Describe how energy efficiency improvements contribute to deep decarbonization.

• A. They increase energy demand by stimulating more consumption.
• B. Lower energy demand reduces emissions across sectors, easing decarbonization efforts.
• C. They only affect the transportation sector.
• D. They remove the need for renewable energy sources.

Answer: (B)

Energy efficiency reduces energy intensity, so you get the same services with less energy input. Because most energy today comes from fossil fuels, using less energy across buildings, industry, and transport directly lowers CO2 emissions. This easier-to-attain lower demand makes it cheaper and faster to decarbonize the remaining energy supply, and it also makes electrification and the deployment of renewable energy more practical and cost-effective. For example, better insulation and efficient heating cut building energy use; efficient industrial motors and processes lower factory energy demand; and more efficient vehicles and infrastructure reduce fuel use in transport. The cumulative effect is a lower emissions baseline and a smoother path to deep decarbonization.

The other ideas don’t fit as well: energy demand generally doesn’t rise because of efficiency (though there can be rebound in some cases, the net effect is still lower energy use); efficiency affects more than just transportation (it spans buildings and industry too); and efficiency does not eliminate the need for renewable energy—zero-carbon power is still needed to achieve deep decarbonization.