Major cities should not rely on renewable sources of energy but should, instead, focus on maximizing energy efficiency, according to Arnulf Grubler, researcher at Yale University and the International Institute for Applied Systems Analysis.

In an energy symposium Monday, Grubler said renewable sources of energy are sufficient for rural areas because they require large amounts of open space to produce enough energy. Because of the limited space available in cities, however, renewables are not sufficient enough to prioritize.

“The largest improvements are when we change systems instead of individual components in systems,” Grubler said. “Locally generated renewables can, at best, provide 1 percent of the energy of cities. … Even if you were to use all the area of London, you could, at maximum, provide 15 percent of the energy used in London.”

Varun Rai, event organizer and assistant professor at the LBJ School of Public Affairs, said the complexity of cities causes their energy needs to be much more demanding.

“In the city, it’s not only that you’re running the building,” Rai said. “You’re also doing management and industrial processes, and that uses a lot of energy. It’s not that renewables cannot do the job; it’s that they can’t when confined. We need to focus on building efficiency. We have to think about things like public transport and urban forming.”

Grubler said there is great room for improvement in the development of systems that are more efficient, such as Vienna, Austria, which has a system with 50 percent efficiency.

Thomas Anderson, a first-year MBA student who attended the symposium, said he believes more should be done to encourage a focus on energy efficiency.

“People need to come up with more clever financial measures to push energy efficiency,” Anderson said.

Carson Stones, global policy studies graduate student and an organizer of the energy symposium, said he agrees with Grubler’s notion that focusing on efficiency in cities is the most important step forward in the urbanization of energy.

“It’s astounding how much more you can get from efficiency than anything else,” Stones said.