas car over time. The time to make up the emissions deficit is longer with these larger vehicles, with grid generated power being made up in the third year and even Solar generated power takes until early in the second year of operation to make up the emissions deficit caused by production.
I didn’t add in the replacement of the battery pack into this equation because the packs last 5+ years and I’m only looking at three years on the graph. However, battery packs degrade over time. If one assumes total replacement at 5 years, the EV will still create lower emissions than the gas burner, except in the case of coal generation. Why? Because the gas burner generates more emissions in two years than a battery lasting 5 years will generate. Replacing the battery still ends up giving the EV and edge over the gas burner. You might ask what happens to the old EV battery? Well, even an EV battery that can hold only a 50% charge has a smaller footprint than the lead acid batteries currently used in solar storage. There is a fledgling industry in taking those used batteries and using them for solar storage, which extends the life many more years. Because the batteries can be repurposed, they don’t need to be scrapped or recycled.
Given the average 10-year life of an automobile, the electric vehicle using US grid power for generation will be cleaner than any gas vehicle in its class. When using cleaner grid power such as that of California, the EV fairs even better. If the owner uses solar energy to power the EV, then the EV is dramatically cleaner. A gas car would have to stop driving somewhere before two years in order to generate the same amount of GHG as an electric vehicle powered by solar would in 10 years.
1) At the point of use, the electric vehicle will always have fewer emissions than a gas-burning vehicle. Due to modern zoning regulations, electric power plants are usually not located near residential areas. So, if you want to clean up the air around your home, school or just in the area you’re driving, an electric vehicle will do the trick.
2) When adding in the emissions caused by generation, under most circumstances, the EV is going to generate fewer emissions than a gas-burning vehicle of the same class. The exception is when coal is used to generate electricity. There are a few states, such as Kentucky, where coal is the source of almost all grid electricity generated. However, when solar is used to generate the electricity, the EV is practically a zero emissions vehicle, with less than three one-hundredths of a gram of emissions per mile. If one lives in a state with US grid level emissions or better, such as the Pacific Coast states of California, Oregon, and Washington, the EV is going to be the greener vehicle. If you can add solar to your house and use that to generate electricity for your EV, regardless of the grid power mix, you’ve pretty much eliminated GHG emissions from your driving.
3) Adding in the production emissions give EVs a slightly less rosy picture, but, still the EV looks better over time. The initial emissions deficit the EV has when it rolls off the production line is made up for in as little as one year of driving a gas burner and at most 3 years. Coal generated electricity is the exception to this rule.
Battery Electric Vehicles are generally cleaner than gas burning vehicles of the same class. When powered by renewable energy sources such as solar, they are significantly cleaner. So much so, that driving a gas burning vehicle for more than one year is worse than all the emissions of driving an electric vehicle until the battery needs to be replaced.
The tremendous (over 11,000 to 1 ratio) operational emissions reduction of driving on solar generated power is one of the reasons Sunspeed Enterprises is committed to using zero emissions power sources for our charging network.
This article is courtesy of ChargedEVs, a publication that covers the electric vehicle industry.
Once again, Tesla has come up with an innovation that could be far more significant than is apparent at first glance. Speaking at the latest shareholders’ meeting, Elon Musk said that Tesla has “just introduced” a liquid-cooled cable to the Supercharger system (around 24 minutes into the video below). Liquid cooling allows the cable to be thinner and more flexible while carrying the same amount of current.
The first working model is at the Mountain View Supercharger location.
Okay, it’s easy to see that recharging your car with a thin and supple cord is more convenient than having to wrestle with a big stiff snake of a cable, but what’s the big deal? The possibility of a big deal is implied by Musk’s next remark: “It also has the potential for increased power of the Supercharger long-term.”
The two main drawbacks of current EVs are limited range and long charging times. Even DC fast chargers can take up to half an hour to deliver a full charge. While the range issue is slowly but surely receding, some believe that there may be an unavoidable limit to how quickly a battery can be charged.
For the complete article, please click here.
This article is courtesy of ChargedEVs
Chemists at Canada’s University of Waterloo have described a key mediation pathway that explains why sodium-oxygen batteries are more energy-efficient compared with their lithium-oxygen counterparts.
“Our new understanding brings together a lot of different, disconnected bits of a puzzle that have allowed us to assemble the full picture,” says Professor Linda Nazar. “These findings will change the way we think about non-aqueous metal-oxygen batteries.”
In a paper published in the journal Nature Chemistry, Nazar and her colleagues describe their discovery of the so-called proton phase transfer catalyst. By isolating its role in the battery’s discharge and recharge reactions, they were able to boost the battery’s capacity, and achieve a near-perfect recharge of the cell.
Unlike the traditional solid-state battery design, a metal-oxygen battery uses a gas cathode that combines oxygen with a metal such as sodium or lithium to form a metal oxide, storing electrons in the process. Applying an electric current reverses the reaction and returns the metal to its original form.
To read the full story, please click here.
Several articles and studies have been done recently regarding whether EV’s are really green. Are gas cars better for the environment? If we could switch to battery electric vehicles, should we?
In reviewing this question, there are three areas that I feel merit review:
- Energy efficiency
- Greenhouse gas (GHG) emissions
- Cost comparison
Each is worth looking at independently. So I’ll look at each in a separate post, this being the first.
First Energy efficiency
Is the EV more energy efficient than a gas burning car? The short answer is yes. In any given class, the EV is more energy efficient than a gas burning car.
How did I come to that conclusion and why is it so definitive?
First, electric motors are tremendously more energy efficient than gas engines used for vehicles. About 80% efficient for the electric motor, and 20% efficient for the gas engine. A quick look at some of the EVs on the road shows that the comparison holds with EVs getting about 3-4x the mileage of gas vehicles in the same class. A Tesla gets about 98 MPGe vs 24 mpg for the average luxury sedan. The best EVs get 100-120 mpge vs 30-40 mpg for the best small cars. The BMW i3 is rated 137 mpge city, a full 100 mpg higher than just about any pure gas burning vehicle’s city mileage. The above numbers are EPA ratings, many EV drivers get better mileage by driving in the EV’s economy mode most of the time. My personal average after 36,000 miles in a 2012 Leaf is 4.1 miles/kwh or ~135mpg combined city and highway.
But this phenomenal mileage may be a little misleading. It is based on the power from the plug or pump to the wheels (PTW), the EV gets an advantage because the electricity has to be generated elsewhere. What about the power required to generate the electricity and for the gas vehicle, what about the cost to drill, refine, transport and pump the gas? So how bad can generation costs be?
Electricity can be generated a number of ways. Solar generates electricity directly from light, wind and hydro electric use the motion of wind or water to generate electricity. Nuclear power uses fission to generate heat to run steam turbines. Natural gas, coal, and bio-combustion generators burn fuels to generate motion directly through an engine or to generate heat to run steam turbines. All of these have different energy costs to build and energy costs to operate. However, even fuel burning generators are more efficient when used to generate electricity rather than motive power. This is mainly because the generator can always be run at the most efficient speed for energy generation while a car’s engine speed is based on the desired speed for the vehicle, which may not be most energy efficient.
Gasoline is pumped from ancient reserves of oil in the earth, refined from oil (or coal, for synthetic fuels) into gasoline, and transported to the gas station for use. There is an energy cost for bringing gasoline to your local gas station that can also be measured and taken into account.
Fortunately, someone has already done most of the legwork on the energy cost for generation also known as the Well-to-Pump (WTP) cost. The Argonne National Laboratory has developed a program called GREET – Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation. This model is designed as a well-to-wheels model for many forms of transportation. The model allows users to add their own data for analysis while building in research that is already complete. I’ll be using data generated using this model for my analysis.
In addition to operational and well-to-wheel energy costs, there’s the energy cost to build. The gas burning car uses about half the power to build that an EV does. The energy cost to build a gas car is equal to around 6-8 month’s worth of driving at the average of 12,000 miles per year. For a gas car, this represents about 5% of the total energy used. If the EV burned gas, the energy cost to build would represent 10% of the total energy used, or the EV uses five percent more than the gas car over the average life of an average vehicle driven an average number of miles. For purposes of this analysis, I won’t be adding this energy cost to the comparison. Just keep in mind that the EV starts with an energy deficit that is balanced out after 6-8 months of driving.
Operational Energy usage of Gas and Electric Vehicles of similar classes
The chart above shows that from plug/pump-to-wheel, in each class, the BEV has a much higher energy efficiency than the gas burning car. However, the electricity has to be generated somehow and there are additional energy costs in drilling and transporting the gasoline. So the chart below adds those generation and drilling costs, to provide the well-to-wheel energy costs.
Total Energy usage of Gas and Electric Vehicles of similar classes, with multiple forms of generation
The graphs show that the electric vehicles are more energy efficient, even if powered by coal.
A Leaf or i3 using a Coal generated source saves somewhere between 20-25% of the energy vs. a fuel efficient car. A Tesla using the same source saves about 30% vs an average car while the RAV4 EV saves about 17% vs its gas burning counterpart.
A Leaf or i3 using US Grid generated power saves somewhere between 45% – 50% of the energy vs. a fuel efficient car. A Tesla using the same source saves about 55% vs an average car while the RAV4 EV save about 33% vs its gas burning counterpart.
The real savings starts to show when solar power is used to generate electricity. All of the EVs get 75% or greater fuel efficiency than a gas burning car when renewable solar energy is used to generate electricity.
A note about hybrids
I deliberately am not including hybrids in this analysis. There are may hybrids and electric assist vehicles on the market and some increase fuel efficiency while others use the electric motor to create more power. To generalize, the hybrid will use more energy to build than a gas car and possibly more than even a battery electric vehicle, but possibly less depending on battery size. The fuel efficiency will be between the gas car and the EV. The hybrid trades lower fuel efficiency for higher range.
The EV is more energy efficient than the gas burning vehicle. That applies even if coal is used to generate the electricity. The transition from gas burning vehicles to electric vehicles will reduce energy consumption in the US. Combining that with solar electricity generation will free up tremendous amounts of power for other purposes.
Next, Part 2 – Green House Gas Emissions
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The Nissan Leaf, already a smash hit in the U.S., is poised to become a similar EV sensation in Europe. The Japanese automaker expects to increase European sales of the Leaf electric car by “double-digit” percentage points in 2015 following record sales in 2014.
European executives likely see sales rising by 25 percent, thanks to a reduction in price, government subsidies that make the Leaf an attractive option for buyers, and favorable lease terms. For instance, in France, the Leaf can be leased for 169 euros a month because of generous government incentives.
The Leaf made its European debut five years ago.
The number of car manufacturers that have invested in fuel-cell technology is slim, which isn’t to say that it’s an ill advised play. Toyota, since its inception, has long been at the forefront of automotive innovation, whether by design and styling, or technical savvy. It was the first automaker to give its cars curves, effectively removing the boxy styles of the 1970s and 1980s.
It launched the Prius Hybrid in 1997 when much of the buying public was busy fawning over gas-guzzling SUVs and pick-up trucks. At the time, it was not a popular decision, but Toyota executives knew the Prius would be a money maker in due time. By the early 2000s, the Prius had become a hit, and the rest of the auto industry was playing catch up. Nearly twenty years later, the Prius is the all-time leader in hybrid sales.
So when Toyota turned its attention to a hydrogen-based model as the fuel of the future, it’s only natural to pay attention. Its track record is just too good to ignore. The 2016 Toyota Mirai, which is the Japanese carmaker’s foray into the hydrogen fuel-cell segment, will go on sale in the U.S. later this year with an expected MSRP of $57,700, according to a report from GreenCarReports.com.
As in any game changing product, there are considerable obstacles. One of which is cost of entry. At first, these vehicles will be high-priced, and heavily reliant on federal and state tax credits, both of which are written with sunset provisions so automakers can’t rely on these subsidies forever.
Then there is the expensive question of transportation infrastructure. According to Popular Mechanics, the current cost of a hydrogen filling station is pegged at more than $1 million, neither the government nor the corporate world has any plans for a rapid expansion of the filling network. Meanwhile, the fuel-cells chief competitor, the electric vehicle, has electricity everywhere. The power grid already exists with charging stations popping up at business parks, municipal centers, parking garages, along major freeway routes, and the list goes on and on.
Furthermore, there is a huge public knowledge gap with just how hydrogen can morph itself into a transportation fuel. Just understanding how hydrogen produces electricity to power a 2-ton automobile requires a refresher course in college chemistry.
Certainly Toyota is facing an uphill battle and we at Sunspeed are encouraged to hear about its courage to test an unproven fuel. Imagine the criticism it received when it poured millions into its hybrid technology, only to watch the entire automotive industry snicker at its business plan.
The key learning here is that the transportation of the future will be more about renewable-based energy and less about smog-inducing fossil fuels. A mixture of electric vehicles, hydrogen fuel-cell cars, and plug-in hybrids will help reduce the global carbon footprint, and make up the majority of the vehicle fleets. It won’t happen overnight, but that is the direction we are heading in.
Elon Musk’s biography (Elon Musk: Tesla, SpaceX, & the Quest for a Fantastic Future) is now available for purchase and most of the reviews have been positive. Charged EVs, a media outlet covering the electric vehicle industry, offers up some tidbits on the 400-page bio.
Among the key takeaways is the author’s view that space exploration is Musk’s true passion, and that everything else is secondary. The author, Ashlee Vance, gained this perspective after spending more than 40 hours in conversation with Musk and speaking with close to 300 individuals about the genius entrepreneur.
Other notes from the book that help shape the persona of Musk is his undying devotion to quantitative thinking. According to the book, Musk never wants to be told that something “can’t be done.” If something is indeed impossible, then you would have to “take it down to the physics.” That science governs his management philosophy isn’t all that surprising since Musk did earn a B.S. in physics from the University of Pennsylvania.
Another interesting story that received a ton of press is the fact that the launch of the Model S in 2013 nearly bankrupted Tesla. It forced Musk to have informal discussions with Google about possibly selling the young company. An offer, however, never materialized from the search engine giant.
Green Car Reports recently posted a good introductory article about the basics of EV (Electric Vehicle) charging.
Here’s the link to the article:
The author provides a good overview of the different levels of charging Level-1 (110v) charging, Level-2 (220v) charging, and DC Fast Charging, also known by me and many others as Level-3 charging, which is 480v. The author doesn’t really explain why DC Fast Charging isn’t Level-3 charging, and I suppose that’s for the best in an introductory article. I believe the reasoning is that, under an older IEEE designation, before the standards were adopted, Level-3 charging referred to a high voltage AC charger. High voltage AC chargers never became popular and have not be adopted in the US. It would seem to me that referring to DC Fast Charging as Level-3 would be appropriate now.
The article goes on to note that level-1 and level-2 have a single standardized connector and that level-3 charging uses three different standards – CHAdeMO, CCS (or SAE Combo) and Tesla. While Tesla chargers only work for Teslas, the CHAdeMO and CCS standards are often available on the same charger in more recent installations. One of the keys for using an EV for longer trips, is to make sure that the vehicle has a fast charging connector installed at purchase. Retrofitting a car for fast charging is usually not possible, though some aftermarket options are available for cars like the RAV4.
The author goes on to note some of the common forms of EV charging etiquette for public chargers. Among them are not to leave your car parked in a charging spot if it’s not charging, don’t charge if you don’t need it, and if you won’t be able to get back to the car to unplug it when the charge is done, leave a note explaining when someone can unplug you so they can charge. Most of all try to get along. The author decides to steer clear of whether plug-in hybrids should charge at public charging stations. From my experience, it’s best never to unplug anyone unless their charge is done and to leave a polite note explaining what you’ve done. As the author says, the goal is for us all to get along.
Electric vehicles have been growing in popularity, so much so that every car manufacturer is dedicating showroom space for the next generation of vehicles. Certain automakers, like Nissan, Tesla, and BMW, have hit home runs with their respective electrified fleets. Others, not so much.
Among the car companies that have whiffed – Cadillac, particularly with its ELR compact-sized coupe. The company now admits that the initial price tag of over $75,000 was too high for the market. According to Green Car Reports, electric-car advocates were stunned when they heard the initial MSRP of $75,995. While the 2014 ELR had a ton of great standard features, it was also the smallest car Cadillac sold and the least powerful.
As a result of the pricing dilemma, fewer than 2,000 ELRs have been sold since the car went on sale more than a year ago, and dealers are now offering remaining 2014 models at prices below $50,000. Just to give you an example of how anemic those numbers are, Tesla sold 1,700 units of its Model S this April.
The 2016 Cadillac ELR – there was no 2015 model year – received more power, additional standard equipment, and a $10,000 price cut.
The ELR is certainly a head turner, with its pronounced grill and sleek design. One can only wonder how well it would have sold if it were appropriately priced right out of the gate.