Prioritize...
After completing this section, you should be able to:
- Define energy intensity and energy efficiency and list three areas where active efforts seek to improve efficiency.
- Understand why electric vehicles have a smaller carbon footprint, even if the electricity used to charge their batteries arises from fossil fuel combustion at a power plant.
Read...
Reducing energy intensity—how much energy we use relative to economic output—is an important cornerstone of addressing climate change. There can be a misconception that emission reductions mean that we have to sacrifice things—get rid of road trips, cut down on transcontinental trips, etc. However, that’s not (necessarily) true. It’s about doing more with less: less energy waste, less reliance on fossil fuels, and fewer emissions. By improving energy efficiency and transitioning to electrification, we can make significant strides toward a cleaner, more sustainable energy future. If a gallon of oil can take us five times as far, we’ve started winning the battle!
Energy efficiency
Improving energy efficiency means reducing the amount of energy needed to power our homes, businesses, and industries. It’s often the easiest, most cost-effective way to cut emissions while saving money. Consider these key areas:
Buildings:
- Heating, cooling, and lighting account for a large portion of energy use in buildings. Insulating homes, installing energy-efficient windows, and using LED lighting can drastically reduce energy consumption.
- Smart technologies like programmable thermostats and motion-sensor lighting further reduce waste.
Transportation:
- Traditional internal combustion engines are notoriously inefficient, converting only about 20-30% of fuel into motion. By contrast, electric vehicles (EVs) are far more efficient, with 60-80% of the energy stored in their batteries powering the wheels.
- Public transit systems, carpooling, and hybrid vehicles also help lower energy use in the transportation sector. Even if a "dirty" bus emits three times as much as a car, having 50 people on that bus dramatically reduces carbon emissions!
Mythbusting
A common misconception is that electric cars are no better for global CO2 emissions than internal combustion engines that run on gasoline. After all, burning fossil fuel sources like coal and natural gas emits CO2 just like cars do. So, if we are emitting carbon to make electricity to charge our batteries, what good are we doing? Well, while it’s true that generating electricity from fossil fuels DOES produce CO₂, the overall emissions from an electric car are significantly lower than those of a gasoline car—even when powered by a grid that relies heavily on fossil fuels! This is because electric motors are far more efficient than internal combustion engines, converting a much higher percentage of their energy input into motion.
Check out the image below. Out of the 8.9 million barrels of gasoline for motor vehicles consumed daily in the U.S. on average, only 1.8 million gallons, or approximately 20 percent, actually propel an internal combustion vehicle forward. The other 80% is "lost" (wasted) on heat and friction, and other inefficiencies. How much energy could we save if we still got the same "1.8 million gallons" of motion with electric cars? That's what the other three panels show. Even by replacing gas engines with a "dirty" electricity source (coal), we reduce energy use by 31% since the "lost" energy between combustion and wheels moving is reduced. Running electric vehicles powered by renewable energy sources like wind and solar? That reduces energy needs by a whopping 75%!
Industry:
- Industries can reduce energy use through better equipment design, optimized processes, and waste heat recovery systems. For example, advanced manufacturing techniques like 3D printing can minimize material waste and energy.
Energy efficiency reduces greenhouse gas emissions while saving money. It’s like fixing leaks in a bucket before refilling it—saving every bit of energy means fewer emissions overall!