King County Metro

Interim Base Electrification - Predictive Analysis and Modeling
Project name Interim Base Electrification – Predictive Analysis and Modeling
Client name King County Metro, Seattle, Washington, United States
The Client King County Metro (KCM) is the Puget Sound region’s largest public transportation agency and 8th largest in the United States. Metro provides bus, paratransit, vanpool, and water taxi services, and operates Seattle Streetcar, Sound Transit Link light rail, and Sound Transit Express bus service. KCM is committed to providing safe, equitable, and sustainable mobility, and prioritizing service where needs are greatest. KCM has emerged as an early leader in adopting and piloting Zero Emission Bus technologies
Product or services provided ZET Advisory


Client industry Transit Agency
The Brief KCM has retained Evenergi to conduct predictive energy modeling and in-depot simulation for its to be constructed Interim Base, home to 124 pantograph-only battery electric buses (64 artics, 60 forty-foots).

KCM is commencing a detailed depot design phase utilizing pantograph down chargers. The process involves reviewing alternative designs to understand the most efficient approach to charging on the site now and into the future (including a potential autonomous future). 

The objective of our work is to provide a framework that establishes the optimal combination of depot layouts, charger speeds and charger types which most benefits KCM. Optimal is defined as the balance between the following factors:

  • Buses have sufficient charge at all times to meet schedules
  • That capital investment in charging infrastructure is minimised
  • Space in the depot is optimized
  • Flexible enough to deal with extreme days and unplanned events (i.e. bus breakdown).
The Approach Evenergi is using BetterFleet™ to undertake predictive modeling and analysis. 

To complete this work, we are: 

  1. Modeling the state of charge of buses as they enter depot, based on-route energy requirements modeling;
  2. Modeling the state of charge as buses leave the depot , with expectations of the energy required to complete the next assigned block.;
  3. Modeling the state of charge impacts based on agreed worst case scenarios, such as route detours, high passenger loading and temperature extremes.; 
  4. Modeling the movement of buses as they enter the depot into pre-agreed “zones” each of which may consist of a number of “lanes” or “spaces”; 
  5. Assigning specific buses to specific zones based on business rules such as bus type, e.g.  “articulated” or “rigid” or chargepoint compatibility.; 
  6. Considering time allocations when buses are potentially unavailable for charging, including cleaning, washing and general service line activities.;  
  7. Modeling scenarios with or without hostlers moving buses, to understand the costs and impact of lane “blocking” being resolved with additional human resources.  
Outcome An interesting aspect of the study, Evenergi is developing a new module of its BetterFleet software for KCM that will simulate in-depot charging ensuring that BEBs can meet their block assignments with the state of charge achieved by depot charging with a first in, first-out strategy. The project is still ongoing and is due for completion by April 2022.

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