In the assessment of long term behavior of the complex
system we have to introduce notion of sustainability as the
measure for the quality of the system. It is defined as the
quality which is measuring the ability of our society to secure and not compromise the ability of future generation to have quality of the life at least the same as our generation.
The safety property of complex system is immanent to any system. It reflects quantitative merit for degradation of the system. Also, it includes rate of changes for any process leading to degradation of the system. Environmental degradation is among the most pressing global issues confronting modern society.
Sustainability and safety are linked with the similar
essential idea to prevent degradation of the quality of the
system. The sustainability is defined as the aggregation
function of physical, social, technological, environmental and resources parameters. The safety is time derivative of the sustainability index.
Demonstration examples of application of the multi-criteria
in the evaluation Sustainability Index and Safety Index of
hydrogen system proves that the evaluation of complex system
is involved in sustainable development research with associate uncertainty suggesting that the research should move toward the search for general principle and guiding questions for new investigation.