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Ecology

Green Energy to Combat Climate Change

We have been burning oil and coal for more than a hundred years, but we now know just how much this damages the global environment. New ways of meeting our energy needs are being developed and new technologies to revolutionize the ways we generate the energy we use are being introduced. Here, we take a look at some of these technologies and their potential.

By: Redacción Panorama de las Américas
Photos: Javier Pinzón

The year 2015 broke temperature records, but this is not an isolated occurrence: each successive year of the 21st century has surpassed the previous one as the hottest on record. From 1850 ―when global temperatures were first measured― to 1980 the mean global temperature was always below 57.2 °F. Between 1980 and 2000, the temperature rose from 57.11 °F to 57.42 °F and from 2000 to 2010 it increased from 57.67 °F to 58.05 °F. The causes of this warming trend are disputed, but most of the international scientific community agrees that it is the result of human use of non-renewable energy sources.

In the United States, 79.1% of oil produced is used to produce gasoline, of which 28.4% is earmarked for generating energy. Burning gasoline produces, among other by    products, nitrogen, water, and carbon dioxide. Carbon dioxide is a greenhouse gas that traps sunlight in the atmosphere, raising the planet’s temperature. To make the situation worse, as we flood the planet’s atmosphere with carbon dioxide, we are also razing the forests that absorb this gas. And we are reaching the limits of the Earth’s tolerance: if the global temperature rises another 3.6 °F, 80% of the world’s corals will die; a 5.4 °F rise will result in four billion people facing water shortages; and an increase of 7.2 °F will leave three hundred million people at the mercy of coastal flooding.

The U.S. Energy Information Administration (EIA) collects data on worldwide energy production. In 2012, 31.4% of the energy was produced from oil, 29% from coal, and 21.3% from natural gas. Biocombustibles constituted 10%, nuclear energy 4.8%, and hydroelectric energy 2.4%. Wind and solar energy, among other types of renewable energy ―listed under the category “other” ―, contributed 1.1%. The percentage is tiny, but that does not mean that the impact of renewable energy is equally small. To put this in perspective, we can compare these numbers with those from 1973. At that time, 46.1% of energy production came from oil, followed by 24.6% from coal, and 16% from natural gas. Only 10.5% came from biocombustibles, while hydroelectric energy came in at 1.8%, with nuclear energy at 0.9%. Renewable energy sources (including hydroelectric energy) constituted barely 1.81%. Since then, the percentage of energy produced from oil has dropped by 15%, while that produced by hydroelectric energy and other renewable forms has reached 3.5%.

We must change the global energy matrix, since the problem with generating energy from fossil fuels is not so much that resources are limited, but that it damages the environment. Technologies for generating non-polluting energy are a better option. There are several types of renewable energy, including wind and hydroelectric.

Wind Energy

Wind energy uses the movement of air to drive enormous turbines installed on towers in places where the wind blows at a sufficient, but not excessive, speed. Wind farms are one of the cleanest ways to generate energy: each tower occupies only a small space and works even when the wind is relatively calm. Too much wind can cause problems, weakening and even destroying the towers. The ensemble of turbines on a farm can constitute a matrix that stores the energy produced and later transfers it to a larger matrix for public consumption, but many of these farms transfer the energy immediately after producing it.

Given that winds fluctuate, we cannot rely solely on this technology for mass energy production. There will always be a need for alternative forms as back-ups to wind farms. Nonetheless, depending on the available space, the number of turbines (and the energy generated), this source could supply energy to meet the demands of large populations. For example: the construction of the Gansu Wind Farm ―the largest in the world― in China began in 2009; more than 3,500 turbines were installed in the first phase. When construction is finished, the farm will have a capacity of 20,000 megawatts.

Latin America is also picking up on this trend. In Panama, for example, the Penonomé Wind Farm built twenty-three turbines during its first phase. After the second and third phases, the farm will boast an additional eighty-six turbines and have the potential to generate 270 megawatts of wind energy every four months, which represents 6% or 7% of energy consumption in Panama. Jamilette Guerrero, general manager of the Panamanian Wind Union (UEP in Spanish), a group representing the sector, explains that the energy generated is provided to the National Interconnected Grid to be distributed throughout the country. In 2015, “the Wind Farm had an installed capacity of 55 megawatts in the first phase and 57.5 megawatts in the second and third phases. This year, twenty-three wind generators, corresponding to the Wind Farm’s second and third phases, were connected to the National Interconnected Grid, generating nearly 4% of the total energy consumed on the national electric grid.”

Solar Energy

This type of energy transforms solar rays into conventional electricity. Its growing use could meet our demand for energy. There are three kinds of solar panel technology: photovoltaic, concentrated radiation, and thermal. Photovoltaic is the most common: when sunlight hits the surface of solar panels, the radiation is converted into direct electrical current. These panels have been in use for more than five decades but they were not mass produced until the year 2000. Concentrated solar energy is obtained by installing mirrors or reflective panels that concentrate sunlight on a fixed point, which produces heat, and which in turn produces energy by means of a thermal motor (a steam turbine, for example). Lastly, thermal panels heat and cool water and spaces.

Considering that 72% of the energy used in homes in the United States in 2010 was destined for these uses (www.seia.org), solar panels have enormous potential. More significantly, this technology offers any group of people under the same roof the chance to produce energy, reduce their carbon footprint, and save money.

Innovation has brought the prices of panels down, while the quality has improved, making home use far more feasible. According to Juan Carlos Navarro Barb of Enesolar (a solar energy firm in Panama), there is enormous potential here: “Solar energy use is growing. The quality of the materials used in production is steadily increasing and they are easier to acquire. In Panama, personal use of solar panels was legalized in 2013, and the financial support provided to thousands of families is key.”

Although solar energy projects have generally been quite successful, ensuring that a substantial percentage of energy is generated by the sun requires an astronomical initial investment. Investing in solar energy on a smaller scale (home) is similar to investing on a larger scale (a country). While the initial expense is significant, the money and resources saved in the future make it an attractive investment. Most developed countries have for years been investing in solar energy as an alternative to traditional sources. In the United States, Nevada Solar One (installation of concentrated solar energy) produces 136 gigawatts of energy a year. The installation consists of 182,000 panels that reflect direct sunlight toward 18,240 tubes filled with heat-transfer liquid; the tubes then produce steam that turns a turbine.

Hydroelectric Energy

Hydroelectric energy is a modern adaptation of centuries-old mills, where water power turned the millstones. The design of the dam increases the pressure of the water flow, which turns a turbine placed horizontally under the dam. The turbine’s kinetic energy is transferred to a generator, which transforms it into electrical energy. Dams block one side of a river, increasing the volume by reducing the space where the water runs; they can even completely block off a river. Reducing the space creates the pressure that moves the turbine, making energy generation more efficient.

The problem with traditional dams is that the increased volume of water on the dammed side of the river results in flooding and permanently changes the course of the river, altering riverine ecosystems. In addition, if the dammed river contains species of fish that swim from the river to the sea or vice versa, their route is permanently blocked. An even more awful consequence is that animals can be mutilated by the turbine as they try to bypass the dam.

Innovations that Optimize Green Energy

Environmental problems like those associated with hydroelectric energy have encouraged new designs, such as diversionary dams, which are built in river channels. As Guillermo de Roux of ENESA explains: “The water diverted from its original course passes through a hydroelectric plant and returns to the river further along.” The diverted water passes through a series of filters to prevent fish, sediment, and other objects from reaching the hydroelectric plants and causing damage. This also prevents the death of fish and the flooding of the area above the dam. To solve one problem of traditional hydroelectric dams, in 2013 the U.S. company WHOOSHH Innovations installed the first “salmon cannon,” that safely “shoots” salmon —whisking them through pneumatic tubes—  to the other side of the dam.

Technological innovations are not limited to the hydroelectric sector. For example, the Altaeros company has created a wind turbine that modifies the traditional blades, incorporating them into a structure resembling a long dirigible that “floats” to detect the best orientation for capturing wind currents; the buoyant turbine anchors itself if the wind is too strong. The self-regulating turbine’s altitude and freedom of movement makes this a more efficient design. Another company, Vortex Bladeless, designed wind towers with no turbines. Instead of blades, the giant reed-like structures take advantage of the oscillation caused by wind vortices to make the structure vibrate and generate energy. In the solar energy field, the company Ubiquitous Energy has created transparent, glass-like solar panels that can replace windows in buildings.

Technology constantly brings us new inventions, and it is more important than ever for us to understand that how we manage natural resources and produce energy will determine the very future of humanity.