#Visualizing dynamic electricity pricing forecast

1 messages · Page 1 of 1 (latest)

frosty wind
#

I was signed up for a trial for dynamic electricity prices and am now looking to visualize the upcoming prices for other users in the house to maybe defer some energy-intensive stuff to a time where prices are cheaper. However, for that, I first need to actually get the data into Homeassistant.

I can fetch the data from an API and have already set this up in my EVCC instance. To avoid fetching the same data twice, I want to use the EVCC API to get the prices already available there. Using curl, this is easy, curl https://evcc.home/api/tariff/grid returns the data available in a format like this: ```{
"rates": [
{
"start": "2025-08-07T19:45:00+02:00",
"end": "2025-08-07T20:00:00+02:00",
"value": 0.270696
},
...
]
}


Now I'm both not sure how I can actually fetch the data from EVCC using Homeassistant and also how I can populate a sensor value with data from the future. Any help is appreciated, thanks 🙂

Once that data is in Homeassistant, I think using some graph card addon will make it easy to visualize it, so it's more about getting the actual data into HA...
knotty fiber
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are you comfortable writing python / writing a HA integration? Because that would be the most straightforward way

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everything else is just going to be a hack

frosty wind
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Yeah, I almost figured that this was the way to go already. However, I had a brief look at the Tibber integration and couldn't figure out right away how/if it stores data for the future...

knotty fiber
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forecasts are made available to the frontend using an action (service)

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they are not stored as far as I know, except cached

frosty wind
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Forecasts as in the ones used for e.g. solar production?

knotty fiber
#

yes

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energy prices of the future are also forecasts

frosty wind
#

Correct

knotty fiber
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here's an implementation of what you would have to make

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you could just copy this integration and adjust it for your data source

frosty wind
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so from a glance this essentially provides a service where the forecast data can be fetched, right?

knotty fiber
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exactly

frosty wind
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Ok, so far so good, but how would I visualize this in a dashboard?

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The EnergyZero docs mention that a template sensor should be created for this, but as far as I can see this will only look back, not into the future

bleak heath
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A template sensor can have arbitrary data structure in attributes, which could be a set of future datapoints.

frosty wind
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I see, then I could use something like the ApexCharts addon which can use something else than the state to create a graph...

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sorry, not addon, card

knotty fiber
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yeah, that could work

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but that's what I meant by a hack. Storing forecasts in attributes will bloat the database

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although it used to be like that for a long time 🤣

frosty wind
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i'm open for other ideas 😄

knotty fiber
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already did haha

frosty wind
#

So if it's a hack anyway, any possibility of avoiding to write a custom integration "just" to fetch some json data and transform it into attributes of a template sensor?

knotty fiber
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if you're going the integration route might as well use a service

frosty wind
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The service route seems to be a dead-end when coming to visualize the retrieved data...

knotty fiber
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why?

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apexcharts can visualize it, I know people have done it

frosty wind
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I can't find the config options then

knotty fiber
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that might still need a template but that's not storing it in attributes at least

frosty wind
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then I could just fetch the data from EVCC and store the response as a string, would that be more efficient?

knotty fiber
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you should be able to use that yeah

frosty wind
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I'll give it a shot then, thank you!

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well... state length cannot exceed 255 characters apparently 🙁

frosty wind
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So I ended up using with what probably is considered a hack, but it works: RESTful sensor which fetches the tariffs from EVCC into its attributes. And then use that attribute in the data_generator of apex chart card. I made sure to exclude the rest sensor from the recorder, so I hope at least that will not be an issue 😅

knotty fiber
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nice!

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could you share that yaml? it will be useful for others