def calculate_LSTM(time_zone_utc):
    """
    Calculates and returns the LSTM, or Local Solar Time Meridian.
    https://www.pveducation.org/pvcdrom/properties-of-sunlight/solar-time

    time_zone_utc: The UTC time zone of your area in hours of UTC offset.

    Returns: The Local Solar Time Meridian in degrees
    """

    return 15 * time_zone_utc