Learn the Difference Between Wind, Solar and Other Types of Renewable Energy
We are living in an exciting time for energy production, with renewable sources of electricity such as wind and solar swiftly expanding across the nation. These green methods of production allow us to harness the power of free, never-depleting sources of energy such as the sun and the wind, all while creating zero carbon emissions. Read on to learn more about the advantages of solar panels and wind turbines, and decide for yourself if there is an answer to the question of which is better, solar or wind energy?
How Does Solar Energy Work?
You may have seen solar panels on rooftops and perhaps even a solar farm, with acres and acres of black, shiny panels hoisted on racks. Inside these panels are photovoltaic cells, and their job is to turn light into electricity. These cells function, according to NASA, by transforming photons from sunlight into electrons. When the electrons are passed through a semiconductor, it creates a current that can be made into electricity. Another less common form of solar energy is solar thermal, which concentrates the sun's rays on mirrors to heat a fluid (usually water). The steam from that fluid powers a turbine that makes electricity.
The State of Solar Power
In the world of renewable energy, solar is booming. During the past decade, material costs have decreased by more than 60 percent and counting. Because it's cheap, more people and jurisdictions are interested in solar. In fact, its capacity tripled between 2015 and 2016, and solar remains the fastest-growing source of electricity generation through 2018. As of the third quarter of 2018, the United States had 60 gigawatts of solar capacity, which could provide enough electricity for roughly 11.3 million homes. Solar is not only fast-growing, it has nearly unlimited potential. According to the U.S. Department of Energy, building photovoltaic panels on just 0.6 percent of the nation's total land area could supply enough electricity to power the entire United States.
What Are the Advantages of Solar Energy?
When you stack up solar's upsides next to other energy sources, it has a rather impressive list of advantages:
- While solar systems take up land space, they don't always have to. Panels can be mounted on rooftops, making them well suited for urban areas.
- Rooftop solar also lends itself to distributed generation, as opposed to centralized, making for a more diverse and resilient electric grid
- Solar is silent, which makes it ideal for more populated areas.
- There are no moving parts, and therefore it needs less maintenance than wind.
- The energy is easy to generate and transport.
- Panels work in cold climates, as air temperature doesn't matter as long as the panels are catching rays.
- Home rooftop panels can reduce a homeowner's electricity costs. During a heat wave, when energy loads are high, this would definitely be an advantage.
- Once you install the panels, power generation is nearly free. You don't have to pay a penny for sunshine.
What Are the Challenges of Solar Energy?
Solar isn't a cure-all for our energy needs in and of itself, however. You're only capturing energy during the daytime, and production levels can vary depending on how clear the sky is. Furthermore, while battery technology is advancing rapidly in its own right, we haven't yet attained an optimal way to store the amounts of energy that would be needed to power large population centers when the sun isn't offering optimal production. For now, we still rely on other energy sources on cloudy days or after dark, although a variety of promising storage systems are under development.
How Does Wind Energy Work?
Wind turbines generate electricity using similar principles as fossil fuel production, just using a different fuel source. If you look at the wind turbine, the electricity is being made at high altitude, right inside the cylinder shape behind the rotating blades. The wind pushes the blades into motion, which turns a shaft. This chain of motion eventually leads to a generator that makes electricity. The electricity then travels down the stem of the turbine and is taken to transmission lines to be transported and distributed to customers.
The State of Wind Energy
Even though solar has been growing more quickly than wind, it will be awhile before its output catches up. Wind is still the largest source of renewable energy in the United States with some 90 gigawatts of production in operation, triple the capacity of a decade ago. Much like with solar energy, the costs of building wind turbines are continuing to fall. And thanks to better technology and engineering, taller turbines can harvest wind more reliably, boosting their capacity.
What Are the Advantages of Wind Energy?
Wind energy also has an impressive list of advantages:
- Wind energy is a clean fuel source, meaning it doesn't pollute the air like power plants that rely on combustion of fossil fuels.
- Wind turbines can be built on farms and ranches, so leasing available land can become a source of income in rural areas while the owners can still use the land for other purposes.
- Wind power is cost-effective. Much like sunshine, wind costs nothing to produce.
- It is a domestic source of energy, and the nation's wind supply is abundant.
What Are the Challenges of Wind Energy?
The biggest problem wind production faces is the cost of transporting the energy generated, as the windiest areas are usually remote. In addition, like solar, wind is an intermittent power source, so you can't count on turbines to provide energy around the clock. Also, wind is less ideal for residential use for two reasons. One, turbines make noise. While the models are getting quieter, your home turbine may be frowned upon by neighbors, your homeowners association or even your city. And in order to generate any significant amount of electricity, you would have to erect a taller turbine — up and away from wind-blocking buildings and trees and other urban obstacles. That too may not make you the most popular person on the block.
Other Sources of Renewable Energy
Wind and solar aren't the only sources of renewable energy in play.
Hydroelectric power remains a big player in electricity production in the United States, particularly in Washington, Oregon and California, and accounts for about 7 percent of energy generation in total. It works by using water to turn electricity-generating turbines and is reliable enough to supply base-load power for large areas of the country. Similar to wind and solar, the fuel source is free, and the production doesn't directly produce carbon emissions.
However, dams built to create hydroelectric reservoirs can be disruptive enough to river ecosystems upstream and down that some people question whether hydroelectric should truly be considered a green source of power at all, and decomposing biomatter in areas flooded by dams can release significant carbon and other contributors to climate change into the atmosphere. Effective capture of hydroelectric power also depends on having a large volume of flowing water in the vicinity, of course.
We also have the ability to capture and use heat for energy directly from the ground. On the household level, that can mean a pump that uses the difference in temperature between the air and the underground to heat your home. On a larger scale, we can use naturally occurring underground heat sources to produce electricity itself. Geothermal taps into a very sustainable resource - there is more heat than we could ever use within the Earth, and it is constantly being produced.
On the other hand, sending infrastructure deep underground is expensive to do, has the potential to emit certain harmful gases into the atmosphere and can also cause earthquakes. Efficient use of geothermal energy also depends on having a heat source close enough to the Earth's surface to exploit, which is only feasible in certain areas of the world.
Humans typically produce biomass energy by converting plant matter into heat or fuel. Your fireplace is a classic example of using biomass, and we also use it to fuel vehicles in the form of ethanol and biodiesel. On a large scale we can burn biomass to produce electricity. Biomass production can make use of otherwise unwanted byproducts like cornstalks, but it also takes away plant resources that would otherwise return nutrients to the soil, and production at any scale requires diverting land away from other uses. Burning biomass also necessarily pumps carbon into the atmosphere, although this is considered less harmful than burning fossil fuels because it's short-term carbon already engaged in the global cycle which would be released when the plant dies and decays anyway, as opposed to burning oil or coal that would otherwise be trapped underground for millions of years.
There are other methods of producing renewable energy that show promise, such as capturing the power of ocean waves and burning hydrogen molecules, but they haven't yet entered into widespread commercial use.
The Future of Renewable Energy
It's important to know the difference between wind and solar energy, but fortunately we don't need to choose one over the other. All types of renewable energy can be used to complement each other, depending on what types of production are available in a given geographic location, and overcome the weaknesses of any one method.
Although the renewable energy industry has experienced great growth in the past decade, coal and natural gas are still generating the lion's share of the electricity for the United States. Even so, experts predict renewable energy will replace fossil fuels by 2050. In the meantime, watch for developments that will help renewables overcome their challenges of storage and capacity.