102 lines
3.3 KiB
Ruby
102 lines
3.3 KiB
Ruby
#
|
|
# Obtain energy prices from Entsoe (transparancy platform)
|
|
# See https://transparency.entsoe.eu/content/static_content/Static%20content/web%20api/Guide.html
|
|
#
|
|
|
|
require 'open-uri'
|
|
require 'nokogiri'
|
|
|
|
class Entsoe
|
|
|
|
URL = 'https://transparency.entsoe.eu'
|
|
|
|
attr_reader :storage_cost
|
|
|
|
def initialize(api_key = "c2287e07-0c26-4950-b430-22b7f75a8f2e")
|
|
@api_key = api_key
|
|
@kwh_prices = {}
|
|
@storage_cost = 0.05 # how much does it cost to store 1 kwh in battery
|
|
end
|
|
|
|
def price_at(formatted_hour)
|
|
unless @kwh_prices.key?(formatted_hour)
|
|
p "Fetching Entsoe tariffs for %s" % formatted_hour
|
|
@kwh_prices.merge!(query_day_ahead_prices(Date.parse(formatted_hour)))
|
|
end
|
|
@kwh_prices[formatted_hour]
|
|
end
|
|
|
|
def prices_at(date)
|
|
hour_start = date.beginning_of_day
|
|
day_end = hour_start.advance(days: 1)
|
|
result = {}
|
|
while(hour_start < day_end) do
|
|
formatted_hour = hour_start.strftime("%F-%H")
|
|
result.merge!({ formatted_hour => price_at(formatted_hour)})
|
|
hour_start = hour_start.advance(:hours => 1)
|
|
end
|
|
result
|
|
end
|
|
|
|
def high_low_hours(date)
|
|
sorted_prices = prices_at(date).to_a.sort_by(&:last) # sort according to price
|
|
highest_hour = sorted_prices.last[0]
|
|
|
|
# From Apr-Oct: do not charge; every hour that has cost > 0 is a high_hour
|
|
if [4,5,6,7,8,9,10].include?(date.month)
|
|
lowest_hour = "" # effectively no charging from grid
|
|
high_hours = sorted_prices.select{|p| p[1] > 0}.to_h.keys
|
|
else
|
|
lowest_hour = sorted_prices.first[0]
|
|
|
|
# calculate hours where rate > charge_rate + storage_cost (typically 0.05)
|
|
charge_rate = sorted_prices.first[1] # assume we charge at lowest hour
|
|
high_hours = sorted_prices.select{|p| p[1] > charge_rate + storage_cost}.to_h.keys
|
|
|
|
# reset lowest_hour (effectively not charging), when price difference smaller than storage_cost
|
|
highest_price = sorted_prices.last[1]
|
|
lowest_hour = "" if (highest_price-charge_rate) < storage_cost
|
|
end
|
|
|
|
return lowest_hour,highest_hour,high_hours
|
|
end
|
|
|
|
def query_day_ahead_prices(date)
|
|
start_date = date.beginning_of_day
|
|
end_date = date.end_of_day
|
|
|
|
# A44 - Document type => Price Document
|
|
# NL = '10YNL----------L'
|
|
|
|
domain = '10YNL----------L'
|
|
url = URL + "/api?securityToken=%s&documentType=A44&in_Domain=%s&out_Domain=%s&periodStart=%s&periodEnd=%s" % [@api_key, domain, domain, start_date.strftime("%Y%m%d%H%M"), end_date.strftime("%Y%m%d%H00")]
|
|
#p url
|
|
|
|
base_request(date, url)
|
|
end
|
|
|
|
private
|
|
|
|
# get position and amount from XML snippet
|
|
# <Point>
|
|
# <position>1</position>
|
|
# <price.amount>196.23</price.amount>
|
|
# </Point>
|
|
#
|
|
# convert price to EUR per kwh, including VAT (21%)
|
|
#
|
|
def parse_point(xml)
|
|
return xml.children[1].text.to_i, ((xml.children[3].text.to_f/1000)*1.21).round(5)
|
|
end
|
|
|
|
def base_request(date, url)
|
|
formatted_date = date.strftime("%F")
|
|
|
|
doc = Nokogiri::XML(URI.open(url))
|
|
prices = doc.xpath('.//xmlns:Point').map{|p| parse_point(p)}
|
|
|
|
#returns a hash with keys formatted "yyyy-mm-dd-hr" and values price (per kwh)
|
|
prices.map{|p| ["%s-%02d" % [formatted_date,(p[0]-1)], p[1]]}.to_h
|
|
end
|
|
end
|