Impact of System Energetics on the Transition to Inexhaustible Energy Resources for Electric Power Generation.

摘要

The transition from conventional fuel-burning power-generation systems to nonfuel-burning systems that rely on inexhaustible energy resources is examined. This analysis determines the impact of system energetics (the balance of energy flows into and out of the energy-producing system) on the viability of making the transition. The system-energetics analysis is characterized by the fossil-fuel payback period,which is defined as the number of operating years required for the sum of the electrical energy produced and the fossil-fuel-equivalent energy inputs to equal zero. Energy models of both fuel-burning (nuclear reactor) and nonfuel-burning systems (solar thermal/electric) are developed. The optimal transition from an existing fuel-burning system to a nonfuel-burning system minimizes stored energy reserves (coal,uranium) required for completing the transition. The sensitivity of the transition-energy requirements is examined with respect to fossil-fuel payback period,plant lifetime,and energy-demand growth rates. A quantitative method is developed for comparing energy resource demands for systems with differing payback periods. These demands can then be compared with availability of known resources to assess the implications of the system energetics on the viability of making the transition. Based upon current estimates of solar-thermal-electric payback periods,energetics does not appear to be a constraint on large-scale deployment for power generation. A self-sustaining nonfuel-burning system will have thermal-capacity requirements at least 3to 10times larger than a comparable fuel-burning system. This implies greatly increased material demands;designs must use common materials and recycling must be implemented. It does not appear possible to maintain high energy-demand growth rates and simultaneously make a transition to the inexhaustibles for power generation. (ERA citation 04:006102)