12.4.8 Energy and transport
Under future climate change, demand for heating decreases and demand for cooling increases relative to 1961 to 1990 levels (Santos et al., 2002; Livermore, 2005; López Zafra et al., 2005; Hanson et al., 2006). In the UK and Russia, a 2°C warming by 2050 is estimated to decrease space heating needs in winter, thus decreasing fossil fuel demand by 5 to 10% and electricity demand by 1 to 3% (Kirkinen et al., 2005). Wintertime heating demand in Hungary and Romania is expected to decrease by 6 to 8% (Vajda et al., 2004) and by 10% in Finland (Venalainen et al., 2004) by the period 2021 to 2050. By 2100, this decrease rises from 20 to 30% in Finland (Kirkinen et al., 2005) to around 40% in the case of Swiss residential buildings (Frank, 2005; Christenson et al., 2006). Around the Mediterranean, two to three fewer weeks a year will require heating but an additional two to three (along the coast) to five weeks (inland areas) will need cooling by 2050 (Giannakopoulos et al., 2005). Cartalis et al. (2001) estimated up to 10% decrease in energy heating requirements and up to 28% increase in cooling requirements in 2030 for the south-east Mediterranean region. Fronzek and Carter (2007) reported a strong increase in cooling requirements for central and southern Europe (reaching 114% for Madrid) associated with an increase in inter-annual variability by 2071 to 2100. Summer space cooling needs for air conditioning will particularly affect electricity demand (Valor et al., 2001; Giannakopoulos and Psiloglou, 2006) with increases of up to 50% in Italy and Spain by the 2080s (Livermore, 2005). Peaks in electricity demand during summer heatwaves are very likely to equal or exceed peaks in demand during cold winter periods in Spain (López Zafra et al., 2005).
The current key renewable energy sources in Europe are hydropower (19.8% of electricity generated) and wind. By the 2070s, hydropower potential for the whole of Europe is expected to decline by 6%, translated into a 20 to 50% decrease around the Mediterranean, a 15 to 30% increase in northern and eastern Europe and a stable hydropower pattern for western and central Europe (Lehner et al., 2005). There will be a small increase in the annual wind energy resource over Atlantic and northern Europe, with more substantial increases during the winter season by 2071 to 2100 (Pryor et al., 2005). Biofuel production is largely determined by the supply of moisture and the length of the growing season (Olesen and Bindi, 2002). By the 22nd century, land area devoted to biofuels may increase by a factor of two to three in all parts of Europe (Metzger et al., 2004). More solar energy will be available in the Mediterranean region (Santos et al., 2002). Climate change could have a negative impact on thermal power production since the availability of cooling water may be reduced at some locations because of climate-related decreases (Arnell et al., 2005) or seasonal shifts in river runoff (Zierl and Bugmann, 2005). The distribution of energy is also vulnerable to climate change. There is a small increase in line resistance with increasing mean temperatures (Santos et al., 2002) coupled with negative effects on line sag and gas pipeline compressor efficiency due to higher maximum temperatures (López Zafra et al., 2005). All these combined effects add to the overall uncertainty of climate change impacts on power grids.