CAMDEN, Maine — At the Hannaford Bros. supermarket here, locally sourced natural products don't end in the produce aisle.
One could look, for instance, in the store's heating oil tank, which over the winter began burning a biodiesel mix produced only a few miles down the road in Rockport. Biodiesel is a more environmentally friendly and efficient fuel than the No. 2 heating oil the store previously burned, according to the Scarborough, Maine-based retailer. Combined with heat recaptur