For the InstructorThese student materials complement the Renewable Energy and Environmental Sustainability Instructor Materials. If you would like your students to have access to the student materials, we suggest you either point them at the Student Version which omits the framing pages with information designed for faculty (and this box). Or you can download these pages in several formats that you can include in your course website or local Learning Managment System. Learn more about using, modifying, and sharing InTeGrate teaching materials.
Student Reading: Hybrid and Electric Cars
Learning Goals: Students will be able to:
- Compare energy costs and environmental impacts associated with hybrid, electric, and fossil fuel-based vehicles.
- Determine energy efficiency improvements associated with regenerative braking.
- Use flywheel technology to convert kinetic energy into electrical energy (rowing machine hooked to a generator, or simple bike light generator).
- Evaluate mineral scarcity for rare earth elements used in batteries.
Learning Assessment: Students interpret graphs showing atmospheric CO2 and combustion engine/Industrial Revolution. Students analyze the use of flywheels to generate electricity.
Before the Automobile
Rough and muddy roads impeded walking and wagons. In the early 19th century, the first railroads addressed this issue. Iron rails made for easier rolling of wagons with special flanged wheels. With the improvement of the steam engine by James Watt, an alternative source of power came to the rails. In 1814, George Stephenson built the first steam locomotive. It was used to haul coal from the mines in England. In 1825, the first public railway opened in England. Railways soon spread across Europe and the United States.
Automobiles changed life in America
Perhaps the automobile more than any other invention of the 19th century did more to shape the way the United States developed in the 20th and 21st centuries. Of course, the automobile is a composite of numerous other inventions: electric lighting, storage batteries, internal combustion engines, hydraulics, etc. Yet the complete package transformed the way we live. The national landscape is crisscrossed by a network of roads that will deliver an automobile within a few steps of most destinations. Only agricultural lands, forests, wilderness areas, beaches, and areas put in preserve for parks are saved form the ever-present ribbons of asphalt and concrete. The design of our communities reflects the dominance of the automobile. Cars facilitated the growth of suburbia as places of residence remote from the work site. Shops and businesses that previously clustered in centers of towns and cities became widely dispersed along corridors of traffic, helping drive urban sprawl.
Cars and trucks made obsolete the vast network of interurban railways that linked towns, cities and countryside together between the 1880s and 1930s. The development of heavy trucks also diminished freight rail service.
The car changed society in countless ways. Modern suburban housing developments often lack sidewalks because designers scoffed at the idea that anyone would want to go anywhere on foot. Some architects design houses with the two-car garage dominating the front approach. Residents drive their cars to the garage door, press the remote control to admit the car, exit the car, and enter the house via a door from the garage. This makes it possible for people to isolate themselves from nature almost exclusively.
Cars gave new freedoms to teenagers. With a bit of money for gasoline, they could borrow the family car and escape from parental control. Untold numbers of children were conceived in the back seats of sedans. Drive-in movie theaters, fast food, and supermarkets exist only because of cars. Coming of age in the United States is marked by the earning of a driver's license. No baptism or bar mitzvah ceremony is as consequential as passing the driver's test.Most Americans view access to an automobile as an essential part of life. As of 2013 there were 256 million cars for the nearly 325 million people in the United States. In 2013 the number of cars worldwide surpassed 1 billion, and some project that number to reach 2.5 billion by 2050. The United States accounted for about 18% of the world's energy consumption in 2014, and 28% of that went to transportation. Almost all of the transportation sector energy comes from petroleum. It is not hard to see that petroleum-burning cars cause massive amounts of pollution, including climate-changing emissions.
The first cars: steam, electric, and gasoline-powered
Automobiles were eyed as a cure to one urban problem few of us think about today—horses and mules ran on biofuel, and littered the roads with countless piles of smelly and slippery dung.
Specialized electric vehicles remained in use after the maturation of the gasoline engine. Electric-driven fork lifts could work indoors, where auto exhaust would be unsafe. Electric golf carts maintained the peace and quiet of fairways and greens.
The 1970s saw renewed interest in electric cars as a way to reduce pollution and use alternative sources of energy. In 1990, California passed a law requiring that 10% of the cars operated in that state produce zero emissions by 2003. This prompted General Motors to develop the all-electric EV 1, which it introduced on a lease basis in 1996. In 2003, GM had a change in heart and removed the vehicles from the market and crushed them. That was after GM and others successfully sued California to get rid of the 10% no-emission standard. George W. Bush, oilman and President of the United States, joined in that suit.
Gasoline-powered cars dominate much of the 20th century
Liquid fuel consumption is driven to a large extent by the use of liquid gasoline in motorized vehicles for transportation, which were introduced around the turn of the 20th century. The central feature of motorized vehicles powered by liquid fuel is the internal combustion engine. Through burning of fossil fuels, chemical energy stored in the fuel is oxidized (burned) and converted to mechanical energy to power the vehicle, and CO2 is emitted as a by-product of combustion (along with water and other chemicals).
In the United States alone, we collectively drive about 3 trillion miles annually. If we take an optimistic look at gas mileage and say that on average vehicles get 30 mpg, then Americans are consuming 100 billion gallons of liquid gasoline annually and emitting CO2 as a by-product to the atmosphere.
Refined gasoline comes from crude oil—about 45% of the volume of a barrel of oil (42 gallons) becomes gasoline. That crude oil, of course, is removed from the ground in locations around the world, some of which are economically and politically "active." Our reliance on fossil fuels has many global ramifications socially and environmentally.
OK, what to do? The simplest solution to overzealous fuel consumption is to stop driving. Since this does not sit well with most Americans, the next thing to do is increase fuel efficiency of the internal combustion engine. This has been done over the years, with modest success: fuel economy generally has improved as automakers have designed more efficient engines placed into smaller cars. Alas, the average number of miles per gallon of the US auto fleet has not improved steadily, since American drivers prefer larger vehicles that get worse gasoline mileage than so-called "economy cars." The US auto fleet includes its share of fuel-efficient cars and gas-guzzlers.
The era of the Hybrid
There are now sixty-one different models of cars with hybrid gasoline/electric systems offered for sale in the United States in 2016. However, some of these hybrid systems are on vehicles that use them to make their dismal mileage rating only slightly better.
The plug-in hybrids
EV — the return of the all-electric car
In 2008, a new company introduced the first major production run of an EV in 8 decades. Tesla Motors premiered its EV Roadster at $108,000, selling over two thousand by 2010. It could go 245 miles per charge and 0–60 mpg in 6 seconds! The company now makes less expensive and tamer versions of the car. Tesla vehicles have massive electrical energy storage up to 100 kWh, sufficient to power a car for hundreds of miles on a single charge. One gallon of gasoline is equivalent to about 33 kWh of electricity; thus, the Tesla is getting over 100 miles per equivalent gallon of gasoline. This is gasoline-free driving (no tailpipe!), with the caveat that energy is being generated to operate the car at the power plant (that uses coal, natural gasoline, nuclear, hydro, or some other alternate energy strategy).
For the less well-heeled, 2010 saw the introduction of EVs at more affordable prices. The Nissan Leaf, for example, has a range up to 107 miles on a charge and in 2017 had a base price of $33 K. The Chevy Bolt has a range up to 238 miles on a charge and in 2017 had a base price of $37.5 K.
The success of the EV depends upon a network of charging stations. To encourage use of EVs, some states provide free charging stations along highways. There are smartphone applications to help drivers locate charging stations. Look at this map to locate charging stations near you.
Electric Vehicle (EV) FAQs:
Where do Electric Vehicles charge?
1. Primarily at home overnight, using surplus electricity.
2. At one of many public charging stations in the area, and at work.
3. At a fast charger along selected highways.
How long does it take to fully charge?
Level 1: 120V AC, charge overnight.
Level 2: 240V AC, charge in 3–5 hours.
Fast Charge: 480V DC, charge in 25–45 minutes.
Actual time depends on vehicle, charge rate, battery size, state of charge, and other factors.
How much does charging add to a home's electric bill?
About $40 to drive 1000 miles/month.
What are the tax incentives for purchasing a new EV?
Federal: Up to $7500 Tax Credit.
- DC: Exemption from excise tax imposed on original certificate of title.
- Reduced vehicle registration fee of $36.
- Maryland: Up to $2000 Excise Tax Credit.
- EV Supply Equipment (EVSE) Tax Credit – 20% of cost up to $400.
- Virginia: Reduced personal property tax in Arlington and Loudon counties.
- Discounted electricity rates for off-peak residential EV charging.
Electric Vehicle energy storage: the importance of Rare Earth Elements
Those who do not have $75K (or even $40K for their newer, less expensive models) to purchase a zippy new Tesla (raise your hands!) might wonder about the environmental impact of vehicles built with electrical generation and storage in mind. Yes, more technology and advanced components in the car translate into greater energy use to construct and assemble the parts, but the energy efficiency of electric and hybrid electric vehicles—over the lifetimes of the vehicles—more than covers the upfront energy costs of creating the vehicles. More important environmentally, however, are the battery packs for hybrids and electric cars. Both nickel-hydride batteries and lithium-ion batteries rely on the mining of nickel, copper and so-called rare earth elements (REEs). The REEs are used both in electric motor construction and in electricity storage in the battery.
FROM Integrate 2012 Team (http://serc.carleton.edu/integrate/teaching_materials/mineral_resources/activities/REE.html):
Extraction of any economic reserve materials depend on four factors: a) abundance of the material in the crust; b) tendency of the material to form economic reserves; c) ease of mining, or ability to mine at a profit; and, d) ease of processing to extract the metal from the ore.
Ease of mining, or ability to mine REEs at a profit: This depends on the "ore grade," or the concentration of the valuable material in the ore. A higher-grade ore generates higher profit. The average REE ore grade for Mountain Pass deposit in California is 9.2%. Considering the fact that copper, a relatively cheaper ore, can be profitably mined at a grade of 0.5%, there is no question that REEs can be mined at a considerable profit without having to depend on China as the sole supplier.
However, common REE ores like monazite contain radioactive elements like thorium. Safely disposing of thorium-rich mine waste is ahuge challenge for REE mining in the United States.
Ease of processing: This is the biggest hurdle in the path of REE production. The fifteen rare earth elements that naturally occur together in the ore have very similar chemical properties. Separating them out from each other is therefore technologically challenging, cost intensive, time-consuming, and energy intensive. Different REE ores, such as monazite and bastnäsite, require different processing methods. The lack of a single standardized processing method adds to the cost of processing and remains a technical challenge. Safely extracting and removing radioactive byproducts also adds to the overall challenge. As of right now, most commercially viable REE processing plants are located in China. Until other countries are able to economically separate the different REEs from the ore, China will remain the sole supplier of REEs in the global market.
In recent years China has reduced the REE export quota, claiming that it should meet the demands of Chinese industries before supplying global demand. As of 2010, China consumes almost 70% of its own REE production. China also claims to have tightened its mining regulations to minimize the environmental impacts of REE mining, resulting in lower REE production. The reduction of REE supply in the face of increased demand has driven up REE prices worldwide:
Some common uses, supply, and demand for five of the rare earth elements are shown in the above table (data from Bade, 2010: Rare Earth Review). Think about the ways in which supply-demand imbalances might impact the future of clean energy initiatives, and brainstorm some feasible ways to address these issues. Another potential problem associated with electrical storage in dense, high-energy batteries is the risk of overheating—a point made clear by the recalled Samsung Galaxy 7 batteries with design flaws that caused them to overheat and catch on fire. Was this simply a case of the company hastily putting a product on the market without sufficient testing, or are the risks of battery failure increased by increasing energy storage? Are Teslas and other EVs any more or less safe than cars driving around with tanks full of flammable gasoline?
David MacKay: Sustainable Energy Without the Hot Air, Technical Chapter on Cars
Denton, T. 2016. Electric and Hybrid Vehicles. Routledge Press. 200 pp.