on the cover solar market development
its own nation, its installed wind capacity is surpassed by only a handful of other countries in
the world. Furthermore, America’s single-larg-est wind farm exists in Texas at the Horse Hollow Wind Energy Center. This 736-MW facility
might soon be overtaken by another Texan wind
farm, if Shell and TXU are able to bring their
vision of a 3,000-MW farm to fruition. Even T.
Boone Pickens, an icon of the Texas oil and gas
business, has hopped on the wind bandwagon
with plans to build a 4,000-MW wind farm in
the Panhandle that, by itself, would exceed the
total installed capacity of every other state in
the nation.
although the current
statewide total of installed
solar capacity is less than
7 m W, the time might be
right for it to follow the path
charted by wind.
Because of the success with wind, interesting political alliances are being formed. Rural
Republicans, who like wind because of the
economic revitalization it offers, are teaming
up with urban Democrats, who like wind’s
low-carbon and renewable characteristics, to
support growth in other forms of renewable
power. Consequently, this past biannual session of the Texas legislature generated a flurry
of bills intended to support solar power. One
new law enables homeowners to finance solar
panels through their property tax bills over a
few decades, instead of forking over thousands
of dollars upfront. In addition, Texas utility
companies already offer attractive incentives
for residential solar installations. Municipal
utility Austin Energy ( austinenergy.com), for
example, offers a rebate of $3.75 per watt for
residential customers. Entergy (entergy-texas.
com) in Houston, Galveston and Beaumont and
municipal utility CPS Energy ( cpsenergy.com)
in San Antonio offer similar rebates.
Although the statewide total of installed
solar capacity is less than 7 MW, the time might
Figure 2: SOLAR RESOURCES IN TEXAS
Average Solar Insolation
in December
Average Solar Insolation
in July
!
Texas has abundant insolation. The average incoming solar energy is shown in December (left) and July (right) for Texas, varying
from about 2. 4 to 8.0 kilowatt-hours per square meter per day across the state’s seasons and geography. Measurement locations
are marked with triangles, with the highest insolation occurring at Presidio. Source: Wogan, da Silva & Webber
abundant resources
Drive solar market
A key driver for energy markets worldwide
remains the location of resources. Texas became
a world leader in oil, gas and wind simply because
vast resources for each are located in the state.
Similarly, states with large solar resources will
dominate the solar power arena.
Texas’ solar resource is among the largest
of any state in the nation, with an average daily
insolation ranging from 2. 4 kilowatt-hours per
square meter a day in the eastern portion of the
state in December to 8.0 kilowatt-hours per
square meter a day in the western portion in July
(see Figure 2, above). Compared with states
like New Jersey and countries like Germany,
both of which have installed more solar so
far than Texas, the relative potential is blindingly obvious. In Austin alone, a recent study
found that more than 2 gigawatts (GW) of solar
capacity could be installed on south-facing,
unshaded rooftops.
In addition to its vast natural resources, Texas
also has the man-made resources that are beneficial for a booming solar market. In particular,
Texas has significant installed natural gas capacity, its own grid structure and commitments to
build additional transmission capacity, all of
which will help bring solar power online sooner
rather than later.
Because of solar power’s variability, many
grid managers and utility operators expect that
new solar installations will need auxiliary natural
gas-fired capacity to function as backup firming
power, with estimates varying anywhere from
0.5 to 1 MW of natural gas required for every
1 MW of solar power. In this regard, Texas
is well ahead of the rest of the country. Over
recent decades, Texas has installed a significant
capacity of natural gas generators for baseload
and peaking power. In fact, the state generates
about half of its electricity from natural gas and
4 percent from wind; by comparison, the nation
generates about half of its electricity from coal
and 1 percent from wind (see Figure 3, facing
page). Much of the natural gas capacity in Texas
is underutilized, making it available to provide
firming power when solar and wind resources
are not available. Developers can then concentrate on building solar farms without also having
to build natural gas plants.
In addition to its extensive natural gas installations, Texas has its own grid. (There are only
three grids in America: East, West and Texas.)
The Texas interconnect, operated by the Elec-
be right for solar to follow the path charted by
wind. If it follows wind’s trajectory over the
next decade, then Texas will become one of the
world’s hottest solar markets.
