Payback Period

An accounting term indicating the time required to recoup an investment. It is expressed as a ratio of investment cost to savings or income (usually annually). For example, if a new high-efficiency boiler costs $10,000 to install and saves $2500 per year in fuel, the payback period is four years. Payback periods are critical to environmental and energy efficiency. Currently, conventions of short-term business thinking look at time periods less than... Read More

Carbon Footprint

The total amount of greenhouse gases emitted directly and indirectly to support human activities, usually expressed in equivalent tons of either carbon or carbon dioxide. Carbon footprints are calculated by countries as part of their reporting requirements under the Kyoto Protocol, as well as by companies, regions, or individuals. Direct greenhouse gas emissions can include tailpipe emissions of CO2 from motor vehicles, methane from landfills, and... Read More

Market Failure

A market’s inability to create maximum efficiency, by not properly providing goods or services to consumers, not efficiently organizing production, or not serving the public interest. The term does not refer to the collapse or demise of a market, but instead to the unintended and unwanted consequences of decisions made by economic actors. A variety of elements can cause market failures including: Abusive market power, such as monopolies Negative... Read More

RoHS Directive

The Restriction of Hazardous Substances directive is EU legislation that bans the sale of electrical and electronic products containing specific toxic contaminants: Lead, Mercury, Chromium, Cadmium, Brominated flame retardants (PBBs & PBDEs) in amounts exceeding set Maximum Concentration Values (MCV). Producers (manufacturers, sellers and resellers of own-brand equipment, and importers and exporters) must demonstrate compliance by submitting... Read More

WEEE Recycling Directive

EU legislation that sets criteria for the collection, treatment, recycling and recovery of Waste Electrical & Electronic Equipment. It makes producers (manufacturers, sellers and resellers of own-brand equipment, and importers and exporters) responsible for financing most of these activities. This directive requires the collection and treatment of any electrical or electronic equipment which is waste including all components, sub-assemblies and... Read More


Engaging in responsible travel to natural areas while conserving the environment and improving the well-being of local people. Those who lead or participate in ecotourism activities strive to: Minimize their impact Build environmental and cultural awareness and respect Provide positive experiences for both visitors and hosts Provide direct financial benefits for conservation Provide financial benefits and empowerment for local people Raise sensitivity... Read More


The worldwide integration of products, services, employment, people, cultures, markets, and economies and the compression of both time and distance that often accompanies it. Globalization often refers specifically to the growing economic interdependence of countries worldwide through increasing cross-border transactions in goods and services, free flow of international capital, and more rapid and widespread diffusion of technology. Globalization... Read More

Radical Resource Productivity

Obtaining the same or increased amount of utility or work from a product or process while using fewer resources, including energy, man-made materials, and natural resources such as air, water, or minerals. The Industrial Revolution sparked a radical increase in human productivity, which relied on a seemingly unlimited supply of natural resources. Similarly, a radical increase in resource productivity can save money, slow or reverse resource depletion,... Read More


Biodiesel is a type of fuel that is highly suitable for diesel engines. More specifically it is derived from a variety of oils such as soybean, corn, algae, and peanut oil, and is distinct from its origin in that it is more easily combustible due to a process of glycerin removal; it can be easily blended with petroleum and/or other biodiesel fuels. 2  Read More

Net-Zero Energy Home

A home employing site-appropriate passive solar design, site-appropriate renewable energy products, and proven energy efficiency/conservation technologies and practices, resulting in an annual contributionto the electricity grid that is equal to or greater than the amount of power the home uses from the grid. Common sources of energy generation for the N-ZEH are PV panels and solar hot water, wind turbines, and geo-thermal heating and cooling systems.... Read More