People are mixing up multiple different numbers and statistics, one being capacity vs generation, and the other being nuclear missing from both posts.
Nuclear stands for 10% capacity, but 20% generation. It do this because nuclear is expensive to build, but once built the operational costs is fairly fixed with low fuel costs. Fossil fuels plats are generally cheap to build but has high fuel costs, and renewables is dependent on weather. As such they both have higher capacity than generation. Coal is slightly the odd one in the mix in that their capacity and generation is about the same.
In term of energy generated, about 60% is fossil fuel, 20% nuclear, 20% renewables (using 2021 numbers).
In terms of capacity, we have 66% fossil fuel, 9% nuclear, 25% renewables.
The prognosis is that in terms of generated power, fossil fuel will decrease, renewables increase, and nuclear stay about the same with a tiny decrease that is related to the overall increase in energy usage.
The prognosis for capacity is an increase in both fossil fuel and renewables. Coal is and has mostly already been replaced with gas. The total capacity is steadily increasing for fossil fuels, while the renewables are increasing also at a slightly faster speed.
40% increase in fossil fuel capacity is still a very bad thing. If the market is investing in increasing the capacity to burn fossil fuel then there is a reason for it. They are intending to burn fossil fuel, and that for several decades into the future. At the same time we will see a higher portion of the generated energy coming from renewables since it is more economical to generate energy from renewables during optimal weather conditions. Any gas being burned during a windy/sunny day is an unnecessary expensive source of energy, unless the initial construction costs of renewables is greater than the profits of the total periods of optimal weather conditions.