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In order to provide the best recommendations regarding WTD's energy usage, the Energy Program is equipped to measure, capture, and analyze WTD's energy consumption data. High-level meters are now installed in many facilities and systems to monitor real-time energy consumption, and most new equipment upgrades include individual power monitoring devices. The Energy Program also collects information with portable meters during occasional audits. All of this data is used to ensure WTD is making smart, cost-effective decisions about energy use.

Energy Map Click for larger version 

Loop® biosolids is a natural soil amendment produced by safely extracting carbon and nutrients from wastewater at King County’s treatment plants. Superior to conventional fertilizers, Loop replenishes soil by returning essential nutrients to the land and, with its proven ability to hold rainwater like a sponge, Loop reduces runoff and erosion.

University scientists have found that in soils where Loop has been applied, it stores carbon and reduces greenhouse gas emissions into the atmosphere. These carbon offsets far outweigh the emissions associated with transportation of Loop and help offset the energy consumption associated with treating wastewater.

Total Energy Use by Location

Energy use chart

WTD’s facilities account for about 58 percent on average of all King County government’s facility energy usage. Almost 80 percent of WTD energy is used at the three regional treatment plants. The majority of WTD’s energy use is not discretionary or wasteful – it is required to fulfill service needs.

Energy Use by Fuel Type

Energy use by fuel type

WTD’s daily electricity needs are more than 17 megawatts (MW), nearly 70 percent of WTD’s total energy use.

Electricity is needed to power pumps, motors, and blowers whereas natural gas and biogas, propane, and diesel fuel boilers, engines, and turbines.

Energy Conservation

Energy Graph

While flow volumes remain fairly steady at West Point Treatment Plant, energy usage has declined.

This is largely due to the 2001 Productivity Initiative that served as a catalyst to initiate significant energy efficiency investments across WTD facilities.

Treatment Plant Electricity Breakdown

Each of King County’s five treatment plants uses electricity differently based on the specific treatment technology and process needs. For example, South Plant is the only plant in our system to scrub biogas, which requires electricity. Due to space constraints, West Point’s design includes high purity oxygen, which is generated on site and requires a significant amount of energy. And while all plants have odor control mechanisms, Brightwater odor control is especially energy-intensive.

(Click each graph for a larger version)

Brightwater Energy Use

South Plant energy use

West Point energy use

Normalized energy use by facilityNormalized energy use

A facility’s energy consumption depends on factors beyond the efficiency of equipment and process systems, and includes precipitation volumes, outside air temperature, and operating characteristics.

Normalizing data is the process of equalizing the impact of these factors on energy use to compare the energy performance of facilities and operations from year to year.

NOTE: WTD’s normalized energy use does not include facilities newer than 2007, such as the Brightwater Treatment Plant or the pump stations serving Brightwater. Normalized energy use does not credit energy created and used onsite.

For more information about resource recovery, please contact us at: