Lessons Learned and Recommendations for Future Resource Plans The Company appreciates that we, and the industry more broadly, are undergoing a

significant transition, not only regarding the types of resources we consider, but also the way in which planning is conducted. There is increasing emphasis on stakeholder participation, alignment between generation, transmission, and distribution planning, and incorporating more detailed analyses of resource attributes. We appreciate the robust engagement of other parties, examining modeling and presenting alternate plans. Ultimately, we believe some of the proposed modifications and different approaches these parties presented will require ongoing work for our next resource plan. In this section, we discuss some lessons learned and frameworks for ensuring all parties participate in a way that helps the Commission consider our resource plans with the best information possible, as well as a discussion of proposed future improvements to our modeling and processes.

1. Proposed Minimum Information Requirements for Parties Submitting Alternative Plans

This resource plan was the first in which several other parties besides the Department conducted full-scale modeling efforts to either validate or test alternate proposed plans for the Commission to consider. We have also responded to substantial levels of requests for information from modeling parties and others; ultimately totaling nearly 1,000 requests spanning nearly two years, many of which directly supported parties completing their own alternative modeling.

Overall, this process has raised valuable issues for consideration, and pressed us to consider new and different approaches than we had previously. We appreciate the engagement from other parties and believe that there are valuable contributions for the Commission to consider in the context of evaluating the Company’s plans.

However, not every modeling party in this docket has adhered to the basic planning principles the Company must follow or been equally forthcoming with information supporting their proposed alternative plans. These factors make alternative plans difficult for us and other interested parties to fully evaluate, much less for the

Commission to adopt outright as a preferred alternative to the Company’s proposed plans. The Company is subject to many requirements when submitting its Resource Plans, and we would not propose all other parties be subject to all of those

requirements as well; however, we believe some additional structure around the IRP process and party participation may be helpful, both in keeping future resource planning processes on track, and providing the Commission all the information it needs to make decisions.

For example, the Company has a statutory requirement to evaluate “a set of resource options that a utility could use to meet the service needs of its customers over a forecast period, including an explanation of the supply and demand circumstances under which, and the extent to which, each resource option would be used to meet those service needs.”⁷⁸ For our service area, this means evaluating the expected loads (plus our required MISO planning reserve margin) annually over the 15 years of the planning period, and accounting for our full five-state upper Midwest service area. We also ensure our planning process takes a full account of the resources already available to us to serve customers, which includes both owned and PPA resources. One simple summary we use to evaluate our plan on these measures is a Load and Resources Table, such as the ones provided in Appendix B. A model that does not evaluate these basic inputs at a bare minimum – and from which the submitting party cannot, or is unwilling to, provide a basic load and resources table – should not be considered a viable alternative to the Company’s proposed plan.

In order to more easily evaluate the merits of a plan that does meet these basic minimum requirements, we believe there are a few other components that are reasonable to request of parties for the record. These include:

• A load and resources table, as described above, that reflects the Company’s load plus MISO reserve margin requirements, the Company’s full set of existing resources and the modeling party’s proposed expansion plan, on an annual basis

• An evaluation of the proposed alternative plan’s PVRR, as well as its PVSC.

The Commission is required by Minnesota statutes⁷⁹ to use a CO2

environmental cost value when evaluating and selecting resource options in all proceedings before the Commission, including resource plan and certificate of need proceedings. Thus, an alternate plan that provides no such measure cannot be further evaluated. We would also propose that – at a minimum – the modeling party provide PVSC values under the same externality/regulatory cost of carbon sensitivity that the Company presents in its primary plan, although we agree that testing other values is appropriate. Any comparison of PVRR values should be between plans that are calculated using a similar

methodology to the Company’s (if not in the same type of modeling software).

• A quantitative bill and/or rate impact analysis of the proposed plan, including whether the plan results in significant differential bill impacts to different

78 Per Minn. Stat. § 216B.2422, subd.1(d).

79 Minn. Stat. § 216B.2422, subd. 3.

customers within a customer class (i.e. participating and non-participating customers).

• An analysis of whether the proposed plan results in unserved energy or other significant reliability concerns within the modeled construct.

• A reasonably comprehensive documentation of input assumptions, to the extent they are different than the Company’s inputs.

• Discussion of how its proposed alternative plan achieves the Commission’s public interest analysis requirements for approving a resource plan, as outlined in Minn R. 7843.0500, subp. 3.

We believe setting forth basic requirements, including but not limited to the above, would support better analysis of any plans submitted as proposed alternatives to the Company’s plan and ultimately help the Commission make a determination regarding our five-year action plans.

2. Distributed Solar as an Optimized Resource

We also recognize that there are some improvements we can make to our future analyses. One such improvement is the inclusion of distributed solar as a selectable resource in our planning, which was a topic of discussion across several parties’

comments. We acknowledge that – partially for reasons related to legacy Strategist capabilities (or lack thereof) – we have more work to do to fully incorporate distributed solar as a selectable demand-side resource in our generation planning.

Rather, our plan contains substantial solar additions and, to the extent incremental distributed solar above what our forecasts indicate is adopted, it could reduce the need for larger-scale solar additions in the future. In short, the Company will, of course, continue to integrate distributed solar that customers choose to adopt, and we are open to working on a modeling construct that enables identification of economic distributed solar additions as part of our next resource plan.

That said, we have significant concerns with the approach the Distributed Solar Coalition took to modeling only the “incremental cost” to the utility to incentivize certain levels of distributed solar generation, saying that this approach was similar to how bundles of energy efficiency and demand response were modeled. We believe this approach would not fully consider all system costs associated with treating

distributed solar as an optimized resource.⁸⁰ The present value of societal costs and revenue requirements associated with resource additions in our Resource Plan do not just represent incremental cost to incentivize, rather it is intended to represent the costs associated with the resources selected to serve our system. In other words, if an

“optimal amount” of customer-procured resource is going to be identified through modeling in the context of the broader system, then either the full cost of that resource must be evaluated through modeling, or the bundles of distributed solar would need to be assessed through an alternative cost effectiveness test and reflect achievable potential levels – like the EE bundles in our modeling were – before the model could select them.⁸¹

In this context, it is further important to note that – while resource planning does not directly contemplate ratemaking structures and equity between customers – the cost of net metering compensation and the value of solar tariff are passed through to non-participating customers, in a similar fashion to the way the cost of a large-scale

resource PPA is passed through to customers through the fuel clause. These cost and equity concerns must also be considered when discussing a vast expansion of rooftop or community-scale solar development, such as the DSC, CUB and others have proposed. Further, modeling economic distributed solar additions requires further

80 In response to XE IR 81, DSC confirmed that it intended for these incentive payments to apply to all MWh produced by the distributed solar resource, not only excess generation; this appears essentially equivalent to proposing a

production credit for distributed solar.

81 As detailed in our original July 2019 IRP filing, EE bundles were derived from data provided by the Center for Energy and the Environment’s potential study or by the Company. As part of the economic potential portion of the CEE analysis, energy efficiency measures were screened using the societal cost-effectiveness test: Minnesota Energy Efficiency Potential Study. Available at Minnesota Energy Efficiency Potential Study: 2020–2029 (mn.gov). The consideration of energy efficiency measures in a portfolio also incorporates the measure’s cost to a customer, via the Societal Test. While not every measure is required to pass this test, the portfolio as a whole is expected to pass it. Therefore, we disagree with the suggestion that the only relevant cost is the cost to the utility to acquire the resource, whether for EE or for other distributed resources. Moreover, all three bundles of EE reflect achievable potential (the amount of economic energy efficiency that is achievable given barriers to participation and utility budgets), not just what is economic (economic potential) or technically possible (technical potential). This differs from the DG Solar bundle approach proposed by the DSC, which uses an economic adoption model without any further adjustment for the amount of DG solar that is achievable. The Company believes that comparable treatment to EE could be possible, but the DSC proposal is not fully consistent with the analytical rigor that is applied to energy efficiency scenarios. For example, when determining the potential for energy savings from a measure like water heating, a research team will consider technical factors beyond cost such as availability of the efficient option at distributors, the prevalence of the measure in homes and businesses, the lifetime of the equipment, and customers’ awareness of the technology as an option to save energy. Applying this same methodology to distributed rooftop solar, for example, would need to consider factors such as available roof area, presence of roof obstructions, age of roof, load bearing capacity of roofs, customer acceptance of any risks involved in on-site solar installations, and others. Further information about each type of potential can be found here: Guide for Conducting Energy Efficiency Potential Studies (epa.gov) (page 2-4). The model the DG Solar method is based on can be found here: Eric Williams, Rexon Carvalho, Eric Hittinger, and Matthew Ronnenberg. Renewable Energy. May 2020.

“Empirical development of parsimonious model for international diffusion of residential solar”.

coordination between the resource planning and distribution planning processes. We recognize the coordination between these processes needs to be stronger and have begun that work (for example, through aligning distributed resource adoption forecasts), but there is still much to be done.

In sum, we are open to working with stakeholders to model distributed solar as a selectable resource but believe the framework by which we appropriately assess the cost of these resources and potential benefits to the system requires further work; we are not comfortable adopting the DSC’s proposed analysis at this stage. We would propose the Commission allow additional time for us to work with parties to develop that framework and address selectable distributed solar in the next Resource Plan.