Solar energy is attracting more interest than ever before and large solar systems are being built around the world, but how do solar farms work?
If you have not heard of a solar farm, then maybe you would know what we mean when we say ‘solar power station’ or ‘solar park,’ but in the end, they all refer to the same thing.
Solar farms share a lot of the same qualities and problems (they both depend on the weather!) as conventional crop farms.
Still, where crop farms use the energy from the sun to help grow their crops, solar farms use that same energy to convert as much of it as possible to electricity.
Now, considering the environmental reports from both the United Nations Development Program (UNDP) and the United Nations Framework Convention on Climate Change (UNFCCC) that emerged this year, there are a few reasons to start changing your energy plan to solar energy.
Similarly, when it comes to fossil fuels, it is a limited resource, so inevitably, they will run out.
Then the whole world will have to invest in renewable energy sources, so for our environmentally conscious and forward-thinking readers, a move to a solar-powered energy plan might seem like a no-brainer.
However, if you do still need a bit more convincing, then maybe our article ’10 reasons to Choose Solar Energy & The Benefits’ might interest you.
For example, did you know that solar panels require next to no maintenance due to the lack of moving parts?
If that has piqued your interest, click here to check out some of the other reasons listed in our article.
It’s no coincidence that solar energy’s predicted growth is expected to be higher than any other renewable energy source that is known to date, and early investment in the technology now will only benefit our planet in the future.
But if you happen to be a bit of a stickler for information and want to know everything about something before you use it (we cherish that type of attitude here at Solar Power Nerd), we will explain how solar farms work so you can make the most informed decision possible.
What Are Solar Cells? What Are Solar Panels?
Before we begin to explain the overarching process of the solar farm, let us first define the nuances of solar panels, a.k.a. Photovoltaic panels (and the solar cells from which they’re made) – since they’re the most crucial and necessary component in capturing and harnessing the power of the sun.
As with any electrical circuit, solar cells create electricity by generating a flow of electrons, but how does it begin?
Simply put, a solar cell is made up of four layers, with the two outmost layers being conductive plates from which the electrons will flow to the power source.
However, it’s from the two innermost layers where most of the solar-electrical magic happens.
The two innermost layers of a solar panel are two different types of silicon – one which has been positively charged (with fewer electrons than standard silicon), and one which has been negatively charged (with extra electrons than standard silicon).
It’s with these two layers of silicon that the particles of light (known as photons) react.
When the sun shines on a solar cell (a solar panel is made up of multiple solar cells), it knocks an electron out from the layer of negatively charged silicon.
Then, due to the inherent charges with the two layers of silicon, the newly removed electron is forced to the outer conductive plate.
From the outer conductive plate, the electron then flows to the connecting wires and then further on to its destination (whether that might be a battery, a light, etc.) in the form of direct current.
While one cell might only generate up to 0.5V, if you string multiple cells up together in one panel, the energy output will increase accordingly.
For example, 12 solar cells together will be enough to charge your phone directly.
If you link a couple of cells along with a battery (much like a solar power bank), then the cells can be used to charge the battery, which will store the energy load and output at enough amperage to charge your phone.
For some more examples of how small, single/double solar cell panels can be used in power banks, check out our article ‘10 Best Power Banks for Camping & Their Reviews‘.
How Do Solar Panels Convert Sunlight into Electricity?
For the more scientifically-oriented amongst you, you might notice that solar panels produce energy in direct current (DC), whereas our modern electrical system is in alternating current (AC).
So how is the energy from the solar panel then converted into the form of electricity that is used in our power grid?
Typically, you will find that attached to each solar array is a solar inverter (a power inverter designed explicitly for use with photovoltaic cells) – with static solar inverters being the most common in this day and age due to the lack of moving parts, which as we explained before, means less maintenance.
Now, solar inverters also have to deal with a lot of continually differing environmental conditions such as temperature and solar irradiation, which causes peaks and troughs in a solar panel’s DC output.
Therefore, to maximize the amount of power at any given moment, the solar inverter needs to employ Maximum Power Point Tracking (MPPT) so that the resistance can be adjusted to an optimum level, which will subsequently optimize the power output.
This technology has now gotten to a point where solar inverters, known as ‘solar micro-inverters,’ can be attached to each solar panel to maximize the output of each solar panel, and as such better maximize the production of the entire plant as a whole.
How Do Solar Farms Maximize The Sun’s Energy?
In the past, it was quite reasonable for solar panels to be installed at a fixed angle, which would be at the optimum angle for photon cell intake throughout the year.
But in some seasons, the intake would be less than optimal due to the sun’s change in angle as it passes through the sky throughout the year.
In recent years there have been significant developments to maximize photon cell intake for each solar panel, and this is what we would love to discuss here.
The first development was single-axis tracking, which would follow the sun as it went through the sky.
While single-axis tracking didn’t account for the change in the sun’s trajectory through the sky as the seasons changed, it did help to catch more photons since the solar panel would follow the sun from sunrise to sunset.
Then there was dual-axis tracking, which does precisely what single-axis tracking does but also accommodates the changes in the sun’s trajectory throughout the seasons.
Therefore, as far as normal flat-paneled solar cells go, the photon intake had been fully optimized.
However, the future of solar power might be even more sci-fi than you might imagine.
A recent development in solar farming is the introduction of potential floating solar arrays (or more colloquially known as ‘photovoltaics’).
Whilst catching direct sunlight might be ideal, the new introduction of these floating solar arrays can also pick any photons which bounce off the water’s surface, thereby potentially catching photons that did not even hit the solar panel in the first place.
Furthermore, it has been shown that this new development in ‘photovoltaics’ increases the efficiency of the solar arrays due to the natural cooling properties of water.
What Happens on a Solar Farm?
When solar farms are made in agricultural areas, one might find that the photovoltaic cells are made in conjunction with a pre-existing agricultural process because solar farms are the most nature-friendly way of providing electricity to a power grid.
This is mostly due to the lack of harmful materials (which is present in the use of fossil fuels) and the lack of moving parts (which is present in wind farms).
There are many examples in the United Kingdom of solar farms being used in conjunction with other types of farming, such as grazing sheep (check this link here for some more information).
Furthermore, there have been a few studies from places such as the Argonne National Laboratory from the US Department of energy that show solar farms to be ‘pollinator-friendly.’
What this term means is that the environment present at a solar farm is ideal for pollinators such as birds and especially bees since the limited mowing and spreading of herbicide promotes the growth of a wide array of different flowers, therefore increasing botanical diversity.
What they also showed, was that if the owners of the solar farm also applied some targeted herbicide for weeds, and sowed some seeds, it could create an ideal pollinator environment.
The promotion and protection of bees is also nothing to be dismissed since it’s estimated that honey bee pollination adds more than $15 billion in value to the U.S. agriculture industry every year (click here for more information).
So what you can take from this section is that solar farms can have multiple agricultural benefits alongside their primary use, some of which (such as the pollinator-friendly environment) is much needed in a time when the population of bees is declining at an alarming rate.
How Big Are Solar Panels on a Solar Farm?
Since we have talked a little bit about how small-scale panels and individual solar cells work, let us now put the commercial/industrial scale panels into a bit of perspective.
Where a single/double cell panel might be small enough to fit on a power bank, the commercial/industrial size solar panels string together a much larger quantity of solar cells.
The panels that you will find at solar farms consist of at least 72 solar cells linked together, and maybe more, depending on the size and age of the solar farm.
One panel of 72 solar cells is, on average, 78 inches long and 39 inches wide with a depth of 1.5-2 inches.
A panel of this size will generate roughly 400W depending on the efficiency of the solar cells used.
This is naturally a whole lot more than the previous examples we’re discussing, but where a solar farm excels is not in the size of one single solar panel, but in the sheer quantity of solar panels that can be present within a single farm.
How Big Are Solar Farms?
The first-ever 1 megawatt-peak (MWp) solar farm was constructed in 1982, with MWp referring to the farm’s theoretical maximum direct current output – in this case, 1 megawatt.
However, since then, the capacity and efficiency of solar farms have only increased with the improvement of photovoltaic technology.
While 1 MWp and 10 MWp solar farms were quite popular in the late 20th century, the more recent solar power stations that were either completed in this decade or are still under construction have MWps of at least 200.
However, some of the biggest solar farms in the world have mind-blowing capacities of over 1 GWp (which is equivalent to 1,000 MWp), such as the Tengger Desert Solar Park, which was completed in 2016 and had a capacity of 1,547 MWp.
The limit does not stop there, though, since some solar parks that are still under construction, such as the Pavagada Solar Park in India, have a planned capacity of over 2 GWp – with this example expecting a whopping 2,050 MWp.
To see a list of some of the biggest modern solar farms and their potential, you can have a look at some of the biggest on this link here.
Such an incredible supply of power must require an incredible amount of space you might think requires an incredible amount of space, but that is simply not the case.
You might imagine that solar farms require an impossible amount of space to provide an adequate amount of energy for a city, but that would be wrong.
The largest solar farm listed in the previously mentioned list takes up a space of 20.46 square miles.
To put this into the perspective of the world, it’s estimated between tens and hundreds of thousands of square miles would be needed to provide enough energy for the whole world, while the Sahara desert alone is over three million square miles.
So relatively speaking, the space needed for the solar panels to provide energy for the world is minimal.
What is more crucial and necessary for a better distribution of solar energy in poorer parts of the world is a more reliable electrical grid for such solar farms to support.
Now you know how solar farms work, but that is not the limit of solar power’s potential!
If you’re interested and want to read about some real-life developments in solar technology that sound completely from the future, then please check out this article here about solar cell fabrics (yes, you read that right), which can potentially be integrated even into your clothing!