What is local energy management?
Local energy management refers to the peak import and export flows seen at the distribution transformer. That is, how much energy is the community having to import to meet demand (likely concentrated to times of high demand such as in the evening peak). Also, how much local generation from rooftop solar or energy storage assets (like the neighbourhood battery or electric vehicles) is being exported from the community and therefore not used locally. You want to be assessing how, or if, the neighbourhood battery is impacting these peak imports and exports and, in turn, achieving its potential goals of increasing local energy consumption and improving local self-sufficiency.
As shown in the figure below, each distribution transformer will be connected to downstream loads, including a number of supply feeders (distribution lines) with associated loads and generation (from rooftop solar).
Metrics for assessing local energy management
There are two metrics that can be used to assess local energy management: the self-solar consumption rate and the self-sufficiency rate.
The daily self-solar consumption (SSC) rate can be calculated as follows:
The total community exports refer to the energy exported to the grid from the community, calculated at the distribution substation that serves the whole community. A higher SSC means less energy was exported from the community therefore more solar generation was used by the community.
The self-sufficiency (SS) rate can be calculated as follows:
The total community imports refer to total energy imported to the community from the grid, calculated at the distribution substation that serves the whole community. A higher SS means less energy was imported from the grid, therefore a higher utilisation of the local solar generation.
To understand the impact the battery itself is having, the SSC and SS rates should be compared to the base case without a battery.
Calculating the SSC and SS rates can be difficult to quantify however, due to their need for import/export data, generation data, and load data at the distribution transformer. Not all transformers will have this information available, and for those that do a DNSP willing to share them is needed.
Data
- Distribution substation meter data (to understand changes in peak imports and exports as a result of the battery’s operation)
- Community solar generation data
- Community load data