add costs section

doc/costs.rst

@@ -0,0 +1,45 @@
+##################
+Cost Assumptions
+##################
+
+The database of cost assumptions is stored in ``data/costs.csv``.
+
+It includes cost assumptions for all included technologies for specific
+years from various sources, namely for
+
+- discount rate,
+- lifetime,
+- investment (CAPEX),
+- fixed operation and maintenance (FOM),
+- variable operation and maintenance (VOM),
+- fuel costs,
+- efficiency, and
+- carbon-dioxide intensity.
+
+The given overnight capital costs are annualised to net present costs
+with a discount rate of :math:`r` over the economic lifetime :math:`n` using the annuity factor
+
+.. math::
+
+    a = \frac{1-(1+r)^{-n}}{r}.
+
+Based on the parameters above the ``marginal_cost`` and ``capital_cost`` of the system components are calculated.
+
+
+Modifying Cost Assumptions
+==========================
+
+Some cost assumptions (e.g. marginal cost and capital cost) can be directly overwritten in the ``config.yaml`` (cf. Section  :ref:`costs_cf`  in :ref:`config`).
+
+To change cost assumptions in more detail, modify cost assumptions directly in ``data/costs.csv`` as this is not yet supported through the config file.
+
+You can also build multiple different cost databases. Make a renamed copy of ``data/costs.csv`` (e.g. ``data/costs-optimistic.csv``) and set the variable ``COSTS=data/costs-optimistic.csv`` in the ``Snakefile``.
+
+
+Default Cost Assumptions
+========================
+
+.. csv-table::
+   :header-rows: 1
+   :widths: 10,3,5,4,6,8
+   :file: ../data/costs.csv

doc/index.rst

@@ -58,6 +58,7 @@ Documentation
 
 * :doc:`wildcards`
 * :doc:`configuration`
+* :doc:`costs`
 
 .. toctree::
    :hidden:
@@ -66,6 +67,7 @@ Documentation
 
    wildcards
    configuration
+   costs
 
 **Rules Overview**