It’s 2015, I always thought the world look like the jetsons right now with flying cars
and clean energy? While we’re still waiting on a flying car, clean energy, especially
solar, has come a long away.
Hey guys Julia here for DNews
We’ve talked about solar power here on DNews before a lot. To see how solar power works
check out this episode right here. But just a quick recap, solar panels are made of photovoltaic
cells. These cells convert sunlight into energy by using photons from the sun to knock loose
electrons. These cells are typically made up of a silicon wafer sandwich. One wafer
is positively charged, the other negative, this creates an electric field. Phosphorus
is added to top the layer to increase the amount of electrons there and boron makes
the bottom more positive. Photons from the sun knock an electron out of that electrical
field and then the cell has some other parts that use that electron as energy.
That’s the basics. Solar panels aren’t a new technology, they’ve been around for
over a hundred years. The first “solar cell” was patented in 1888. But since then, it’s
kind of been slow going. Almost 90 years later RCA Laboratories come out with the silicon
version of a solar cell… but it only had an efficiency of 1.1% Basically that means
for the amount of energy going into a solar cell from the sun, only 1.1% of that is converted
into usable electricity.
And research into solar technology is like I said, slow going. One researcher said gains
of 0.2 percent are the norm and gains of 1 percent are seen as significant breakthroughs.
Since the 70s efficiency has only increased from 1.1% to around 20% for most conventional
models. In comparison traditional forms of electricity from fossil fuels are only at
about 40% efficient.
But even the US Government wants to do better. Over a decade ago the DARPA initiative put
out a request for 50% efficiency in solar panels. So far, research has come close. In
2007 researchers from the University of Delaware announced they created a cell with 42.8 percent
efficiency up from 40%, which in this field was a huge deal. Their solar panel gained
in efficiency by separating sunlight into three different energy bins of high, medium
and low, and directs them onto cells of various light-sensitive materials to cover the solar
spectrum. And in late 2014 Australian researchers announce a 40% efficient panel in the journal
Progress in Photovoltaics. It boosted efficiency by including another filter to capture more
bandwidths of light that are usually wasted by other models. But it’s still not the
typical model you’d see on homes. Most conventional panels only reach an efficiency of about 20%.
But maybe the future doesn’t even lie with silicon. Research into a different material
called perovskite has taken off over the past few years. Perovskite is a naturally occurring
mineral with a crystalline structure made out of calcium and titanium. But it’s really
easy to synthesize in a lab out of a organic-inorganic hybrid of lead or tin halide that's mixed
with organic groups like methylammonium.
The crystalline structure makes it especially good for solar applications. But one of the
most exciting things about this new type of solar cell is how far it’s come in such
a short time. Perovskite research seems to be moving at very brisk pace compared to silicon.
In only six years it jumped from 3.8% efficiency in 2009 to a certified 20.1% in 2015, which
is on par with conventional silicon panels. So maybe they could reach DARPA’s goal in
no time. One materials scientist I spoke with, Daniel Dryden said “their insane rate of
improvement is definitely worth paying attention to as more than just the newest fad.”.
While perovskite panels aren’t on the market yet, some start ups promise they’ll have
some ready to go by 2017. So it’s definitely something to keep an eye on.
One of the other great features of perovskite that gets researchers excited is how cheap
it is to make. Which could benefit those in rural areas without access to traditional
electricity.
Be sure to check out our other episode on Seeker Stories, where we discovered how constant
blackouts and a lack of electricity in general impacts daily life in Tanzania.
To learn more about energy poverty, visit One.org/energy