220.127.116.11 Energy demand
Buildings account for a significant part of total energy use, up to 50% in some developed countries (Lorch, 1990; also see Levine et al., 2007), and the design and energy performance of buildings are related to climate (Steemers, 2003). Work related to climate change and building energy use can be grouped into two major areas – weather data analysis and building energy consumption.
Weather data analysis
A study on 1981 to 1995 weather data (Pretlove and Oreszczyn, 1998) indicated that temperature and solar radiation in the London area (UK) had changed significantly over the period, and climatic data used for energy design calculations could lead to 17% inaccuracies in building energy-use estimates. Based on 1976 to 1995 temperature data from 3 key UK sites, Levermore and Keeble (1998) found that the annual mean dry-bulb temperature had increased by about 1°C over the 19-year period, with milder winters and warmer summers. In sub-tropical Hong Kong SAR, the 40-year period (1961 to 2000) weather data showed an underlying trend of temperature rise, especially during the last 10 years (1991 to 2000) (Lam et al., 2004). The increases occurred largely during the winter months and the impact on peak summer design conditions and cooling requirements, and hence energy use, was considered insignificant. In the 1990s and 2000s, many countries experienced extreme phenomena (notably heatwaves in summer), which induced exceptional peaks of electric power consumption (Tank and Konnen, 2003). These had notable impacts on human mortality (Section 1.3.7) and local socio-economic systems (Easterling et al., 2000; Parmesan et al., 2000; Johnson et al., 2004). Two well-documented cases are the heatwaves in Chicago in 1995 (Karl and Knight, 1997) and in Europe in 2003 (Schär et al., 2004; Trigo et al., 2005).
Building energy consumption
One example related to energy and climate concerns cooling during hot weather. Energy use has been and will continue to be affected by climate change, in part because air-conditioning, which is a major energy use particularly in developed countries, is climate-dependent. However, the extent to which temperature rise has affected energy use for space heating/cooling in buildings is uncertain. There is a concern that energy consumption will increase as air-conditioning is adopted for warmer summers (see Levine et al., 2007). It is likely that certain adaptation strategies (e.g., tighter building energy standards) have been (or would be) taken in response to climate change (e.g., Camilleri et al., 2001; Larsson, 2003; Sanders and Phillipson, 2003; Shimoda, 2003). Adaptation strategies and implementation are strongly motivated by the cost of energy. Besides, in terms of thermal comfort, there is also the question of people adapting to warmer climates (e.g., de Dear and Brager, 1998; Nicol, 2004).