An ode to PV solar power
I love talking about energy. And I especially love talking about solar energy. There’s something different — special, almost magical about photovoltaic (PV) solar power as compared to all the other energy sources.
Here-below are a few things I find fascinating about PV solar power that we don’t talk about often. And after reading about these special features, maybe you too will be convinced that we should continue to explore and develop this magical source of energy.
NB: I use the terms PV solar and solar interchangeably in the article below, not to be confused with solar thermal power.
I love photovoltaic solar power because you are unique in the way you generate electricity.
Because of its unique physics, photovoltaic (PV) solar is the only commercially viable technology that does not use a turbine generator to produce electricity.
A turbine generator functions based on Michael Faraday’s discovery in 1831 that when a closed circuit conductor is placed in a varying magnetic field, a current is induced.
The turbine converts a moving fluid — generally steam, but also water, air, combustion gases — into rotational energy. The generator converts the rotational energy into electricity.
In other words, a turbine generator is basically a metal rod (a rotor) covered in magnets that generates electricity when it is rotated by some “moving liquid” force:
- Fossil fuels are burned to heat water and generate steam or hot gases to rotate the turbine
- Nuclear and solar-water heating plants likewise generate steam to rotate the turbine
- With geothermal energy, hot water from the earth is converted into steam which again is used to rotate the turbine
- With wind power, the wind-blown blades rotate the turbine
- With hydroelectric power, moving water rotates the turbine
PV solar however needs no turbine generator to produce electricity. PV solar functions based on the photoelectric effect discovered by Edmond Becquerel in 1839: when exposed to sunlight, some materials absorb the photons and release electrons. When these free electrons are controlled*, an electric current results which can be used as electricity.
*More specifically, a typical solar cell is created from layers of silicon that are P-Type (excess of “holes”) and N-Type (excess of electrons) that create an electric field at the P-N junction. When light hits the solar cell, electrons are driven towards the the N region and the holes towards the P region creating a potential difference and when a load is connected between the two regions, electrons will flow through the load, and thus we have electricity! See the video below for a visual explanation of this phenomenon.
Sunlight hits a plate and poof, we have electricity. Seems magical to me.
I love PV solar because you are modular.
And modular means democratic. Distributed.
With solar, people are empowered to choose how and where their electricity is generated. Solar can come in all shapes and sizes.
When we talk about PV solar, we can be referring to a 30MW solar farm (100,000 panels — 45 ha) that generates electricity for thousands of households. While an individual cannot alone finance this sort of installation, one can choose where his or her electricity comes from by selecting a specific electricity provider. Or one can also choose to partially invest in such a project with crowd-lending platforms such as Lendopolis in France.
We can also be referring to a 3kW residential solar system (10 panels — 16m2) on the rooftop of a house that covers part of the home’s electricity needs.
Or a portable 30W solar charger (that can fit over your backpack) to power some smartphones or small electronics.
We can’t throw a tiny wind turbine or a nuclear plant in our backpack. But we can with solar.
And once again, that makes solar pretty special.
I love PV solar because you have no moving parts…
Solar panels have no moving parts unlike wind turbines or any turbine generators, and consequently there’s no “wear and tear”, allowing solar panels to be ultra-durable and last a long time with minimal maintenance. Manufacturers usually provide a 20–25 year warranty and beyond that, panels installed in the 1980s are still performing at effective levels today.
…and in effect, you can power objects in space.
The durability of PV solar panels, combined with their unique physics and modularity, make them well-adapted to power satellites and other spacecraft that are exposed to direct sunlight. In fact, spacecraft were one of the first applications of photovoltaics starting with the Vanguard I satellite launched in 1958.
Solar-powered satellites generally have a useful lifetime between 5 and 15 years, sometimes even more (the Vanguard I is actually still in orbit!). Thanks to solar cells, these satellites can operate continuously for long periods of time and in effect, provide communication and navigation services that we so depend on.
While solar has mostly and logically powered spacecraft in the inner Solar System — the planets closest to the sun — PV solar has also been used to power NASA’s Juno space probe. Juno is equipped with three solar panel wings which not only generate electricity for the probe, but also stabilize the spacecraft. Juno was launched in August 2011, entered Jupiter’s orbit in 2016, and is designed to stay in orbit until 2025.
The same PV solar technology used to power our homes can be used to power a probe in outer space for 15 years, that’s pretty badass.
Simple, modular, durable — Here comes the sun!
When we talk about solar, as we do about other energy sources, we usually talk about cost, intermittence, CO2 emissions, and waste and recycling…
Bur with this article, I wanted to instead bring attention to some of unique qualities of PV solar that we don’t talk about as often: the fact that solar power’s unique physics make it just simple, the fact that solar is modular, the fact that it has no moving parts and can power things in space. For all these reasons and more, PV solar intrigues and energizes me in ways other energy sources do not.
Did I mention that I also find solar panels quite beautiful?
