[Congressional Bills 118th Congress]
[From the U.S. Government Publishing Office]
[S. 4144 Introduced in Senate (IS)]
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118th CONGRESS
2d Session
S. 4144
To improve the reliability and adequacy of the bulk-power system by
ensuring that key uncertainties in generation, transmission, energy
storage systems, and loads are considered in resource adequacy modeling
and integrated resource planning, and for other purposes.
_______________________________________________________________________
IN THE SENATE OF THE UNITED STATES
April 17, 2024
Mr. Heinrich (for himself, Mr. Wyden, and Mr. Padilla) introduced the
following bill; which was read twice and referred to the Committee on
Energy and Natural Resources
_______________________________________________________________________
A BILL
To improve the reliability and adequacy of the bulk-power system by
ensuring that key uncertainties in generation, transmission, energy
storage systems, and loads are considered in resource adequacy modeling
and integrated resource planning, and for other purposes.
Be it enacted by the Senate and House of Representatives of the
United States of America in Congress assembled,
SECTION 1. SHORT TITLE.
This Act may be cited as the ``Grid Modeling of Dynamic Energy
Loads and Resources Act of 2024'' or the ``Grid MODEL Act of 2024''.
SEC. 2. DEFINITIONS.
In this Act:
(1) Bulk-power system.--The term ``bulk-power system'' has
the meaning given the term in section 215(a) of the Federal
Power Act (16 U.S.C. 824o(a)).
(2) Commission.--The term ``Commission'' means the Federal
Energy Regulatory Commission.
(3) Effective load carrying capability; elcc.--
(A) In general.--The term ``effective load carrying
capability'' or ``ELCC'' means the ability of a
generating resource to produce electricity when the
grid needs it, measured as the additional load (or
perfect replacement capacity) that the system can
supply with a particular generator of interest with no
net change in reliability.
(B) Clarification.--The additional load (or perfect
replacement capacity) referred to in subparagraph (A)--
(i) may be measured using LOLE, EUE, or
other metrics; and
(ii) may be divided by the nameplate
capacity of the generating resource to yield a
percentage.
(4) Electric reliability organization.--The term ``Electric
Reliability Organization'' has the meaning given the term in
section 215(a) of the Federal Power Act (16 U.S.C. 824o(a)).
(5) Electric utility.--The term ``electric utility'' has
the meaning given the term in section 3 of the Federal Power
Act (16 U.S.C. 796).
(6) Expected unserved energy; eue.--The term ``expected
unserved energy'' or ``EUE'' means the cumulative amount of
energy (in megawatt-hours) per year that is not provided to
customers due to outages.
(7) Independent system operator.--The term ``Independent
System Operator'' has the meaning given the term in section 3
of the Federal Power Act (16 U.S.C. 796).
(8) Integrated resource planning.--The term ``integrated
resource planning'' means modeling and evaluating how projected
long-term electricity demands (such as electricity demands over
periods of 5, 10, 20, or more years) within a service area can
be met with a combination of electric generation resources that
best achieve desired metrics, such as metrics relating to
reliability, resilience, and cost.
(9) Loss of load expectation; lole.--
(A) In general.--The term ``loss of load
expectation'' or ``LOLE'' means the expected number of
days per year that the available generation capacity is
less than the system load for the applicable power grid
region or service area.
(B) Clarification.--As of November 2023, a commonly
acceptable value for loss of load expectation is 0.1
days per year, as described in the standard of the
North American Electric Reliability Corporation
entitled ``Planning Resource Adequacy Analysis,
Assessment and Documentation'' and numbered BAL-502-RF-
03.
(10) Planning reserve margin.--
(A) In general.--The term ``planning reserve
margin'' means the quotient, expressed as a percentage,
obtained by dividing--
(i) the difference between--
(I) deliverable electric system
supply capacity for a power grid region
or service area; and
(II) net demand in that power grid
region or service area; by
(ii) net demand in that power grid region
or service area.
(B) Clarification.--As of November 2023, a reserve
margin falling within the range from 15 percent to 25
percent is typical for a power grid region or service
area.
(11) Power grid.--The term ``power grid'' means that
portion of an Interconnection (as defined in section 215(a) of
the Federal Power Act (16 U.S.C. 824o(a))) that is located
within the United States, including the relevant portion of
each of the following:
(A) The Eastern Interconnection.
(B) The Western Interconnection.
(C) The Texas Interconnection.
(12) Power grid region.--The term ``power grid region''
means a geographic area--
(A) located within a power grid; and
(B) for which a regional entity (as defined in
subsection (a) of section 215 of the Federal Power Act
(16 U.S.C. 824o)) has enforcement authority under that
section.
(13) Probabilistic modeling.--
(A) In general.--The term ``probabilistic
modeling'' means a modeling approach that uses
statistics to simulate and quantify the likelihood of
achieving desired metrics, taking into consideration
all modeled uncertainties, for determination of the
optimal resource portfolio, such as a modeling approach
consistent with the document of the North American
Electric Reliability Corporation entitled
``Probabilistic Assessment Technical Guideline
Document'' and dated August 2016, including the
recommendations described in that document.
(B) Inclusion.--The term ``probabilistic modeling''
includes modeling that can identify the most important
parameters that impact a simulated metric for further
characterization or optimization.
(14) Regional transmission organization.--The term
``Regional Transmission Organization'' has the meaning given
the term in section 3 of the Federal Power Act (16 U.S.C. 796).
(15) Reliability standard.--The term ``reliability
standard'' has the meaning given the term in section 215(a) of
the Federal Power Act (16 U.S.C. 824o(a)).
(16) Resource adequacy.--The term ``resource adequacy''
means the adequate supply and provision of electricity from
various electric generation resources to meet projected
electricity demands in a particular power grid region or
service area.
(17) Service area.--The term ``service area'' means the
area or region served by--
(A) an electric utility;
(B) a Regional Transmission Organization; or
(C) an Independent System Operator.
(18) State regulatory authority.--The term ``State
regulatory authority'' has the meaning given the term in
section 3 of the Federal Power Act (16 U.S.C. 796).
SEC. 3. PROBABILISTIC MODELING FOR BULK-POWER SYSTEM RESOURCE ADEQUACY
MODELING AND INTEGRATED RESOURCE PLANNING.
(a) In General.--The Commission, pursuant to section 215(d) of the
Federal Power Act (16 U.S.C. 824o(d)), shall--
(1) as soon as practicable after the date of enactment of
this Act, order the Electric Reliability Organization to submit
to the Commission, not later than 18 months after the date of
that order, or as soon as practicable thereafter, 1 or more
proposed reliability standards or modifications to reliability
standards to require, and ensure consistent methods (based on
best-practices) for, the use of probabilistic modeling that
includes consideration of key uncertainties in generation,
transmission, energy storage systems, and loads for resource
adequacy modeling and integrated resource planning relating to
the bulk-power system, reflecting the specific needs,
resources, and attributes of a given power grid region or
service area; and
(2) as soon as practicable after the submission of a
proposed reliability standard or modification of a reliability
standard under paragraph (1), approve the proposed reliability
standard or modification in accordance with that section, if
appropriate.
(b) Requirements.--
(1) Generation.--With respect to generation, the
reliability standards approved under subsection (a) shall
require that probabilistic modeling for resource adequacy
modeling and integrated resource planning shall include, to the
maximum extent practicable, consideration of uncertainties
relating to, as applicable for a given power grid region or
service area--
(A) the impact of distributed generation resources;
(B) degradation from aging (such as soiling and
degradation of photovoltaic modules and batteries);
(C) planned and unplanned outages;
(D) the impact of weather (such as solar
irradiance, wind, precipitation, snowpack, and extreme
temperatures) on conventional and distributed
generation resources;
(E) correlated outages (such as correlated outages
due to winter storms, extreme heat, wildfires, and
other extreme weather events);
(F) costs of generation resources, including costs
of acquired energy efficiency as a resource; and
(G) other relevant generation uncertainties, as
determined by the relevant electric utility, Regional
Transmission Organization, Independent System Operator,
or State regulatory authority.
(2) Transmission.--With respect to transmission, the
reliability standards approved under subsection (a) shall
require that probabilistic modeling for resource adequacy
modeling and integrated resource planning shall include, to the
maximum extent practicable, consideration of uncertainties
relating to, as applicable for a given power grid region or
service area--
(A) the impact of weather (such as the impact of
temperature on transmission facilities, including line
ratings);
(B) congestion and thermal overload;
(C) costs of new or modified transmission
infrastructure; and
(D) other relevant transmission uncertainties, as
determined by the relevant electric utility, Regional
Transmission Organization, Independent System Operator,
or State regulatory authority.
(3) Energy storage.--With respect to energy storage, the
reliability standards approved under subsection (a) shall
require that probabilistic modeling for resource adequacy
modeling and integrated resource planning shall include, to the
maximum extent practicable, consideration of uncertainties
relating to, as applicable for a given power grid region or
service area--
(A) round-trip efficiency;
(B) battery capacity fade;
(C) the impact of weather (such as the impact of
drought on pumped hydrologic storage);
(D) the impact of distributed energy storage;
(E) costs of energy storage; and
(F) other relevant energy storage uncertainties, as
determined by the relevant electric utility, Regional
Transmission Organization, Independent System Operator,
or State regulatory authority.
(4) Loads.--With respect to loads, the reliability
standards approved under subsection (a) shall require that
probabilistic modeling for resource adequacy modeling and
integrated resource planning shall include, to the maximum
extent practicable, consideration of uncertainties relating to,
as applicable for a given power grid region or service area--
(A) the impact of temperature and weather,
including extreme weather events, on loads;
(B) the timing and changing mix of loads,
including--
(i) increased electrification of
transportation, including bidirectional
charging and discharging of batteries used in
electric vehicles;
(ii) increased electrification of home
appliances, such as hot-water heaters and
ovens, and space heating and cooling; and
(iii) increased electrification of
industrial processes; and
(C) other relevant electric-load uncertainties, as
determined by the relevant electric utility, Regional
Transmission Organization, Independent System Operator,
or State regulatory authority.
(c) Use of Modeling.--The reliability standards approved under
subsection (a) shall require probabilistic modeling to be used, at a
minimum--
(1) to simulate and quantify desired metrics (such as loss
of load expectation, expected unserved energy, effective load
carrying capability (also known as ``capacity value''),
planning reserve margin, and cost), taking into consideration
the relevant uncertainties described in subsection (b), to
assist in the determination of the optimal resource portfolio
for the applicable power grid region or service area; and
(2) to identify the parameters and processes considered
under subsection (b) that--
(A) are the most important, in that they have the
most impact on the magnitude or uncertainty of the
applicable simulated metrics; and
(B) can be further characterized or optimized to
improve the modeling and determination of the optimal
resource portfolio for the applicable power grid region
or service area.
(d) Existing Approaches; State Requirements.--
(1) In general.--The reliability standards approved under
subsection (a)--
(A) shall take into consideration, and shall allow
for the continued use of, any probabilistic modeling in
use by an electric utility, a Regional Transmission
Organization, or an Independent System Operator as of
the date of enactment of this Act; and
(B) shall not preempt, or exempt any electric
utility, Regional Transmission Organization, or
Independent System Operator from compliance with, any
probabilistic modeling requirement under State law.
(2) Requirements.--To the maximum extent practicable, the
reliability standards approved under subsection (a) shall allow
for compliance with those reliability standards to be
achieved--
(A) in a manner consistent with--
(i) the probabilistic modeling described in
subparagraph (A) of paragraph (1); and
(ii) any requirements described in
subparagraph (B) of that paragraph; and
(B) by demonstrating--
(i) the use of probabilistic modeling in
accordance with subparagraph (A) or (B) of that
paragraph; and
(ii) that the probabilistic modeling
adequately reflects, or has been modified or
used in a manner to adequately reflect, the
requirements described in subsections (b) and
(c).
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