[Image above] Credit: Lawrence Livermore National Laboratory

Americans have seen the light when it comes to clean energy… literally.

Solar energy use spiked 33 percent in 2014, thanks to soaring solar industry expansion and affordable prices for panel installation.

The first quarter of 2015 alone saw $50 billion of renewable energy investments—that’s up from $9 billion in 2004, reports a Scientific American online article citing Bloomberg New Energy Finance. Not only that, the number of photovoltaic systems installed in the U.S. has grown every year since 2000.

And solar energy isn’t the only breakout clean energy star. Americans’ energy use saw an uptick in 2014, but it was mostly fueled by renewables—a combination of solar, natural gas, and wind—according to recent energy and carbon emission flow charts from Lawrence Livermore National Laboratory (Livermore, Calif.).

The Laboratory publishes annual energy consumption charts. “Overall, Americans used 0.9 quadrillion (quads) British thermal units (BTUs) more in 2014 than they did in the previous year, an increase of about 1 percent,” according to a LLNL news report.


The energy flow charts released by Lawrence Livermore National Laboratory show that overall energy use was up in 2014, but it was largely fueled by renewable energy sources. Credit: Lawrence Livermore National Laboratory.

A companion chart released by LLNL shows trends in U.S. energy-related carbon dioxide emissions, and LLNL reports the good news that “Americans’ carbon dioxide emissions increased, but only barely, to 5,410 million metric tons, from 5,390 million metric tons in 2013.”

But carbon emissions from coal and petroleum are trending downward as the country relies less and less on fossil fuels.

The result? The LLNL data show the overall carbon intensity of the American energy economy is shrinking.

Moreover, the Energy Information Administration (EIA) anticipates in its 2015 Annual Energy Outlook that the use of renewables and energy efficiency will continue rapid growth. The agency expects the total share of renewables in the U.S. will grow to 18 percent by 2040.

Shifting to clean energy sources today is an important move toward a more energy-efficient tomorrow, but are we overlooking a less-obvious, but abundant, source of emission-free energy?

Enter the untapped power of waste heat—a byproduct of all industrial processes—like the heat you feel from the exhaust of your car. And it can be captured and used to generate emission-free renewable-equivalent power. If it’s harvested.

Credit: Waste Heat to Power; YouTube

The thing about waste heat is that it’s often, well, wasted. It just gets released into the atmosphere through stacks, vents, and mechanical equipment—and slips out of our hands forever.

Luckily, materials scientists are already on the case. An article published in the June-July ACerS Bulletin by Ceramatec’s Charles Lewinsohn details new ceramic microchannel heat exchangers that can improve efficiency and reduce emissions by recovering and transferring waste heat in high-temperature and corrosive environments.

This cost-efficient technology has the potential to make many industrial processes much more efficient and sustainable.

What other opportunities exist for clean low-emission energy solutions? Leave a comment and add to the discussion!