Energy Related Underground Storage

The storage of energy in one form or another is a well established practice, demonstrated by the familiar sight of large oil storage steel tanks. Today, however, the problems of energy storage are taking on a new complexion. Increased emphasis on large and sometimes untried forms of energy storage is being generated by: (1) The uncertainties we face concerning future oil and gas supplies. (2) The growing need for the storage of peak-shaving energy on large utility systems. (3) The growing volume of highly toxic and energy generating wastes resulting from nuclear power plants. Concurrent with the growth of these pressures, legitimate environmental concerns now demand that the methods of storage which are utilized meet adequate criteria of safety and preservation of surface land, as well as fulfilling technical and economic functions. From these elements, increasing awareness has grown of the potential role that can be played by underground space in providing a storage medium for energy related materials. The vessels which must be built for underground energy storage will be built by the tunnel engineer, and the design requirements of such vessels will go far beyond the classical tunneling requirement to drive a stable, reasonably dry tunnel between two points. Depending on the nature of the material to be stored, the manner in which the storage is to be operated, and the specific risks to the environment which are involved, rock chambers must be designed as special purpose storage vessels. The tunnel engineer may be required to demonstrate that unusual pressure and temperature conditions can be sustained by the rock, or that containment of a toxic material can be assured. In certain cases there will be emphasis on