Can "sustainable" business models be valued?

At AccuServe, we are currently valuing a company that is a wholesaler of fish and related products that is operating under a sustainable development model. While "sustainable" business models are one where environmental concerns take some precedence over a purely profit-seeking businesses, it is important that these companies through a verifiable measure prove what "sustainable" really means. Sustainable business should lead to less green house gases (GHGs) footprint, at the least, and not just simply "humane" ways of doing business, which is more difficult to measure. We are establishing a valuation model where green businesses can be valued for the sustainable element they bring into the business model and not penalize them for it. Many businesses and investors are resorting to premium prices as a way for justifying such business models. But it should not have to be that way. If investors are able to access subsidized government funds to promote green businesses, then the reduction in GHGs footprint should serve as incentive enough to warrant a higher valuation. Fortunately, mechanisms exist to measure CO2 footprint in dollar terms and this additional dollar value should be added to the value of the business either through a reduction in discount rates or through a net addition to the overall enterprise value.