INTEROFFICE MEMORANDUM

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Harold Clark
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INTEROFFICE MEMORANDUM Date: March 3, 2015 To: Boise Public Works Commission From: Anthony Perreira, P.E., Project Manager Subject: Energy Consumption at Major Facilities Managed by Public Works This report contains new information shown in bold.

1 INTEROFFICE MEMORANDUM Date: March 3, 2015 To: Boise Public Works Commission From: Anthony Perreira, P.E., Project Manager Subject: Energy Consumption at Major Facilities Managed by Public Works This report contains new information shown in bold. This memo is presented twice annually to update the Commission on the status of energy consumed and energy conservation projects occurring at major City-owned facilities managed by Public Works. Changes from the previous report are shown with bold font. Energy Use Narrative for Wastewater Facilities Biogas use at both facilities has been very reliable and has allowed the offset of natural gas use. A pre-design report was completed in June of 2013 for a combined heat and power (CHP) project. This design is for a facility to receive food wastes and brown grease for the purpose of digestion and gas production. At this time a 200 ton per day facility is the preferred system size to take advantage of economies of scale. CHP is being passed over in favor of cleaning biogas to pipeline quality to create renewable natural gas (RNG). Design work is planned to be done in FY 2017, with construction to be completed in FY Construction is nearing completion of the thickening and fermentation building at West Boise WWTF as part of the phosphorus removal project. Startup of this facility will happen in May of This new process will add to the base load energy usage of the treatment plant. For ventilation and fresh air purposes, the building requires a high air exchange rate and therefore has a high heating demand to temper this air. There is currently not enough biogas being produced by the treatment process to provide the heating load required for this new facility. Natural gas will be used for heating the building rather than using biogas or the existing heating loop hot water. The HVAC system for the building will incorporate a heat recovery unit to capture waste heat from the exhaust air. The heating system has been designed for easy conversion to hot water heating. If the CHP project is implemented, heat recovered from the CHP using the added biogas from brown grease and food waste would effectively provide the additional heating capacity needed. A new dual-fuel boiler (biogas or natural gas) has been installed at the Lander Street WWTF to increase the system heating capacity and improve equipment redundancy. This new boiler has been used as the primary boiler operating on digester gas for most of the heating season. The existing gas distribution system does not have adequate pressure to serve this boiler on extremely cold days. At these times the old boiler needed to be used on natural gas to provide the additional heat required. These times were minimal 1

2 and did not add a significant increase to natural gas usage. The digester gas distribution system will be studied before the 2015 heating season in hopes of improving this situation. Lander Street WWTF and West Boise WWTF have been part of the Idaho Power WasteWater Energy Efficiency Cohort (WWEEC) since January of The staff at the Lander Street treatment plant has implemented various process changes that have resulted in significant energy savings. Changes have been made to the operation of the influent pumps, aeration basin dissolved oxygen (DO) control, UV treatment and post aeration. All site lighting at the LS plant has been converted to LED. West Boise staff has also worked to find improvements at their plant to save energy. They have optimized DO levels in the aeration basins and have seen lowered energy use with the new UV equipment that was commissioned in Lighting across the facility is being converted to LED. West Boise has discovered in the course of this program that the plant is already designed to operate very energy efficiently which limits their opportunities. They also currently have major construction happening on the site with adds to overall energy use. The staff at both WWTFs is constantly looking for new ways to save energy. One of the major benefits of participating in the WWEEC program is the interest this has generated among the plant staff to look for new and innovative ways to save energy. The WWEEC program continues until December of 2015 but it is the intent to implement a program which will continue to foster staff energy awareness. Current and Planned Projects to Reduce Utility Energy Consumption Project Name Dates Purpose West Boise new Construction underway; in service Natural gas heating system designed for THK/PSF building May 2015 easy conversion to hot water if CHP project West Boise Food and Grease Waste Receiving Facility Pre-design has been completed summer 2013, design planned to begin in FY is constructed. Divert food waste from the landfill and grease trap waste from hazardous waste landfill for beneficial use generating biogas for RNG Energy Use Narrative for City Hall and City Hall West The City Hall Complex is comprised of three separate buildings connected by a central atrium that was remodeled into occupied space with the City Hall seismic upgrade. Electricity is used in the City Hall complex for space cooling, equipment motors and controls, lights, computer and security systems, domestic water heating, and other minor loads. Electricity is also used as a backup for space heating in the event geothermal heat is not available. The motors for all the major heating, ventilating and air conditioning (HVAC) components at City Hall Downtown were put on variable frequency drives (VFDs) at the end of FY 2013 which resulted in a 25% decrease in power consumption year to date versus last year. This was not reflected in power cost until 3 rd quarter of the fiscal year when Idaho Power reduced their annual adjustment mechanism. Space heating for the complex is supplied primarily by geothermal water. During the summer months there is no geothermal water use. Geothermal water use has allowed less need for localized electric space heaters. There is an accompanying reduction in electrical use that is attributed to this change that was made in the geothermal system operation. Geothermal is less 2

3 costly than electricity and this change also capitalizes on the City s use of an environmentally friendly resource. City Hall West utilizes natural gas in boilers for space heating, and in a separate boiler for domestic water heating. Electricity is used for space cooling, equipment motors and controls, lights, computer and security systems, and other minor loads. Historical data for electricity and gas use are attached. The City has only fully occupied the building since the spring of The energy use history documents the efforts of building staff to optimize energy use to meet occupancy needs with existing equipment. The solar heating demonstration project using DOE EECBG funds was put into service on December 23, Quarterly energy savings from solar represent only a fraction of 1 percent of the total building energy consumption. Energy Use Narrative for Twenty Mile South Farm Practices at the Farm have been developed to use irrigation water efficiently with the current infrastructure. Efficient water use can be related directly to electrical usage by the irrigation well pumps delivering water to the irrigation equipment (for example, kwh per million gallons pumped) and applying water commensurate with crop requirements. TMSF continues to monitor irrigation rates by field and crop for comparison to local evapotranspiration data. The attached TMSF electrical use chart has been updated using data from the Idaho Power website and reflects power consumption for the TMSF irrigation wells. Approximately 95% of the TMSF power consumption is used for pumping irrigation water. The attached chart shows a comparison of actual calendar year power consumption data for the irrigation wells from 2011 through 2015 (see page 12). The City has contracted with SPF Water Engineering to implement an Observation and Maintenance Program for the irrigation wells at the farm, which should continue to ensure adequate water delivery in the most efficient manner possible. This program resembles the program SPF implemented for the Boise Parks and Recreation Department. The intent of the program is to document and track well system performance and efficiency to help identify abnormal or deteriorating conditions that would warrant further investigation or maintenance. The farm continues to implement measures such as this to increase efficiency of the irrigation system. SPF will conduct another Observation and Maintenance Study when the irrigation system is started in the spring of The City also contracted with SPF Water Engineering to conduct an efficiency study for the TMSF in The preliminary draft report was received by Public Works staff in late January, Several of the recommendations from the efficiency report were implemented during the 2013 crop season, including: - Operation of booster pumps on Well #7. This work was completed in May, Another recommendation was to modify the sequence of well operation. Well #12 is now a primary well and it was configured to be able to call Well #1 when additional water pressure was required in the system. The sequencing on primary Well #6 was also modified. This was completed in August,

4 - The TMSF also modified the bowls on Well #2 to make it run in a more efficient manner. This was completed in October, For 2014, the following recommendations from the SPF Efficiency Study were implemented: - Installation of center pivot sprinkler irrigation systems on Fields 233 and 251. This was completed in March, Replace a mainline in Field 313 that will significantly reduce energy loss in this part of the system. In 2015, the final major recommendations from the SPF Efficiency Study are scheduled to be completed. These scheduled upgrades include the following: - Installation of flow meters on up to 8 wells (as budget allows). This will allow flow measurement on all major wells at the farm. The data collected will be used to better define the cost per gallon of water produced from each well. This information will be used to further refine well operations at the farm going forward. This project is scheduled to be completed in the spring of Installation of a new center pivot on Field 235 in the southeast corner of the farm. Although not explicitly called out in the SPF Report, this pivot will replace the last major wheel line section of the farm and will conserve both water and electricity. This project is planned to be completed immediately after the wheat is harvested in the fall of Calendar Year kw-hours Acres Irrigated kw-hr per irrigated acre ,353,284 3,327 2, ,569,300 3,327 2, ,680,920 3,327 2, ,795,120 3,327 1, ,681,958 3,327 1,708 4

5 AJP/ap Attachments: - Lander Street WWTF Unit Energy Use- Natural Gas - CHW Q1-4 Power - West Boise WWTF Unit Energy Use- Natural Gas - CHW Q1-4 Electric $ - Lander Street WWTF Unit Energy Use- Natural Gas Only - CHW Gas Usage by Quarter - Lander Street WWTF Unit Energy Use- Digester Gas Only - CHW Gas Dollars by Quarter - West Boise WWTF Unit Energy Use- Natural Gas Only - TMSF Electrical Usage for Irrigation Wells - West Boise WWTF Unit Energy Use- Digester Gas Only - Lander Street WWTF Unit Energy Use- Electricity - West Boise WWTF Unit Energy Use- Electricity - City Hall power consumption by quarter FY City Hall Electricity Dollars by Quarter 5

6 FY 2012 Annual Cost: $ 10,870 for 3.2 therms/mg FY 2013 Annual Cost: $ 11,396 for 3.7 therms/mg FY 2014 Annual Cost: $ 11,435 for 3.6 therms/mg FY 2015 YTD Cost: $ 9,591 for 9.7 therms/mg FY 2015 budget: $ 10,810 (spent 88.7% of budget) FY 2012 Annual Cost: $ 26,287 for 6.6 therms/mg FY 2013 Annual Cost: $ 37,206 for 9.6 therms/mg FY 2014 Annual Cost: $ 60,414 for 14.8 therms/mg FY 2015 YTD Cost: $ 27,658 for 20.6 therms/mg FY 2015 budget: $ 49,529 (spent 55.8% of budget) Compare Natural Gas and Digester Gas use at Lander St WWTF Wastewater Treatment Facilities Utility Energy Reduction Projects 6

7 Compare Natural Gas and Digester Gas use at West Boise WWTF Wastewater Treatment Facilities Utility Energy Reduction Projects 7

8 Wastewater Treatment Facilities Utility Energy Reduction Projects 8

FY 2012 Annual Cost: $349,982 for 1,744 kwh/mg FY 2013 Annual Cost: $408,767 for 1,770 kwh/mg FY 2014 Annual Cost: $442,553 for 1,709 kwh/mg FY 2015 YTD Cost: $127,137 for 1,615 kwh/mg FY 2015

9 FY 2012 Annual Cost: $349,982 for 1,744 kwh/mg FY 2013 Annual Cost: $408,767 for 1,770 kwh/mg FY 2014 Annual Cost: $442,553 for 1,709 kwh/mg FY 2015 YTD Cost: $127,137 for 1,615 kwh/mg FY 2015 budget: $449,425 (spent 28.3% of budget) FY 2012 Annual Cost: $681,003 for 2,939 kwh/mg FY 2013 Annual Cost: $797,939 for 2,737 kwh/mg FY 2014 Annual Cost: $925,577 for 2,737 kwh/mg FY 2015 YTD Cost: $287,451 for 2,802 kwh/mg FY 2015 budget: $741,606 (spent 38.8% of budget) Wastewater Treatment Facilities Utility Energy Reduction Projects 9

10 Wastewater Treatment Facilities Utility Energy Reduction Projects 10

11 Wastewater Treatment Facilities Utility Energy Reduction Projects 11

12 Wastewater Treatment Facilities Utility Energy Reduction Projects 12

13 Wastewater Treatment Facilities Utility Energy Reduction Projects 13

INTEROFFICE MEMORANDUM

INTEROFFICE MEMORANDUM Date: October 1, 12014 To: Boise Public Works Commission From: Anthony Perreira, P.E., Project Manager Subject: Energy Consumption at Major Facilities Managed by Public Works This