As it stands power generation isnt a huge issue. We could meet our total consumption with just solar, wind and hydro.

The reason these are "not enough" is because we have to balance loads which PV solar and wind arent good at alone. The grid is designed to operate at 60hz (which is directly relates to voltage and current) >60hz and everything on the grid is destroyed (power surge), <60hz and you get brown outs. Your options here are to either up useage or reduce production when >60hz, and to reduce useage or up production. Steam turbines are really good at this because you can turn them on/off easily, add fuel or apply a brake for controls. Between wind ans PV solar, you pretty much only have access to a brake.

The solution is energy storage. concentrated solar power (CSP) uses mirrors to heat salt which then transfers the heat to a steam turbine. Batteries are very effective (a fresh lithium battery is probably the most efficient option) Pumped hydro is ~80% efficient.