The idea suggests itself. The in-principle solution for mankind’s energy problem is synthetic fuel. Its energy supply is constant and reliable. It is also scalable, if one first produces electricity by renewable power sources, such as wind or solar power, which are abundantly available, and then converts it with power-to-gas or power-to-liquid technologies into synthetic fuel or gas. Synthetic natural gas SNG is probably easiest and most convenient to handle, because existing LNG stations in harbors, gas pipelines and gas networks can be used to store and to transport the energy to any point of need.There one can use SNG in existing end-usage devices. Just like fossil fuel or fossil natural gas.
The problem, however, is the production costs of SNG gas or synthetic fuel. You can simply take a conventional wind turbine or photovoltaic panels and then convert the generated electricity into SNG gas or synthetic fuel. This will result in a very high production cost for the gas or fuel, though, and therefore in a high gas or fuel price. A multiple cost as compared to natural gas or other fuel of fossil origin will prevent public acceptance of this solution to prevent emission of greenhouse gases.