Trombe wall for passive solar heating and daylighting at the National Renewable Energy Laboratory’s Visitor Center. By providing passive heat from the sun’s energy, this building design decreases the need for burning fossil fuels such as propane or natural gas to heat its interior. Source: National Renewable Energy Laboratory.
Improving energy efficiency reduces how much energy is needed to achieve the same amount of work. For example, a more energy efficient home will provide the same quality of services to inhabitants in terms of hot water, heating, cooling, and lighting but using a smaller amount of energy. While clean energy is growing at an exponential rate, meeting global energy demands with clean energy in the timeframe needed to limit global warming to below 2ºC requires a reduction in overall energy needs (IPCC 2014).
Improved technologies and system designs can result in more efficient energy usage, and in turn, energy savings. Despite incremental improvements in efficiency over time, efficiency remains an untapped resource. According to a recent report by IEA Energy Efficiency, only 30% of global energy is currently subject to energy efficiency standards. Despite minimal energy efficiency policies in place, between 2010 and 2018 the average global improvement in primary energy intensity was 2.1% per year (IEA Energy Efficiency 2019).