President Donald Trump may talk a good talk for American coal miners, but his administration is still powering along on the renewable energy course charted by his predecessors in the White House. In one of the latest developments, the Department of Energy’s National Renewable Energy Laboratory is enthusing over the results of two new high-efficiency breakthroughs that leverage solar energy to “split” hydrogen from water.
That’s just two examples. NREL is celebrating its 40th anniversary this year. The lab — and, by extension, the Trump administration — is using the occasion to showcase the current state of its numerous renewable energy research initiatives, the result of continued investment through multiple Democratic and Republican administrations.
Solar powered hydrogen production: Part I
Renewable hydrogen is the key to unlocking the power of the hydrogen economy. Hydrogen is an abundant, zero-emission fuel. And energy enthusiasts have long dreamed of harnessing it for widespread use to replace coal and other fossil fuels.
The problem is that the primary source of hydrogen fuel is still fossil energy, specifically natural gas.
That is beginning to change. Researchers are looking at renewable biogas for hydrogen production, and “water-splitting” powered by solar cells or wind energy is also a focus of alternative hydrogen production.
NREL’s latest contribution to the solar water-splitting field is a big one.
The lab has achieved proof-of-principle for a new solar cell that can capture excess energy that is normally vented as waste heat.
Specifically, the new device is a photo-electrochemical cell that can “push the peak external quantum efficiency for hydrogen generation to 114 percent.”
As described by NREL, the new cell leverages a process called multiple exciton generation (MEG) to arrive at the seemingly impossible feat of surpassing 100 percent efficiency.
MEG enables the solar cell to produce extra electrons, surpassing the amount that enter it. Here’s the explainer from NREL:
“The maximum theoretical efficiency of a solar cell is limited by how much photon energy can be converted into usable electrical energy, with photon energy in excess of the semiconductor absorption bandedge lost to heat. The MEG process takes advantages of the additional photon energy to generate more electrons and thus additional chemical or electrical potential, rather than generating heat.”
Instead of transferring the electrons to an electrical current, the solar cell stores the MEG-enhanced electrons in a chemical bond, namely, hydorgen.
For those of you keeping score at home, the chemical aspect of the new cell explains why it’s called a photo-electrochemical cell. Solar cells that convert sunlight to an electrical current are called photovoltaic cells.
Solar powered hydrogen production: Part II
Also in the photo-electrochemical field, another team of NREL researchers has nailed the record for achieving the highest efficiency level for solar powered water-splitting.
For its new photo-electrochemical cell, the team “grew” a new semiconductor material in a specialized reactor. The new cell hit the mark of 16.2 percent, significantly higher than the next-highest efficiency level of 14 percent achieved by an international team back in 2015.
Aside from giving NREL bragging rights to a new world record, the new cell has the potential to lower the cost of renewable hydrogen.
The team also demonstrates the value of long-term federal investment in foundational research. The roots of the new cell go all the way back to a concept device NREL developed in the 1990s.
Coal under the bus
President Trump flipped on several key campaign promises in just one week, and the chances for him to make good on his oft-repeated promise to bring back coal jobs are also flattening out to near zero.
To a great extent, the pressure on coal is coming from cheap natural gas, and the Trump administration has a built-in advocate for natural gas in newly-minted Secretary of State Rex Tillerson, the former head of ExxonMobil.
ExxonMobil is typically known for its oil operations. But under Tillerson’s leadership, the company embarked on a concerted effort to grow its natural gas business in the U.S. and globally — specifically at the expense of coal.
The coal industry has no such internal voice in the Trump administration, despite Trump’s promises.
Until recent years, renewable energy has played a much smaller role in the demise of coal here in the U.S. That’s about to change as renewable energy technology improves and costs come down.
As with natural gas, renewables also have a strong advocate in the White House. Energy Secretary Rick Perry has espoused some dicey viewpoints on social issues. But as the former governor of Texas, he shepherded the state into a renewable energy leadership role that includes solar, biofuel and advanced energy storage as well as a heavy dose of wind power.
Secretary Perry has continued to pitch renewables through the Energy Department’s news releases and social media, and through his own Twitter feed.
Apparently the secretary received orders from the Trump administration to withhold U.S. endorsement from an important G-7 climate declaration last week. But Perry’s public statement on his meeting with G-7 leaders included a not-so-subtle pitch for renewable energy:
“I discussed with my fellow ministers that the Trump administration believes that economic growth and the environment can successfully go hand-in-hand,” Perry said.
“An example of this success is my experience as a governor when we made good policy decisions that grew our economy, and added 4 million new residents to my state. At the same time, we reduced our emissions and improved our environment.”
Perry went on to throw a bone to coal, but only in the context of developing advanced nuclear energy and “high efficiency, low-emission” natural gas, too.
He also emphasized a finding by the International Energy Agency favoring natural gas:
“The IEA also shared the major impact that natural gas, including U.S. [liquified natural gas] exports, will have on energy security and environmental quality. This will benefit consumers.”
These lines hammered another nail in the coal coffin:
“Innovation is also a top priority for the Trump administration. We are committed to developing, deploying and commercializing breakthrough technologies and developing the necessary policies that will help renewables become competitive with traditional sources of energy.”
Perry’s remarks were aimed at the global energy marketplace with the ultimate effect of dampening export potentials for the U.S. coal industry as well as fostering the continued downward slide of domestic consumption.
It appears that the Trump administration has an awfully funny way of bringing back coal jobs.
On the other hand, if President Trump makes a slight grammatical revision in his campaign promise — that is, bringing back jobs for coal miners — he could look to the explosive growth of employment in renewable energy, energy efficiency and related fields for a leg up.
Photo: via NREL.