COMMISSION 
AGENDA MEMORANDUM                Item No.       7d 
BRIEFING ITEM                   Date of Meeting    October 24, 2017 
DATE:    September 25, 2017 
TO:     Dave Soike, Interim Executive Director 
FROM:   Elizabeth Leavitt, Senior Director, Environment & Sustainability 
SUBJECT:  Evaluating Solar Energy at the Port of Seattle 
EXECUTIVE SUMMARY 
The Environmental Center of Expertise (COE) staff in collaboration with Aviation Facilities and
Infrastructure staff will brief Commission on the findings of several studies of the costs and
benefits of generating solar energy at aviation and maritime facilities. The results of these
studies are compared to other energy strategies currently being implemented or considered by
the Port to meet Century Agenda goals. Staff will present recommendations to Commission on
developing solar projects that could generate electricity for the Port. 
Key Information: 
Port staff has developed a number of renewable and energy efficiency strategies in order to
meet two Century Agenda goals: 
Reduce port-owned carbon emissions by 50% and 
Meet all increased energy needs through conservation and/or renewables. 
These strategies include a range of energy efficiency projects, renewable fuels, green fleet,
wind energy and other initiatives, including solar energy. Port staff recently completed several
studies of solar energy, one at Sea-Tac Airport and two at the Maritime Division, evaluating
eight and nine locations, respectively.
Staff evaluated solar arrays at all locations for total cost of ownership, the net present value of
the investment, and the cost per ton of carbon reduced. Findings varied due to a number of
factors including: issues related to the specific utility serving the location (e.g., cost of
electricity, renewable energy in the existing portfolio, the potential for grants and other
incentives), and other constraints such as regulations that limit the orientation of an array.
Costs for the solar projects ranged from $250,000 to $19 million, with net present values 
ranging from negative $280,000 to negative $18 million over a 30-year lifetime. All of the solar
projects evaluated for the airport generate less than 1% of the total airport electricity needs.
Solar projects for the maritime locations generated 3% to 15% of the electricity needs for the
individual buildings they would serve. 

Template revised September 22, 2016.

COMMISSION AGENDA  Briefing Item No. __7d__                    Page 2 of 2 
Meeting Date: October 24, 2017 

Similarly, costs per ton of carbon reduced ranged between a low of $5,000/ton to a high of
$10,000/ton. The low end of the range reflects a project that has a $317,000 grant that 
reduces the cost of the project by approximately half. 
Staff compared these costs to the carbon reduction estimates from other initiatives currently
underway at the Port. The low end of the cost per ton for solar arrays is comparable to some
energy efficiency projects such as replacing light fixtures at Shilshole Bay Marina with LED.
However, a number of Port initiatives provide carbon reduction at significantly lower cost per
ton than solar arrays. For example, Puget Sound Energy's Green Direct program provides access
to wind-powered electricity for approximately $60/ton, significantly less than the lowest
estimate ($1,800/ton) for carbon reduction from solar. Similarly, projects such as converting
natural gas buses to electric, and purchasing renewable natural gas for Sea-Tac's boiler fuel
reduce carbon for approximately $350 to $900/ton, significantly less expensive than solar. 
Lastly, staff considered the impact of renewable energy and conservation strategies on other
community benefits embedded in the Century Agenda goals including small business growth
and workforce development. Our analyses suggest that because Washington produces solar
panels and has a workforce committed to installing solar arrays, solar projects could contribute
to these values as well. Alternatively, other carbon reduction strategies such as converting fleet
buses to run on electricity may not. 
In light of these considerations, staff recommends that the Port: 
1.  Continue to pursue the solar project for Pier 69 
2.  Research solar or wind projects in eastern Washington to obtain the benefits of solar at
lower costs 
3.  Continue to pursue cost-effective carbon reduction strategies across Port facilities. 
We look forward to sharing this information with the Commission and obtaining their feedback
on the analyses and staff recommendations. 
ATTACHMENTS TO THIS BRIEFING 
(1) Presentation slides 




Template revised September 22, 2016.