15-1021 v3.X Storage Requirements for Affordable Housing

Question:

The minimum size of the battery storage system required for energy resiiency is at least 10% of the lighting load plus refrigeration for one week. Can you please clarify: If the storage system is sized to meet 10% of the lighting load plus refrigeration, does the standard also require that circuitry be included to all refrigerators (difficult to do in an affordable housing project), or can any stored electricity in excess of what is needed for emergency lighting be disributed to other areas of the building (possibly to the elevator, the community room ligthing or other support spaces)? Can a battery system (say a Tesla Wall) be used to provide regular power to emegency lighting (and other common area lighting) on a daily basis, rather than in emergencies only? The emergency lighting in our project is exterior lighting that stays on during a power outage. If the powered and circuited lighting from the battery source (or inverter) exceeds 10% of the total lighting load plus refrigeration for a week, have we satisfied the requirement for storage even if refrigerators are not on a circuit to the battery system? The amount of energy storage is based on actual metered data, but to design the system, we need to make assumptions based on installed wattage (plus refrigeration for a week). Is it acceptable to use calculations and lighting schedules to determine the probable load of the system? If the system ends up being slightly undersized, do you expect us to add additional storage capacity? Would a special needs affordable housing project be considered for relief from the storage requirement? If we installed an inverter (instead of emergency lights with battery backup) to power the emergency lighting, without providing any additioanl excess capacity to power refrigerators, would the project still be eligible for the Energy Petal?

Answer:

1. All projects may use an alternative resiliency strategy that diverts some lighting energy to other uses, and multi-family projects may address refrigeration for a week for the project, rather than by units, under the following new Exception:

I06-E14 Alternative Compliance for Resilience
Projects may divert some portion of the required lighting energy (10% of average lighting energy for a week) to other more critical needs, such as elevators, ventilation or heating. Multi-family housing projects do not need to connect all refrigerators in the project to battery power if they have sufficient common refrigerators to support all occupants for a week. Circuitry from the battery system must be provided to all common refrigerators at a minimum.

Documentation:
I06-a Exception Narrative - A narrative explaining how they determined sufficient refrigeration and lighting connectivity for resilience.
I06-c Technical Documentation - Calculations supporting resilience plan.  

2. Yes, a battery system may provide regular power to emergency lighting so as long as there is always enough energy stored so that the storage requirements for resilience are met as per the August 2014 v3.0 Energy Petal Handbook (EnPH pg 7).

3. The requirements for energy storage have been met if the powered and circuited lighting from the battery source (or inverter) exceeds 10% of the total lighting load plus refrigeration for a week and sufficient lighting and refrigeration to function are connected to that source.

4. It is acceptable to use calculations and lighting schedules to determine the probable load of the system. If the energy storage system is undersized, the Auditor will determine if the estimate was made in good faith based on realistic estimates. If the estimate was realistic, it will be accepted even if slightly low. If the team did not use realistic parameters in their modeling and actual load is significantly off from predictions, they may be required to add battery capacity.

5. If a project team thinks they have a substantial case to request a relief from energy storage requirements, they should make a separate inquiry to the Dialogue explaining their reasoning. Financial limitations are not a sufficient reason to avoid requirements.


Post ID 3318

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