November 3, 2015

Using technologies like solar panels, wind turbines, and electric cars, the world can get all its energy from renewable sources–not at some point in the future but today. So says Mara Prentiss, a Harvard physics professor who will be speaking on the topic at the Thomas Crane Public Library, 40 Washington Street, at 7:00 p.m. on November 18.

In her talk, cosponsored by the library and Quincy Climate Action Network, Prentiss, the author of the new book Energy Revolution, will argue that the transition to renewables is not only technically feasible but also economically advantageous. For example, she says, “the price of solar panels has dropped enormously.… Bloomberg has reported that in 36 states it will be cheaper next year to produce your own solar electricity than get your power from the grid.” Meanwhile, she says, midwestern US states are already using wind turbines to supply a big chunk of their electric power, with Iowa getting more than 40% of their power from wind in peak months.

In addition to renewable energy production, Prentiss will also discuss grid and storage technologies that can assure a constant flow of electricity even when the electrons come from intermittent sources like wind and solar.

To get our energy by burning fossil fuels is inherently inefficient, Prentiss says. Because of a physics principle called Carnot’s Theorem, devices that use heat to generate energy, including gasoline engines and coal- or gas-fired power plants, peak out at 50 percent efficiency, she says, no matter how ingenious their design, with the rest of the energy in their fuel given off as waste heat. Motors like the ones in electric cars, by contrast, have efficiencies ranging from 90 to 98 percent.

Besides, burning fossil fuels, whether it’s in cars or power plants, “creates a whole lot of problems,” Prentiss says. “In the US, we focus on climate change, but in the developing world, air quality is a bigger issue. In places like New Delhi and Beijing the air is often so polluted it is hard to breathe.”

Nevertheless, she says, “I’m not trying to tell people what to do. I’m just explaining choices of which they may not be aware.”