PepsiCo announces all-plant-based plastic bottle (From Dr. Marcus Eriksen)

By Stiv Wilson on March 23, 2011

It's a new Pepsi soda bottle, made from new PET plastic, that's derived from plants, such as switch grass, pine bark and corn husks rather than petroleum. The benefit is clear: no more fossil fuels. But what is the cost?

We had a recent conversation about the new 100% plant-based PET soda bottles with a representative from the Container Recycling Institute (CRI). It's a noteworthy step in the right direction to introduce fully plant-based, fossil fuel-free packaging. We had a similar conversation with Proctor & Gamble executives last month - another large company that is also switching to plant-based plastic for some packaging. One principal reason that accounts for the shift in resources is the economics of plants vs. petroleum to produce polyethylene or PET. With the cost of petroleum rising, plants become a cheaper alternative. P & G is working with a company in Brazil to convert sugar cane fiber into polyethylene.

But does plant-based mean "biodegradable"? No.

There is some clarification needed here, in that these plant-based plastics are not biodegradable, and may still contribute to the polluting of marine environment if lost. Chemically, they are the same as petroleum-based PE and PET. It is important to understand that plant-based plastic does not mean they will biodegrade like your yard clippings will. But there are such plastics in production. PLA is a common bioplastic used for many products today, and PHA, produced by Metabolix, is a marine degradable bioplastic alternative to plant or petroleum derived PE or PET. The ASTM standards for PHA show that a cup lost at sea will lose 50% of its volume in 18 months. But what we don't want is for any plastic, regardless of its content, to enter the marine environment.

The difficult issue to address for all plastic is recovery. How do you get back what the customer consumes? Recycling programs fail by comparison to redemption programs - and this is where the greater challenge lies. What was interesting to hear from the CRI folks was how difficult it is to get redemption values to stick for plastic containers, which is shown to be the most effective method of recovery for post-consumer plastic. Do you remember turning in a glass CocaCola or Pepsi bottle for a dime? The ability for the public to redeem plastic or glass container for a monetary deposit works very well in Canada, Europe and much of the developing world that still reuses glass bottles. The argument from beverage companies is simple: we would rather have your city waste management (which is billed to taxpayers) deal with post-consumer plastic, than buy back bottles for a redemption value, which beverage companies pay for. This is the Extended Producer Responsibility that PepsiCo and CocaCola resist, even though it is what works best.

That's the bottom line. The battle of plant vs. petroleum, or recycle vs. redemption, always falls on economics. The greenwashing of introducing a plant-based bottle is secondary.