Of late, much discussion has been on the use of biomass to produce liquid fuels. This seems like a monumental task as the price of oil isn’t high enough to justify switching to biomass-based fuels and the ever-hot topic of food versus fuel always stirs up significant debate. An example of a biomass derived liquid fuel is ethanol, which has been used as an additive in gasoline for quite some time. However, ethanol offers distinct disadvantages versus current hydrocarbon-based fuels, such as, low net energy return on energy invested, a lower volumetric energy content and the fact that it cannot be readily integrated into existing fuel infrastructure.
The question that should be asked without prejudice is “Is there a chance for companies to be sustainably focused and still make / save money from biomass-derived products?” That includes not using tax incentives or government subsidies in calculating value since they cannot be counted on. The reason why its difficult for companies to push sustainably-based products is that they are expensive, and ‘most’ customers will not pay the higher cost.
With that said there appears to be a few logical paths forward for companies on offering sustainable products.
1. If certain specialty chemicals that demand a higher cost due to their unique qualities can be derived ‘inexpensively’ from biomass.
2. If new biomass derived chemicals can be synthesized that offer unique qualities at a reasonable cost and cannot easily be achieved from petroleum.
3. The starting materials are derived from biobased (sustainable) raw materials and the product generated are biodegradable.
Instead of using biomass as a means of producing liquid fuels there may be a more ‘real opportunity’ to use biomass-derived materials for production of bio-based packaging. Currently, there are a number of different companies that offer bio-based packaging that includes Nature-Pack’s use of renewable plant starches and plant oils, TIPA’s Compostable Packaging and a few others, Green Dot Bioplastics and Sulapac.
The problem with many of these products is they are higher in upfront cost and they don’t perform as well as their petroleum-based counterparts. However, there has been a significant amount of work on producing sustainable monomers that also produce good, biodegradable products.5 For example, there are two polymeric systems where their monomers can come from bio-based sources, lactic acid and butylene succinate, and their resulting polymeric products are readily biodegradable, PLA (polylactic acid) and PBS (polybutylene succinate). Both these hit the third point above and Table 1 shows both polymers and provides further information on them.
Biodegradable polymers and their bio-based source along with their mode of degradation. Tradenames and companies that produce these products are also provided.
PLA has been found as a good replacement for polystyrene (PS) and polypropylene (PP) when it comes to cold drink cups, deli and takeout containers and fresh produce packaging. PBS has also been shown to produce films, trays and pouches for the food industry. PBS can also be used in flexible packaging, adhesives and construction materials.
Although the properties of bio-based packaging aren’t a 100% replacement for petroleum-based products per up front cost and packaging properties, the upfront cost of these products have been going down significantly (better processing) and consumers are getting used to the different feel and look of the packaging. As companies learn how to better market these products, for example, through life-cycle-analyses (LCA’s), wider acceptance will be gained. LCA’s have shown that bio-based products are ultimately less expensive than their petroleum-based counterparts due to the lower cost for waste removal / degradation and other savings from lower energy consumption, lower extraction / refining cost, etc. However, the consumer doesn’t necessarily appreciate the overall cost, only what they purchase at the store.
Essay by: Thomas Holland
Deerfield High School