Title
Permit review for 301 18th Ave SE - Solar Installation
Recommended Action
Act on the permit request following consideration of the characteristics of this property and requested solar application (see options below); and determine whether to recommend amendments to the Commission’s Guidelines for Solar Installations.
Report
Issue:
Whether to approve the homeowner’s proposed solar installation as an exception to the Commission’s current Guidelines for Solar Installations, and if so, whether to recommend amendment to the Guidelines for Solar Installations for consideration by the Heritage Commission.
Staff Contact:
Marygrace Goddu, Historic Preservation Officer, Community Planning & Development, 360.480.0923
Presenter(s):
Garner Miller, Heritage Review Committee Chair
Background and Analysis:
The Commission adopted Guidelines for Solar Installations for historic buildings and districts in February 2021. The guidelines support placement of panels on roof areas not visible from the street and discourage placement on street-facing roofs, but do provide some flexibility for street-facing placement when there are no other “viable” options. “Viable” is defined as a Total Solar Resource Fraction (TSRF) of 80% or higher, to be assessed and documented by a professional solar consultant or installer.
This homeowner is able to exceed the viability threshold using roof sections at the rear of the home but is seeking to place additional panels on the street-facing side of the home to increase the overall capture of solar energy. The proposed location is on the roof of a shed-dormer, which is expected to have very limited visibility from street-level. The panels in this location would not meet the 80% TSRF.
The Commission’s Guidelines for Solar Installations are not clear regarding the placement of panels on the street-facing side of the home when the proposed locations are not visible or are minimally visible.
Additional clarification may be helpful regarding how the 80% TSRF is to be applied. Other measurable considerations could be considered, such as the total solar offset to be gained and/or a homeowner’s efforts to improve the home’s energy efficiency and reduce energy consumption prior to proposing solar on the front of the home.
The Guidelines are currently interpreted to mean that street-facing placement is allowable when the following two conditions occur:
1) The proposed street-facing, visible location receives enough sunlight to generate a minimum of 80% Total Solar Resource Fraction (TSRF);
and,
2) An 80% TSRF cannot be achieved with any other combination of less visible rooftop locations on the property - meaning the homeowner looked at other placement options first.
The Committee is asked to consider:
1. Whether this permit should be approved, and by what reasoning.
2. Whether and how the Guidelines for Solar Installations might be amended.
Neighborhood/Community Interests (if known):
Historic homeowners and historic districts.
Options:
- Approve the permit as an exception and recommend to the full Heritage Commission that the Guidelines for Solar Installations be amended to clarify them or to adjust the review method or measurement.
- Do not approve the permit.
- Approve the permit with conditions.
Attachments:
Guidelines for Solar Installations
Photos
Shade Study
Solar Panel Design