How do these farms work, exactly?
Last updated on 11/26/19, by Esmeralda Torres | Written by Nina Goodey
What are Solar Farms?
Solar farms are massive installations of solar panels to generate power for the local electrical grid, and they’re becoming increasingly more common as the price of solar panels drops.
You’ve probably seen news about enormous solar projects being constructed in Egypt, India, China, and other countries. How do these farms work, exactly? Are they similar to a homeowner’s rooftop installation?
Mostly, yes. Solar farms (also called solar parks or photovoltaic power stations) are just large-scale solar panel installations, usually built on land, not otherwise useful (like a desert). The panels used can be fixed or mounted on solar trackers that rotate to keep the panels facing the sun. Some solar farms currently being tested even float on water!
How much power do they generate?
Well, most solar farms are built to generate at least 1 MWp, or one megawatt peak, the maximum amount of DC (direct current) output. A solar farm that generates one megawatt is strong enough to power about 400-900 homes. Solar farms are especially great since solar energy is often cheaper than fossil fuels to generate, the farms require almost no maintenance, and homeowners who can’t install their own solar panels can still enjoy the power of the sun.
Compared to traditional power plants, solar farms can be constructed quickly to start generating power right away, and many countries have enacted financial incentives to subsidize the cost of construction. Typically, they’re built within a few miles of a suitable grid connection point and the developer will put up power lines to connect the farm to the grid, which is good for those communities.
Sounds simple enough, right? However, connecting these farms to the grid can be difficult. When solar developers consider a project, they have to carefully plan the safest and least expensive way to hook up that power with the main utilities. The larger the farm, the harder it is to safely link that output to the grid, and connecting ties are expensive (up to $1 million/mile). If that farm is far away from a suitable power substation it gets more and more expensive to hookup. That’s why even though solar farms can be fantastic for us and the environment, they’re difficult to plan and expensive to construct.
When was the first solar far built?
Historically, the first 1 MWp solar farm was built near Hesperia, California in 1982, quickly followed by another 5.2 MWp solar farm also in California. Neither are operational now, but new farms are being constructed or planned in those locations. Following these two parks, Germany and then Spain held records for largest solar farm output. Currently, the world’s highest-generating solar park is Tennger Desert Solar Park in China, at 1.547 MWp (roughly 75% of Hoover Dam’s maximum output), followed by two solar parks in India.
Solar farms aren’t good just for generating electricity from the sun! A number of solar farms also have wind turbines installed to maximize the use of space to create even more clean power. Some farms are also agrivoltaic - meaning they’re used for both farming and solar power, making them truly environmentally-friendly. One study found that combining solar panels and shade-tolerant crops led to a more than 30% increase in economic value for agrivoltaic farms, compared to conventional.