Solar Energy: What you need to know

          By Bruna Costa

Other than photosynthesis, what is the sun good for? Energy, of course. Yes, and energy we can make intelligent use of. With that in mind, what else do we need to know? 

Solar energy is quickly becoming a popular and sustainable method for powering all our needs. You have probably heard of solar by now. In fact, if you are reading this, you are either curious, considering getting solar energy, or already have it installed in your home, nonprofit, or commercial business. Perhaps you understand the value of deep knowledge and want to know more. It's profitable to make the right choice. Knowledge, after all, is power, and the more you know, the better you are at making informed choices. Yes, and so, let's learn about Solar Energy. 

From a glance, solar is an inexpensive, low-carbon technology that harnesses renewable energy from the sun. It's an easy choice.  After all, the sun is a free, virtually inexhaustible resource that provides the earth’s animals and plants with their energy. If it is natural for animals and plants, why can’t we use the sun too? We can and, very well, maybe we should. With that said, there are still many questions that abound in the intelligent use of Solar Energy. These questions are as follows: How can use solar energy? How much will it cost us? How will it work? How does it differ from other forms of energy? Yes, and what companies are there for our usage? 

 The current main energy resources include coal, oil, natural gas, hydropower, wind, solar, biomass, and geothermal. You probably know which ones are natural and which ones are renewable ( hydro, wind, solar, biomass, and geothermal are natural). On the other hand, petroleum, natural gas, and coal have made up at least 80% of the total U.S energy consumption for more than 100 years. Renewable energy is the fastest-growing energy source in the world right now. We needed something that would replace the finite nature of fossil fuels ( fossil fuels will not be around for forever). The problem is we are still using fossil fuels as the main source of power. Fossil fuel is, at this present moment, still the most popular, fairly effective, and cheapest solution. So, without further adieu, this guide serves to discuss Solar Energy and how we are using it to make changes. 

History of Solar

Believe it or not, solar energy has been around since as early as 7^th century B.C. Humans used glass materials to create fires a long time ago. This was a very primitive model of solar energy. Later, in the late 1700s and 1800s, scientists began using a more advanced version of solar energy to power ovens for baking and to power the energy of steamboats.  In 1839, the important discovery finally emerged, the photovoltaic effect was discovered by Alexandre Edmond Becquerel, who discovered that “shining light on an electrode submerged in a conductive solution would create an electric current.” Still - even that wasn’t enough to start the solar energy movement, as solar was inefficient until over 100 years later when Russell Ohl invented the solar cell…when we move on even further through time,  we discover that Charles Fritts created the world’s first rooftop solar array in 1883. It was actually Albert Einstein who was able to describe the photoelectric effect in 1905. This won him the Nobel prize in physics.

What exactly is Solar Power?

Solar Power is the transfer of energy from sunlight into electricity and heat. Yes, but how is it converted exactly? This is done either directly using photovoltaics or indirectly using concentrated solar power. How does this mainstream technology work in more detail? 

Photovoltaics(PV)

Photovoltaics (PV) is the name for the phenomenon of converting sunlight into electricity. This conversion is done with the use of semiconducting materials ( usually silicon). Semi-conducting materials come in the form of the solar panels you see on rooftops or in ground-mounted solar farms. If you are driving by the country, you have probably seen them before. They are typically blue, indistinguishable, and come in the shape of a rectangle. This process or phenomenon is completed successfully using the semiconducting materials that conduct and make use of the photovoltaic effect. The photovoltaic unit consists of a module that is a packaged array of solar cells. These are also known as photovoltaic cells. Solar panels work by letting photons (particles of light) knock electrons free from atoms, which generates a strong flow of electricity.

So how does it work in more detail? Each photovoltaic cell is made up of 2 slices of semi-conducting material, usually silicon, which is the same material that is used in microelectronics. This is not to be confused with silicone (a synthetic compound found in rubber, adhesives, lubricants, and other insulations). In the simplest terms, a photovoltaic cell is basically a sandwich made up of 2 slices of semi-conducting material. The material is silicon ( most usually). Photovoltaic cells work by creating an electric field. An electric field is like a magnetic field only slightly different. An electric field occurs when opposite charges are separated creating the electricity that we harness.  In order to enhance the process, sometimes “doping” occurs in which they seed phosphorous into the silicon which adds extra electrons. Again, an electric field will occur between the silicon layers. That is why semi-conducting materials are needed (for the photoelectric effect to occur).

What is Concentrated Solar Power?

Concentrated solar power in contrast to photovoltaics uses mirrors or lenses to concentrate a large area of sunlight onto a small area ( typically a receiver). While photovoltaics uses modules and is direct.  For this specific process to work, the focus is on concentrating a large area of sunlight into a small area (as the name says). The electricity is generated when the light is converted into heat (or solar thermal energy). This will drive the heat engine (which is usually a steam turbine) that powers the plant. This energy is used as a heat source for conventional power plants. CSP usually consists of two parts, one that collects solar energy and converts it into heat energy and another that will convert it into electricity. CSP works by using 3 unique technology methods. The three methods are the Trough systems, the Power Tower systems, and the Dish Engine systems.

Trough Systems:  Trough systems work by using large, U-shaped reflectors (otherwise known as focusing mirrors) that tilt toward the sun.  There are oil-filled pipes running around or within the trough that are heated to scalding hot degrees and up to 750 degrees Fahrenheit. The hot oil will be used then to make the steam turbines and generators work.

Power Tower Systems

In this CSP technology, heliostats, or large mirrors ( often several of them) are used to track the sun’s rays. These mirrors are a tracking system which will focus a concentrated amount of sunlight onto a tower receiver. Just like in the trough system, the concentrated sunlight will heat a working fluid in order to make steam for an electricity generator. It may also be stored for later usage.

Dish Engine Systems

In this system, large mirrored dishes or parabolic mirrors (ones that are about 10x larger than your backyard satellite dish) are used to focus and concentrate the sunlight onto the receiver. This method usually produces less power than the other two methods. The beam of light is reflected from the solar collector and onto the receiver as in the other methods which is transferred to the engine or generator.

Unfortunately, most concentrated solar energy power cannot compete economically with photovoltaics as photovoltaics is a more economically valid form of solar energy. These are the common forms you see on homes and in mounted forms. They can also be very impressive when you stumble upon an entire solar farm with them.

Economics

The sun as we know it is an inexhaustible resource. That makes it, in the truest form of the definition, an economically valid option. So why are fossil fuels still the most popular resource?  Right now, solar is in the process of becoming a cheaper alternative although it is not able to compete without incentives. Germany is currently the world’s largest producer of solar providing 7% of the annual electricity consumption. The sun will be around for another 6.5 billion years according to NASA. The sun never stops, and quite like the energizer bunny the Sun keeps going and going….

The sun gives off an incredible amount of energy. The United Nations Development program once found that the annual potential energy of the sun was 1, 575 – 49, 837 exajoules (EJ). This is several times larger than the total world energy consumption, which was about 559.8EJ in 2012. The sun obviously gives us more then what we need and with such power.  For this reason, solar is quickly becoming an economically valid option for the world at large. It only seemed logical that this would happen with time.  “Use of solar energy is near a solution” was the headline in the New York Times on 4 April 1931. Now, nearly 90 years later, it is already a great solution for us, and since the beginning of 2014, the price of solar has dropped nearly 50%. That means the price will continue to lower and is already becoming more affordable with maturing markets. Moreover, job growth in the solar market is increasing significantly and well over 100% as well. 

People who are interested in solar energy care about the environment, and are forward-thinking. They care about money just as much as they care about solving problems. Solar is more expensive than the current energy we use but this difference does eventually reach a break-even point. While we are working on making it a cheaper alternative, it is not yet able to compete without incentives. The biggest incentive is the tax break which is still in place. Solar is also an import independent resource and installing solar panels will provide for long term subsidy benefits. The long-term validity of solar makes it worth our time as solar panels are durable and have low maintenance. Your property value also goes up with the addition of solar (what a great bonus). What’s more, people now understand humanity’s need to switch to a low-carbon technology – a technology with less pollution and less toxic, and otherwise harmful effects on our world. We need to consider renewable energy as a valid means of productively helping our planet and to help keep the world a beautiful place to live in.

How to install solar panels and get solar!

As with anything in life there are steps to completing an assignment, task, or goal. These steps may be complicated.

Whether through a loan, cash, or other monetary forms of payment, the first thing you do is sign a solar contract. You will also be applying for state and federal solar incentives such as federal ITC, local solar programs, and clean energy financing initiatives like PACE.  At this point, an engineer will come to see if your house is suitable for the installation of solar panels. Your roof must be of a sound structure as the solar panels will be installed onto your roof. The panels are connected and installed onto racks which are placed onto the roofs by an installer.

So, what does the Earth Have to do with it?

Intelligently making use of energy that is sustainable and clean is important if we want to live in a better world. Humanity has already declared that it is ready to push forward in its attempt to transfer to a low-carbon technology. It is sad that we have been destroying life on earth for so long, but we are working towards progress. The good news is that resurrection does occur, and nature bounces back quickly if given a chance. Of course, it does take time and we must keep moving forward.

Global warming, as you have already heard of, occurs when greenhouse gas emissions are high. Carbon dioxide concentration is now higher than it has been for millions of years. Even without knowledge of what it is, you see pollution spewing from cars and buildings, and getting into our atmosphere. Sunlight is an important clean resource which may reduce pollution and improve our sustainability factor. The union of concerned scientists states that in as little as 18 days of solar irradiation, the sun will be able to deliver as much energy as all the natural gas reserves put together.  Why wouldn’t we consider solar energy is the better question? If it is expensive for you, keep it in your mind that things are changing and solar is growing fast. You will be able to break even after a few years and save money while reducing carbon emissions.

Now, to go another step- that is, to not just consider renewable energy, but obtain renewable energy in the first place is more than just what sounds good, it is what we know to be good. Energy is, of course, not always clean.  Oil, coal, and natural gas are non-renewable energy sources (otherwise known as fossil fuels) that have been a huge source of energy for thousands of years. In fact, as of 2017, the world’s primary energy sources consisted of petroleum (34%) and coal (28%). Natural gas consisted of (23%). The total amounted to about 85% in total. For the past twenty years, the use of fossil fuels has caused at least 75% of the world’s total greenhouse emissions.

If you are looking to help the environment and power your home, you are probably looking into Solar Power as your source of energy.  Solar Energy is an inexhaustible, virtually pollution-free fuel source. It is a renewable source of electricity that is derived from the sun (Barlas, 2019). The large magnitude of the sun’s energy makes it a highly desirable electricity source. In its 2000 World Energy Assessment, the United Nations Development Program found that the annual potential energy of the sun was 1, 575 – 49, 837 exajoules (EJ). This is several times larger than the total world energy consumption, which was about 559.8EJ in 2012. You can with confidence use the sun's energy. 

More than photosynthesis for plants, the sun is an obvious source of energy for humans too. For this reason, many think about making use of solar energy to power their homes.  In 2011, the International Energy Agency said that "the development of affordable, inexhaustible and clean solar energy technologies will have huge longer-term benefits. It will increase countries’ energy security through reliance on an indigenous, inexhaustible and mostly import-independent resource. It will also enhance sustainability, reduce pollution, lower the costs of mitigating global warming, and keep the fossil fuel prices lower than otherwise. These advantages are global. 

In conclusion, why solar?

Sustainable energy is the practice of using energy in a way that “meets the needs of the present without compromising the needs of future generations to meet their own.” Renewable energy sources are known as solar energy, wind energy, geothermal energy and tidal energy (Kutscher, Milford & Kreith, 2018).

Sustainable energy sources can be used to generate electricity to heat and cool buildings, and to power transportation systems and machines. As the cost of renewable energy sources decreases, more and more people begin to turn to renewable energy sources. Furthermore, effective government policies support investor confidence that these markets will continue to expand. Renewable energy is breaking into the mainstream of energy markets. Sustainability science emerged in the 21^st century as a new academic discipline (Kates, R, 2001). What this means is that renewable energy is likely to push forward and continue to yield progress. It is something of imminent importance and something to at least consider.

So, should you install solar and is it worth it for you? These are questions for you to decide.and consider.