It is difficult to say for certain which source of energy will be mainly used in the coming years as it depends on various factors such as technological advancements, government policies, and market dynamics. However, there are a few trends that can be observed.

Renewable energy sources such as solar, wind, and hydropower have been gaining momentum in recent years due to their environmental benefits and decreasing costs. Many countries have set targets to increase their share of renewable energy in their overall energy mix. This suggests that renewable energy will likely play a significant role in the future.

On the other hand, fossil fuels like coal, oil, and natural gas still dominate the global energy landscape. Despite efforts to transition to cleaner alternatives, these sources are expected to continue being used, especially in developing countries where energy demand is growing rapidly.

Additionally, nuclear energy remains a controversial topic, with some countries expanding their nuclear power capacity while others are phasing it out due to safety concerns and public opposition.

In conclusion, the future energy mix will likely be a combination of various sources, with an increasing emphasis on renewables. However, the exact proportions and dominance of each source will depend on a range of factors and cannot be accurately predicted.