Sustainable energy is energy that provides the needs of the present without compromising the ability of future generations to meet their energy needs. Renewable energy and energy efficiency are said to be the "twin pillars" of sustainable energy policy.
Efficiency is essential to slowing the energy demand growth so that rising clean energy supplies can make deep cuts in fossil fuel use. If energy use grows too fast, renewable energy development will chase a receding target. Likewise, unless clean energy supplies come online rapidly, slowing demand growth will only begin to reduce total emissions; reducing the carbon content of energy sources is also needed.
Energy efficiency can apply to all sources of energy.
- The Twin Pillars of Sustainable Energy: Synergies between Energy Efficiency and Renewable Energy Technology and Policy Report E074, 2007. From the website of the American Council for an Energy-Efficient Economy
- Global Best Practice in Renewable Energy Policy Making 2007, From the website of the International Energy Agency (2007).