Solar monitoring app

Monitors solar panel output using the Fronius inverter API and power consumption in realtime and persists the data to a MySQL database for display in Grafana.

• Monitors instantaneous power generation and consumption
• Calculate cost of power used
• Monitors per-string power generation
• Retrieves Solcast solar forecasts (https://solcast.com/)
• Uploads actual generation to tune the Solcast forecast

Usage

Configure solar panel system in Solcast

Setup and run the app:

• Build the application using Maven: mvn clean package
• Install and run MySQL (https://www.mysql.com/ or https://mariadb.org/)
• Setup the database using /solar-sql/src/main/resources/mysql/setup.sql (substitute your own passwords)
• Add power tariffs (see below for details)
• Configure properties in application.properties
  • app.inverter.host - hostname/IP of the inverter web API
  • app.solcast.api-key - your Solcast API key value
  • app.solcast.site-id - your Solcast site ID
  • spring.datasource.username - your MySQL app user
  • spring.datasource.password - your MySQL app user password
• Run the application

To view the output, use Grafana:

• Install and run Grafana
• Configure the MySQL datasource
• Import the Solar dashboard found in /solar-core/src/main/resources/grafana/Solar.json

Sample output:

Power tariff configuration

There are two types of tariffs:

• Usage tariffs - what you are charged for using electricity.
• Feed-in tariffs - what you are paid (or possibly charged) for exporting electricity.

Tariff Data Structure

The application uses the Tariff data structure to represent power tariffs. The fields in the Tariff class are:

Field	Type	Description
feedIn	boolean	true for a feed-in tariff, false for a usage tariff.
startEffectiveDateEpoch	long	The time when this tariff begins to be effective, in seconds since the epoch or as a date string.
endEffectiveDateEpoch	Long	The time when this tariff stops being effective, in seconds since the epoch. Can be null.
dayOfWeek	DayOfWeek	The day of the week this tariff applies to (e.g., SUNDAY, MONDAY).
startOfPeriod	LocalTime	The time of day when this tariff starts being effective (e.g., 00:00:00, 15:00:00).
endOfPeriod	LocalTime	The time of day when this tariff stops being effective (e.g., 10:00:00, 23:59:59).
pricePerKwh	BigDecimal	The price for one kilowatt-hour (kWh) (e.g., 0.2174).

Loading Tariffs

To load tariffs into the application, follow these steps:

1. Create a CSV File: Create a CSV file containing the tariff data. The file must include both usage and feed-in tariffs for each day of the week, covering the entire day from 00:00:00 to 23:59:59.

   Example CSV file:

   feedIn,startEffectiveDateEpoch,endEffectiveDateEpoch,dayOfWeek,startOfPeriod,endOfPeriod,pricePerKwh
   true,2024-11-10 00:00:00,,SUNDAY,00:00:00,23:59:59,0.033
   false,2024-11-10 00:00:00,,SUNDAY,00:00:00,15:00:00,0.2174
   false,2024-11-10 00:00:00,,SUNDAY,15:00:00,21:00:00,0.4082
   false,2024-11-10 00:00:00,,SUNDAY,21:00:00,23:59:59,0.2174
   

2. Configure the Application: Update the application.properties file to point to the CSV file:

   app.tariff.file-path=/path/to/tariff-file.csv
   app.tariff.date-format=yyyy-MM-dd HH:mm:ss
   app.tariff.timezone=Australia/Melbourne

3. Trigger the Update: Call the /update-tariffs endpoint to load the tariffs into the application. This endpoint validates the tariffs and applies them to the database.

Examples

Flat Tariff Example

If you are paid $0.033 per kWh for export, regardless of the time of day, the CSV entry for Sunday would look like:

true,2024-11-10 00:00:00,,SUNDAY,00:00:00,23:59:59,0.033

Time-of-Use Tariff Example

If you are charged different amounts depending on the time of day, you will have multiple rows per day. For example:

• $0.2174 between midnight and 3pm,
• $0.4082 between 3pm and 9pm,
• $0.2174 between 9pm and midnight.

The CSV entries for Sunday would look like:

false,2024-11-10 00:00:00,,SUNDAY,00:00:00,15:00:00,0.2174
false,2024-11-10 00:00:00,,SUNDAY,15:00:00,21:00:00,0.4082
false,2024-11-10 00:00:00,,SUNDAY,21:00:00,23:59:59,0.2174