How to use scrape component

I have created a scrape sensor like so:

- platform: scrape
  name: Current Power
  unit_of_measurement: kW
  resource: http:/....
  select: "power"  

And within that html file I se values such as:
,"energy_accu":35.0,"power":1030.0,"time_zone":"Europe/Dublin"....

The sensor is still coming back with unknown but as you can see there “power” does have a value of 1030.0 so maybe I am calling it wrong?