Study investigates the environmental emissions of battery electric buses, economic impacts (i.e., cash flow), and air pollutant externalities for public health.
Nationwide, United States
On the Front Lines of a Sustainable Transportation Fleet: Applications of Vehicle-to-Grid Technology for Transit and School Buses
Summary Information
This study investigated the potential of Vehicle-to-Grid (V2G) service availability from battery electric (BE) transit and school buses in the United States in terms of economic and environmental benefits. Different independent system operators (ISOs) or regional transmission organizations (RTOs) regulate electricity prices, and environmental emission rates for each region are determined by each region’s power plant types. This study examined possible V2G applications in five different ISO/RTO regions for transit buses and school buses, and performed an additional comparison to internal combustion engine diesel transit and school buses.
The four ISO regions and one RTO region included in this study were:
- The Pennsylvania-New Jersey-Maryland (PJM) interconnection (RTO region)
- The New-York ISO (NYISO) region
- The ISO-New England (ISO-NE) region
- The Electric Reliability Council of Texas (ERCOT) ISO region
- The California ISO (CAISO) region.
Detailed data were collected on diesel and BE fuel options for both transit and school buses. A Life Cycle Assessment (LCA) methodology that utilized a wheel-to-wheel (WTW) approach was used to assess the relevant downstream and upstream impacts of V2G service over a 12 year study period (2015 - 2027).
- Downstream impacts ("on-site" impacts, quantified as tailpipe and tire & brake wear (TBW) related emissions) were gathered from the emission data for diesel transit and school buses from the Environmental Protection Agency’s (EPA) widely utilized MOVES Tool.
- Upstream impacts ("off-site" impacts, emissions from petroleum refineries and the applicable power generation and supply sectors) analysis results were gathered from Argonne National Laboratory's GREET Model.
Findings
- BE transit buses using the V2G system can eliminate 1000 metric tons of CO2-equivalent GHG emissions on average over the lifetime of the system, and BE school buses can eliminate more than 1,400 metric tons over a lifetime.
- Using V2G technology can also eliminate the air emissions caused by combustion power plants (which are not environmentally efficient) when accommodating high electricity demand fluctuations. The V2G system can provide enough electricity back to the grid to reduce the mean air externality value of transit BE buses by $13,000 and school BE buses by $18,300 (a net benefit).
- Life cycle cost results indicate that although BE buses require two or three times higher initial costs compared to diesel bus types, overall net costs are less than diesel bus ownership for BE buses (see below table)
Value Type | School Bus - BE | School Bus- Diesel | Transit Bus - BE | Transit Bus - Diesel |
---|---|---|---|---|
Purchase Price |
$230,000
|
$110,000
|
$800,000
|
$340,000
|
Lifetime Fuel Cost (diesel or electricity) |
$21,915
|
$82,494
|
$87,181
|
$500,113
|
Maintenance Cost |
$66,814
|
$140,461
|
$311,892
|
$415,856
|
Charging Station Purchase Cost |
$23,446
|
$0
|
$23,587
|
$0
|
Charging Station Maintenance Cost |
$8,971
|
$0
|
$8,979
|
$0
|
Battery Replacement Cost (due to operation) |
$29,819
|
$0
|
$76,073
|
$0
|
V2G Cost (V2G Equipment + battery degradation) |
$79,285
|
$0
|
$79,423
|
$0
|
V2G Capacity payment Revenue |
$229,498
|
$0
|
$96,261
|
$0
|
V2G Energy payment revenue (exchanged electricity) |
$56,329
|
$0
|
$56,469
|
$0
|
Resale Value |
$32,658
|
$17,199
|
$106,123
|
$43,810
|
Government incentives (if applicable) |
$84,876
|
$0
|
$106,146
|
$0
|
Net |
$56,888
|
$315,756
|
$1,022,135
|
$1,212,158
|