One of the most promising energy sources in the immediate future is certainly energy saving, that is, all those actions that lead not so much to produce energy in new ways, but, much more simply, to consume less of it.
In particular, there are two strategies to reduce consumption:
• increase energy efficiency
• decrease consumption
The difference between the two strategies can be explained with a simple example, to increase energy efficiency a halogen bulb is replaced with a led bulb; to decrease consumption, the bulb is turned off.
The first strategy implies the search for an identical result with a lower energy consumption, the second involves a reduction in consumption, but is not conservative.
The first strategy can be easily implemented through rules, laws and regulations, for example by promoting the sale of household appliances, machinery, etc. less energy-consuming or even prohibiting the sale of those who use too much energy. [1]
Although, at first glance, this may seem the most correct and less penalizing strategy for decreasing the global demand for energy, there is the so-called Jevons paradox [2] whose effects could limit real energy savings and, in many cases, even lead to an increase in energy consumption. [3]
Although the validity and generalization of this paradox is under discussion [4] many studies confirm that greater energy efficiency leads to an increase in consumption which absorbs on average 60-70% of the reduction effect and that, in many cases, it reaches more than 100%, that is, energy consumption after the advent of a technology that has reduced energy needs, have increased in absolute terms. [5]
It is not easy to calculate the real impact of the introduction of a technology that increases energy efficiency, but if we look at its medium-long term effects on the entire global system it seems obvious that, in a sufficiently long period of time, it causes an increase of global energy consumption. [6]
Forcing to turn off a light bulb may not be feasible; convincing to do so appears, perhaps, utopian; in fact, however, the only road that leads to a real decrease in global energy needs seems to go from a paradigm shift from consumerism to a sustainable model from an energy point of view.
Only by placing a limit on energy consumption dictated by the ecological sustainability of energy production will it be possible to make the entire energy production / consumption system sustainable and this, at least for now, necessarily entails a real decrease in consumption and not just greater efficiency in use of the energy produced.
Will we be able to reduce global energy consumption at least until all the energy produced is from renewable sources?

Sources:

1 Outlaw halogen bulbs 
2 Jevons Paradox 
3 Energy efficiency and consumption 
4 Paradox of Jevons 
5 Energy Efficiency Rebound 
6 Jevons paradox on a global scale