Perhaps you should try some spelling variations:
energy reduction » energy radiation, energy transduction, energy function
potential cost » potential costs, potential host, potential causes
potential co2 » potential co, potential c, potential costs
production » reproduction, introduction

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((potential co2) OR (potential cost)) emission AND ((energy reduction) OR (energy production)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((potential co2) OR (potential cost)) emission and ((energy reduction) or (energy production))".
• Adding a wildcard symbol may retrieve word variants: ((potential co2) OR (potential cost)) emission and ((energy reduction) or (energy production))*.