def cloud_cover_to_ghi_linear(cloud_cover, ghi_clear, offset=35):
    """
    Convert cloud cover to GHI using a linear relationship.

    0% cloud cover returns ghi_clear.

    100% cloud cover returns offset*ghi_clear.

    Parameters
    ----------
    cloud_cover: numeric
        Cloud cover in %.
    ghi_clear: numeric
        GHI under clear sky conditions.
    offset: numeric, default 35
        Determines the minimum GHI.

    Returns
    -------
    ghi: numeric
        Cloudy sky GHI.

    References
    ----------
    Larson et. al. "Day-ahead forecasting of solar power output from
    photovoltaic plants in the American Southwest" Renewable Energy
    91, 11-20 (2016).
    """

    offset = offset / 100.
    cloud_cover = cloud_cover / 100.
    ghi = (offset + (1 - offset) * (1 - cloud_cover)) * ghi_clear
    return ghi