Thanks to Nicola Jones and colleagues at Yale Environment 360 for this:
Nearly three-quarters of all the energy produced by humanity is squandered as waste heat. Now, large businesses, high-tech operations such as data centers, and governments are exploring innovative technologies to capture and reuse this vast renewable energy source.
When you think of Facebook and “hot air,” a stream of pointless online chatter might be what comes to mind. But the company will soon be putting its literal hot air — the waste heat pumped out by one of its data centers — to good environmental use. That center, in Odense, Denmark, plans to channel its waste heat to warm nearly 7,000 homes when it opens in 2020.
Waste heat is everywhere. Every time an engine runs, a machine clunks away, or any work is done by anything, heat is generated. That’s a law of thermodynamics. More often than not, that heat gets thrown away, dribbling out into the atmosphere. The scale of this invisible garbage is huge: About 70 percent of all the energy produced by humanity gets chucked as waste heat.
“It’s the biggest source of energy on the planet,” says Joseph King, one of the program directors for the U.S. government’s Advanced Research Projects Agency-Energy (ARPA-E), an agency started in 2009 with the mission of funding high-risk technology projects with high potential benefit. One of the agency’s main missions is to hike up energy efficiency, which means both avoiding making so much waste heat in the first place, and making the most of the heat that’s there. ARPA-E has funded a host of innovative projects in that realm, including a $3.5 million grant for RedWave Energy, which aims to capture the low-temperature wasted heat from places like power plants using arrays of innovative miniature antennae.
The problem is not so much that waste heat directly warms the atmosphere — the heat we throw into the air accounts for just 1 percent of climate change. Instead, the problem is one of wastage. If the energy is there, we should use it. For a long time, says Simon Fraser University engineer Majid Bahrami, many simply haven’t bothered. “The attitude has been that the environment can take this waste; we have other things to worry about,” he says. “Now we have to be more efficient. This is the time to have this conversation.”
The global demand for energy is booming — it’s set to bump up nearly 30 percent by 2040. And every bit of waste heat recycled into energy saves some fuel — often fossil fuels — from doing the same job. Crunching the exact numbers on the projected savings is hard to do, but the potential is huge. One study showed that the heat-needy United Kingdom, for example, could prevent 10 million tons of carbon dioxide emissions annually (about 2 percent of the country’s total) just by diverting waste heat from some of the UK’s biggest power stations to warm homes and offices. And that’s not even considering any higher-tech solutions for capturing and using waste heat, many of which are now in the offing.
To help reduce carbon emissions — not to mention saving money and lessening reliance on foreign fuel imports — governments are increasingly pushing for policies and incentives to encourage more waste heat usage, big businesses like IBM are exploring innovative technologies, and start-ups are emerging to sell technologies that turn lukewarm heat into usable electricity.
For more than a century, waste heat has been used for its most obvious application: heat (think of your car, which uses waste heat from its engine to heat your interior). In 1882, when Thomas Edison built the world’s first commercial power plant in Manhattan, he sold its steam to heat nearby buildings. This co-generation of electricity and usable heat is remarkably efficient. Today, in the United States, most fossil fuel-burning power plants are about 33 percent efficient, while combined heat and power (CHP) plants are typically 60 to 80 percent efficient. …
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