When the Sustainable Packaging Coalition released its definition of sustainable packaging in the fall of 2005, we included in the criteria the use of renewable energy throughout the life cycle of packaging. At the time, this was criticized as being too aspirational. Yet, at the same meeting, when the definition was released, the memory of Hurricane Katrina was fresh in everyone's minds, and oil had just exceeded $70 a barrel. While renewable energy may seem like a distant vision, the business and environmental case for alternative energy is building quickly as it becomes clear that renewable energy sources are essential for the long-term sustainability of our economic system and the planet.

Many companies appear to agree and are moving toward a more renewable energy future. Company activities ranges from direct investment in renewable energy technologies (e.g., installation of wind, solar) to direct purchase of renewable energy (e.g., direct purchase of wind energy) and indirect purchase of renewable energy through certified Renewable Energy Credits (RECs) or other offset mechanisms. These activities send a signal that renewable energy is an important business consideration and one that is growing in significance.

Given that renewable energy sources are not all equal, what are the more promising renewable energy sources? Geothermal, tidal, solar and wind are renewable-energy sources that are also emission-free; they do not emit carbon dioxide (CO2) or other greenhouse gases and common air pollutants. In the U.S., there are promising possibilities, depending on the region. The Western U.S. has significant geothermal potential, the Southern states are well suited for solar and the upper Midwest and many offshore areas are ideal for wind production. Energy production from tidal energy is a relatively new area, but it is obviously limited to marine locations. Unlike geothermal and tidal energy, solar and wind energy sources are subject to variability in weather.

Hydroelectric is a renewable-energy source that is widely recognized and utilized. However, as the damming of the world's rivers great and small has shown, there are significant ecosystem impacts associated with the installation of hydroelectric systems. Some of these impacts are irreparable and include the loss of critical habitat, the destruction of high-value ecosystems and species loss. While it is emission-free, hydroelectric energy can result in significant biodiversity impacts and is also subject to long-term climate variability in the form of droughts.

Biomass, or the use of biologically derived materials for energy generation, is also considered a renewable-energy source and is carbon-neutral. Agricultural wastes are currently being explored as potential biomass feedstock. However, biomass is not an emission-free source of energy, and it is associated with other emissions. Biomass is used extensively in the fiber industry, as wood and bark waste are significant byproducts of its production process.

As of 2004, only about six percent of the energy consumed in the U.S. was from renewable-energy sources, and most of this was from hydroelectric sources. Despite a lack of aggressive federal leadership on renewable energy, states and industry are moving quickly toward renewable energy. Currently, 23 states have renewable-energy portfolio standards, and four states have voluntary renewable-energy goals. Diversifying one's energy portfolio not only supports the development of renewable energy, but it is also an astute hedge against the increasing volatility of petroleum-based energy markets.

Further resources on this topic can be found at The Energy Information Administration website, www.eia.doe.gov/neic/brochure/renew05/renewable.html. Information on states that offer financial incentives for renewables can also be found at www.dsireusa.org/.