The reasons are these: warming of the environment; conservation of energy resources; personal economy; disregard of others; helping less advantaged people. 

1. Warming of the environment
There are several possible causes of environment warming. Anthropomorphic warming has human characteristics and is caused by or has effects on humans.  Causes of global warming cannot be attributed with certainty and are theoretical. There are many causes possible. Human causes could result from various emissions. Reduced carbon dioxide emission has been theorised to have an additional reduced warming benefit. A simpler theory is thermal emissions from human activity enter the atmosphere and oceans and warm them.
By reducing these activities, there could be less warming of the environment. Activities that could be reduced with this benefit are energy conversion, transportation, residential heating, air conditioning, combustion, fermentation, decomposition and respiration. 

2. Conservation of energy resources

Reducing use of energy resources of all kinds, fossil fuels, hydro and renewable energy could save them for use in the future, by others. Less withdrawal of solar energy by renewable energy technologies would reduce warming of the environment by their low temperature waste heat, with the Sun’s higher temperatures driving the ‘renewal’, by the 2nd Law of Thermodynamics.

3. Personal economy

Markets are supposed to rationalise supply and demand of energy in competition with others. Monopolies of suppliers and consumers can prevent appropriate responses to emerging depletion of resources and new technologies. Reduction in energy use could be encouraged by governments. Conversely, energy suppliers encourage consumption to maintain their sales. Individuals can be free to reduce their energy consumption, but their role could seem to them small and not worthwhile until leaders espouse this cause in the public interest.

4. Disregard of others

Energy use has not been limited, except by economic and environmental costs. Users have taken as much energy as they want, like oxygen from the air. People in some countries have helped themselves to much more energy than others. Energy ends up, eventually after use, polluting the environment and oceans for others, by the 1st Law of Thermodynamics. Thus some greedy energy users cause more environment warming and more depletion of energy resources, than others, without having entitlement to do so. 

5. Helping  less advantaged people

Energy consumption has universal value and is a broad indicator of quality of lifestyle differences between nations. Distribution has depended on historical circumstances. Developing countries could reasonably be allowed more growth in their low energy use than developed countries having high energy use. Such allowance could be voluntary, with high energy-using individuals sacrificing high-energy technologies and activities of marginal value to help those less advantaged. Otherwise sharing might have to be mandated. 

Please consider these 5 reasons and reduce your energy consumption.

My book Animal Farm 2 coming shortly addresses these energy issues https://martinknox.com