Modern society has to cope with the problem of energy choice, concerning conventional and renewable sources of energy via electrifying many dimensions of economic activities. No one source of energy evades costs, and conceptual framework and methodology for commeasuring costs and benefits are in a great demand. With this purpose in mind, methodology of cost-benefit analysis has been proposed as the synthesis of quantitative and qualitative methods for comparative assessment of energy alternatives. Quantitative analysis focuses on monetized estimations of energy impacts on environment and population health, and deals with subsidies, shadow prices and time value of money. Qualitative analysis concerns important factors, hardly possible to estimate in monetary terms, but significant for reaching meaningful goals, e.g. the common good. In this context, the perspective of applying value approach to assessing energy alternatives has been demonstrated. As a very vivid case for examining the proposed methodology, there has been chosen a vast megaregion – Siberia, rich in fossil fuels and possessing high potential of renewables, first of all, solar and wind energy. On the basis of empirical data and evidences, concerning three particular power plants, located in Siberia – coal-fired, gas-fired and solar PV, there have been elaborated monetized estimations of true value of three alternatives of electrici­ty generation in megaregion.