Energy is the largest variable operating cost after raw materials for most of the process industries and its efficient use is key to sustaining profitable operation. Natural gas is the most common incremental fossil fuel and its general increase in price and in price volatility over the past few years are well known with most experts projecting these trends to continue in the future. Table 1 gives typical specific energy usage (Btu/t product) for common processes¹ and the value of a 10% energy reduction in terms of increased financial operating margin at an energy price of $7 per million Btu (mBtu). This value is a significant portion of the total operating margin for most of these processes.

In addition to the direct energy price, it seems likely that the US will eventually adopt some regulations regarding greenhouse-gas emissions. If the regulations in other countries are a guide, these may take the form of a "cap and trade" on CO₂ emissions.