mirror of
https://github.com/Akkudoktor-EOS/EOS.git
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Andreas
c0c9a1f669
Everything up to the knee is backed by residual load, everything beyond it only by an export at the median feed-in tariff - the two halves have very different confidence. The breakpoint list alone does not say where the split is, so consumers had to guess it from the segment lengths.
128 lines
4.9 KiB
Python
128 lines
4.9 KiB
Python
"""Tests for the concave terminal value of the energy left in the battery."""
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import numpy as np
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import pytest
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from akkudoktoreos.optimization.genetic.terminalvalue import (
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build_terminal_value_curve,
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trailing_window,
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)
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def _curve(**overrides):
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"""Two expensive slots, one cheap one, no PV, 10 kWh of usable battery."""
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params = dict(
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prices_euro_per_wh=np.array([0.0004, 0.0003, 0.0001]),
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load_wh=np.array([1000.0, 1000.0, 1000.0]),
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pv_wh=np.array([0.0, 0.0, 0.0]),
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feed_in_euro_per_wh=np.array([0.00008, 0.00008, 0.00008]),
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max_energy_wh=10000.0,
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lcos_euro_per_kwh=0.0,
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dc_to_ac_efficiency=1.0,
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grid_export_allowed=False,
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)
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params.update(overrides)
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return build_terminal_value_curve(**params)
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def test_marginal_value_follows_the_most_expensive_hours_first():
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"""The first stored kWh replaces the most expensive slot, then the next."""
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curve = _curve()
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# 0.40, 0.30 and 0.10 EUR/kWh, in that order.
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assert curve.marginal_euro_per_kwh == pytest.approx([0.4, 0.3, 0.1])
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assert curve.energy_wh == pytest.approx([0.0, 1000.0, 2000.0, 3000.0])
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assert curve.value_euro == pytest.approx([0.0, 0.4, 0.7, 0.8])
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def test_curve_is_concave_and_saturates():
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"""Marginal values only decrease, and beyond the last breakpoint nothing is added."""
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curve = _curve()
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marginals = curve.marginal_euro_per_kwh
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assert all(a >= b for a, b in zip(marginals, marginals[1:]))
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# The residual load of the window is 3 kWh - more energy replaces nothing.
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assert curve.value(3000.0) == pytest.approx(0.8)
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assert curve.value(9000.0) == pytest.approx(0.8)
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def test_value_interpolates_within_a_segment():
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"""Half of the first slot is worth half of the first segment."""
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curve = _curve()
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assert curve.value(500.0) == pytest.approx(0.2)
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def test_pv_reduces_the_residual_load():
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"""Only load that PV cannot cover can be replaced by stored energy."""
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curve = _curve(pv_wh=np.array([600.0, 1000.0, 0.0]))
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# Slot 0 keeps 400 Wh, slot 1 is fully covered by PV, slot 2 keeps 1000 Wh.
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assert curve.energy_wh == pytest.approx([0.0, 400.0, 1400.0])
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assert curve.marginal_euro_per_kwh == pytest.approx([0.4, 0.1])
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def test_lcos_is_subtracted_from_the_marginal_value():
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"""Storage cost is already charged on discharge and must not be credited twice."""
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curve = _curve(lcos_euro_per_kwh=0.05, dc_to_ac_efficiency=1.0)
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assert curve.marginal_euro_per_kwh == pytest.approx([0.35, 0.25, 0.05])
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def test_negative_prices_do_not_create_value():
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"""Storing energy for an hour that pays nothing is not worth anything."""
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curve = _curve(prices_euro_per_wh=np.array([0.0004, -0.0001, 0.0]))
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assert curve.marginal_euro_per_kwh == pytest.approx([0.4])
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assert curve.value(5000.0) == pytest.approx(0.4)
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def test_export_tail_only_with_direct_marketing():
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"""Surplus beyond the residual load is worth an export - if export is allowed."""
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without = _curve(grid_export_allowed=False)
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with_export = _curve(grid_export_allowed=True)
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assert without.value(10000.0) == pytest.approx(0.8)
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# 7 kWh beyond the residual load at the median feed-in tariff of 0.08 EUR/kWh.
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assert with_export.value(10000.0) == pytest.approx(0.8 + 7.0 * 0.08)
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assert with_export.marginal_euro_per_kwh[-1] == pytest.approx(0.08)
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def test_residual_energy_marks_the_knee():
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"""The knee separates load-backed value from the export tail."""
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without = _curve(grid_export_allowed=False)
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with_export = _curve(grid_export_allowed=True)
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# 3 kWh of residual load in the window, whether or not export is allowed.
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assert without.residual_energy_wh == pytest.approx(3000.0)
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assert with_export.residual_energy_wh == pytest.approx(3000.0)
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# Only the export tail reaches beyond it.
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assert without.energy_wh[-1] == pytest.approx(3000.0)
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assert with_export.energy_wh[-1] == pytest.approx(10000.0)
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def test_curve_is_capped_by_the_usable_battery_energy():
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"""A battery smaller than the residual load ends the curve early."""
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curve = _curve(max_energy_wh=1500.0)
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assert curve.energy_wh[-1] == pytest.approx(1500.0)
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assert curve.value(5000.0) == pytest.approx(0.4 + 0.5 * 0.3)
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def test_empty_window_yields_an_empty_curve():
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"""Without data there is no curve, and no credit."""
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curve = build_terminal_value_curve(
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prices_euro_per_wh=np.zeros(0),
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load_wh=np.zeros(0),
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pv_wh=np.zeros(0),
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feed_in_euro_per_wh=np.zeros(0),
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max_energy_wh=10000.0,
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)
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assert curve.energy_wh == []
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assert curve.value(5000.0) == 0.0
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def test_trailing_window_takes_the_end_of_the_horizon():
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values = np.arange(10, dtype=float)
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assert list(trailing_window(values, end_slot=8, window_slots=3)) == [5.0, 6.0, 7.0]
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# A window longer than the horizon yields what there is.
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assert list(trailing_window(values, end_slot=2, window_slots=5)) == [0.0, 1.0]
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assert list(trailing_window(None, end_slot=8, window_slots=3)) == []
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