Self-consumption

(Also be known as load-following)

In most cases you would want to select this battery control scheme. This control scheme gets the battery to:

1. Charge from any excess solar generation remaining after offsetting the load until the battery is full. This occurs when generation > load.
2. Discharge to meet any load after self-consumption until the battery is empty. This occurs when load > generation.

Due to the logic that applies by this battery control scheme, it will be the best control scheme to maximize self-consumption with a battery.

This battery control scheme is designed to maximize electricity bill savings of a Time-of-Use electricity bill by withholding capacity to offset the usage during peak electricity pricing.

Note: most cases using the "Self-consumption" control scheme will result in similar savings, since the battery discharge period generally coincides with the peak pricing periods. There are also some occasions when "Self-consumption" may have a higher bill saving than this battery logic due to the fact that the battery must withhold capacity for peak TOU periods and hence the battery may not be fully utilized to increase self-consumption.

This battery control scheme is designed to maximize customer bill savings by smartly charging/discharging the battery based on time-of-use cost of electricity, and generation and energy usage characteristics.

It achieves this by identifying optimal periods to:

• • Conserve energy to ensure that the usage during the highest pricing periods get offset first before prioritizing cheaper time periods.
  • It will discharge the full battery capacity to the grid to try achieve energy export during time periods with favorable export rates (i.e., export rates that are greater than the peak cost of electricity).
  • It will charge the battery during off-peak pricing periods (generally this would be at night-time) to ensure the battery has sufficient capacity to offset the load during the next day. The optimization is smart enough to know not to fully charge the battery to 100% capacity at night-time in order to reserve some capacity to charge from excess solar the next day.

(For California) This battery control scheme enables your project to take advantage of the high export rates in August/September put in place as part of the NEM 3.0 transition.

Note: OpenSolar does not currently validate system's battery control capabilities to optimize for favorable export rates. We recommend pros to continue using the "Self-consumption" battery control scheme if you are unsure.

This battery control scheme is designed to maximize savings for a bill that includes demand charges.When a utility tariff includes demand charges, these can make up a significant portion of a customers' monthly spend. A key benefit of installing storage is enabling the customer to limit exposure to demand charges by discharging at points of highest demand.

The Peak Demand Shaving control scheme prioritizes reducing peak demand (kW), thus reducing demand charges.

• By default, the control scheme will seek to reduce the peak demand to the average demand per month.

Note that this control scheme is most effective when:

• The battery is sufficiently sized such that it is able to effectively reduce the peak demand
• There is enough solar generation to adequately top up the battery each day. It does try to charge from the grid in these scenarios where the system is not large enough, but it will never draw more energy from the grid such that it will create a new peak demand.

This battery control scheme is generally not optimal for most system designs and is very specific for a niche use case in New Zealand. The battery will do the following:

1. Charge the battery from the grid between 1-5am (low electricity prices) and 3-5pm (to top up the battery before peak electricity pricing in the evening)
2. Battery can ONLY charge from excess solar generation between 11am - 5pm
3. All other times the battery will charge when there is excess solar generation or discharge to offset the load.

Note: Given the niche use case of this battery logic, in most scenarios it does not result in improving electricity bill savings.