Our vision is to create a sustainable energy future for Arizona. A sustainable energy future requires balancing the delivery of reliable and affordable energy in unison with environmental stewardship. By the end of 2017, over 50 percent of our diverse energy mix was carbon-free. We achieved this mix with a combination of traditional and renewable energy resources and energy efficiency actions. We continue working to make that mix cleaner. These efforts include closing coal units, modernizing natural gas plants, deploying renewable energy and improving energy efficiency. And our Palo Verde Nuclear Generating Station continues to be the country’s largest source of carbon-free energy, far surpassing other energy sources for producing clean, around-the-clock power. Palo Verde accounts for nearly 80 percent of all carbon-free energy generated in Arizona.
Our focus on reducing our carbon footprint is not limited to energy generation. We also have made our own buildings more energy efficient and continue converting our fleet to more fuel-efficient vehicles. Through these combined efforts, APS avoided 5.1 million metric tons of carbon dioxide emissions that otherwise would have been emitted in 2017.
In line with projected population growth in Arizona, we anticipate significant customer growth in our service territory over the next 15 years. We expect renewable energy and energy efficiency to meet more than 50 percent of that growth. This will help us achieve our long-term goal to reduce our carbon-emission rate to less than 600 pounds per megawatt-hour (lb/MWh) by 2032.