Why cities are so well-suited to renewable-energy growth

Kate Gordon (@katenrg) is a vice chair at the Paulson Institute. 

Last week, 175 countries signed onto a global agreement to significantly reduce carbon emissions in the face of the threat of climate change. Many of those same countries—particularly India, China, and Nigeria—are simultaneously experiencing major urbanization trends that will move billions of people into cities over the next several decades. In fact, according to the United Nations, approximately 2.5 billion people will likely join the world’s urban population by 2050, almost entirely in Asia and Africa. By that time, two-thirds of the world’s population is projected to be living in urban areas, according to the United Nations.

In the past, we’ve always seen urbanization and increased energy use go hand in hand, as rural workers move to cities and gain a more middle-class, consumer-oriented lifestyle. But the challenge of global warming means that today’s urbanization has to follow a different path, one that’s actually sustainable for both individuals and the climate.

The great news is that cities are the perfect proving ground for some of the most important technologies that will anchor a lower-carbon future: renewable energy systems. As cities become larger and more centralized–and especially if city planners prioritize density over sprawl–they have the opportunity to bring massive amounts of renewable energy onto existing power grids and also to pioneer new, more distributed energy models. In doing so, these new global cities can become models for bringing down emissions while also becoming far more resilient in the face of increased extreme weather events and other catastrophic climate impacts.

Why are cities so well-suited to renewable energy growth? Simply put, cities are where the people are.

Locating a large wind or solar power system miles away from consumers can cause up to 15% loss through transmission alone. It can also create major rate increases to pay for transmission and distribution infrastructure. In contrast, locating smaller solar systems within cities requires less transmission and provides more consistent power. In places like California, where communities are allowed to jointly own or lease solar systems through “shared solar” programs, these benefits are being realized today. The National Renewable Energy Laboratory estimates that if other U.S. cities adopted similar policies, that shared solar could represent nearly 50% of the distributed solar market in 2020 in this country alone.

Dense urban areas can also take advantage of smaller “microgrids,” which can either connect into the larger grid or disconnect from it in extreme weather events or other grid emergencies. From New York to Yanqing, a small county near Beijing, urban centers around the world are embracing microgrids as a way to deploy lower-carbon electricity while increasing resilience in the face of natural or national security risks to the grid. These can be powered by a variety of renewable sources, including solar and wind, combined with more consistent “baseload” power from geothermal power stations, gas turbines, or fuel cells.

One of the major benefits of renewable energy over fossil-based energy, other than the obvious fact of renewables bringing down carbon emissions, is that renewable systems can be placed anywhere and aren’t dependent on moving fuels from production sites to generation sites. But there are downsides, including that many renewable energy sources are intermittent. The sun doesn’t shine and the wind doesn’t blow all the time, critics argue, whereas coal can be burned 24/7.

Herein lies another benefit of cities: the ability for city dwellers to use today’s technologies, specifically electric cars, as batteries to store renewable energy. The wind mostly blows at night—so urban residents can charge their cars at night and capture that energy, turning it into driving miles the next day. Same with cars plugged in during the day at work sites during peak sun shine hours. As battery technology gets more and more advanced, urban transportation networks will also become electrical storage networks.

Cities are increasingly realizing these benefits. Las Vegas has committed to becoming a 100% renewable energy city by 2017, powered in large party by a huge utility-scale solar power system being built in nearby Eldorado Valley. The city of Zhangjiakou in northern China has promised to become 80% powered by renewables by 2030, and could even become an energy exporter to the surrounding Beijing-Tianjin-Hebei region if strong interconnection policies are put in place.

Now is the time for cities across the globe, especially those springing up in Asia and Africa, to embrace renewable energy technology to power their homes and businesses. In doing so, these cities can leapfrog the old-school development models of the West and become the new model for sustainable and resilient development in the 21st century.