How Overbuilding wind and solar lowers costs of the overall energy grid and increases reliability. Scientific American

My post here is Aussie in focus - but the Scientific American article is in there, and the principles apply to any nation.

We really need a good national plan with extra HVDC across the continent. Wind and solar are now so cheap we can Overbuild them across a wide geographic area which radically reduces storage - which is one of the most expensive parts of the Energy Transition. Overbuild across a wide area - and storage requirements plummet! Basically - if you're suffering intermittency you have not built enough! This is old news, see Scientific American 2015. Renewable Energy Intermittency Explained: Challenges, Solutions, and Opportunities

Australia’s lucky in that we’re in the Sunshine Belt. Just a 170% Overbuild is enough to power today's electricity grid. This model only needs 5 hours storage. A near 100pct renewable grid for Australia is feasible and affordable, with just a few hours of storage

Professor Andrew Blakers won the Queen Elizabeth Prize for Engineering for designing the PERC solar cell now in 90% of all solar panels worldwide. He estimates Australia needs 2 days of storage to cover the worst Dunkelflaute (energy droughts). That is batteries for the first few hours, then OFF-river pumped hydro for a few days.
Solar’s stunning journey from lab curiosity to global juggernaut wiping out fossil fuels The world has about 100 TIMES the potential OFF river pumped hydro sites it could need. Global Greenfield Pumped Hydro Energy Storage Atlas

Finally - offshore wind is about double the cost of on-shore. But here's where it is great! It tends to work late into the evening when solar and even on-shore wind may have stalled. Phd in Wind Power Rosie Barnes explains here (1 minute - March 2024). So overbuild across Australia, including off-shore wind, and we'll have power cheaper than coal or gas.