To delete a site you will need to provide its ID. See here how to get the sites IDs.
Delete site
import requests

api_key = "Your API key" # Set your API key
site_id = "a923653c-26f1-1b29-955d-ffde5d182276" # Set the site ID

url = "https://api.rebase.energy/platform/v2/sites/{site_id}"
headers = {'Authorization': api_key, 'Content-Type': 'application/json'}

response = requests.delete(url, headers=headers)
response.raise_for_status()
response = response.json()
Response example
{
    "message": "Site deleted successfully"
}