The ATA’s Sunulator grid-connected solar economics simulation tool has been upgraded to cover locations Australia-wide as well as simulating systems that include battery storage.
The ATA is very excited to have recently released the next version of Sunulator, our Microsoft Excel tool that models the economic and environmental performance of grid-connected solar systems.
The new version now includes 177 locations across Australia, as well as systems that use battery storage.
In Sunulator you can input a detailed consumption profile (48 intervals per day for 365 days) to generate an accurate picture of system requirements. Alternatively, you can manually build a consumption profile based on assumptions regarding seasonal and daily electricity consumption.
Sunulator nets off generation against consumption for each 30-minute interval over a full year. This provides an accurate picture of how much solar generation will be consumed on-site (and when), versus how much will be stored and discharged from batteries (and when), versus how much will be exported to the grid (and when).
Using up to six scenarios for different solar system designs, you can compare the economic results. Based on electricity tariff information, Sunulator calculates the impact on the user’s electricity bill and projects the savings over a 30-year timeframe.
The national extension
The ATA has now processed and included 177 locations with the model. These have been chosen to broadly represent the range of climates within each Australian state and territory.
To model the climate, ATA purchased location-specific sunshine and temperature data for all of Australia. Somewhat counter-intuitively, solar generation reduces for every degree above 25 °C—so without adjustment for temperature variation, generation is likely to be slightly overstated, particularly in northern Australia.
The other timely new feature is the ability to analyse battery storage.
The two most common battery chemistries for household/small business energy storage are lead acid and lithium ion. Sunulator can simulate these two chemistries, with the ability to input specific battery charge/discharge rates and efficiencies.
An important aspect of system design is the operation of the rule set – which must decide when and how to charge and discharge the battery. Rule set strategies are evolving, with Sunulator currently including
solar buffer and tariff optimisation.
The solar buffer strategy relies on a sensor in the meter box/switchboard to detect the level of export/import from the grid. Solar is first used to supply on-site appliances, with any excess used to charge batteries, minimising export to the grid. When consumption is greater than solar generation, energy is discharged from the batteries to avoid import from the grid.
Tariff optimisation operates as per the solar buffer, but has additional features that are useful when a peak/off-peak tariff applies.
The battery can charge from the grid in the early morning during off-peak. The system uses a forecasting method to estimate the day’s solar generation and consumption. It then decides on the optimal off-peak charge to minimise the amount of grid import that will be required during the peak tariff period, while avoiding solar excess during the day.
Rule set strategies can be modified by setting limits for charge/discharge rates at any time of the day.