Tariffs: add formulas

[andig]

Fix #16977

Available Variables: price, charges, tax, math (go package)

Examples: Raw spot price with 0ct lower cap and 50ct upper cap

  grid:
    type: template
    template: energy-charts-api
    bzn: DE-LU
    formula: Math.Min(math.Max(price, 0), 0.5)

TODO

• add to templates

[naltatis]

Hab das gerade getestet. Sieht gut aus.

[andi0b]

@andig Großartig, danke!

charges und tax scheinen jedoch nicht übergeben zu werden und sind immer 0.0.

evcc/tariff/embed.go

Lines 42 to 45 in 1de1548

	t.calc = func(price float64) (float64, error) {
	if _, err := vm.Eval(fmt.Sprintf("price = %f", price)); err != nil {
	return 0, err
	}

[andig]

Fixed in master

[timpetersson81]

@andig does this allow me to add zone based tariffs to the dynamic electricity prices?

[andig]

No :(