Until a few years ago, there was little interest in utilizing the heat of the earth directlyfor space heating, water heating, air conditioning, clothes drying, process heating, aquacultureand agriculture heating, etc. Fossil fuels were readily available and relativelyinexpensive. The future was assured with cheap energy through scientific accomplishments.

The sudden increase in fossil fuel prices imposed a new reality upon present energy usageand future projections. The'initial and, in some quarters, present thinking has beenrestricted to using all energy sources to produce electric power. Electricity seems quitereasonable because of its versatility, ease of transport and ready marketability.

It must be pointed out that the highest form of energy is work. The value of energy ismeasured by the work it can do. While this paper does not deal with the totality of the largecomplex set of energy-related problems having economic, social, political and technicalcomponents, it does focus on the technical problem of using geothermal energy to reduce wastewhile energy is being used. Efficiency with which energy is used can be measured by howclosely the amount of available work used to accomplish a task corresponds to the minimumamount the task requires. The key to maximum efficiency is determining the minimum loss ofavailable work that is entailed in accomplishing a particular task. The goal is not conservationof energy but conservation of the ability to do work.