WORLD-GENERATION MAY/JUNE 2015 V.27 #2
28
PERSPECTIVE
Engineering
Design -
200
Project
Design -
200
Operations -
250
Financial
Viability -
125
Cost to
Customer -
225
Participation
In Planning -
100
Figure 3 – SPP Transmission Bid
Evaluation Criteria and Maximum Points
We now shift gears to another critical
aspect of what will affect transmission in the
coming years – environmental regulations,
and specifically, the Clean Power Plan (CPP).
Overall CPP Impacts on Transmission.
The CPP is likely to drive retirements and
changes in generating resource mix and dis-
patch patterns that could alter transmission
flows and impact overall system reliability.
Each one of the CPP’s building blocks, to
the extent they are relied upon by a state or
company for compliance, could have an
effect on transmission.
ICF continuously monitors and analyzes
the outlook for generation, and the likely
level of retirements and resources available
to meet the demand for power. The figure
below indicates ICF’s projections of which
plants will retire and which ones will stay on
line based on explicit limits on CO2 emis-
sions. Overall the older and smaller the
plant, the more likely it is to retire rather
than make the investments required to com-
ply with emissions regulations. From an
installed base of just over 300 GW, ICF
anticipates that the CPP will lead to dozens
of GW of early retirements, on top of dozens
of GW that will be retired by 2020 in
response to the Mercury and Air Toxics
(MATS) rule. The EPA itself has projected
that the CPP could result in an additional 49
GW of coal retirements by 2030.
2
Of course,
the final form of the CPP and factors such
as the level of gas prices will affect the level
of coal retirements.
In general, if there is a healthy surplus of
power capacity available in a region and new
generating units are in the pipeline, genera-
tion unit retirement may have a minimal
impact on the reliability of the grid.
However, significant retirements and chang-
es in generating resource mix, locations and
dispatch can cause changes in transmission
flow patterns and/or changes in substation
voltages, resulting in usage of the transmis-
2 Source: EPA’s “Regulatory Impact Anal-
ysis for the Proposed Carbon Pollution
Guidelines for Existing Power Plants and
Emission Standards for Modified and
Reconstructed Power Plants”, Table 3-12
sion system that is different from what it
was designed for. Indeed, the retirement of a
single generating facility may be considered
critical to the operation of the grid if it
increases power flows over certain transmis-
sion lines to the point where it causes them
to overload or creates variations in substa-
tion voltages beyond the reliable operating
limits. In fact, many power plants are cur-
rently located in load pockets or otherwise
constrained areas where they are needed to
support system reliability.
Retirements and other elements of the
CPP will certainly affect the level of invest-
ment required in the transmission system,
as the dispatch of the system, and the oper-
ation of the system to maintain reliability,
minimize congestion and provide access to
renewable power will all need to change, as
coal plants are removed and more natural
gas and renewables come on stream.
How large is the required transmission
investment? In a word, it could be consid-
erable. Recently, ICF undertook a study to
Figure 4 – ICF Projected
Coal Retirements by
2020
assess the impact of the CPP on the need
for investment on just one of the functions
of the transmission system – that of trans-
mission security. By transmission security,
we refer to the ability of the grid to contin-
ue operating reliably following sudden and
unanticipated events, such as the loss of
power from a major generating station or
the loss of a key transformer. The invest-
ments required for such security would
include new transmission lines, transmission
system upgrades, and reactive power devic-
es to resolve the line overloads and exces-
sive voltage variations that could occur.
ICF selected one region – MISO – and
assessed the need for transmission security
investment that would arise from the CPP.
What we found was that such investment
was vital to maintaining such security. In
fact, as Figure 5 shows, without such timely
investment, the system would experience a
high number and intensity of thermal line
overloads (12 such overloads at 120% or
(continued page 29)
WHO GETSTO BUILDTRANSMISSION?
CONTINUED FROM PAGE 27
