Sprint Studies for the i2x Roadmap

The Interconnection Innovation e-Xchange (i2X) is a partnership platform to bring together diverse stakeholders involved in the interconnection of solar and wind energy resources to the electric grid. i2X is a program of the U.S. Department of Energy’s (DOE) Solar Energy Technologies Office (SETO) and Wind Energy Technologies Office (WETO), funded under the Bipartisan Infrastructure Law (BIL). Pacific Northwest National Lab (PNNL), National Renewable Energy Lab (NREL), and Lawrence Berkeley National Lab (LBNL) support SETO and WETO in i2X.

To address increasingly pervasive climate concerns and achieve deep decarbonization in alignment with the Biden Administration’s 2035 decarbonization goals, the electric grid is transforming rapidly, with interconnection processes for solar and wind resources becoming more complex as penetration levels increase. Throughout the United States, queue times to interconnect solar and wind have been rising, jeopardizing ambitious state-level decarbonization goals. i2X will develop innovative solutions and provide technical assistance to enable faster, simpler, and fairer interconnection of solar energy, wind energy, and energy storage resources while ensuring the electric grid reliability and resilience.

i2X will publish a roadmap incorporating analytics from two sprint studies, augmented by learnings from the technical assistance projects. Each sprint study will be tightly scoped, with feedback from the i2X community, to be completed in six to nine months. The first sprint study will focus on a better queue. Some of the ideas include better automation, clustered impact studies, and sharing of grid upgrade costs. The second sprint study will focus on queue alternatives, for example, an auction-based process of hosting capacity or grid needs, informed by experience with auctions of broadband spectrum. There may be cross-cutting improvements to achieve more equitable outcomes, not just more economically efficient outcomes. The metrics and simulation tools will support analysis of both equity and economic outcomes.

The proposed sprint study design intends to first establish a baseline model of the first-come, first-served interconnection queue process, and then measure changes against this baseline of proposed improvements and alternatives to the queue. Some of these improvements include: increased access to information prior to entering the queue; mechanism to study interconnection requests in groups (i.e., clusters); increased financial commitments; increased readiness requirements; availability of optional informational interconnection studies outside of the queue process. The baseline transmission and distribution system interconnection queue models proposed for this effort are described in the figures below.

State Machine Models

BES Interconnections

Figure 1 captures the key states within the interconnection queue, with the probability of movement between states determined by a set of dependent parameters, (x_i ) ?, described below.

StateDiagram1

Figure 1: State diagram for the transmission system interconnection queue process

Optional Informational Study
Conditional Parameters for Transitions out of S1: Proposed.
1. Readiness
  - Permitting requirements/status
  - Site control
  - Commercial readiness
  - Land use restrictions
  - Application fees paid
2. Project jurisdiction
3. Scoping Meeting
4. Feasibility Study

Outcomes: Application Validation/Acceptance/Approval of Negligible Impact Interconnections

Conditional Parameters for Transitions out of S2: Feasibility Study
1. Strictly Time Dependent
  - Current simulation time
  - Time of submission to study
2. Interconnection Queue Specific
  - Violation/cost estimates
  - Project size
  - Project location
  - Project complexity
  - Withdrawal penalties
3. Accumulators
  - Project budget
  - Fees spent
  - Time spent [person-hours]

Outcomes: Estimated system upgrades, costs, and implementation timeline

Conditional Parameters for Transition out of S3: System Impact
1. Strictly Time Dependent
  - Current simulation time
  - Time of submission to study
  - Cluster window, if applicable (annual, semi-annual, etc.)
2. Interconnection Queue Specific
  - Cluster vs individual
    Type of cluster (geographic, electric, etc.)
    
    Number of projects in cluster
    
    Capacity of cluster
  - Project size
  - Project location
  - Project complexity
  - Cost allocation estimate (and/or difference to estimate from feasibility study/informational study)
  - Withdrawal in lower (or equal in case of clusters) queue positions (triggering re-study)
  - Withdrawal penalties
3. Accumulators
  - Project budget
  - Fees spent
  - Time spent [person-hours]

Outcomes: identifies system upgrades (as needed), refined estimate of cost & implementation timeline, notification of necessary re-study

Conditional Parameters for Transition out of S4: Re-Study. This state should be identical to S3 in terms of its dependencies with the following exceptions
1. No cluster window
2. Limit on number of re-studies
3. No further withdrawals
4. Includes affected system studies
Conditional Parameters for Transition out of S5: Facilities Study
1. Strictly Time Dependent
  - Current simulation time
  - Time of submission to study
2. Interconnection Queue Specific
  - Difference in cost estimation of System Impact and Re-Study
  - Project size
  - Project location
  - Project complexity
  - Withdrawal penalties
3. Accumulators
  - Project budget
  - Fees spent
  - Time spent [person-hours]

Outcomes: cost for facilities and upgrades (engineering, equipment, procurement, and construction), detailed estimates of time to procure, construct, and install upgrades.

The players that can influence these probabilistic parameters include: the interconnection applicant; other interconnection applicants ahead in the queue (first-come, first-serve); other interconnection applicants within the queue (cluster); electric service provider; regulator. Outside influences on these parameters include: access to information prior to entering the queue, such as hosting capacity maps; current queue status; estimated upgrade costs, including the cost allocation protocol for clusters; and optional information study.

DER Interconnections

Figure 2 captures the key states within the distribution system interconnection queue, based on the NY PUC Standardized Interconnection Requirements and Application Process, with the probability of movement between states determined by a set of dependent parameters, (x_i ) ?, described below.

StateDiagram2

Figure 2: State diagram for the distribution system interconnection queue process

Inquiry and Inquiry Review
1. Optional request for pre-application report
Conditional Parameters for Transitions out of S1: Proposed.
1. Readiness
  - Permitting requirements/status
  - Site control
  - Land use restrictions
  - Application fees paid
2. Strictly Time Dependent
  - Time of submission to review
3. Interconnection Queue Specific
  - Completeness of Application
  - Project size
  - Project location
  - Project complexity
  - Scoping Meeting
4. Accumulators
  - Project budget
  - Fees spent
  - Time spent [person-hours]

Outcomes: Notification of Acceptance, notice of plans to witness test/verification process, cost estimate for interconnection facilities/distribution upgrades

Conditional Parameters for Transitions out of S2: Preliminary Screening Analysis
1. Strictly Time Dependent
  - Time of submission to review
2. Interconnection Queue Specific
  - Project size
  - Project location
  - Project complexity
  - Passes Technical Screens
  - Elect Preliminary Screening Analysis Results Meeting
  - Elect Supplemental Screening Analysis
  - Elect Full CESIR (Coordinated Electric System Interconnection Review)
  - Cost allocation estimate
3. Accumulators
  - Project budget
  - Fees spent
  - Time spent [person-hours]

Outcomes: Interconnection Acceptance or Notice of failure to pass technical screens, cost allocation estimate for interconnection facilities/distribution upgrades or cost estimate for CESIR

Conditional Parameters for Transitions out of S3: Supplementary Screening Analysis
1. Strictly Time Dependent
  - Time of submission to review
2. Interconnection Queue Specific
  - Project size
  - Project location
  - Project complexity
  - Elect Supplementary Screening Analysis Meeting
  - Elect Full CESIR
3. Accumulators
  - Project budget
  - Fees Spent
  - Time spent [person-hours]

Outcomes: Interconnection Acceptance or Notice of failure to pass technical screens, cost estimate for interconnection facilities/distribution upgrades or cost estimate for CESIR

Conditional Parameters for Transitions out of S4: CESIR
1. Strictly Time Dependent
  - Time of submission to review
2. Interconnection Queue Specific
  - Project size
  - Project location
  - Project complexity
  - Updated interconnection design package, if necessary
  - Requested electrical studies/three-line diagram
3. Accumulators
  - Project budget
  - Fees spent
  - Time spent [person-hours]

Outcomes: Utility system impacts review, system compliance review, cost estimate for interconnection facilities/distribution upgrades, qualifying upgrade disclosure

Ideas from Project Plan and Engagements

Identify at least two different improvements to the current queue-based DER interconnection process that could provide measurable improvement. These may include:

Incremental queue enhancements, e.g., clustering, tool automation, shared cost of circuit upgrades.

Queue replacements, e.g., a proactive auction-based process to fill hosting capacity and/or grid needs.

Soft improvements, such as providing education about the interconnection process for targeted groups.

New tools, such as a “PVWatts for grid connections.”

Adoption of modern standards like IEEE 1547-2018 and IEEE 2800-2022, which could lead to regularization of processes between states and to new technical design practices.

Separate process improvement for more equitable outcomes, not just more economically efficient outcomes. The metrics and simulation tools will support analysis of both equity and economic outcomes.

Develop scoping plans for sprint studies that will analyze and compare the process improvement proposals. Obtain scope approval from DOE, with input from the Technical Advisory Group. Recruit stakeholder participation. Perform the sprint study using open-source tools and data sources. Follow procedures to maintain data privacy and business confidentiality. Preserve the data, tools, and analysis on the i2X web site, as nondisclosure agreements and privacy issues allow.

Compare empirical results from simulated processes with voluntary participation by utilities and DER applicants. The simulated process may run in parallel with the actual process. Identify participants, data sources, targeted stakeholder sectors, and states to participate in these experiments. Interview participants about how they made their decisions to approve or disapprove an application, to withdraw an application from the queue, etc. Publicly available test systems may be used in this work.

Define a public system with electric power grids (as realistic as possible to existing), and configurable DER application queues. The cost and schedule metrics may define specific components to be included, e.g., impact study costs, network upgrade costs, and certain commissioning delays. New tools may simulate the results of a baseline queue management based on current queue-based DER interconnection process and the two future queue management options, over a ten-year period. The baseline and options may be compared based on i2X metrics. Monte Carlo and Pareto methods may be applied to account for uncertainties, trade-offs, and minimum regret goals.

Queue-Based Mechanism

The analytical evaluation of queue management options would use a state-machine model of the Queue, as discussed earlier, in conjunction with a grid model to simulate location-dependent hosting capacities and grid upgrade costs.

Assume clusters per NOPR

Incorporate new equity metrics

Shared costs of system upgrades

When is a project ready to proceed?

Site control and power purchase agreement

Payments to stay in queue

Project financing in place

Cluster formation and management options

Model building improvements

Tool and re-study automation

QueueSprint

Simulation-based Evaluation of Queue Management Options

Auction-Based Mechanism

An auction of renewable connection capacity would completely bypass the interconnection queue. The resource requirements, available locations, and hosting capacities would be pre-determined. Minimum bid levels could be required to cover any grid upgrade costs

Parallels to wideband spectrum auction

Relationship between resource procurement processes, often under state jurisdiction, and interconnection processes under FERC jurisdiction

Set-asides for communities and underserved populations

Incorporate new equity metrics

Identifying locations and quantities for new solar and wind resources

Investing in renewable energy development zones (transmission)

Requirements to participate

Bid clearing mechanisms

AuctionSprint

Auction-based Alternative to the Queue

Coverage from First Round of Sprint Studies

The following table describes three general improvements to the queue-based process, one of which is the auction-based alternative. The project plan calls for only two improvements in the first round, one of which would be the auction-based process.

Table 1 Queue improvements, test systems, and expected outcomes for the first round of sprint studies.
Improvement	System and Scenario	Expected Outcomes
Study Automation	WECC: 3-month cluster studies 118: 1-month project studies 9500: 1-month project studies LVN: 3-month cluster studies	Reduced cost of studies Reduced time of studies
Shared Upgrades	WECC: Series capacitors 118: Transmission lines 9500: Inverter functions LVN: Network protectors	Reduced variabilty in grid upgrade cost
Auction of Capacity	WECC: add 30% renewables 118: add 20% renewables 9500: community-based wind LVN: community-based solar	Reduced variability in cost Reduced variability in time Reduced total study costs Reduced grid upgrade costs

Deferrals from the first round of sprint studies:

Targeted improvements on the acceptance rate of applications. There will be outputs of acceptance rate, but we don’t know the effect ahead of time and have not chosen improvements with a goal of increasing the acceptance rate. This was a relatively new suggestion from DOE in the leadership meeting discussion of metrics for i2X.

Energy equity and environmental justice (EEEJ) effects. This depends on the definition and acceptance of EEEJ quantitative metrics.

Additional test systems and suggested improvements, which might come from technical assistance (TA), solution exchanges, or sponsor suggestions. These can be added to the sprint study platform in future work.