sungrow/tariff.go

/*
   Copyright 2023 Josh Deprez

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

	   http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

package main

import (
	"time"
)

const (
	//dailySupplyCharge = 105.750 / 100    // 1 July 2020 - 30 June 2021
	//dailySupplyCharge = 98.234 / 100 // 1 July 2021 - 30 June 2022
	//dailySupplyCharge = 98.234 / 100 // 1 July 2021 - 30 June 2022
	dailySupplyCharge = 1.099030 // 1 July 2022 - 30 June 2023

	//solarFeedInTariff = fixedTariff(8.471 / 100)  // 1 July 2020 - 30 June 2021
	//solarFeedInTariff = fixedTariff(6.501 / 100) // 1 July 2021 - 30 June 2022
	solarFeedInTariff = fixedTariff(0.088830) // 1 July 2022 - 30 June 2023
)

var tariff93 = &onOffPeakTariff{
	// 1 July 2020 - 30 June 2021:
	//onPeak:  32.137 / 100,
	//offPeak: 14.963 / 100,
	// 1 July 2021 - 30 June 2022:
	//onPeak:  29.852 / 100,
	//offPeak: 13.9 / 100,
	// 1 July 2022 - 30 June 2023:
	onPeak:  0.333990,
	offPeak: 0.155510,
	isPeak: (&weekdayHours{
		zone: time.FixedZone("UTC+10", +10*60*60),
		on: [24]bool{
			7:  true,
			8:  true,
			9:  true,
			16: true,
			17: true,
			18: true,
			19: true,
			20: true,
		},
	}).isPeak,
}

// type tariff interface {
// 	pricePerKWh(time.Time) float64
// }

type fixedTariff float64

func (f fixedTariff) pricePerKWh(time.Time) float64 { return float64(f) }

type onOffPeakTariff struct {
	onPeak, offPeak float64
	isPeak          func(time.Time) bool
}

func (o *onOffPeakTariff) pricePerKWh(t time.Time) float64 {
	if o.isPeak(t) {
		return o.onPeak
	}
	return o.offPeak
}

type weekdayHours struct {
	zone *time.Location
	on   [24]bool
}

func (w *weekdayHours) isPeak(t time.Time) bool {
	t = t.In(w.zone)
	switch t.Weekday() {
	case time.Saturday, time.Sunday:
		return false
	default:
		return w.on[t.Hour()]
	}
}