BioCycle November 2008, Vol. 49, No. 11, p. 41
IN MANY of the emerging carbon reduction discussions, there seems to be a good deal of confusion about which shade of carbon is greenest. Is it “greener” to recycle ancient fossil carbon, or to develop recent biomass carbon? A serious reduction of atmospheric carbon requires both shades of green.
I am a green plant professional myself. My natural bias is to place a slightly higher value on the “recent” carbon of biomass production than I do on the “ancient” carbon of fossil fuels. These biases are natural as long as they don’t interfere with the larger, economic race toward a low-carbon economy.
The ancient sources of carbon that generate our conventional liquid fuels, coal and natural gas, pull perfectly functional carbon out of the earth. As we use it for fuel and other applications, it is released into the atmosphere. This release of buried carbon adds to the overall concentration of resident carbon in the atmosphere. These fossil fuel sources are referred to as carbon-positive.
Alternatively, the recent carbon of biomass has the potential to be carbon-negative. This is not an automatic. Green plants sequester carbon, but when they are burned or composted they emit carbon dioxide (CO2). When too much fossil carbon is emitted in the production of biomass, or insufficient carbon is sequestered when it is harvested, biomass will not be carbon negative.
Emitting CO2 is not bad. We all do it every time we exhale. Global release of CO2 has been going on for as long as there has been life on the planet. Today however, its concentration in the atmosphere is too high. The imbalance of fossil-derived carbon has created a CO2 challenge. Activities that have the potential to lower atmospheric CO2 are generally considered green.
Carbon-neutral technologies, like solar and wind energy, are considered “green,” even though they have nothing to do with green plants or ancient carbon. Carbon neutral energy sources do not add to atmospheric carbon – and they offset existing uses of ancient carbon. While no carbon is sequestered, CO2 emissions can be reduced by using a carbon-neutral technology.
PLASTIC AS A CASE IN POINT
Conventional plastic is made from ancient carbon sources. And recycling plastic releases less CO2 than making more plastic from ancient carbon. Thus recycling plastic is considered a “green” technology.
Curiously, biodegradable plastic cannot be recycled into more plastic. It is made to degrade. The early bioplastics were mostly made from ancient carbon plastic with some new biomass plastic mixed in. The newer technologies are much more degradable.
The greater innovation with bioplastic is that it is made from recent carbon (biomass) thus its production releases smaller quantities of ancient carbon. It is a single-use plastic, but can be recycled into other things. Efforts are underway to enhance the compostablity of bioplastic, which also can be burned as fuel.
The downside is that bioplastics cannot be commingled with conventional plastics in a recycling program, and there isn’t any infrastructure currently set up to manage them separately. When bioplastics show up in the conventional plastics recycling system, it adds costs to remove them. This is a technology development problem, not an indictment on the future success of bioplastics.
The November issue of DC Velocity, a logistics/freight industry publication, ran a thought-provoking review of the various green attributes of plastic versus wooden pallets. I was not surprised, given my green plant bias, that wooden pallets are greener in their production and destruction than plastic pallets. But plastic pallets do have “green” attributes. They last longer and are about half the weight, reducing energy costs in shipping. Plastic pallets had fewer recycling options. Could bioplastics work well in pallet production? That would reduce carbon emissions in production and reduce fuel emissions in transportation.
COMBINING NEW AND OLD
Combining new carbon with old carbon is also an option to reduce overall CO2 emissions. For example, small additions of biomass to solid and liquid fuel systems generally reduce the carbon air emissions from fossil fuels. Show Me Energy Cooperative in Centerview, Missouri, is already generating 100,000 tons/year of biomass fuel for use in a coal-fired power plant. Green Circle Bio Energy, Inc. in Cottondale, Florida, is producing 500,000 tons of pellets for European power plants. In October, the company announced it was considering moving into the U.S. coal-fired power plant market.
Increased demand for biomass and recent carbon feedstocks is even beginning to divert MSW carbon from landfills. This is happening because there is a premium value placed on shifting to recent, biomass carbon sources of energy and other materials. It is absolutely just as important to rapidly adopt new methods to recycle and reuse ancient carbon materials.
Successful navigation of a reduction in atmospheric carbon will require an aggressive, unified campaign to develop the “green” of recent carbon and the “green” of recycling ancient carbon. There is no either/or option.
Mark Jenner, PhD, operates Biomass Rules, LLC and has over 25 years of biomass utilization expertise. Burning Bio News is Jenner’s monthly scorecard of bioenergy project adoption, available at www.biomassrules.com.
November 24, 2008 | General
Biomass Energy Outlook: How Green Is Your Carbon?
BioCycle November 2008, Vol. 49, No. 11, p. 41