A while ago I posted a story about a project aimed at reducing post harvest losses. I noted that losses are often a consequence of imbalances between supply and demand. Without demand prices plummet and a crop effectively becomes a waste. There are also wastes connected to processing eg fruit peels. These wastes are either available free or at low cost depending on their location.
Projects that use these wastes as raw material often look extremely favourable but can quickly loose their feasibility if the demand for the waste allows the owner of the waste to increase its price.
Here is a documented case – waste oil from restaurants has trebled in price in three years as demand for it as a feed for biodiesel has increased
(click image for full story online)