Currently, the entire energy industry is striving for more alternate, eco­nomical, and environmentally friendly options. The industry is divided into three parts. Old fossil energy relies on the energy sources coming from the ground. The use of this energy source releases carbon to the atmosphere which is becoming more and more unacceptable due to its impact on the environment. Although over the next decade, oil and coal may be replaced more and more by a cleaner natural gas, this form of energy will continue to receive some environmental objections unless the problems of carbon diox­ide and volatile hydrocarbons released to the environment are appropriately handled. Over the next several decades, fossil energy will still be the domi­nant force in the energy industry.

Renewable bioenergy comes from materials that grow on the ground and in its life cycle, it is carbon neutral to the environment. Thus it is more acceptable to the public on environmentally friendly grounds. Bioenergy coming from bio­mass is, however, of limited supply and carries some serious logistic problems of transportation, storage, and pretreatment. Waste (which is predominantly a form of bio or cellulosic energy) is an interesting source for energy and prod­ucts, and it will play an increasingly important role in the energy industry.

The third and final source of energy is green and clean energy such as wind, solar, hydroelectric, hydrothermal, hydrogen, nuclear, and so on which do not release any carbon into the atmosphere. Wind, solar, hydro­electric and hydrothermal energy sources are also renewable, but they are location-dependent and more work is needed to make them economical. At the present time they are largely used for stationary sources of energy. Hydrogen is the purest and most abundant form of energy. Public accep­tance of nuclear energy at this time is uncertain.

The resources available for these three types of energy industries vary greatly among countries and in the future each country will optimize its own local situation. It is clear that the use of mixed feedstock for produc­ing energy has to be an important part of the strategies for future energy industry development. It will allow more flexibility and a greater acceptance by the public on environmental grounds. As summarized in the previous section, more work is needed to make this strategy more practical and attrac­tive. The future for mixed feedstock is, however, bright, and novel ideas will further accelerate its use in the energy industry.

There are those who believe that in the long term, electricity and hydrogen are the solutions to our energy needs. Even if this is true, a mixed feedstock should play an important role in achieving this goal.