Currently coal is mostly used for electricity production. At current production levels North America's supply will last 247 years, South America's supply will last 354 years, Europe and Eurasia's supply will last 300 years, Africa and Mideast supply will last 233 years, Asia Pacific will last 113 years. If we only use it for electricity production, we should always have enough for cooking, refrigeration, laundry, lighting, communications, machines in factories, etc.

People are referring to oil shortages when they are talk about the impending energy. This affects transportation primarily. Unlike coal, North America's oil reserves will last only another 12 years, worldwide about 41 years. If you think it won't happen, consider that when early explorers discovered the Grand Banks, they reported to the monarchy that there were enough fish to "feed our people until the end of time". You've heard of the moratoriums on fishing! And that's a renewable resource! Cellulose ethanol might make a dent in this, extend it somewhat. But it is going to happen eventually. Expect either new energy technologies, or major cultural change. Large urban populations are at least 100 km from the nearest food source, and we need motor vehicles to move food supplies, or we will all starve. This process will occur perpetually for the next few hundred years as we even run out of coal. That's inevitable too! Just a few hundred years - more time has passed since Columbus discovered America. Again, either new technology, or major cultural change. Obviously both are expected.

Solar power really hasn't been tapped yet. I imagine a large optical platform in geosynchronous orbit, refracting a high-power beam of solar energy to a dry cloudless desert region (death valley, sahara desert, australia, etc) where giant solar chimneys produce fuels for transportation, which are then shipped worldwide. We would have to sacrifice these land areas, since they would be scorched by the energy beam. It might be safer to beam energy to the middle of the pacific ocean, where a deep column of ocean water is heated to the boiling point, and secondary pipes carrying ethylene glycol drive turbines, or produce fuels. Just like today, tankers would ship the fuels to ports worldwide. Safety would be enhanced, since the pacific ocean covers most of an entire hemisphere of the world. So large errors in beam tracking could be tolerated without damage. Plus, the deep ocean doesn't have any wildlife. Most ocean-dwelling sea creatures live near shore, in water shallow enough for sunlight to reach the seafloor, so plants can take root and grow.