Script with Dutch power prices

[jeroen@stevens.biz]

Hi. I want to read out the current hourly power prices (Dutch EPEX spot market). With this info I want to switch on heavy power users (car charging, airco etc) and switch off my solar panels when the market prices are below -/-0,06729 per kWh (since then the energy taxes don't compensate the negative market price, taxes are 0,03679 per kWh + 0,0305 per kWh). I found a website where I can read out these prices, but how can I let a script return the hourly values in a way I can make decisions with it?

With this simple script (where I've put in the time range of 1 day), I get the following output;

--/--

local https = require('ssl.https')
local ltn12 = require('ltn12')
local json = require('json')
local cBody = 'TariffReturn'
local cReq = {}

result1 = https.request({
  url = 'https://mijn.easyenergy.com/nl/api/tariff/getapxtariffs?startTimestamp=2022-05-29T22%3A00%3A00.000Z&endTimestamp=2022-05-30T22%3A00%3A00.000Z&grouping=',
  method = 'GET',
  headers = {
    ['content-length'] = #cBody,
    ['content-type'] = 'application/json'
  },
  source = ltn12.source.string(cBody),
  sink = ltn12.sink.table(cReq)
})

if (cReq) then
  mydata =  json.pdecode(table.concat(cReq))
  log(mydata)

end


--/--

In the output I refer to this part:

--/
....
[4]
  * table:
  ["Timestamp"]
    * string: 2022-05-30T01:00:00+00:00
  ["TariffReturn"]
    * number: 0.1845
  ["TariffUsage"]
    * number: 0.223245
  ["SupplierId"]
    * number: 0


/--
where '  ["TariffReturn"]
    * number: 0.1845
the price per kWh is for every kWh consumed (or delivered) between 2022-05-30, 04.00 - 05.00u

The notation is a little bit confusion, since the table states it is at 01.00.

I check the output of easyenergy with one of the other EPEX spot market parties: https://prijzen.powerhouse.net/forecast/

Any help is welcome.

Jeroen