Energy consumption is projected to grow due to demographic and socio-economic factors (see Section 11.3.2). However, average and peak energy demands are also linked to climatic conditions. Increases in peak energy demand due to increased air-conditioner use are likely to exceed increases for base load. The risk of line outages and blackouts is likely to increase (PB Associates, 2007). More peak generating capacity is likely to be needed beyond that for underlying economic growth (Howden and Crimp, 2001). For a 2°C warming, peak demand increases 4% in Brisbane and 10% in Adelaide, but decreases 1% in Melbourne and Sydney (Howden and Crimp, 2001). About 10% of the existing asset levels may be required to allow for climate-related increases in peak demand by 2030 (PB Associates, 2007). However, annual total demand may be less sensitive to warming; a likely reduction in winter heating demand counteracts the increasing summer demand, e.g., New Zealand electricity demand decreases by 3%/°C increase in mean winter temperature (Salinger, 1990).
Climate change is likely to affect energy infrastructure in Australia and New Zealand through impacts of severe weather events on wind power stations, electricity transmission and distribution networks, oil and gas product storage and transport facilities, and off-shore oil and gas production (see Chapter 7). There are also likely to be costs and damages that can be avoided by adaptation and mitigation (see Section 18.4). An assessment of potential risks for Australia (PB Associates, 2007) found (i) increased peak and average temperatures are likely to reduce electricity generation efficiency, transmission line capacity, transformer capacity and the life of switchgear and other components; (ii) if climate changes gradually, both the generation utilities and the equipment manufacturers are likely to have enough time to adjust their standards and specifications; and (iii) vulnerability to the above impacts is low, but there is medium vulnerability to a decline in water supply for large-scale coal, hydro and gas turbine power generation.
In New Zealand, increased westerly wind speed is very likely to enhance wind generation and spill-over precipitation into major South Island hydro catchments, and to increase winter rain in the Waikato catchment (Wratt et al., 2004). Warming is virtually certain to increase snow melt, the ratio of rainfall to snowfall, and river flows in winter and early spring. This is very likely to assist hydroelectric generation at the time of highest energy demand for heating.