Previously in our "2035" series, we've asked experts to make their best guesses about the next 20 years in the areas of artificial intelligence and autonomous vehicles.
This time around, we've invited some earnest conjecture on the matter of renewable energy in the year 2035. Twenty years out is actually a pretty good time frame for asking the obvious question: Will renewable energy sources surpass fossil fuels, globally, as our main source of energy by 2035?
While it's rather unsatisfying, rhetorically speaking, the most accurate answer is: kinda-sorta.
For non-transportation purposes, clean energy solutions like wind and solar should be firmly established globally by the year 2035, says John Orr, director of the Sustainable Energy Project Center at Worcester Polytechnic Institute.
"However, there is nothing on the horizon that, in 20 years, could provide the needed energy density for air transportation and a substantial amount of terrestrial transportation other than liquid fuels," Orr says. "And nothing that in that time period could enable us to make a sufficient volume of synthetic liquid fuels."
In other words, we're likely to still be using gasoline and jet fuel, and a lot of it. So what we're using the energy for will be a major factor on whether renewables surpass fossil fuels. A great deal will also depend on where we're using it -- and who's in charge of public policy in those places.
"In some countries across the world, renewables are already capturing a significant fraction of the market and impacting the costs associated with conventional generation," says Alexis Abramson, professor of mechanical engineering at Case Western and faculty director of the Great Lakes Energy Institute.
"To avoid catastrophic impact on the economy, some of these countries have changed policies to slow down the market penetration of renewables," Abramson adds. "So I think while the market share of renewables will continue to grow across the world, there will be opposing policy effects that temper that growth ... such that by 2035, we will still have a good balance of renewable and non-renewable sources."
George Crabtree, director of the Joint Center for Energy Storage Research at Argonne National Laboratory, says that clean energy sources have a good deal of momentum going into the new millennium. "Since 2005, renewables have grown much faster than expected, and the trend is likely to continue," he said.
Crabtree also cites falling prices in solar electricity and technological improvements in wind power as reasons to be optimistic.
"The remarkable growth of renewable generation compared to fossil in new deployments suggest that renewable could rival or overtake fossil by 2035," Crabtree says. "This is a welcome development that will help the economy, jobs and innovation as much as it boosts clean and sustainable energy."
Then there's the matter of precisely how we will be distributing energy in the year 2035.
Jim Poss, founder of BigBelly Solar and an instructor in environmental entrepreneurship at Babson College, believes decentralization will be key to future energy issues -- and he's wiling to hazard some hard numbers.
"In 2035, the U.S. will be 60 percent powered by renewables," Poss says, adding that he'd adjust that number upward if campaign finance were overhauled by 2020. "Utilities will diminish in scale and power, as decentralized power sources and 'power bartering arrangements' enable each of us to become our own utility. Improvements in decentralized energy storage will be paramount."
Globally, however, the outlook is more grim. "The developing world will be primarily powered by fossil fuel until at least 2050, exacerbating climate problems," Poss says. "Droughts and floods will wreak havoc. Environmental refugees will pour across borders, challenging security, sovereignty and stability."
It's a refrain echoed by several experts: In the year 2035, energy consumption will be inextricably knotted up with politics, social issues and climate change concerns. Just like it is now.
"The shift to renewables begs several serious questions in geopolitics that will sort themselves out between now and 2035," says Michael Womersley, professor of Human Ecology at Unity College in Maine.
"Some previously fossil-dependent countries have already cottoned on to the fact that you can't stay dependent on fossil fuels if solar is cheaper than the retail grid, and there is expensive climate change caused by fossil fuels," says Womersley, director of the Unity College's Center for Sustainability and Global Change. "You have there both a very tasty carrot and a really big stick."
With so many variables in play, it's hard get anything like a clear view of clean energy in the year 2035. But optimism is a renewable energy source, too.
"If I weren't optimistic, I wouldn't come to work every day and try to tackle these challenges," says Seth Darling of the Argonne National Laboratory.
"But that doesn't mean it'll be easy or that success is assured. We are facing probably the biggest challenge we have ever faced as a species -- in the form of climate disruption driven primarily by our burning of fossil fuels. It could be our undoing, or it could be the challenge that finally brings us together as a global society."