Solar Energy: Is it Really a Sunny Solution?

Solar energy is a renewable energy source that captures the light and heat from the Sun and converts it into solar power. Solar energy can be categorized as either passive solar or active solar. Active solar techniques use mechanical or electrical devices to convert the sun's heat into another form of usable energy. The most common types of active solar techniques use photovoltaic systems (i.e. solar panels), concentrated solar power (using mirrors or lenses to concentrate sunlight), or solar water heating. Passive solar techniques on the other hand involves orienting and designing a building to the Sun to collect, store, and distribute heat energy from the sunlight without disturbing occupants with moving parts or electronics. These buildings are built with materials that have light dispersing properties, and the buildings themselves naturally circulate air (SEIA).

Courtesy of MDV-SEIA

So how did solar energy come to be? Who can be credited with looking at the Sun and thinking "Gee, let's harness that and transform it into energy!" In 1876 William Grylls Adams and one of his students, Richard Day, found that when selenium was exposed to light, electricity was produced. These selenium cells were definitely not the most efficient things, but they did prove that light can be converted into electricity (Encyclopedia of Earth). 

Courtesy of Solar Systems USA 

Later on, in 1953, Calvin Fuller, Gerald Pearson, and Daryl Chapin improved upon William Grylls Adam's discovery and created the silicon solar cell. These cells produced enough electricity to run small electrical devices. After some work, they managed to push the conversion efficiency from 4% to 11% (NREL). 

Courtesy of NREL

In 1956, the first solar cells are available to the general public, but the cost was far beyond the means of the ordinary citizen. A 1 watt solar cell cost $300! So instead of selling solar cells on their own, they were incorporated in toys and radios and offered to consumers. In the late 1950's and early 1960's solar cells were used to power USA's and Soviet's space programs. After the success of the solar cells used during these explorations, solar power became the standard for space bound satellites. As time passed, scientists were actively researching and experimenting in order to find a way to lower the cost of solar cells. In the early 1970's they discovered a process that lowered the cost from $100 per watt to just $20 per watt. With the significantly lower cost, solar cells began to show up in a whole bunch of places from railroad crossings to houses (Experience). 

With the cost being affordable to the ordinary consumer, solar power became much more popular, especially as people learned about the pros of it. Solar energy is a renewable and inexhaustible energy source. The Sun will be around for another estimated 6.5 billion years. So until then, we have nothing to worry about. Also, the Sun is a very abundant source of energy. The surface of Earth receives 84 terrawatts of power. That's 4 times more power than how much power is consumed worldwide. Not to mention, solar power is also a clean source of energy. The only pollution caused by solar energy takes place during the manufacturing, transportation, and installation of the power systems. Even then, this pollution is negligible to the pollution caused by conventional energy sources. Furthermore, homeowners who use solar power have the option to "sell" excess electricity when they produce more electricity than what they consume. According to One Block Off the Grid, adding solar panels to your home can bring in a monthly savings of more than $100 in many states. In fact, in Hawaii, residents save on average $64,000 after just 20 years. Finally, solar energy technologies are extremely low maintenance, and only require cleaning a couple times a year (Energy Informative). .

But are the effects of using solar power all good?

One of the biggest disadvantages of solar power is the fact that it is an intermittent energy source. Since solar power does depend on the Sun, it is difficult to predict overcast days. Also, sunlight is obviously limited during certain times of the day (morning and night). This makes it difficult to depend solely on solar power, and also restrains the use of it to generally sunny areas. Second, solar power requires a lot of space. A large amount of solar panels or cells are necessary to provide enough electricity and they need to be stored somewhere.

All in all, solar energy is a pretty popular source of energy, with new and improved technologies still being developed. But is solar energy really the best option? Or do its cons outweigh its pros?

Hydropower: Water You Talking About?

In light of the movement to "go green" which stemmed from the general public realizing the severe environmental issues at play, more and more people began to support the use of renewable energy sources in order to significantly reduce greenhouse gas emissions, and other pollution side effects.

One of the more prominent renewable energy sources is hydropower. Hydropower is defined by the International Hydropower Association as, "power that is derived from the energy of falling water or fast water, which may be harnessed for useful purposes." The flow of water is used to turn turbines, which causes magnets inside of a generator to turn and create electricity. From as early as between 202 BCE and 9 CE, humans have taken advantage of the water cycle, and have harnessed the power that water can provide.

The first operational hydroelectric generating station was created in 1882 in Appleton, Wisconsin.

Courtesy of America's Story

This station produced 12.5 kilowatts of power, which is enough electricity to power 250 lights. Within the next 20 years, around 300 new hydroelectric plants were built and operating around the world. And by the early 1900's, around 40% of the United State's electricity was being provided by hydroelectric power. This percentage decreased as time passed, and in 2014, hydropower only generated 6% of the total electricity generated in the United States.

Courtesy of OilPrice

Despite this seemingly low percentage, around 20% of the world's electricity consumption in 2006 was generated by hydropower, making it the most used renewable energy source in the world. So what exactly makes hydropower such a popular source of electricity generation?

First, hydropower is viewed as "green" since it is a clean energy source. The process used to create power using hydropower is not contaminating, so it doesn't produce any toxic or greenhouse gases that pollute the atmosphere. The only contamination that occurs results from the process of building the hydropower plants.

Second, hydropower is known to be reliable and safe. Since the only fuel used is water, there will be constant power thanks to the constant flow of water in rivers and other bodies of water. Not to mention, since water is the only fuel used, there is no biohazard that results if a hydropower plant were to malfunction. 

Third, these hydropower plants generate power cheaply, and require low ongoing costs. An existing hydroelectric plant can create electricity at as low of a cost as $0.0035 for a kilowatt hour. Also, once built, hydroelectric plants require almost no maintenance and minimal replacements. 

However, nothing is perfect, and there are obvious downfalls to the use of hydropower. 

First, hydropower can cause serious environmental damage. The presence of the hydroelectric plants can injure and kill fish and other aquatic organisms. Not to mention, the plants alter the water flow which influence the way that the fish migrate. The water found in the reservoirs used in plants are known to be more stagnant, which means the water will contain more sediment and nutrients which is the perfect enviornment for algae. This can cause an algae bloom, where algae and weeds crowd out other aquatic life. 

Second, the hydropower plants can take a long time to be built and cause many problems during this process. The average construction time for a plant takes from 4 to 7 years, and a larger plant would take around 10 years. Also due to the altered water flow caused by the hydroelectric plant, floods may occur in low-lying areas. In order to prevent casualties as water is released in full force from the dam, oftentimes, many people are forcibly moved and relocated. 

So, what do you think? Are the fallbacks due to hydropower worth it? Or should we stop the constructions of new hydroelectric plants and stop the use of the ones that are already constructed? 

Works Cited

Office of Energy Efficiency and Renewable Energy 

International Hydropower Association

National Geographic