The residential and commercial sectors can adopt energy-efficient technologies. Technologies with pay-back periods of five years or less are available for many types of equipment now used in buildings. Other options are mandatory or voluntary energy-efficiency standards, public and private research into more efficient products, and information and training programs. A combination of regulatory, information, and incentive programmes may offer the best approach to boosting the energy efficiency of these sectors. The spread of new technologies and practices is often blocked by cultural, institutional, legal, informational, financial, and economic barriers.
Government policies can help to remove some of the blockages.
Governments can also support carefully targeted research, development, and demonstration projects for technologies that can reduce emissions and improve efficiency. Another option is to introduce emissions targets together with tradable emissions permits that companies can buy and sell. Deep reductions in greenhouse gas emissions from fossil fuels are possible over the next 50 to 100 years. Technology innovation and an emphasis on renewable energy sources, particularly biomass, will be essential for achieving these goals, and some countries may also consider nuclear energy. Since many different combinations of technologies could be used, this future energy-supply system could be constructed in any number of ways.