What is the difference between bioplastic and regular plastic? What are the cost differences? How about the waste differences?

What are bioplastics?
In general, bioplastic products are made from biopolymers. Biopolymers almost always have oxygen or nitrogen atoms in their polymer backbones (the feature that is mainly responsible for their biodegradability) Synthetic polymers that have only carbon-carbon single bonds in their backbones are resistant to degradation and will not readily breakdown.

Bioplastics are made using plant starches, usually from corn, potato and sugar cane (bagasse). Bagasse is an agricultural by-product of the sugar cane industry in China and can be used to manufacture disposable products. Rather than throwing away or burning used sugarcane stalks, the pulp is made into a paper like substance that is then turned into various disposable products. Corn plastics are plastics made from PLA (polylactide). PLA is made from lactic acid. Lactic acid is made from dextrose by fermentation. Dextrose is made from cornstarch and cornstarch is made from carbon dioxide and water.


Do bioplastics cost more?
According to Steve Levine, one of the creators of the Spudware product, cornplastic products used to be seven to eight times more expensive than ordinary plastic products. The cost today is still higher but more in the range of four times greater. However with Levine’s potato based fork the difference in price is reduced further. The wholesale price for a spudware fork is around 4 cents where as a standard plastic fork is around 2 cents.

Although the cost per product is still higher with bioplastic, there may be significant changes to the overall bioplastic industry in the future that may further reduce costs. The company Cereplast with a capacity to produce nearly 40 million pounds of bio-based resins per year is the second largest producer of bio-resins in the country. In a 2006 article in FoodProductionDaily.com, the Cereplast chairman claimed that his products are the same price or lower than traditional plastic resins and that as fuel prices continue to rise the biodegradable plastics industry will become cheaper, since organic plastics require less fuel to create.

What are the costs with petroleum plastics?
Although bioplastics at present appear more expensive, there are other hidden costs to the consumer of standard plastic products that are not reflected on the price tag of a package of plastic forks or in the price of a beverage in a plastic cup. The economic effects of plastic pollution on the environment costs the consumer as a taxpayer and resident of a coastal state. 80% of marine debris is the result of washed away plastic, which has forced the state government and municipalities to spend millions of dollars on clean-up efforts attempting to meet US EPA Total Maximum Daily Loads for trash in impaired CA waterways. California’s economy is also dependent in large part on the ocean and ocean resources whose sustainability may be jeopardized by excessive plastics pollution.

Plastic production and plastic waste also cost all residents of the planet in terms of environmental health hazards. During processing, significant toxic emissions into air and water have been associated with plastics plants, with the plastics industry contributing 14% of the national total of air emissions. Emissions of contaminated waste water are estimated to be 300-500 gallons a minute per plant.

In the waste phase, when a plastic product undergoes only primary degration it can increase in potential toxic effect by resulting in a wider distribution of the plastic particles in the environment and these partially degraded plastics may have an acculumation of potentially toxic end products. Phthalic acid esters (PAEs) are one kind of important environmental hormone, which can enter into the environment with the usage and disposal of plastics products and possess high environmental and health risks.

Why are petroleum based plastics such a waste?
Plastic is the fastest-growing portion of our waste stream and now makes up the second-largest category by volume, next to paper, of trash going into our landfills. The California Integrated Waste Management Board estimates that less than 5% of plastic in California is recycled and the reason is not entirely that plastics never make it into recycle bins.

With the current state of plastic recycling in the U.S., items such as plastic utensils will most likely end up in the landfill, even if you put them in a recycle bin. Plastics that you put in curbside recycling bins are not necessarily recycled. Even if the product has the chasing arrows, the standard sign for “recyclable” it does not mean that when placed in the recycle bin it will actually get recycled. The American Plastics Council has been pursued by 11 state attorney generals for making false claims about the recyclability of their products.

There is not an economic incentive for plastic manufacturers to use recycled plastic and the low demand is translated into a low rate of plastic recycling. Virgin plastic pellets or flakes are available for about the same amount of money as recycled plastic and plastic manufacturers find little incentive to purchase recycled plastic. There are also limits to the products that can be made from recycled plastic. The U.S. Food and Drug Administration prohibits food containers to be made into new food containers because they can't be heated at temperatures high enough to sterilize them.

The majority of the plastics we recycle, regardless of type, end up in China, where there are worker safety standards are virtually nonexistent and materials are processed under unsanitary and unsafe conditions. Because plastics are not classified as hazardous wastes, they are not regulated by international law.


What is the waste with bioplastics?
Biodegradable plastics generally degrade in under 180 days. PLA will compost in approximately 30-45 days in a commercial composting facility. Composting may take longer in a home composting bin. The Biodegradable Products Institute offers a certification for true “compostability”. To qualify as a compostable plastic, the product must be converted to carbon dioxide, water and biomass, disintegrate or not be visible after composting, and degradation must not cause any harmful by-products and the compost must be able to support plant growth. Not all bioplastics on the market will meet these requirements for compostability. To find out more about this certification go to (bpiworld.org)

Sources: FoodProductionDaily.com, newstarget.com, Sustainableplastics.com, Californiaprogressreport.com, www.ecologycenter.org. Bioscience, Environmental Health Perspectives, San Francisco Chronicle, Northcoast Journal

The Sustainable Calculator: Planes vs. Trains

The Sustainable Calculator seeks to calculate the answers to everyday questions about sustainability. Send in your question to eetorbert@ucdavis.edu.

Question: Is it better for one person to fly or drive to Los Angeles from Davis? How about two people?

Maybe the real question is why would one person, much less two, want to go to Los Angeles? But since there’s no accounting for taste, the question of how to get to Los Angeles involves trade-offs in economics, greenhouse gas emissions, and energy usage.

The calculation is shown below, but after all mathematical contortions are over and done, the car emits 194 lbs of carbon dioxide and the plane emits 245 lbs of carbon dioxide per passenger, if the plane is full. The gasoline costs you $30, and the plane ticket costs $75. Of course, you don’t have to own a plane to fly in it, so to correctly compare the prices, we need to add the cost of renting a car. Renting a car in Sacramento for a one way trip to L. A. costs $60, on average, bringing the total cost to $90.

Carbon dioxide is one of the greenhouse gases, but not the only one. Automobiles emit NO_x, CO, hydrocarbons (HC), and hydrofluorocarbons (HFC – 134). The NO_x and CO gases are reactive, which means they quickly react with oxygen to form ozone in the lower atmosphere. This contributes to smog, but does not directly contribute to global warming. HFC -134 is a very potent greenhouse gas and has 3300 times the twenty-year global warming potential as CO₂. The EPA estimates that CO₂ accounts for 95% of the greenhouse gases emitted from a car.

The car emits these greenhouse gases at the surface of the earth, but airplanes emit carbon dioxide, water, soot, aerosols, HFCs and NO_x into the upper troposphere. The effects of the emissions are both warming and cooling: the NO_x (which becomes ozone) actually helps by reacting with methane to form water, thus eliminating a potent greenhouse gas. The water and particulates emitted creates contrails and cirrus clouds which both insulate the earth and reflect incoming radiation. The IPCC (Intergovernmental Panel of Climate Change) estimates the warming effect of airplanes to be 2.7 times as great as the effect of CO2 emissions alone. Using this estimate, the plane flight emits 662 lbs. of CO₂ equivalents. The car, on the other hand, emits 204 lbs. of CO₂ equivalents. Final tally: driving by yourself emits less greenhouse gases than the plane, but costs more if you rent the car.

So flying to L.A. means flying to a warmer climate in more ways than one, but how about Boston? One person driving the 3100 miles to Boston from San Francisco will take 97 gallons of gas, and emit 1981 lbs of CO₂ equivalents. Non-stop flights are the most fuel efficient, since gaining altitude consumes approximately three times as much fuel as cruising. A non-stop flight to Boston on an Airbus 320 (a 150 seater) costs $729 and emits 2489 lbs of CO₂ equivalents. One stop in L.A. reduces the price to $203, but increases emissions to 3154 lbs. The downside of driving, of course, is the 41.3 hours it would take (without stops). It might be a long, expensive ride to see snow fall, but hey, at least there's still snow.

The Sustainable Calculator:

Toyota Corolla ’05, Sacramento to LA:

Fuel used = 400 miles / 40 MPG = 10 gallons gasoline

CO₂ emitted = 10 gallons × 19.4 lbs CO₂ / gallon = 194 lbs CO₂

CO₂ equivalents = 194 lbs CO₂ / 0.95 = 204 CO₂ equivalents

Cost = $3 / gallon × 10 gallons + $60 renting fee = $90

Ford Explorer ’05, Sacramento to LA:

Fuel used = 400 miles / 20 MPG = 20 gallons gasoline

CO₂ emitted = 20 gallons × 19.4 lbs CO₂ / gallon = 388 lbs CO₂

CO₂ equivalents = 388 lbs CO₂ / 0.95 = 408 lbs CO₂ equivalents

Cost = $3 / gallon × 20 gallons + $85 renting fee = $145

Plane (CRJ 100), Sacramento to LA:

Flight length = 92 minutes (15 minutes climbing, 15 minutes descending)

Fuel used = 0.25 hours × 690 gallons / hour + 1.03 hours × 350 gallons / hour

+ 0.25 hours × 80 gallons / hour = 554 gallons jet fuel

Fuel per passenger = 554 gallons / 50 passengers = 11.1 gallons / passenger

CO₂ emitted = 11.1 gallons / passenger × 22.2 lbs CO₂ / gallon = 246 lbs CO₂ / passenger

CO₂ equivalents = 246 lbs CO₂ × 1.9 = 664 lbs CO₂ equivalents

Cost = $75

Toyota Corolla ’05, San Francisco to Boston:

Fuel used = 3100 miles / 40 MPG = 97 gallons gasoline

CO₂ emitted = 97 gallons × 19.4 lbs CO₂ / gallon = 1882 lbs CO₂

CO₂ equivalents = 1882 lbs CO₂ / 0.95 = 1981 lbs CO₂ equivalents

Cost = $3 / gallon × 97 gallons + 4 × $60 renting fee = $297 + $240 = $531

Plane (Airbus 320), San Francisco to Boston, Non-stop:

Flight length = 5 hrs. 45 minutes (20 minutes climbing, 20 minutes descending)

Fuel used = 0.33 hours × 3030 gallons / hour + 5.08 hours × 1010 gallons / hour

+ 0.33 hours × 260 gallons / hour = 6231 gallons jet fuel

Fuel per passenger = 554 gallons / 150 passengers = 41.5 gallons / passenger

CO₂ emitted = 41.5 gallons / passenger × 22.2 lbs CO₂ / gallon = 921 lbs CO₂ / passenger

CO₂ equivalents = 921 lbs CO₂ × 1.9 = 2489 lbs CO₂ equivalents

Cost = $730

Data for these calculations came from: http://www.epa.gov/, http://www.fueleconomy.gov/, www.grida.no/climate/ipcc/aviation, www.transwatch.co.uk, http://www.mapquest.com/, http://www.travelocity.com/, http://www.delta.com/, http://www.united.com/, http://www.avis.com/, http://www.enterprise.com/, and http://www.aua.com/ .