The Obstacle Course on the Path to Repurposing Used Electric Vehicle Batteries (EVB). Part V: Placement of the Battery System
This is the fifth blog post in our series, this time we’re going to discuss a big challenge if you want to install battery storage: where can you put the battery? This is a big topic with a lot of challenges that are not consistent across geographies so this may be one of many blogs on this particular topic!
In this blog, we’ll discuss:
Our project goals: every battery installation is different so first we want to make sure you understand what we’re working towards
What’s involved if you do plan to do a battery installation at your facility
Regulations and fire codes
Examples of sites we evaluated and key challenges
Our goals
Every project is different, so be clear on what you want to achieve. In our project, we are installing a behind-the-meter solar plus used EV battery system to provide resiliency for a commercial/industrial building. Here, the CEC defined resiliency as supporting critical loads for 24 hours. This is unique as we are designing an extra-long duration energy storage system (typical systems are 2 to 4 hours). What’s also unique is we aren’t trying to completely replace all power in the event of an outage, but only to support what a business defines as critical.
Other project requirements included building sizes no greater than 30,000 square feet and since it’s funded by the CEC’s EPIC program it must be in SCE, PG&E, or SDG&E territory. In Southern California, many big cities like Los Angeles and Anaheim that have their own municipal utility do not qualify. Why is this important? Because we are naturally not going to be working with those jurisdictions for permitting purposes. You can find more details about the grant in its solicitation here.
What’s involved
There is no such thing as a one-size-fits-all for batteries. It takes planning and fine tuning to properly size and site the battery. You need information like the following, much of which requires at least a site visit or two and lots of coordination with building owners and tenants:
12 months of interval data (your electricity usage every 15 minutes). See figure 1 for an example
The buildings’ electrical plans
Location of important things like property lines, nearby fire hydrant(s), electrical distribution panels, location of meter(s), and emergency exit paths
Photos and location(s) of the electrical room
The existence of fire sprinklers and HVAC systems
What the critical loads are and how they map to the electrical circuits, and
Detailed measurements of the preferred battery installation location (see figure 2 for example)
Figure 1: sample interval data for 1 day
Figure 2: Detailed measurement of ideal battery location
The cost and effort to install a battery system is very high and ideally should last you years, so you also need to keep in mind what future plans you have for the space where you want to store the batteries. For example, if you hope to also convert the space into a break area for employees, well, there could be fire codes that prevent that from happening.
Regulations and fire codes
Sadly, this is not consistent across jurisdictions (City, County, State, Country) and can vary if it’s commercial or residential, so please don’t use this as a guide for your projects! Keep in mind, these codes are designed for the worst case scenario, so while it may be onerous, it’s for everyone’s protection. A big thank you to Matt Paiss, a retired fire captain, who serves on our technical advisory committee by helping us navigate the complexities of different codes and standards. Some of the standards have not considered used batteries, so this is where it can be up to interpretation of the local jurisdiction.
Some of these include: Section 1206 of the California Fire Code covers Electrical Energy Storage Systems (ESS) and NFPA 855 Standard for the Installation of Stationary Energy Storage Systems.
Key restrictions related to fire codes that affected our planning include:
What are the paths of egress: entry / exit paths and evacuation paths in emergencies. Even if it’s not normally used, it will count. Once known, we cannot have any batteries within 10 feet of these paths of egress.
Battery enclosures must be 10 feet from property lines.
Batteries can be as close as 3 feet if there is a fire-resistant barrier, like concrete.
Where is the nearest fire hydrant? If it’s too difficult or impossible for the fire department to access the battery system, it’s a no-go!
The system must be 10 feet from vegetation or the site owners must be willing to remove the vegetation.
Is the location indoor or outdoor. Indoor has stricter rules if people are nearby versus far away in a fairly deserted parking lot.
Can you start to see how quickly you can "run out of space" given these rules?
Examples of sites we evaluated
We evaluated up to 10 sites and all had different reasons for why we couldn’t make the battery storage work. We realized this would be a big issue for existing buildings especially in urban areas where available space is limited.
Example 1: 3 potential battery locations, none worked.
In the photo above, the red boxes highlighted the proposed locations for the battery storage. The blue arrows indicated paths of egress.
Option 1: this indoor location was thought to be initially ideal but there was a walkway that was right on the other side of the wall.
Option 2: outdoor area away from the front of the building would block a major path of egress and was not far enough from the property line.
Option 3: outdoor area but was too close to another path of egress.
We eventually identified a fourth option which would take up a few parking spots (next to wear the trash is). However, after sizing the battery system and taking fire codes into account, we needed to take up closer to 4 parking spots versus our initial estimate of 2. Given the location had less than 20 spots and limited street parking, this site was no longer a viable candidate for our used battery storage project.
Example 2: Large open space but a lot of back and forth on ideal placement
In this next example, we were lucky to have a large open space with very few paths of egress. After initial analysis and discussion with the site occupant, we came up with the above location for the battery. The only question we had was whether they could give up enough space for a 20-ft container to provide more backup power. When we shared this with the occupant, they realized neither locations were ideal as they had plans to add a loading bay door where it says 40’ in the image. They would then need more space in the center for storage.
Fortunately, we were able to find a suitable alternative by placing a 10 ft container where it currently says courtyard. We would need to add fencing to prevent any paths of egress too close to the battery, but otherwise, success!
Lastly, any discussion on battery placement must include UL9540A (Test Method for Evaluating Thermal Runaway Fire Propagation in Battery Energy Storage Systems), that is a separate blog post in itself!
Contact us at info@rejouleenergy.com if you want to leverage our technology to test your batteries in or out of the vehicle. What are your thoughts? Did we leave anything out? Please comment and share so we can all engage in conversation and learn from each other.
If this project and/or our work piques your interest, please check out our open positions here.
Cheers,
The ReJouligans
Legal notice:
This document was prepared as a result of work sponsored by the California Energy Commission. It does not necessarily represent the views of the Energy Commission, its employees, or the State of California. Neither the Commission, the State of California, nor the Commission’s employees, contractors, or subcontractors makes any warranty, express or implied, or assumes any legal liability for the information in this document; nor does any party represent that the use of this information will not infringe upon privately owned rights. This document has not been approved or disapproved by the Commission, nor has the Commission passed upon the accuracy of the information in this document.©2021 ReJoule Incorporated. All Rights Reserved.
