National Electric Transmission Congestion Study - W2agz.com

prices during binding hours in 2008 and 2015.
Some of the high transmission loading is driven by
the two metro areas’ reliability needs, but some is
caused by the recent proliferation of new generation
capacity in Arizona built to serve California loads.
Transmission planners have identified a set of transmission
solutions that should help address the Arizona
problems and manage new generation interconnection
and flows more effectively. However,
until there is more certainty with respect to approval
for these new lines, generation construction, and
long-term procurement contracting between wholesale
purchasers and producers, transmission adequacy
in the Phoenix – Tucson area will merit continued
attention from the Department of Energy.
5.4. Enabling New Resource
Development: Conditional
Constraint Areas
One of the principal benefits of new transmission is
to enable the development of new supply resources
in remote area to serve urban load centers. A variety
of companies are refining proposals to develop
large concentrations of new generation in specific
areas—such as wind in the Dakotas and Western
Kansas, mine-mouth coal in the Powder River Basin
and Appalachia, and nuclear power in the Southeast.
If this concentrated generation capacity were
to be developed without associated transmission facilities,
its output could not be delivered to loads because
the existing grid would not be able to accommodate
the flows. Significant investments in new
backbone transmission will be needed to enable the
commercial success of such generation development
projects.
The congestion study analysts used two alternative
generation development scenarios to assess their
impacts on transmission congestion. The Eastern
Interconnection scenario assumed substantial new
wind development in the Northern Great Plains and
Western Kansas, and the Western Interconnection
analysis used a scenario projecting new wind development
in Southern California and Wyoming and
new coal development in Wyoming and Montana.
In both scenarios, it is clear that only a limited
amount of output from new generation capacity
could be delivered from the source nodes to markets
using existing transmission facilities without causing
new congestion problems. This conclusion
should not be surprising. The transmission networks
in these areas were designed to accommodate
existing or projected local and sub-regional requirements,
as opposed to major increases in the volume
of electricity produced for export. In some areas upgrades
are already needed to meet nearby requirements.
Concerns about energy security and the need for
greater diversification in electricity supplies are
leading to increased emphasis on development of
domestic energy resources. Federal and state policies
will greatly affect which areas are developed
and when. Some of these policy decisions have already
been made: twenty-two states, representing
more than 40% of U.S. electricity sales, have
adopted some type of renewable portfolio requirement.
Wind power is expected to constitute the bulk
of new renewable purchases (i.e., non-hydro) and
for the foreseeable future wind is expected to be the
dominant renewable capacity investment. 57
The U.S. has vast reserves of coal, most of which is
located far from load centers. Although historically
most coal has been delivered by rail to power plants
sited near load centers (as opposed to mine-mouth
generation and delivery of electricity to load centers
by wire), railroad capacity is also constrained and it
has become about as difficult and expensive to build
new rail as it is to build new transmission. Thus,
many proposals to build new coal-fired generation
contemplate building an associated high-voltage or
ultra-high voltage line to deliver the coal to distant
load centers.
As discussed previously, the degree of congestion
projected in a simulation model is determined in
large part by the assumptions made—for example,
if one were to design a 2015 western case with
2,000 MW of new coal-fired power plants on-line in
Wyoming, and add major new lines to deliver that
57 Nonetheless, sizeable amounts of potential commercial-scale geothermal, solar, and biomass generation capacity were identified as possible by
2015 in the report of the Clean and Diversified Energy Advisory Committee (CDEAC) to the Western Governors, June 2006. Much of this
non-wind renewables capacity would also require development of new transmission capacity.
U.S. Department of Energy / National Electric Transmission Congestion Study / 2006 49