On November 16, 2023, the U.S. Department of Energy (“DOE”) issued a Notice of Proposed Rulemaking (“NOPR”) to update its National Environmental Policy Act (“NEPA”) implementing regulations to add a categorical exclusion for specific energy storage systems and revising categorical exclusions for upgrading and rebuilding transmission lines and solar photovoltaic (“PV”) systems. Comments on the NOPR are due January 2, 2024.

NEPA mandates Federal agencies to provide a detailed statement on the environmental impacts of proposals for major Federal actions significantly affecting the quality of the human environment. DOE is proposing revisions to its NEPA procedures, which include three types of review for proposed actions: environmental impact statement, environmental assessment, and categorical exclusion. A categorical exclusion is a “category of actions that typically do not have a significant impact on the human environment and thus do not necessitate an environmental assessment or environmental impact statement.” To apply a categorical exclusion, the DOE must ensure that (1) the proposed action fits within a listed categorical exclusion, (2) there are no extraordinary circumstances that could significantly impact the environment and necessitate further assessment, and (3) the proposal hasn’t been improperly divided to fit the definition of a categorical exclusion.

The NOPR includes three proposed revisions. First, DOE proposes to revise the categorical exclusions in its NEPA implementation regulations for upgrading and rebuilding existing powerlines. The current categorical exclusion applies to upgrading or rebuilding existing powerlines “approximately 20 miles in length or less.” The proposed changes remove the mileage limitation, add new conditions, and add options for relocating within an existing right of way or previously disturbed or developed lands. DOE noted that upgrading and rebuilding powerlines can mitigate adverse environmental impacts, for example, by relocating small segments of the existing line to avoid sensitive environmental resources. Additionally, DOE noted these actions can improve the resilience of the powerlines.

Second, DOE proposes to add a new categorical exclusion for specific energy storage systems. Based on prior NEPA reviews and technical reports, DOE asserted that compressed air energy storage, thermal energy storage, or other technologies normally do not “pose the potential for significant environmental impacts,” and therefore, should be eligible categorical exclusions.

Third, DOE proposes to revise the categorical exclusions in its NEPA implementation regulations for solar PV systems. The current DOE categorical exclusion covers installing, modifying, operating, and removing solar PV systems located on a building, other structures, or land within a previously disturbed or developed area, typically less than 10 acres. DOE proposes to replace the term “removal” with “decommissioning.” DOE asserted that decommissioning includes recycling and other actions that occur when a facility is taken out of service. DOE also proposes to remove the acreage limitation for proposed projects, allowing the categorical exclusion to apply to systems generating up to hundreds of megawatts. DOE reasoned that acreage is not a reliable indicator of potential environmental impacts.

DOE noted that the proposed changes are based on the collective experience of the DOE and other federal agencies, current technology, regulatory requirements, and standard industry practices. DOE invites public comment on the proposed changes by January 2, 2024.

DOE’s NOPR, issued in Docket No. DOE-HQ-2023-0063, can be found here.