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Peak Shaving, Smart Charging, V2G Charging
Published on 10 December 2021
Frans Bal
Dr.
About this good practice
Charging e-buses may put the grid infrastructure to its limits, especially when large number of e-buses are charged almost simultaneously. Futhermore, peak hours may induce high(er) prices per kWh.
To achieve peak shaving, V1G and V2G, i.e. optimal charging of e-buses, a smart connection between the e-buses and the grid is compulsory. V1G enables (price) adjusted rate of charging, V2G has the extra of energy trade. The e-buses involved fulfilled all the needed technical requirements: they have the right VC-VCCU and the battery management system needs no upgrade to switch from V1G to V2G. The V2G-charge units to connect the e-bus to the grid are much more expensive compared to V1G ones. With V1G and V2G lower energy costs are achieved.
Compared to V1G, with V2G the benefits exceed in terms of balancing the grid, reducing costs and emissions. The case study shows that an V2G upgrade does contribute just moderately to the battery pack degradation: after 8 years there is a reduction of a few % compared to V1G. But, the extra degradation of the battery pack due to V2G (dis)charging had no impact on the e-bus operations and is no issue for the operator due to an e-bus service life of 8-9 years.
Via smart scheduling and adaptive load balancing among bus depot chargers peak shaving can be achieved. Adding an energy storage system is a major upgrade to it
To achieve peak shaving, V1G and V2G, i.e. optimal charging of e-buses, a smart connection between the e-buses and the grid is compulsory. V1G enables (price) adjusted rate of charging, V2G has the extra of energy trade. The e-buses involved fulfilled all the needed technical requirements: they have the right VC-VCCU and the battery management system needs no upgrade to switch from V1G to V2G. The V2G-charge units to connect the e-bus to the grid are much more expensive compared to V1G ones. With V1G and V2G lower energy costs are achieved.
Compared to V1G, with V2G the benefits exceed in terms of balancing the grid, reducing costs and emissions. The case study shows that an V2G upgrade does contribute just moderately to the battery pack degradation: after 8 years there is a reduction of a few % compared to V1G. But, the extra degradation of the battery pack due to V2G (dis)charging had no impact on the e-bus operations and is no issue for the operator due to an e-bus service life of 8-9 years.
Via smart scheduling and adaptive load balancing among bus depot chargers peak shaving can be achieved. Adding an energy storage system is a major upgrade to it
Resources needed
None
Evidence of success
With both solutions lower energy costs are achieved, viz.: V1G reduces costs per kWh almost by half, V2G slightly more.
In 2020 the extra revenue generated by trading the energy via V2G did not cover the upgrade cost compared to the V1G infrastructure (yet).
The extra degradation of the battery pack due to V2G (dis)charging is no issue for the operator.
Already with simple smart scheduling of and adaptive load balancing among bus depot chargers peak shaving can be achieved
In 2020 the extra revenue generated by trading the energy via V2G did not cover the upgrade cost compared to the V1G infrastructure (yet).
The extra degradation of the battery pack due to V2G (dis)charging is no issue for the operator.
Already with simple smart scheduling of and adaptive load balancing among bus depot chargers peak shaving can be achieved
Potential for learning or transfer
The developed in-depth business case study framework methodology can be applied elsewhere. It can enhance local bus operation characteristics and contextual differences.
From an economical and ecological perspective, it shows the potentional for other regions to consider and investigate smart charging via V1G or V2G, peak shaving and load balancing regarding their own business case
From an economical and ecological perspective, it shows the potentional for other regions to consider and investigate smart charging via V1G or V2G, peak shaving and load balancing regarding their own business case
Good practice owner
Organisation
Utrecht University of Applied Sciences
Netherlands
Utrecht
Contact
Frans Bal
Dr.