Insofar as renewables have desirable environmental attributes (and some notably corn-based ethanol may not), the preferable approach is to price these attributes and let the market choose the technologies that produce the best balance between environmental and non-environmental considerations.
The article cites as an example a Cornell University study where undergraduates were asked to choose a car based on either the car attributes or the way the various attributes made them feel.
Armed with an understanding of your risk appetite and relationship to debt, some investors may choose to carry debt after all due to its positive attributes.