Do the environmental costs of hybrid car production outweigh the long-term benefits of these vehicles?

The hybrid vehicle has been hailed as a revolutionary step for the automotive world. Ten years after the global release of the Toyota Prius, factors such as climate change and energy concerns have driven the surge in hybrid sales, crossing the two million mark, with nearly half sold in North America [source: Autoblog].

Americans aren't drawn to the Prius for its aesthetics or speed. They purchase it primarily to cut fuel costs and reduce their carbon footprint. In numerous American cities, personal vehicles contribute the largest share of pollution, releasing massive quantities of harmful greenhouse gases, such as carbon dioxide, nitrous oxide, carbon monoxide, and sulfur oxide, into the air and our lungs [source: EPA]. Environmentally conscious buyers view the Prius and other hybrids as a crucial investment in both the planet's future and our collective well-being.

Are hybrids truly as eco-friendly as they appear? How much of their green image is marketing and how much is backed by science? Hybrids, with their secondary electric motor, burn less fuel than traditional vehicles and release fewer greenhouse gases during use. That's a positive, but what about the manufacturing process? In 2007, an auto industry report claimed that factoring in production waste made the gas-guzzling Hummer greener than the Prius [source: Slashdot]. While this claim was largely debunked by environmentalists, it raised a crucial question: does the pollution generated during hybrid production negate the environmental benefits of 'green' driving?

The answer may surprise you. A thorough investigation by the U.S. Department of Energy’s Argonne National Laboratory reveals that producing hybrid cars demands more energy than building conventional cars, leading to higher greenhouse gas emissions and more fossil fuel consumption during manufacturing. The process of making hybrid batteries, in particular, consumes significantly more energy than producing a standard car battery, leading to increased emissions of gases such as sulfur oxide [source: Burnham et al].

However, do the environmental costs of hybrid vehicle production outweigh the long-term benefits of driving a more environmentally friendly car? The answer is a definite 'no.' Over the course of 160,000 miles (257,495 kilometers), a conventional car requires far more energy and produces significantly more greenhouse gases, effectively canceling out any environmental disadvantage incurred during hybrid production [source: Burnham et al].

Continue reading as we examine the statistics surrounding both hybrid production emissions and the emissions from driving a hybrid, and uncover what 'green' really means.

Pollution Caused By Building a Hybrid Car

Building a hybrid car involves a process almost identical to that of creating a traditional vehicle, utilizing cutting-edge technology and automated assembly lines. This manufacturing method demands significant energy, particularly in the forging of materials like steel, aluminum, glass, and plastic. Interestingly, producing lighter vehicles can sometimes use more energy than building heavier cars because lighter metals, such as aluminum, are more difficult to forge than stainless steel [source: Moon]. It is estimated that between 10 to 20 percent of a vehicle's total greenhouse gas emissions are generated during the manufacturing process alone [source: California Energy Commission].

Toyota has acknowledged that the production of its lightweight Prius requires more energy and results in higher carbon dioxide emissions than its gasoline-only counterparts [source: Williams]. This is primarily due to the inclusion of advanced components in hybrids like the Prius, which feature a second electric motor and large battery packs, making them more energy-intensive to produce.

Batteries are a crucial component in hybrid vehicles. The regenerative braking system allows hybrids to generate and store energy at low speeds or while idling. Unfortunately, both nickel-hydride and newer lithium-ion batteries depend on the mining of nickel, copper, and rare earth metals. Lithium-ion batteries alone contribute to 2 to 5 percent of a hybrid vehicle's lifetime emissions, while nickel-hydride batteries are responsible for higher sulfur oxide emissions—around 22 pounds (10 kilograms) per hybrid compared to just 2.2 pounds (1 kilogram) for a conventional vehicle [sources: Samaras and Burnham et al.].

There are additional environmental concerns tied to the rare earth metals used in hybrid battery magnets. In recent years, lithium, a key component, has been mainly sourced from China, where the government’s low prices allowed it to dominate the market [source: Strickland]. China’s ability to sell lithium cheaply was largely due to its disregard for environmental standards during mining. For example, in the Bayan Obo region, miners extracted gold-infused metals using acids that contaminated groundwater and destroyed surrounding farmland. Even Chinese officials have admitted the environmental damage caused by rare earth mining, with one regulator stating, "This has caused great harm to the ecology and environment" [source: Bradsher].

Hybrid Car Air Pollution Statistics

Since hybrid cars rely on regular gasoline, they release the same greenhouse gases as conventional cars. However, due to their superior fuel efficiency -- the U.S. Energy Information Administration reports an average mileage of 38.7 miles per gallon (16.5 kilometers/liter) for hybrids compared to just 26.7 miles per gallon (11.4 kilometers/liter) for conventional gasoline vehicles -- hybrids consume far less fuel to travel the same distance.

If each gallon of gasoline produces 20 pounds (9 kilograms) of carbon dioxide, a hybrid car emits 51.6 pounds (23.1 kilograms) of CO2 per 100 miles (161 kilometers), while a conventional vehicle emits 74.9 pounds (34 kilograms). Over the lifespan of the vehicle, hybrids more than offset their heavier manufacturing emissions. Let’s dive into additional lifetime emissions data.

The Argonne National Laboratory conducted a comprehensive comparison of hybrid and conventional vehicles across their entire life cycle, considering vehicle production, operation, and the energy used to create fuel for both types of cars. Assuming both vehicles travel 160,000 miles (257,495 kilometers) during their lifetime, the conventional vehicle uses 6,500 Btu of energy per mile, while a hybrid consumes just 4,200 Btu per mile. This greater energy input leads to significantly higher lifetime greenhouse gas emissions for conventional cars—more than 1.1 pounds (500 grams) per mile compared to 0.75 pounds (340 grams) per mile for hybrids [source: Burnham et al.].

There's an intriguing aspect to the hybrid vs. conventional car discussion. Companies like Toyota, known for their hybrid models, are preparing to launch a new type of plug-in hybrid. These vehicles feature larger battery packs and can be charged at home like electric cars. With this added charge, they can travel an additional 10 to 20 miles (16 to 32 kilometers) on electric power before the gas engine engages. Toyota projects sales of 20,000 to 30,000 units of the 2011 Plug-in Prius, with even more expected in the future [source: Green].

The challenge with plug-in hybrids (and electric cars in general) lies in the fact that electricity isn't always a greener option than gasoline. In the U.S., more than 45% of electricity is sourced from coal-powered plants [source: EIA]. According to an additional report from the Argonne National Laboratory, charging a plug-in hybrid with coal-generated electricity could lead to up to 10% more greenhouse gas emissions than a conventional vehicle and up to 60% more than a standard hybrid [source: Elgowainy].