src/oemof/solph/constraints/integral_limit.py
# -*- coding: utf-8 -*-
"""Constraints to limit total values that are dependent on several Flows.
SPDX-FileCopyrightText: Uwe Krien <krien@uni-bremen.de>
SPDX-FileCopyrightText: Simon Hilpert
SPDX-FileCopyrightText: Patrik Schönfeldt
SPDX-FileCopyrightText: Johannes Röder
SPDX-FileCopyrightText: Johannes Kochems
SPDX-FileCopyrightText: Johannes Giehl
SPDX-License-Identifier: MIT
"""
from pyomo import environ as po
from oemof.solph._plumbing import sequence
def emission_limit(om, flows=None, limit=None):
r"""
Short handle for generic_integral_limit() with keyword="emission_factor".
Can be used to impose an emissions budget limit in a multi-period model.
Note
----
Flow objects require an attribute "emission_factor"!
"""
generic_integral_limit(
om, keyword="emission_factor", flows=flows, limit=limit
)
def emission_limit_per_period(om, flows=None, limit=None):
r"""
Short handle for generic_periodical_integral_limit()
with keyword="emission_factor". Only applicable for multi-period models.
Puts a limit on each period's emissions.
Note
----
Flow objects required an attribute "emission_factor"!
"""
generic_periodical_integral_limit(
om, keyword="emission_factor", flows=flows, limit=limit
)
def generic_integral_limit(om, keyword, flows=None, limit=None):
r"""Set a global limit for flows weighted by attribute named keyword.
The attribute named keyword has to be added
to every flow you want to take into account.
Total value of keyword attributes after optimization can be retrieved
calling the
`om.oemof.solph._models.Model.integral_limit_${keyword}()`.
Parameters
----------
om : oemof.solph.Model
Model to which constraints are added.
flows : dict
Dictionary holding the flows that should be considered in constraint.
Keys are (source, target) objects of the Flow. If no dictionary is
given all flows containing the keyword attribute will be
used.
keyword : string
attribute to consider
limit : numeric
Absolute limit of keyword attribute for the energy system.
Note
----
Flow objects require an attribute named like keyword!
**Constraint:**
.. math:: \sum_{i \in F_E} \sum_{t \in T} P_i(p, t) \cdot w_i(t)
\cdot \tau(t) \leq M
With `F_I` being the set of flows considered for the integral limit and
`T` being the set of time steps.
The symbols used are defined as follows
(with Variables (V) and Parameters (P)):
================= ==== ====================================================
math. symbol type explanation
================= ==== ====================================================
:math:`P_n(p, t)` V power flow :math:`n` at time index :math:`p, t`
:math:`w_N(t)` P weight given to Flow named according to `keyword`
:math:`\tau(t)` P width of time step :math:`t`
:math:`L` P global limit given by keyword `limit`
================= ==== ====================================================
Examples
--------
>>> import pandas as pd
>>> from oemof import solph
>>> date_time_index = pd.date_range('1/1/2012', periods=6, freq='h')
>>> energysystem = solph.EnergySystem(
... timeindex=date_time_index,
... infer_last_interval=False,
... )
>>> bel = solph.buses.Bus(label='electricityBus')
>>> flow1 = solph.flows.Flow(
... nominal_value=100,
... custom_attributes={"my_factor": 0.8},
... )
>>> flow2 = solph.flows.Flow(nominal_value=50)
>>> src1 = solph.components.Source(label='source1', outputs={bel: flow1})
>>> src2 = solph.components.Source(label='source2', outputs={bel: flow2})
>>> energysystem.add(bel, src1, src2)
>>> model = solph.Model(energysystem)
>>> flow_with_keyword = {(src1, bel): flow1, }
>>> model = solph.constraints.generic_integral_limit(
... model, "my_factor", flow_with_keyword, limit=777)
"""
flows = _check_and_set_flows(om, flows, keyword)
limit_name = "integral_limit_" + keyword
setattr(
om,
limit_name,
po.Expression(
expr=sum(
om.flow[inflow, outflow, p, t]
* om.timeincrement[t]
* sequence(getattr(flows[inflow, outflow], keyword))[t]
for (inflow, outflow) in flows
for p, t in om.TIMEINDEX
)
),
)
setattr(
om,
limit_name + "_constraint",
po.Constraint(expr=(getattr(om, limit_name) <= limit)),
)
return om
def generic_periodical_integral_limit(om, keyword, flows=None, limit=None):
r"""Set a global limit for flows for each period of a multi-period model
which is weighted by attribute called keyword.
The attribute named by keyword has to be added
to every flow you want to take into account.
Total value of keyword attributes after optimization can be retrieved
calling the :attr:`om.oemof.solph.Model.integral_limit_${keyword}()`.
Parameters
----------
om : oemof.solph.Model
Model to which constraints are added.
flows : dict
Dictionary holding the flows that should be considered in constraint.
Keys are (source, target) objects of the Flow. If no dictionary is
given all flows containing the keyword attribute will be
used.
keyword : string
attribute to consider
limit : sequence of float
Absolute limit of keyword attribute for the energy system.
Note
----
Flow objects required an attribute named like keyword!
**Constraint:**
.. math:: \sum_{i \in F_I} \sum_{t \in T} P_i(t) \cdot w_i(t)
\cdot \tau(t) \leq L(p) \forall p \in \textrm{PERIODS}
For the parameter and variable explanation, please refer to the docs
of generic_integral_limit.
"""
flows = _check_and_set_flows(om, flows, keyword)
limit_name = "integral_limit_" + keyword
if om.es.periods is None:
msg = (
"generic_periodical_integral_limit is only applicable\n"
"for multi-period models.\nFor standard models, use "
"generic_integral_limit instead."
)
raise ValueError(msg)
if limit is not None:
limit = sequence(limit)
else:
msg = (
"You have to provide a limit for each period!\n"
"If you provide a scalar value, this will be applied as a "
"limit for each period."
)
raise ValueError(msg)
def _periodical_integral_limit_rule(m, p):
expr = sum(
om.flow[inflow, outflow, p, t]
* om.timeincrement[t]
* sequence(getattr(flows[inflow, outflow], keyword))[t]
for (inflow, outflow) in flows
for t in m.TIMESTEPS_IN_PERIOD[p]
)
return expr <= limit[p]
om.periodical_integral_limit = po.Constraint(
om.PERIODS,
rule=_periodical_integral_limit_rule,
name=limit_name + "_constraint",
)
return om
def _check_and_set_flows(om, flows, keyword):
"""Checks and sets flows if needed
Parameters
----------
om : oemof.solph.Model
Model to which constraints are added.
flows : dict
Dictionary holding the flows that should be considered in constraint.
Keys are (source, target) objects of the Flow. If no dictionary is
given all flows containing the keyword attribute will be
used.
keyword : string
attribute to consider
Returns
-------
flows : dict
the flows to be considered
"""
if flows is None:
flows = {}
for i, o in om.flows:
if hasattr(om.flows[i, o], keyword):
flows[(i, o)] = om.flows[i, o]
else:
for i, o in flows:
if not hasattr(flows[i, o], keyword):
raise AttributeError(
(
"Flow with source: {0} and target: {1} "
"has no attribute {2}."
).format(i.label, o.label, keyword)
)
return flows