PyPSA · fneum · Jul 10, 2023 · Jul 6, 2023 · Jul 6, 2023 · Jul 7, 2023
diff --git a/doc/components.rst b/doc/components.rst
@@ -438,18 +438,10 @@ these are used in the LOPF and the `example of a CHP with a fixed
 power-heat ratio
 <https://pypsa.readthedocs.io/en/latest/examples/chp-fixed-heat-power-ratio.html>`_.
 
-To define the new columns ``bus2``, ``efficiency2``, ``bus3``,
-``efficiency3``, etc. in ``network.links`` you need to override the
-standard component attributes by passing ``pypsa.Network()`` an
-``override_component_attrs`` argument. See the section
-:ref:`custom_components` and the `example of a CHP with a fixed
-power-heat ratio
-<https://pypsa.readthedocs.io/en/latest/examples/chp-fixed-heat-power-ratio.html>`_.
-
-
-If the column ``bus2`` exists, values in the column are not compulsory
-for all links; if the link has no 2nd output, simply leave it empty
-``network.links.at["my_link","bus2"] = ""``.
+The columns ``bus2``, ``efficiency2``, ``bus3``, ``efficiency3``, etc. in
+``network.links`` are automatically added to the component attributes. The
+values in these columns are not compulsory; if the link has no 2nd output,
+simply leave it empty ``network.links.at["my_link","bus2"] = ""`` or as NaN.
 
 For links with multiple inputs in fixed ratio to one of the inputs,
 you can define the other inputs as outputs with a negative efficiency

diff --git a/doc/release_notes.rst b/doc/release_notes.rst
@@ -11,9 +11,18 @@ Upcoming Release
   now allows the passing of a list of buses for which aggregation of __all__ carriers is desired. Generation from
   a carrier at a bus is aggregated now if: It is __either__ in the passed list of aggregated carriers, __or__ in the
   list of aggregated buses.
+* PyPSA now supports stand-by cost terms. A new column
+  `stand_by_cost` was added to generators and links. The stand-by
+  cost is added to the objective function when calling
+  ``n.optimize()``.
+* Links with multiple inputs/outputs are now supported by default. The Link
+  component attributes are automatically extended if a link with ``bus2``,
+  ``bus3``, etc. are added to the network. Overriding component attributes
+  at network initialisation is no longer required.
 * The ``n.optimize`` accessor now provides functionality for rolling horizon optimisation using ``n.optimize.optimize_with_rolling_horizon()`` which splits whole optimization of the whole time span into multiple subproblems which are solved consecutively. This is useful for operational optimizations with a high spatial resolution.
 * PyPSA now supports stand-by cost terms. A new column`stand_by_cost` was added to generators and links. The stand-by cost is added to the objective function when calling ``n.optimize()``.
 
+
 PyPSA 0.24.0 (27th June 2023)
 =================================
 

diff --git a/examples/notebooks/biomass-synthetic-fuels-carbon-management.ipynb b/examples/notebooks/biomass-synthetic-fuels-carbon-management.ipynb
@@ -1,6 +1,7 @@
 {
  "cells": [
   {
+   "attachments": {},
    "cell_type": "markdown",
    "metadata": {},
    "source": [
@@ -26,79 +27,18 @@
     "import matplotlib.pyplot as plt"
    ]
   },
-  {
-   "cell_type": "markdown",
-   "metadata": {},
-   "source": [
-    "First tell PyPSA that links can have multiple outputs by overriding the component_attrs. This can be done for as many buses as you need with format busi for i = 2,3,4,5,.... \n",
-    "\n",
-    "See https://pypsa.org/doc/components.html#link-with-multiple-outputs-or-inputs"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "override_component_attrs = pypsa.descriptors.Dict(\n",
-    "    {k: v.copy() for k, v in pypsa.components.component_attrs.items()}\n",
-    ")\n",
-    "override_component_attrs[\"Link\"].loc[\"bus2\"] = [\n",
-    "    \"string\",\n",
-    "    np.nan,\n",
-    "    np.nan,\n",
-    "    \"2nd bus\",\n",
-    "    \"Input (optional)\",\n",
-    "]\n",
-    "override_component_attrs[\"Link\"].loc[\"bus3\"] = [\n",
-    "    \"string\",\n",
-    "    np.nan,\n",
-    "    np.nan,\n",
-    "    \"3rd bus\",\n",
-    "    \"Input (optional)\",\n",
-    "]\n",
-    "override_component_attrs[\"Link\"].loc[\"efficiency2\"] = [\n",
-    "    \"static or series\",\n",
-    "    \"per unit\",\n",
-    "    1.0,\n",
-    "    \"2nd bus efficiency\",\n",
-    "    \"Input (optional)\",\n",
-    "]\n",
-    "override_component_attrs[\"Link\"].loc[\"efficiency3\"] = [\n",
-    "    \"static or series\",\n",
-    "    \"per unit\",\n",
-    "    1.0,\n",
-    "    \"3rd bus efficiency\",\n",
-    "    \"Input (optional)\",\n",
-    "]\n",
-    "override_component_attrs[\"Link\"].loc[\"p2\"] = [\n",
-    "    \"series\",\n",
-    "    \"MW\",\n",
-    "    0.0,\n",
-    "    \"2nd bus output\",\n",
-    "    \"Output\",\n",
-    "]\n",
-    "override_component_attrs[\"Link\"].loc[\"p3\"] = [\n",
-    "    \"series\",\n",
-    "    \"MW\",\n",
-    "    0.0,\n",
-    "    \"3rd bus output\",\n",
-    "    \"Output\",\n",
-    "]"
-   ]
-  },
   {
    "cell_type": "code",
    "execution_count": null,
    "metadata": {},
    "outputs": [],
    "source": [
-    "n = pypsa.Network(override_component_attrs=override_component_attrs)\n",
+    "n = pypsa.Network()\n",
     "n.set_snapshots(range(10))"
    ]
   },
   {
+   "attachments": {},
    "cell_type": "markdown",
    "metadata": {},
    "source": [
@@ -116,6 +56,7 @@
    ]
   },
   {
+   "attachments": {},
    "cell_type": "markdown",
    "metadata": {},
    "source": [
@@ -139,6 +80,7 @@
    ]
   },
   {
+   "attachments": {},
    "cell_type": "markdown",
    "metadata": {},
    "source": [
@@ -163,6 +105,7 @@
    ]
   },
   {
+   "attachments": {},
    "cell_type": "markdown",
    "metadata": {},
    "source": [
@@ -204,6 +147,7 @@
    ]
   },
   {
+   "attachments": {},
    "cell_type": "markdown",
    "metadata": {},
    "source": [
@@ -229,6 +173,7 @@
    ]
   },
   {
+   "attachments": {},
    "cell_type": "markdown",
    "metadata": {},
    "source": [
@@ -283,6 +228,7 @@
    ]
   },
   {
+   "attachments": {},
    "cell_type": "markdown",
    "metadata": {},
    "source": [
@@ -340,6 +286,7 @@
    ]
   },
   {
+   "attachments": {},
    "cell_type": "markdown",
    "metadata": {},
    "source": [
@@ -371,6 +318,7 @@
    ]
   },
   {
+   "attachments": {},
    "cell_type": "markdown",
    "metadata": {},
    "source": [
@@ -388,6 +336,7 @@
    ]
   },
   {
+   "attachments": {},
    "cell_type": "markdown",
    "metadata": {},
    "source": [
@@ -407,6 +356,7 @@
    ]
   },
   {
+   "attachments": {},
    "cell_type": "markdown",
    "metadata": {},
    "source": [

diff --git a/examples/notebooks/chained-hydro-reservoirs.ipynb b/examples/notebooks/chained-hydro-reservoirs.ipynb
@@ -1,6 +1,7 @@
 {
  "cells": [
   {
+   "attachments": {},
    "cell_type": "markdown",
    "metadata": {},
    "source": [
@@ -23,56 +24,18 @@
     "import matplotlib.pyplot as plt"
    ]
   },
-  {
-   "cell_type": "markdown",
-   "metadata": {},
-   "source": [
-    "First tell PyPSA that links will have a 2nd bus by overriding the component_attrs. This is needed so that water can both go through a turbine AND feed the next reservoir"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "override_component_attrs = pypsa.descriptors.Dict(\n",
-    "    {k: v.copy() for k, v in pypsa.components.component_attrs.items()}\n",
-    ")\n",
-    "override_component_attrs[\"Link\"].loc[\"bus2\"] = [\n",
-    "    \"string\",\n",
-    "    np.nan,\n",
-    "    np.nan,\n",
-    "    \"2nd bus\",\n",
-    "    \"Input (optional)\",\n",
-    "]\n",
-    "override_component_attrs[\"Link\"].loc[\"efficiency2\"] = [\n",
-    "    \"static or series\",\n",
-    "    \"per unit\",\n",
-    "    1.0,\n",
-    "    \"2nd bus efficiency\",\n",
-    "    \"Input (optional)\",\n",
-    "]\n",
-    "override_component_attrs[\"Link\"].loc[\"p2\"] = [\n",
-    "    \"series\",\n",
-    "    \"MW\",\n",
-    "    0.0,\n",
-    "    \"2nd bus output\",\n",
-    "    \"Output\",\n",
-    "]"
-   ]
-  },
   {
    "cell_type": "code",
    "execution_count": null,
    "metadata": {},
    "outputs": [],
    "source": [
-    "network = pypsa.Network(override_component_attrs=override_component_attrs)\n",
+    "network = pypsa.Network()\n",
     "network.set_snapshots(pd.date_range(\"2016-01-01 00:00\", \"2016-01-01 03:00\", freq=\"H\"))"
    ]
   },
   {
+   "attachments": {},
    "cell_type": "markdown",
    "metadata": {},
    "source": [
@@ -111,6 +74,7 @@
    ]
   },
   {
+   "attachments": {},
    "cell_type": "markdown",
    "metadata": {},
    "source": [
@@ -187,6 +151,7 @@
    ]
   },
   {
+   "attachments": {},
    "cell_type": "markdown",
    "metadata": {},
    "source": [
@@ -226,6 +191,7 @@
    ]
   },
   {
+   "attachments": {},
    "cell_type": "markdown",
    "metadata": {},
    "source": [

diff --git a/examples/notebooks/chp-fixed-heat-power-ratio.ipynb b/examples/notebooks/chp-fixed-heat-power-ratio.ipynb
@@ -1,6 +1,7 @@
 {
  "cells": [
   {
+   "attachments": {},
    "cell_type": "markdown",
    "metadata": {},
    "source": [
@@ -24,52 +25,13 @@
     "import pypsa, numpy as np"
    ]
   },
-  {
-   "cell_type": "markdown",
-   "metadata": {},
-   "source": [
-    "First tell PyPSA that links will have a 2nd bus by overriding the component_attrs. This can be done for as many buses as you need with format busi for i = 2,3,4,5,...."
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "override_component_attrs = pypsa.descriptors.Dict(\n",
-    "    {k: v.copy() for k, v in pypsa.components.component_attrs.items()}\n",
-    ")\n",
-    "override_component_attrs[\"Link\"].loc[\"bus2\"] = [\n",
-    "    \"string\",\n",
-    "    np.nan,\n",
-    "    np.nan,\n",
-    "    \"2nd bus\",\n",
-    "    \"Input (optional)\",\n",
-    "]\n",
-    "override_component_attrs[\"Link\"].loc[\"efficiency2\"] = [\n",
-    "    \"static or series\",\n",
-    "    \"per unit\",\n",
-    "    1.0,\n",
-    "    \"2nd bus efficiency\",\n",
-    "    \"Input (optional)\",\n",
-    "]\n",
-    "override_component_attrs[\"Link\"].loc[\"p2\"] = [\n",
-    "    \"series\",\n",
-    "    \"MW\",\n",
-    "    0.0,\n",
-    "    \"2nd bus output\",\n",
-    "    \"Output\",\n",
-    "]"
-   ]
-  },
   {
    "cell_type": "code",
    "execution_count": null,
    "metadata": {},
    "outputs": [],
    "source": [
-    "network = pypsa.Network(override_component_attrs=override_component_attrs)\n",
+    "network = pypsa.Network()\n",
     "\n",
     "network.add(\"Bus\", \"Frankfurt\", carrier=\"AC\")\n",
     "network.add(\"Load\", \"Frankfurt\", bus=\"Frankfurt\", p_set=5)\n",