This report considers the global energy consumption from the viewpoint of thermodynamic balance between the Earth and the cosmic environment. To follow such a b alance is postulated to be necessary to maintain proper functioning of the biosphere and stable climate conditions on the Earth. This viewpoint implies the following principles of energy consumption: (i) the energy should be consumed from the renewable sources only and (ii) the amount of the consumed energy should not exceed the amount

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... f energy that incomes to the Earth. Three major sources of the renewable energy are considered, i.e., a d irect incoming solar irradiation, a chemical energy through products of photosynthesis and, finally, an outgoing radiation from the Earth as a heated body. It is shown that the first and the third sources are potentially the most effective ways of the energy consumption. The last one, however, is not properly developed now. With the first two sources, the energy consumption rate cannot exceed a limit of 10 17 W, but practically due to technical restrictions it can be set as 10 14 W, which is approximately an order higher of the contemporary rate of energy consumption by the mankind. Development of the third source of energy is shown to allow us to increase the above limit up to one order of magnitude more. However, one should take great care of using this source of energy since it can affect climate changes also.