Title
Water Services Department 23rd Avenue Wastewater Treatment Plant Microgrid
Description
This report provides the Water, Wastewater, Infrastructure and Sustainability Subcommittee with a summary of the 20-year agreement with Arizona Public Service (APS) to provide standby power services to the Water Services Department (WSD) 23rd Avenue Wastewater Treatment Plant (WWTP).
THIS ITEM IS FOR INFORMATION ONLY.
Report
Summary
APS and the City of Phoenix Water Services Department propose to work collaboratively at the 23rd Avenue WWTP. The proposal is to provide standby power to the WWTP through use of a 6.25 megawatt microgrid. Microgrids are local energy grids with control capabilities that can disconnect from a traditional energy grid and operate autonomously. The microgrid would be capable of supporting emergency power requirements to the entire WWTP site. The City would be responsible for a cost share of the capital costs and any fuel usage over the life of the agreement. APS would be responsible for permitting, design, construction, and operation and maintenance of the microgrid.
The 23rd Avenue WWTP provides wastewater treatment services to the central Phoenix area. The facility has been in operation since 1932 and has a treatment capacity of 63 million gallons per day (mgd). Currently, there are 6 standby power generators located throughout the WWTP providing emergency power generation to key facilities. A recent study initiated by WSD to evaluate the 23rd Avenue WWTP standby power needs for full standby capability to all facilities and evaluated the condition of the existing standby generators. The evaluation recommended replacement or modifications to existing on-site generators at an estimated capital cost of over $7 million.
The APS - Water Services Department agreement presents an opportunity to reduce capital expenditures from WSD for all resiliency power needs at the WWTP. The estimated capital cost to the City for the microgrid facility would be approximately $3.4 million, which is $3.6 million less than the estimated cost of replacing the standalone generators at the site as identified in the study. Additionally, APS would be responsible for all operations and maintenance costs associated with the microgrid facility, thus providing additional cost savings to WSD for the lifetime of the agreement.
There are also several non-monetary benefits to the agreement. The WWTP would have first use rights of the microgrid. APS would use the system when not in use by the WWTP as needed to address capacity, energy and frequency response. The microgrid will include Tier 4 generators which are more energy efficient and emit less air pollutants than the Tier 2 generators now in service at the WWTP. This change in equipment has the potential to reduce the air quality permitting requirements through Maricopa County. Finally, the microgrid would support the entire facility load, which will provide the plant with redundant backup power needs for all systems at the WWTP.
Financial Impact
The initial impact of the contract, beginning in Fiscal Year 2019-20, is estimated at $3.4 million in capital costs.
Location
Water Services Department 23rd Avenue Wastewater Treatment Plant
Council District: 7
Department
Responsible Department
This item is submitted by Deputy City Manager Karen Peters, and the Water Services Department.