The fossil-fuel based energy crisis primarily makes itself felt through the inability to produce sustainable energy resources from natural gas and oil.
Both natural gas and oil could be partially substituted by:
Nuclear energy is for various reasons only sparingly used and wind energy is unevenly available, in varying amounts of power.
Water energy requires geographical conditions that are only seldom found. Bioorganic raw material can only satisfy at most 5% to 8% of energy needs worldwide, and waste recycling depends on the existence of usable waste materials.
There remains the diversity of natural gas and oil energy resources, which are abundantly available and equally widely well-known.
A sustainable energy supply that is targeted for the next 50, 100 or 200 years is in no way guaranteed. Energy crises, shortfalls in the energy market and near total energy failures are already foreseeable and even inevitable in the not too distant future. This situation is sufficiently understood without, however, any solutions having been found.