PV Battery Operating costs
==========================

Operating costs are annual expenditures on equipment and services that occur after the system is installed. You can specify separate costs based on the nameplate capacity and annual generation of the photovoltaic system and battery.

.. note:: The operating cost inputs are in Year 1 dollars. SAM applies the inflation rate from the Financial Parameters page to calculate the operating cost in each year of the cash flow. If you specify a non-zero escalation rate for an operating cost category, it applies both the inflation rate and escalation rate.

.. note:: For financial models with reserve accounts on the Financial Parameters page, you can use either the operating costs or the major equipment replacement reserve accounts for the cost of major equipment replacements.

 For expenses such as component replacements that occur in particular years, you can use an :ref:`annual schedule <annualschedule>` to assign costs to individual years.

PV
~~

The PV operating costs account for the cost of operating and maintaining the photovoltaic system, including modules, inverters, and balance-of-system components.

**Capacity**
  The nominal capacity of the photovoltaic array in DC kilowatts from the :doc:`System Size<../detailed-photovoltaic-model/pv_system_size>` page  .

**Fixed annual cost, $/yr**
  A fixed annual cost that applied to each year in the project cash flow to account for photovoltaic system operating costs.

**Fixed cost by capacity, $/kWdc-yr**
  A fixed annual cost based on the photovoltaic system's capacity   .

**Variable cost by generation, $/MWhac**
  A variable annual cost based on the annual AC generation of the photovoltaic system, not including energy discharged by the battery or generated by the fuel cell.

Battery
~~~~~~~

Battery operating costs account for the cost of operating and maintaining equipment associated with the battery, such for maintaining battery cells, control equipment, and wiring. It may also include HVAC equipment for heating and cooling the battery environment, and battery replacements. 

**Capacity**
  The battery's nominal storage capacity in DC kilowatt-hours from the Battery Storage page.

**Fixed annual cost, $/yr**
  A fixed annual cost that applied to each year in the project cash flow to account for battery operating costs.

**Fixed cost by capacity,  $/kWhdc of battery storage capacity**
  A fixed annual cost based on the battery's storage capacity.

**Variable cost by generation, $/MWhac of electricity discharged by the battery**
  A variable annual cost based on the total annual electricity discharged by the battery in AC megawatt-hours.

**Replacement cost, $/kWdc of battery storage capacity**
  The replacement cost in Year 1 dollars per unit of battery capacity. SAM uses the inflation rate from the :doc:`Financial Parameters <../financial-parameters/fin_overview>`   page to calculate the replacement cost in the replacement year.

.. note:: To include battery replacements costs in your analysis, be sure to choose a battery replacement option on the Battery Storage page.

Escalation Rate
~~~~~~~~~~~~~~~

For each operating cost category, you can specify an optional annual **Escalation Rate** to represent an expected annual increase or decrease in operating cost above the annual inflation rate specified on the :doc:`Financial Parameters <../financial-parameters/fin_overview>` page.

Specify an escalation rate of zero for an operating cost that increases annually at the rate of inflation, a positive escalation rate for a cost that increases at a higher rate than the inflation rate, or a negative escalation rate for a cost that increases at a lower rate than the inflation rate. (Set the inflation rate to the negative value of the inflation rate for a cost that does not increase with inflation.)

Land Lease costs
~~~~~~~~~~~~~~~~
.. include:: ../includes/snip_operating_cost_land_lease.rst

.. _annualschedule:

Using Annual Schedules to Specify Operating costs in Specific Years
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. include:: ../includes/snip_o_and_m_periodic_costs.rst