How Solar Farms Work: Complete Guide & Details

Tim Hamlin
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Solar Panels & Solar Cells

The solar panels (also referred to as solar cells) are the devices that capture and convert the energy from the sun. They can be fixed to the ground or attached to a roof to provide heat

And electricity from the sun. Engineers design solar cells to optimize light absorption in order to create solar panels that work efficiently at generating the energy from the sun.

Solar cells are made of silicon, which can generate a flow of electricity when exposed to light. This flow of electricity is the measure of how much energy each solar cell is able to produce. The more photovoltaic electrical energy that each solar cell can create is referred to as its ‘efficiency rating.’

Silicon wafers can be made into silicon solar cells through a process called diffusion. An electric current is applied in the wafer that causes atoms of one element to diffuse into the silicon atoms. By then adding a second element, the resulting silicon will have the ability to produce electricity at a higher efficiency.

Developers often use gallium and boron to form efficient solar cells. These additions allow the silicon to absorb more light, thus increasing the potential for creating electrons.

The more silicon that has gallium and boron added, the more efficient the resulting solar cell will be. When manufacturers use amorphous silicon these solar cells are not considered to be as efficient as crystalline silicon.

How Is The Energy Converted?

Solar panels convert light into electricity. This is done through a photovoltaic effect, which is a physical process that occurs when light directly strikes a material. A photon of light excites an electron in a photovoltaic cell (a semiconductor) which shifts from its lowest state to its highest stable energy state.

Of course, the energy is ultimately converted into electrons in order to generate power. Electricity is then created by the movement of electrons through the circuit and magnetism. The free electrons create a small magnetic field, which energizes a generator and creates power.

How does this relate to solar panels? The semiconductor material, which absorbs the photons, is made into a material called a "cell" that's a coating on the back of the photovoltaic cells. The solar panels are made out of these cells in panels and then arranged in a way that captures the sunlight.

How Do Solar Farms Maximize The Sun’s Energy?

All solar farms utilize solar panels for energy conversion into electricity. While there is some variation in the methods used by different companies, all these use photovoltaics, which capture light and convert it into direct current (DC) electricity that can then be used to power homes and buildings, or stored in batteries for later use.

In order to be most efficient, solar panels are placed facing the sun, with their tilt controlled via a small motor. The increased angle allows the cells to capture more energy from the sun. Different solar farms utilize different amounts of space, some running to dozens of acres.

What Else Happens In A Solar Farm?

Some of the most important details of solar farms involve the revenue stream and who participates in it. Solar farms currently sell electricity to grids via power purchase agreements (PPAs), which is a contract between an energy developer and customer.

The terms vary from contract to contract but in general, customers will purchase fixed amounts of electricity at a fixed rate over a period of time, with the understanding that the prices will climb over time. The period of time in a PPA is usually between 15-20 years. Because solar and wind energy are currently subsidized heavily, several regions of the world have begun to use reverse auctions to determine rates for producer and consumer.

The reverse auction is similar to a traditional one in regard to the companies submitting bids. With the auction though, several customers will submit bids for how much electricity they need and the lowest bids win.

An additional benefit to the solar farm over other forms of electricity generation is the intermittency of the output. Solar farms are ideally placed in locations that receive a lot of sunlight, which means that their generation production will be highest during the daylight hours.

Every form of energy generation, including solar and wind requires back-up in order to keep electricity flowing at all times. Solar farms, for example, have gas turbines and mirrors that are used in production as the sun sets, as well as the initial stages of production.

How Big Are The Solar Panels In a A Solar Farm?

Solar panels are typically square or rectangular and rigid. They are heavy and measure 36"x48"x1" is size and they are about 1/8th" to 1/4" thick.

They are manufactured in a huge variety of styles including 2-axis tracked, single-axis (built in drive mechanism), and fixed racking.

Tracking style panels are used in remote applications that aren't connected to the grid.

How Big Are Solar Farms?

Solar Farms are big! They cover a lot of ground. The largest farm in the world is Sunflower Solar Farm located in Sanland, South Africa. Featuring 22 million solar panels, the farm covers 4,400 acres. To give you an idea how big an acre is, it is the equivalent of 43 football fields. That is one heck of a lot of panels! Other large farms include the Topaz Solar Farm in California (2.5 million panels) and the Agua Caliente Solar Farm, also located in California (1.7 million panels).

The power output of these large solar farms varies but the Agua Caliente farm can produce 550 megawatts, enough to power over 250,000 homes. The Topaz farm can produce 550 megawatts also. The Sunflower Solar Farm in South Africa can produce 500 megawatts.

That sounds impressive but this really is just the start. Experts project that global energy production from solar farms will exceed 342 gigawatts by the end of the decade.

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