Geoscience Reference
In-Depth Information
impacts on energy consumption. Water savings have been calculated for California by
several authors, including Gleick et al. (2003), Klein (2005), Cooley et al. (2008), and for
Las Vegas (Cooley et al., 2007).
8) CONCLUSIONS
Broadly speaking, the main conclusions of the SAP 4.5 report concerning the efects
of climate change on the future demand for energy in buildings remain valid. The
annual demand for heating energy likely will decline and the annual demand for cool-
ing energy likely will increase. In the northern states, where heating currently pre-
dominates, the impact on heating will be greater than the impact on cooling and the net
impact on energy demand will be an energy savings. In the southern states and in some
mid-latitude states, increases in cooling will more than compensate for declines in heat-
ing and the net use of energy in buildings will increase. These efects persist for both the
older climate scenarios and the newer scenarios used by the IPCC.
What has changed are some of the details. Studies published since 2007 have atempt-
ed to estimate the efects of climate change while taking into account complicating fac-
tors such as the increased purchase and utilization of air conditioning as temperatures
increase; electriication of heating systems as warming climates make heat pumps more
practical; diferential impact of increasing internal heat gains from lighting and plug
loads on heating and cooling loads; efects on building loads of urban sprawl and urban
heat islands; and “graying” of the population. More studies have addressed increases
in system peak electrical loads due to increased cooling. Expanding the electrical gen-
eration, transmission, and distribution system to meet additional peak electrical load
is a major potential capital cost of warming, regardless of what happens with total
energy consumption. Most of the detailed complicating factors mentioned above tend to
increase cooling demand and reduce heating demand, thus compounding the efects of
climate change alone.
Climate change also is expected to increase the demand for water in agriculture
and, along with growth in the population and economy, put more demand pressure
on existing sources of water supply. In turn, this increased demand pressure for water
in most places will mean that more energy must be used in pumping and conveying
water for irrigation (and sometimes urban supply) and that more water will be lost in
conveyance, storage and power plant cooling. Growing human populations increas-
ingly compete for more distant water of poorer and poorer quality, which with more
water demand likely will mean that more water and more waste water will have to be
treated more aggressively to achieve drinking water standards. That, in turn, takes more
energy, mostly electricity. More quantitative information has become available on the
energy cost of water demand and supply as climate changes. In some states with elabo-
rate long-range irrigation and urban water distribution systems or deep groundwater
sources, the energy costs of supplying water are substantial and have the prospect of
becoming larger still.
More studies are paying atention to adaptive responses in eforts to reduce impacts
of climate change on energy and water bills and the environment. Examples include
low-E windows to reduce solar gain and cooling loads, carefully designed building
lighting, mass, shading, orientation and lot placement to reduce cooling and heating
