Wind Power: Are You a Big Fan?

Although most of you have heard about wind power, I bet not all of you knew that wind power is technically a form of solar energy! Wind is caused by an uneven heating of the atmosphere by the sun along with irregularities of the earth's surface, and the rotation of the earth. Through the use of wind turbines, this wind energy is "harvested' and used to generate electricity.

Courtesy of Inhabitat

Wind turbines can be thought of as a reverse fan. Instead of using up electricity to make wind, turbines harness the motion energy of the wind and transforms it into electricity. When wind turns the blades of the turbine, the blades spin a shaft, which is connected to a generator that makes electricity. 

Today, there are two types of wind turbines that are used. Horizontal-axis turbines include a blade or rotor, which converts the motion energy of the wind to rotational shaft energy; a drive train that includes a gearbox, which amplifies energy output of the rotor, and generator; a tower that supports the rotor and drive train; and other miscellaneous equipment (e.g. controls, electrical cables, and ground support equipment) (Turbines Info). 

Vertical axis wind turbines are the second type. Vertical axis wind turbines are less efficient than horizontal axis ones, which is why most people have only seen horizontal-axis turbines (pictured above). The most commonly used vertical axis wind turbine is the Darrieus model. In this turbine, two vertically oriented blades revolve around a vertical shaft. Using the same process of airplane wings during lift off, the turbine's blades take advantage of a "lift" force that is created when air is passed through the blades. Instead of flying away though, the blades are attached to a generator shaft, and the air passed by is converted into rotational momentum which turns the generator (Mother Earth News). 

Courtesy of InDepthInfo

Wind energy has been used as early as 5000 BCE to propel boats along the Nile River. Later on in 200 BCE, windmills were being used in China to pump water, and vertical-axis windmills were grinding grain in Persia and the Middle East. 

Courtesy of not-about-books

In America, colonists used windmills to grind wheat and corn, pump water, and cut wood at sawmills. However, after electricity was developed, wind plants that could be connected to electricity grids were invented, creating a new use for wind power. 

During the oil shortages of the 1970's, the use of wind turbines to create electricity seemed to be a very viable option. The government took advantage of this and from 1974-1980 they worked closely with the industry to develop large commercial wind turbines. After this program, 13 experimental turbines were put into operation, and many of the multi-megawatt turbines used today came from these first 13 turbines. 

However, when the oil shortage was over and prices decreased during the 1980s and early 1990s, wind power became viewed as uneconomical. Despite this, wind energy flourished in California due to federal and state tax incentives which were implemented to encourage the use of renewable energy sources. Sadly, the use the wind energy slowed dramatically after these incentives were removed (energy.gov). 

Wind energy, has many advantages that are similar to other renewable energy sources. Wind energy is a clean source since it doesn't require the use of any destructive chemicals. Also, relying on wind energy lessens our needs for fossil fuels from outside nations, helping our national economy. Furthermore, wind energy has seen enormous growth in the last decade, with an increase in wind power capacity of an average of 30% per year. Wind energy accounts for about 2.5% of the total worldwide electricity production. Lastly, wind turbines can be built on existing farms where farmers can reap benefits but not lose a lot of their land. 

Wind energy also creates many disadvantages. First, wind doesn't generally blow reliably, making it difficult to have a consistent source of energy when the weather isn't cooperating. Second, the sharp blades of wind turbines can be a threat to wildlife, specifically birds and other flying creatures. Third, wind turbines make a sound that is between 50 and 60 decibels which although not extremely loud, can become a nuisance. Finally, wind energy can only be harnessed in certain locations where the wind speed is high enough. Most of these areas are in remote areas, which means new infrastructure needs to be built and maintained in order to bring power to residential homes in the city. 

As this blog comes to a close, I hope my posts have opened your eyes to the myriad of renewable energy sources available. Maybe in the future you'll take advantage of some of them to power your house, or vote on legislation regarding the use of these renewable energy sources. 

Biomass: A Not So Trashy Option

Another alternative energy source "underdog" is biomass energy. Despite the lack of general knowledge on biomass energy, it's actually the oldest source of renewable energy, and has been used since the discovery of fire. Biomass energy, also known as bioenergy, is energy from plants and plant-derived materials. The plants and plant-derived materials store solar energy in their chemical bonds through the process of photosynthesis. Wood is the most widely used energy resource used, but other sources such as residues from agriculture, oil-rich algae, and organic components of municipal and industrial wastes can be used as well. In fact, even the methane fumes given off by landfills can be used (NREL).

Courtesy of Eco-Friendly Boilers for Renewable Living

Although it is not as obvious as other energy sources, biomass energy is yet another renewable energy source since the resources used for biomass energy can re-grow in a relatively short period of time in comparison to the hundreds of millions of years it takes for fossil fuels to form.

Before the industrial revolution, biomass, in the form of wood, was used for nearly 91% of all energy consumption. Biomass energy officially got its name around 1975, when the idea really caught on and took off. During this time, imported oil costs were rising and the issues caused by mining coal became public. Biomass was an appealing alternative since it used natural materials that were abundant (Biomass.net). 

In the 1980's the Office of Technology Assessment estimated that more than 25% of the US's energy needs would be fulfilled by biomass energy, but this estimation was never reached, and won't be reached if fossil fuels are still used (Biomass.net). 

Currently, biomass covers about 10% of the world's energy supply. 66% of this 10% is its use in developing countries for cooking and heating. In the United States, there is enough land and agricultural networks to replace half of the nation's gasoline or nuclear energy use. But, the world's population has only taken advantage of about 7% of its annual production of biomass (Biomass Magazine). 

There are many different processes that can be used in order to get power form biomass. The first process is burning. The heat from burning biomass can be harnessed to heat homes or create steam which can then be used to generate electricity. The second process takes advantage of methane gas. When biomass rots it releases methane gas which can be transformed into natural gas. That's right! The stink that trash gives off as it rots can be used for energy! Finally, biofuels utilizes some crops, such as corn and sugar cane, and converts it into the biofuel ethanol (Middlebury). 

Biomass is viewed as a viable option because of the advantages it possesses. First, biomass being used as a fuel reduces the need for fossil fuels for the production of heat, steam, and electricity. The reduction of fossil fuels also reduces the greenhouse gases released into the environment, and also preserves fossil fuels which are nonrenewable. Second, using biomass can reduce dependence on foreign oil since biofuels provide a renewable liquid transportation fuel. Not to mention, biomass energy supports the US agricultural and forest-product industries and increases job opportunities. The crops that will be used for biomass can grow sustainably on land that doesn't support intensive food crops. Therefore, it doesn't affect the current agriculture. Furthermore, the use of waste materials reduces landfill disposal, making space for other things. 

Finally, the biggest advantage of biomass energy is its potential to decrease greenhouse gas emissions. Although burning biomass releases just about the same amount of carbon dioxide as burning fossil fuels does, burning fossil fuels is the equivalent to releasing "new" greenhouse gases. This is because the carbon dioxide released from burning fossil fuels was energy stored through the process of photosynthesis millions of years ago. Conversely, burning biomass releases carbon dioxide that is balanced by the carbon dioxide that was captured during its growth. 

However, like all energy sources, there are also disadvantages. First, the process of creating biomass energy is pretty expensive. The materials used for biomass are living, and therefore are expensive to care for. Second, biomass energy is not as efficient as fossil fuels. In comparison to gasoline, the biodiesel ethanol is highly inefficient. Not to mention, ethanol often needs to be mixed with gasoline to work anyways. Finally, biomass energy requires more fuel to do the same job as conventional fuels, which can cause environmental problems of its own. In order to get enough lumber to power a nation full of vehicles or even a power plant, companies would need to destroy a considerable forest area. With deforestation already being a problem, doing so could cause extreme consequences (Energy Informative). 

Maybe in the future, new and improved technologies will be invented that will solve the issues that arise from using biomass energy, making it an option with more advantages than drawbacks. 

Geothermal Energy is Gaining Steam

If someone were to ask you to list renewable energy sources, I'm sure geothermal energy isn't the first thing you think of. Most people don't know the details of geothermal energy, but its use has been steadily increasing throughout the years. 

Geothermal energy is thermal energy generated and stored in the Earth. This thermal energy originates from the formation of the Earth and the radioactive decay of uranium and potassium in Earth's core. The difference in temperature between the core of the Earth and the surface is known as the geothermal gradient, which is what provides energy in a form of heat from the core to the surface (How Stuff Works).

Courtesy of  How Stuff Works

The core of the Earth is about 4,000 miles beneath the surface and can reach temperatures of up to 7,600 degrees Fahrenheit. At this temperature, rocks melt and the resultant molten rocks are known as magma. Magma's density is less dense than the rocks surrounding it which causes it to rise to the surface. Sometimes, the magma that rises to the surface escapes through cracks, erupting out of volcanoes. But, volcanic eruptions don't happen constantly, since most of the time, the magma stays beneath Earth's surface. This magma heats any surrounding rocks and the water trapped within these rocks. Some of the water escapes through cracks in the surface and forms pools of hot water, or bursts of hot water and steam known as springs and geysers respectively. The rest of the heated water stays in pools under Earth's surface, known as geothermal reservoirs (Union of Concerned Scientists).

Geothermal energy is mainly used in three ways: direct geothermal energy, geothermal heat pumps, and geothermal power plants. Direct geothermal energy is used in areas where hot springs or geothermal reservoirs are located so the hot water can be piped directly in to heat homes or office buildings. The geothermal water is pumped through a heat exchanger, which transfers heat from the water into the building's heating system. This water is then pumped back down into a well and cycled back through to be reheated and used again (The Conversation). 

A geothermal heat pump is located a few feet under the ground, where the soil or water remains a constant 50-60 degrees Fahrenheit year round. This seemingly small amount of heat is used to heat or cool homes and offices as fluid circulates through a series of pipes (called a loop) underground or beneath the water of a pond or lake and into a building. During the summertime, this process is reversed to cool the building. The pipes draw the heat away from the house and carry it to the ground where it is absorbed (Water Furnace). 

Courtesy of Water Furnace

Finally, the last way to use geothermal energy is through a geothermal power plant. Hot water and steam from deep underground is piped up through underground wells and used to generate electricity in the power plant. There are three types of geothermal power plants. Dry steam plants use the hot steam to spin turbines which generate electricity. Flash steam plants use water that's between 300 and 700 degrees Fahrenheit that is brought up from a well. Some of the water turns to steam which turns turbines, and when the steam cools it condenses back into water and is returned to the ground. Lastly, binary cycle plants use moderately hot geothermal water, and passes it through a heat exchanger. Here, heat is transferred into a liquid that boils at a lower temperature than water. When that fluid is heated it turns to steam which spins turbines. 

Courtesy of Union of Concerned Scientists

The first recorded use of geothermal energy occurred more than 10,000 years ago by American Paleo-Indians who utilized the water from hot springs for cooking, bathing, and cleaning. The first geothermal electric power plant which used steam to generate power was invented in 1904 by Italian scientist, Piero Ginori Conti. 

Courtesy of Unione Geotermica Italiana

Improving upon Piero Ginori Conti's design, the first geothermal plant in the USA was started in 1922. It had a low capacity of 250 kilowatts, producing little output and was eventually shutdown due to a technical glitch. Later on, in 1946, a fully functioning geothermal heat pump was installed in Portland, Oregon. In 1973 due to the oil crisis, many countries began looking for a renewable energy source that reduced heating and cooling costs. This increased the popularity of geothermal heat pumps. Today, geothermal power supplies less than 1% of the world's energy, but it is projected to supply 10-20% of the world's energy requirement by 2050 (Conserve Energy). 

Geothermal energy is such an appealing source of energy because it is such a stable and reliable source of energy. The power output of a geothermal power plant can be predicted with extreme accuracy, which means it's good for meeting the base load energy demand, as opposed to less stable sources of energy such as wind and solar. Second, harnessing geothermal energy doesn't involve any fuels, which leads to stable electricity prices and prevention of cost fluctuations. Finally, geothermal energy doesn't take up a lot of land since it can be build partially underground. 

With it's advantages also comes disadvantages. The main problem being certain environmental issues that are associated with geothermal energy. Greenhouse gases below the surface of the earth tend to accumulate near geothermal power plants. Also, geothermal power plants are associated with sulfur dioxide and silica emissions and reservoirs can contain traces of heavy metals including mercury, arsenic and boron (Triple Pundit). 

Geothermal energy in general is regarded as environmentally friendly, sustainable, and reliable, which makes it a no-brainer in some areas, but heavy upfront costs prevent us from realizing the full potential. How much influence geothermal power will have really depends on technological advancements, energy prices, and politics. We'll just have to see what the situation will look like in the next couple decades. 

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