We need to drastically increase the amount of renewables energy in the world, mainly solar and wind since hydroelectricity is already close to the maximum installed capacity.

I think everyone can agree to that.

The next question is how much and what do we need around it to power a whole country with a minimum of CO2 emissions.

I know about 6 scenarios that has been done for France, if anyone knows about similar scenarios for other countries please share them.

All the scenarios include some degrees of flexibility in the consumption.

To be able to have a stable grid all the scenarios have to include battery storage and thermal production. Today thermal production in the world is mostly gas and coal that are terrible for climate but to have no emissions it will probably be biomass, biogas or hydrogen.

Including a bit of nuclear in the mix (13% nuclear/87% renewable) greatly help to stabilize the grid. This small amount of nuclear divides by 2 the amount of solar needed, divide by 2 the amount of battery storage and reduce by 30% the need for thermal power station compared to a scenario with 0% nuclear and 100% renewables.

There is other scenarios with more nuclear but it shows that nuclear can ease a bit the pressure on renewable energy.

In this case, to replace the last 13% (16GW) of nuclear in the mix we would need to install 90GW of solar + 9GW of thermal power + 13GW of battery.

It shows having a power grid fuelled with renewable energy will become exponentially difficult has it get close to 100%.

There is probably a good ratio between 50%-90% of renewables energy and nuclear energy can be a very good candidate for the rest.

https://rte-futursenergetiques2050.com/panorama/scenarios