This isn't going to happen simply because it would introduce enormous strategic vulnerabilities. The first act ina war would be to sever an opponent's grid connections to their neighbors because that would massively erode their ability to maintain an orderly civil society.

We've lived in a geopolitical world since Britain converted its navy from coal to oil prior to WWI, making itself dependent on Middle East oil (the UK didn't realise its North Sea reserves until the 1960s, they weren't developed until the 1970s/80s, contributing hugely to the Thatcher boom). Choke-points of oil exporters (particularly Iran, OPEC), pipelines (TAPLINE), canals (Suez, Panama, etc.), straits (Hormouz, Malacca, etc.) have all been at the centre of global geopolitics for well over a century.

Solar changes the who and where, but really not the what significantly. Solar is far more distributed and less concentrated, and options for distribution are potentially more diverse (cables, direct power beaming, synfuel production and distribution) in ways that an oil-based economy hasn't been.

Even within national borders, power production and distribution are sufficiently centralised and choke-pointed that they are vulnerable to significant disruption, even by non-targeted accidents and natural disasters. Major national and regional power outages are not especially frequent, but neither are they unfamiliar: <https://en.wikipedia.org/wiki/List_of_major_power_outages>.

During periods of conflict, national and irregular forces routinely target power infrastructure, with significant but rarely absolutely crippling effect. For the past three-and-some years, two major eastern-European adversaries have been directly targeting one anothers' energy infrastructure. Though the results are costly, neither has been bombed back to the stone age, or even the pre-electrical era:

"Resilience Under Fire: How Ukraine’s Energy Sector is Adapting – and What It Means for Europe"

<https://rasmussenglobal.com/wp-content/uploads/2025/06/REPOR...> (PDF)

This won't happen because the lines are bi-directional. It would be like chopping off their own energy supply. Because of the Earth's rotation, neighbors can take advantage of each other's sunlight. Parts of Europe and North Africa's energy markets are already working on this.

For the past 100+ years, the US has been spending a significant amount of money on protecting oil supplies to protect its oil billionaires and its economy. It's the #1 budget item, outspending the combined military spending of the next 10 economies. This can be reduced to zero, and ultimately, the $ 39 trillion deficit can be eliminated.

Or if everyone depends on another maybe we will not go into a war with each other.