Clean technology refers to renewable energy sources (such as wind power, solar power, biomass, hydropower, and biofuels), recycling, information technology, green transportation (such as electric motors), green chemistry and many other sources of energy efficiency. Its purpose is to create electricity and fuels with a smaller environmental footprint, to minimise pollution, and to make buildings, transport and infrastructure both more energy efficient and environmentally neutral.

Clean technologies can be competitive with, if not superior to, their conventional counterparts, and many offer significant additional benefits. Many countries now have clean technology advocates to speak about the countries’ problems with pollution and inefficiency.

New clean technology projects can obtain finance through the generation of carbon credits. A carbon credit is the term for any tradable certificate or permit representing the right to emit one tonne of carbon dioxide, or another greenhouse gas equivalent to one tonne of carbon dioxide.

Carbon credits and carbon markets are a facet of national and international attempts to limit the growth in concentrations of greenhouse gases. The aim is to allow markets to drive industrial and commercial processes in the direction of lower emissions and less carbon intensive approaches than those used when there is no cost to emitting carbon dioxide and other green house gases into the atmosphere.

Investments in clean technology have grown considerably since around the turn of the century. According to UN figures wind, solar, and biofuel companies received almost $150 billion in new funding in 2007, as rising oil prices and a shift in political thinking regarding climate change (in the US, both John McCain and Barrack Obama supported climate change policies in the 2008 Presidential election) encouraged investment in renewable energy. Around $50 billion of that funding went to wind power and, overall, investment in clean-energy and energy-efficiency industries rose 60% from 2006 to 2007.

Cleantech is the term used to describe any product or service that improves operational performance, productivity, or efficiency while at the same time reducing costs, energy, inputs, consumption, waste, or environmental pollution.