[draft] pvlib prototype

[willhonaker]

Add pvlib wrapper for pv generation via pvlib library.

Adds pvlib module - integrates pvlib.modelchain.ModelChain() with geodata cutouts, enabling pv simulations across time, x, and y indices of a cutout. Also adds ModelChainConfig class to streamline the configuration of ModelChain instances.

Also updates era5 module to also download dewpoint_temperature (d2m) for use in calculation of relative humidity and precipitable water (required input for some pvlib models).

Main functions/classes:

pvlib_model()

• Extracts necessary weather variables from a geodata cutout.
• Generates simulations using pvlib.modelchain.ModelChain().
• Returns an xarray.Dataset containing AC pv output across cutout coordinates.

ModelChainConfig

• Class for defining ModelChain configs, allowing for reuse of modeling parameters across different PV systems and cutouts.

Helper functions:

• _prepare_pvlib_ds(): Processes and format input weather data for use with pvlib models.
• _calculate_pvlib_solarposition(): Computes solar position data using pvlib.solarposition.get_solarposition().
• _calculate_ghi(): Computes global horizontal irradiance (GHI) from direct and diffuse components.
• _calculate_relative_humidity(): Estimates relative humidity from air temperature and dewpoint. Calculated using dewpoint_temperature from era5 module. Calculated using August-Roche-Magnus equation
• _calculate_precipitable_water(): Calculates precipitable water using pvlib.atmosphere.gueymard94_pw().

References: