It may seem slightly ridiculous to consider the prospects for a future solar-hydrogen economy at an institute for theoretical physics in Waterloo, Canada. After all, Canada is the capital of unconventional oil, also known as oil sands, also known as tar sands, which supply more than a million barrels of oil per day to the U.S. And the primary use of today's existing hydrogen economy—a $200 billion a year proposition—is adding the energetic molecule to such unconventional oils to make them more palatable to the global energy infrastructure.

But rebranded as "artificial photosynthesis," an alternative hydrogen future did get consideration at the Equinox Summit of the Waterloo Global Science Initiative last week. The summit's effort paired "future leaders" with old-school scientists to imagine an a new energy scenario for 2030, one that would cut greenhouse gas emissions, restrain a global society that relies on burning fossil fuels, and provide modern energy to the billions of people who do not enjoy it today.

That last fact alone argues potentially that the world is going to need a lot more energy, of one kind or another. "The Earth is a 14-terawatt light bulb that is always left on," notes chemist Jillian Buriak of the University of Alberta, who is working on nano-scale solar solutions and helped advise the summit. By 2030, "based on the most conservative numbers, we need 28 to 35 terawatts of power" to provide enough energy for more than 7 billion people.

And whereas the last century's technologies did achieve wonders, they may not be up to the task of meeting the needs of the present century. "What we learned to do in the 20th century, we learned to drill into the ground to extract petroleum and natural gas, convert it into food and eat the food," adds political scientist Thomas Homer-Dixon of the University of Waterloo. That enabled the human population to double twice over the course of the 20th century while agricultural yields increased four-fold. At the same time, global energy use increased 80-fold.

To allow that energy use trend to continue was the main goal of the Equinox Summit. After four days of talks, presentations and work, the votes were in. The future leaders agreed on a course that includes the following: fast breeder and other alternative nuclear reactors, including a thorium-based fuel cycle; geothermal; massive renewable energy installations and grid-scale battery systems; building more energy-efficient cities (as well as retrofitting existing buildings); electrifying transport and using technology to spur better use of public transportation, for example with an app that allows bus-tracking to eliminate unnecessary waiting; and a rural electrification package that would pair flexible plastic photovoltaics with advanced batteries.

Hydrogen did not make the final cut, perhaps because it is largely manufactured by mixing natural gas and high-temperature steam today. Nor did the tremendous challenge of scaling up these technologies to displace fossil fuels enter the debate. Given the technical challenges alone of creating a thorium-fueled reactor that relies on a high-powered proton particle accelerator, that might have proven a death knell for any nuclear result.

Better batteries—or "electricity in a bottle," as chemist Maria Skyllas-Kazacos of the University of New South Wales in Australia puts it—would be the linch-pin of many of these solutions, allowing electric energy to be stored. As it stands, no battery on offer can come anywhere near the energy density of liquid fuels; gasoline stores 12,000 watt-hours per kilogram compared to the best of today's lithium ion batteries at just 150 watt-hours per kilogram. "It's never going to achieve gasoline. To say otherwise would just be hype," says battery chemist Linda Nazar of the University of Waterloo. "Nature won't allow us to go there."

Of course, what matters most is what, if anything, the participants will do in the future. The summit's conclusions might be presented at venues ranging from the World Economic Forum in Davos in 2012 to the American Association for the Advancement of Science in Vancouver next February. Regardless, the most important contribution of the summit may have been the planting of some of these ideas in the minds of folks who will still be making policy decisions in 2030.

And the most significant transformations may be in the details: better building insulation, vehicles that go further on a liter of gasoline or diesel, and more efficient cooling and heating systems. "The most important energy technology of all is the building," says energy expert Walt Patterson.

After all, if the entire nation of Canada swapped their current furnaces for the most efficient models on the market, natural gas use would plummet and greenhouse gas emissions from burning the gaseous fossil fuel would fall by 40 percent. "There is no renewable energy that will get you 40 percent less carbon on a scale like that," notes environmental scientist Vaclav Smil of the University of Manitoba, who has made a career of studying energy transitions, like the one from wood to coal. "Changing furnaces is an energy transition." And one that needs to be accelerated.

Image: NASA Earth Observatory image by Jesse Allen and Robert Simmon using EO-1 ALI data courtesy of the NASA EO-1 team