elnino-ict/dynamic-ess

Dynamic ESS

A node-red flow that uses VRM forecasting and algorithm to optimize when to sell, buy and hold the grid to zero.

Note:

• To use this code, your installtion on VRM needs to be enabled for a beta group. Until that is done an Error 500 will be shown.
• This is a POC/beta node. In the future this node will become obsolete as the functionality will move directly into VRM.

Flow screenshot

The dynamic ess node is for users that have an energy storage system (ESS) in combination with a solar system and want to set it automatically to the optimal value. Where optimal means that it is set so you will pay the least amount for your energy usage. There are several factors determining the optimal value, all being taken into account. These factors are:

• the VRM id
• the solar prediction
• your (dynamic) energy contract price
• your battery size
• the charge speed of your battery
• the discharge speed of your battery
• your predicted consumption

If all of these values are known, VRM can make a calculated optimum setpoint available via its application programming interface (API). The dynamic ess node utilizes that API to fetch it in a userfriendly way. Where optimum means the setting that should result in the lowest energy costs.

Some of the information is deducted from set parameters. Like the country determines the energy price (as retrieved from ENTSOE) and the longitude and latitude determine the solar forecast. It uses solcast and the Global Horizontal Irradiance (GHI) for getting the predicted solar yield.

Usage

As the information is being retrieved via the VRM API, a token is needed to be able to get the required information. This token will then be used instead of your VRM credentials. See create an access token below on how to do that.

Furthermore you will need to fill out the longitude and latitude of your PV system.

While it is probably possible to deduct the country based on the longitude and latitude, it is a lot easier if you fill it out yourself. So you will need to fill out the country as well. This information is used to retrieve the current energy price from ENTSO-E. ENTSO-E is the European association for the cooperation of transmission system operators (TSOs) for electricity. All EU countries use this as source for determining their next day dynamic energy prices.

Create an access token

In order to use the dynamic ess node, you will need an VRM API access token. Creating such a token requires a two-step action, taken on the VRM API. The process is described below.

Bearer token

First point your browser to: https://vrm-api-docs.victronenergy.com/#/operations/auth/login

On the right of the screen there is an interactive box, where you can entery your VRM credentials and push the Send API Request button.

Make sure to add the "remember_me": true, allowing some extra time to create the access token.

If you use 2-factor authentication, you can add "sms_token": "123456", where the number is the token from your 2-factor authentication app.

The Response should be something like:

{
  "token": "eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsImp0aSI6IjRjMzczOTk5NDFmYWU0NDdjMWVmMmZmNzNmMzU5NTQ4In0.eyJ1aWQiOiIxMjI5MTAiLCJ0b2tlbl90eXBlIjoiZGVmYXVsdCIsImlzcyI6InZybWFwaS52aWN0cm9uZW5lcmd5LmNvbSIsImF1ZCI6Imh0dHBzOi8vdnJtYXBpLnZpY3Ryb25lbmVyZ3kuY29tLyIsImlhdCI6MTY3Njg4MjYzMSwiZXhwIjoxNjc2OTY5MDMxLCJqdGkiOiI0YzM3Mzk5OTQxZmFlNDQ3YzFlZjJmZjczZjM1OTU0OCJ9.TjrtftTjU0r4n9nCxE2l6XnxpR2_ltS8R_EBJW_MaY1bs0i1x-6wu6GVNT42sqYP8wUxUEdV2qezKPvFSuG3TJVTcK6VJ6k6nhS7fHtmQ66-wyi917HOK7uw37PuOGzdEi2SrR8vg_Qd3kF6yhki8zcphMgeNqOD2hXHSUjbb3WUTKyMMG6fu0e9VgdY35wXzHZSzdbbQlkR9e6TIqDFYGEFjL_NpXhG48fVdxjtPgZXGeOzyuRUwezveZNo1-Pr4FTOsEa3_-krxSmwvktwa0sk0EjBLArnb-z6FI2Mpg-Vhv9EdeL5jP1zL6dOdSmE1rseemf7mS45zBB-FTN0qA",
  "idUser": 122910,
  "verification_mode": "mobile",
  "verification_sent": false
}

The long string after the token word is the Bearer token. You will need both the token and the idUser for creating the access token.

Access token

Once you have a valid Bearer token, you can create an access token. Point your browser to https://vrm-api-docs.victronenergy.com/#/operations/users/idUser/accesstokens/create and fill out the parameters. Give the access token a name in the body and hit the Send API request button.

Store the access token in your password vault as you won't be able to retrieve it again. You will also need to fill out this token in the dynamic ess node.

When you are done you can point your browser to https://vrm-api-docs.victronenergy.com/#/operations/auth/logout and Send API Request for logging out and invalidating the Bearer token.

You can also list and revoke existing tokens via the VRM API.