DERs: Solar, Battery Storage Could Reduce Fleet Electrification Costs

April 12, 2021

Deployment of medium- and heavy-duty battery electric vehicles for commercial fleets is accelerating. Commercial offerings of these vehicles have increased, and medium- to large-scale vehicle purchases are beginning to occur in leading fleets. At the same time, local, state and federal policy and goal setting for zero-emission vehicle adoption is expanding. However, lack of access to fleet operations data that can be used to quantify needs, costs, and operational conditions involving vehicle charging have led to significant uncertainty about the value of EV-specific utility rates, on-site electricity generation, and storage systems proposed as important components of fleet electrification projects.

GNA recently completed a study estimating charging costs based on real world trip data provided by a pair of commercial fleets — NFI and Schneider — in an effort to map out the costs of charging and how to mitigate some of these expenses with utility rate selection and use of distributed energy resources, or DERs, such as on-site solar panels and battery energy storage systems.

NFI and Schneider provided real world trip data on costs of charging with use of DERs and utility rate selection.

Facing the Facts, Understanding the Needs

The Class 8 truck sector represents one of the of the most noteworthy sources of emissions, and efforts to electrify these fleets has presented a number of hurdles to overcome. Fleet-specific driving schedules combined with hauling heavy loads over long distances has made this possible progression even more difficult with the range constraints of electric trucks. This fact is noted by fleets that would need to depend on these vehicles meeting charging and operational demands with the electric vehicle technology that currently exists.

With this understanding, our study looked at data from two separate Class 8 semi-tractor deployment projects in California to evaluate the costs of charging and the extent to which existing truck trips could be electrified with current and near-term battery-electric trucks and charging systems. The study focused on four key areas: fleet needs, electric loads, charging rates and scenarios, and integration of DERs. We evaluated 16 different combinations of charging power and traction battery capacity — varying from battery capacities between 300-1000 kWh and charging station power from 50-800 kW — to assess charging costs against real world trip data.

GNA studied two Class 8 truck deployments focused on fleet needs, electric loads, charging rates, and integration of DERs.

DERs Increase Savings

Before adding the increased savings DERs can offer, our evaluation determined that the fleets would see lower annual fueling costs both in the first year, as well as over 20 years, showing between $4.6 and $5.8 million in increased savings compared to operating diesel trucks. For the study fleets, we found that the use of managed charging universally resulted in lower charging costs, regardless of the selected utility rate plan. Additionally, the use of EV-specific rate options generally provides the lowest charging costs for fleets.

However, one exception exists to the benefit of EV-specific rates. Where significant DER can be deployed to support fleet charging, fleets can reduce charging costs by switching from EV-specific rates to DER-specific rates. This supports the idea that upfront investments for DERs can prove to be worthwhile for the right fleet electrification projects over the 20-year analysis period in this study. It must be noted that this timeframe is longer than many fleets consider for return on investment and the capital-intensive nature of DER projects and long timeframes for return on investment may be more suited to utilities and other infrastructure-based companies that routinely invest in projects with 20-year operational lifetime

GNA found that managed charging resulted in lower charging costs, where DER can be deployed costs are further reduced.

In addition to reducing charging costs for the fleets, we also determined that a battery storage system provided a significant reduction in peak energy demand from the grid. This proved to help avoid grid impacts and increase savings if they were incorporated into utility grid planning. Overall, the use of DERs reduced the combined peak load by up to 6 MW for a fleet of nearly 50 trucks. When scaled, this adds up to a significant savings to utilities, helping them reduce grid buildout costs when infrastructure projects are paired with DERs.