..
  SPDX-FileCopyrightText: 2019-2020 The PyPSA-Eur Authors

  SPDX-License-Identifier: CC-BY-4.0

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Cost Assumptions
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The database of cost assumptions is stored in ``model_file.xlsx``.

It includes a sheet `costs` which specifies the 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.

.. note::

    Another great resource for cost assumptions is the `cost database from the Danish Energy Agency <https://ens.dk/en/our-services/projections-and-models/technology-data>`_.

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 ``costs`` sheet of ``model_file.xlsx`` as this is not yet supported through the config file.

You can also build multiple different cost databases for different scenarios. Copy all costs in the ``costs`` sheet ``model_file.xlsx`` and paste them in an empty row 
below the existing data and give the copied data a new scenario name (e.g. copy and paste costs to new rows and name the scenario "least_cost").


Default Cost Assumptions
========================

.. csv-table::
   :header-rows: 1
   :file: configtables/model_file_costs.csv