Environmental Engineering Reference
In-Depth Information
Figure 11.2 Trend toward grid-connected
photovoltaic installations [150]. The total
capacity has been increasing strongly, so this
figure does not imply a reduction in capacity in
remote industrial
or
remote habitation
categories, but rather that the
grid connected
category, which includes large
solar farm
installations plus grid-connected rooftop
installations, has been rapidly increasing and is
projected to further increase.
the equivalent power capacity was 105 GW, much larger than the solar electric
capacity at that time. It is reported that 20 GW of solar water heating capacity was
installed in 2007 [148]. These systems have no problems either with intermittency or
with distribution of the energy. For heating water, such a system is 10 times more
ef
cient than using solar electric power to run a water heater.
In Figure 11.1 the solar category shows about two-thirds of the investment as
small distributed capacity, compared to large installations. This is described as
overwhelmingly photovoltaics on rooftops, which have been subsidized especially
in Germany and are well known in California. (A scenario of rooftop photovoltaics
proposed for New York City was described in Chapter 5.) The rooftop photovoltaics
are predominantly grid connected, and illustrate a trend noted in Figure 11.2.
11.2
Renewable Energy Beyond Solar and Wind
Figure 11.1 indicated major but falling investments in biomass and biofuels in 2010
versus 2009. Also noted are investments in small hydropower and marine (water
turbines andwave energy devices), and in geothermal. Several of the energy topics we
have classied as renewable and covered in this topic are not listed in Figure 11.1.
Thismightmean the numbers are too small to list or even that no activity is occurring,
