In Australia from 1978 to 2009, researchers examined changes in energy efficiency. They wanted to see what made energy use per unit of economic activity go down. They broke it down into energy efficiency, types of fuels used, and how different industries work. They found that better energy efficiency and the types of industries make energy use per activity unit drop. Energy efficiency mattered more than industry types. Also, the good effects of industry types on energy use slowed in recent years. Energy use and carbon emissions in Australia go hand in hand. To cut down on energy use and carbon emissions in Australia, improving energy efficiency is crucial for the future.