Independent Engineering for Floating Solar PV – Healdsburg, CA

Partner Engineering and Science, Inc. was engaged by White Pine Renewables to perform a variety of services for a floating solar photovoltaic (PV) project located in Healdsburg, California. This project, once completed, will provide energy to the project site and City of Healdsburg for a 25-year term starting on the Commercial Operation Date (COD).

The services requested included an Independent Engineering (IE) Report, Reliance Letter, Decommissioning Cost Letter, as well as a Punchlist Review upon the project’s completion, estimated around end of December 2020. The Independent Engineering Report analyzed and reviewed the following components of the solar project:

• Energy production estimates
• Engineering, Procurement, and Construction (EPC) contract
• Operation & Maintenance (O&M) contract
• Power Purchase Agreement (PPA) for technical content
• Interconnection Agreement (IA)
• Permitting process

The project entails two arrays that will be located on the north and south ponds of the City’s Wastewater Treatment Facility. The 4,780.6kW-DC/3,000kW-AC floating solar project consists of:

• Floating-ballasted arrays with fixed-tilt east/west racking – these floating arrays hold 2 planes of modules back-to-back with one facing east and one facing west in a tent-looking structure.
• A total of 11,660 bifacial modules – these are double-sided modules that allow sunlight to convert into energy from both the top and bottom.
• 20 high-power, utility-scale string inverters – these are used to convert the DC (direct current) output of PV solar panels into a utility frequency AC (alternating current) so that it can be fed into a commercial electrical grid.

The project achieves two objectives for the City. First, the 4.78MW project would help generate approximately 7,181 megawatt hours (MWh) of clean energy annually. Second, the arrays help to mitigate algae growth in the pond.

That amount of energy the Healdsburg Floating Solar PV project produces annually is enough to power roughly 1,110 California homes, which use an average of 6,471 kWh per year according to the U.S. Energy Information Administration (EIA, 2018 – see chart below). California is approximately 39% below the 2019 national average, that states home electricity use to be 10,649 kilowatt hours (kWh) annually.