Estimating Energy Efficiency Potential

To develop the energy efficiency supply curves, a fuller description of the methodology is available here. High-level considerations included are:

1. Types of Potential
2. Key Data Sources
3. Climate Change
4. Building Codes and Appliance Standards

Types of Potential

The Council considers three factors in ascertaining the cost-effective energy efficiency potential of measures: technical feasibility, technical achievability and economic achievability. When each of these factors is applied, it results in different levels of potential: technical, achievable technical, and achievable economic. The relationship among the three factors and level of potential is illustrated in the figure below.

Levels of Energy Efficiency Potential

Adapted from National Action Plan for Energy Efficiency[1]

Technical potential assumes that the most energy-efficient measures considered are installed everywhere they are technically feasible. The measures must be commercially available and reliable at the start of the plan period.[2] After the assessment of technical feasibility, the next step is to apply market barriers. The Council assumes that between 85 and 100 percent of all technical potential can be achieved by the end of the plan period (20 years) to determine the achievable technical potential. Finally, through the resource strategy analysis, the Council looks at whether potential conservation measures are economically achievable. This potential is then translated into savings targets, to be achieved from utility programs, market transformation activities of the Northwest Energy Efficiency Alliance (NEEA), and activities outside of programs including market-induced savings and savings from codes and standards (also known as momentum savings).

Key Data Sources

To inform the individual measure costs and savings, several sources are used. Primary among them is the Regional Technical Forum (RTF). The 2021 Power Plan incorporates the most recent updates by the RTF until the date when these inputs went into the resource strategy analysis (through March 2020 for the draft plan inputs). For measures not considered by the RTF, the Council relies on secondary studies, including: evaluation results by regional utilities, the Energy Trust of Oregon, and the Bonneville Power Administration (Bonneville); research conducted by Bonneville, NEEA, and the U.S. Department of Energy National Labs (e.g. Pacific Northwest National Lab, Lawrence Berkeley National Lab), and other sources.

The total number of units in the region is largely based on the sector-specific stock assessments conducted by NEEA. These include:

• 2016-2017 Residential Building Stock Assessment (RBSA)
• 2014 and 2019 Commercial Building Stock Assessments (CBSA)
• 2014 Industrial Facilities Site Assessment (IFSA)

These assessments provide a snapshot of the appliance and equipment saturations of buildings across the region. Note, the 2016-2017 RBSA and 2019 CBSA are new for the 2021 Power Plan.[3] In addition to the 2014 IFSA, the Council staff conducted research into individual industrial segments to help calibrate regional industrial loads by segment and end use. 

To estimate the seasonal variation of the savings, the Council relies on end-use metering data; loads collected at the final point of consumption of electricity. For many end-uses, these are based on the End-Use Load and Consumer Assessment Program (ELCAP) database. The 2012 Residential Building Stock Assessment included a metering component, and so many of the residential non-heating and cooling end-use load shapes were updated based on the newer data. Additional end-use load shapes are estimated from metering work in California,[4] or lacking any metered data, simulated shapes from building energy models, or other engineering analysis and staff judgment.

Other sources for applicability factors or other inputs include: the Energy Information Agency’s Manufactured Energy Consumption Survey and Commercial Building Energy Consumption Survey, national surveys by the U.S. Department of Agriculture, Bonneville’s energy efficiency implementation manual, other regional conservation potential assessments, Environmental Protection Agency’s ENERGY STAR program reports, federal standards rulemaking documents of the U.S. Department of Energy, and market and building codes analyses completed by NEEA.

Climate Change

A key difference between the 2021 Plan savings assumptions and those used by the RTF or other sources is the Plan incorporates the impact of climate change. This was primarily done for HVAC measures by incorporating changes to weather files used in building simulation models. Details to the methodology to revise the weather files can be found here. For weather-sensitive measures where the savings are not established via a building simulation model, the heating and cooling savings were modified by an approximate factor similar to that seen from the modeled measures. In other words, for a residential heating measure, the modeled results show a decrease by about 80 percent of the savings due to climate change. For measures impacting heating that are without a building simulation model, a factor of 0.80 is applied to the savings.

Since the portfolio analysis only includes one supply curve, the energy efficiency supply curves only incorporate one climate change scenario: CanESM2. This scenario was selected because it represents the widest range in projected temperatures over the plan time horizon. Overall, the climate change impact reduced savings for winter measures, and increased the impact for cooling measures, both due to warmed temperatures. See this presentation for more information.

Building Energy Codes and Appliance Standards

In the development of the Plan, the Council uses existing federal and state appliance and equipment standards and state building energy codes in its baseline as a starting point from which to estimate energy efficiency potential. For the 2021 Plan, federal standards, state standards, and state building energy codes that were in place as of the end of 2019 are part of the baseline (and frozen efficiency forecast), as well as known future compliance dates. Any new codes and standards that are enacted after the supply curve development (i.e., 2019) represent codes and standards savings and count toward the plan’s efficiency goals. Since 1980, codes and standards savings have accounted for approximately 15 percent of the total regional savings.

Codes and standards are an effective means by which to acquire efficiency. Their efficiency is realized at a lower total cost compared to ratepayer-funded programs because they avoid program administrative costs. They also impact the entire market by replacing lower efficiency equipment at the end of their useful lives. The savings realized by federal standards are also more equitable than ratepayer-funded programs because the cost of meeting a standard is borne directly by the consumers who benefit from the increased efficiency through lower power or natural gas bills. NEEA plays a key role in developing and energy codes and appliance standards.

The table below includes a listing of the federal standards for electric products that were finalized since the Seventh Plan and are now part of the 2021 Plan baseline. The table also includes the published and compliance dates along with an estimate of the energy efficiency saving from these standards between 2016 and 2021. In addition to the electric products in the table, DOE also adopted standards for fossil-fired products including residential and commercial boilers, and commercial warm air furnaces.

Federal Standards in the 2021 Plan Baseline

State building codes have also improved since the adoption of the Seventh Power Plan. Since publication of the Seventh Plan, Washington adopted a new residential and commercial building code, which went into effect in July 2016. Additionally, Washington recently updated its energy codes for both sectors, scheduled to be effective February 2021. In addition to state building codes, Washington has also instituted a broad range (17 new product types) of state appliance standards, including:

Oregon's current residential energy code went into effect on January 1, 2018. Oregon has also adopted ASHRAE 90.1-2016 as its new commercial code effective on January 1, 2020. Oregon’s 2021 code for both residential and commercial will go into effect fully by October 1, 2021, and were enacted after the development of the supply curves. Oregon has also adopted (as of June 1, 2021) a full set of state appliance standards (also enacted after supply curve development) which include the following products:

Both Idaho and Montana enacted new codes after the development of the supply curves. In 2020, Idaho adopted the 2018 IECC for commercial and the 2018 IECC with amendments for residential effective January 1, 2021. Similarly, in early 2021, Montana adopted the 2018 IECC for commercial and the 2018 IECC with amendments for residential, effective February 13, 2021.

[1] National Action Plan for Energy Efficiency (2007). Guide for Conducting Energy Efficiency Potential Studies. Prepared by Philip Mosenthal and Jeffrey Loiter, Optimal Energy, Inc. www.epa.gov/eeactionplan

[2] Section 839(4)(A) of the Northwest Power Act

[3] At the time of the draft supply curve, the 2019 CBSA data were not fully analyzed and so it was used in limited ways, with some of the analysis relying on the 2014 CBSA. Subsequent to the Plan's release, a revised set of supply curves for the commercial sector will be developed that fully rely on the 2019 CBSA and be made available for reference. 

[4] California Commercial End-Use Survey (CEUS), completed in 2006.