Renewable Energy

A sustainable way of living.

Renewable Energy is energy that is continually and rapidly collected and replenished from natural resources. These natural resources include solar, wind, hydroelectric, and geothermal resources. These resources can be renewed and reused. There is no shortage of energy when it comes to the use of renewable energy.

One source of renewable energy is biofuels. Biofuels are renewable fuels derived from a biological source, such as trees, grasses, animal waste, and crops, that can replace fuels that are derived from crude oil. Wood is the most common biofuel. Biofuels produce a lower net amount of CO₂ into the atmosphere. These levels of CO₂ can be managed by the planet. Plants absorb CO₂ in growth, therefore, low levels of CO₂ are healthy for the environment. The overproduction of CO₂ by fossil fuels and other nonrenewable energy sources is unhealthy, as it cannot be naturally managed by the ecosystem.

Sustainable Energy

Solar Power

Solar power is the most available resource. Though sunlight is the most available resource, less than 1% of the electric power is generated from sunlight. The sun releases two types of energy that can be used for electricity. The sun’s heat produces longer wavelengths but low energy, while the sun’s light produces shorter wavelengths and high energy.

Concentrating solar power (CPS) uses the sun’s heat to generate electricity. Mirrors and other reflective objects are used to concentrate light energy into a receiver. The heat from the concentrated light is used to power a steam turbine and generate electricity. These are used on a large scale. CPS plants require large areas for solar collection for commercial use. Another collection method is a device referred to as a photovoltaic (PV) cell. A PV cell, or solar cell, is a device that converts light energy into electric energy directly. A solar cell (also referred to as a solar panel) allows for light to be passed, absorbed, or reflected on its surface. Sun rays do not hit one singular site all day nor every day. Since sun rays are not consistent, the collection of solar power requires a large enough space for the capture of sunrays. Solar panels offer this amount of space. Solar panels are quite inefficient. They are unavailable to absorb efficiently over the entire solar spectrum. Energy wavelengths that do not absorb due to the target band are released or reflected. If more energy is needed, PV cells can be combined into modules or arrays to make up large structured solar panels.

Solar energy is more expensive than fossil fuels. Though it is more expensive, it is sustainable.

Wind Power

Wind energy is collected by wind turbines or windmills. A wind turbine consists of a tower and blades that must be elevated enough to be exposed to sufficient wind speeds to produce electricity. When wind enters the wind turbine’s shaft, it turns a generator to produce electricity. This source of energy has grown throughout the past decade. Large amounts of wind turbines create wind farms. Wind farms generate energy that can be used to power many homes and structures as they generate megawatts (MW) of electricity a day. With hundreds of megawatts of energy produced a year, wind farms have quickly become one of the most cleanest and readily available renewable resources. Wind farms must consider the wind speed, the fraction of time that sufficient wind exists, land rights, and the invasion of private land. Though wind turbines can be turned off or on according to the wind speed to optimize the production of electricity, these small details can affect the cost, efficiency, and environmental impact.

Wind turbines do pose a threat to the environment in some way. Wind turbines pose a threat to wildlife. Though they are fuel-efficient, cost-effective, clean, and readily available sources, wind turbines are known to inhibit the quality and length of life of birds, bats, and other flying animals. These turbines also take resources and money to build. The cost and resources that are used are seen as large economical investments and cannot always be implemented due to these factors.

Hydropower

Water energy is collected through a water wheel or hydroelectric dams. When water flows over a wheel, the momentum of water movement aids in the production of electricity. Both small and large hydroelectric dams harness this movement of water. When water falls across the wheels or dams turbine blades, the potential energy of water is trapped in a reservoir and is converted into kinetic energy. This collection of kinetic energy is put through a generator and turned into electricity (Figure 1.1).

Potential energy is the energy of a particle or system of particles has from its relative position, composition, or condition. Kinetic energy is the energy an object posses because of its motion. Water at the top of a waterfall or dam has potential energy because of its position; when it flows downward through generators, it has kinetic energy that can be used to do work and produce electricity in a hydroelectric plant.

Hydropower is renewable as it is generated by the water cycle which is driven by the sun. This way of energy collection poses little threat to the environment and ecosystems the energy plant surrounds. It is an affordable, easily maintained way of energy collection.

Figure 1.1 (a) Water at a higher elevation, for example, at the top of Victoria Falls, has a higher potential energy than water at a lower elevation. As the water falls, some of its potential energy is converted into kinetic energy. (b) If the water flows through generators at the bottom of a dam, such as the Hoover Dam shown here, its kinetic energy is converted into electrical energy. (credit a: modification of work by Steve Jurvetson; credit b: modification of work by “curimedia”/Wikimedia commons)

Geothermal Energy

Geothermal energy is the heat given off from the core of the Earth. “Earth-heat” or geothermal energy relies on frilling into underground reservoirs containing hot water and steam and drawing the heat to Earth’s surface. Geothermal energy is renewable due to the constant production of heat in the Earth’s core. This heated water or condensed steam drives generators to produce electricity, similar to water energy production. Heat given from geothermal energy can also flow straight into homes, providing a direct heating and energy source. The energy source has not reached its full potential, as it has not been used or explored as much as the other sources of energy,

This way of energy collection poses little threat to the environment but may cause large disturbances. Due to the method of collection, the collection of geothermal energy may cause earthquakes. The process of drilling disturbs sentiment that has not been touched for years, altering Earth’s structure. Geothermal energy is also hard to maintain, as fluid needs to be pumped into the reservoirs before the geothermal energy is depleted and locations must be specific to exploit the source. Geothermal energy has a large potential, as it cannot be used up. It is a stable source of electricity that is reliable. Geothermal collections leave little-to-no carbon footprint in comparison to fossil fuels. Pollution is still present but its carbon footprint is retained to a minimum.

Sustainability

The use of renewable sources falls within the limits of available natural, social, and physical resources that allow ecosystems to thrive now and in the future. Each of these resources talked about above relies on resources that are easily replenishable or do not need replenishing because they are produced naturally.

Solar power is energy that is generated from sunlight. Since sunlight is constantly obtainable, this resource is classified as a sustainable resource. Though it can be costly, it is sustainable. Wind power is best collected on off-shore wind farms where wind strength is hard and uniform. This source is sustainable as wind is naturally occurring and the production of energy produces little carbon footprint. Though wind turbines affect some wildlife, wind energy can be used in a sustainable future. Hydropower is a flexible, clean, and affordable way of energy production. Since water is renewable and is readily produced in the atmosphere, hydropower provides reliable and safe energy production without environmental harm or damage. This way of energy use also provides flood control, irrigation support, and clean drinking water. This source is sustainable with multiple uses. Geothermal energy is always available to be collected but must be maintained by the replacement of geothermal water and steam with fluid. This energy source provides a lot of potential for future use as it does not need to be replenished. The heat from the Earth’s core is constantly obtainable making this source a sustainable resource in energy production.

It is important to look at sustainability as we continue into the future. Without sustainable resources, the environment will diverge into an unsustainable way of life. As climate change is a large and developing issue, it is important to look for a possible change in our current carbon footprint. The quicker we change and improve the way we use energy, the more promising future we create.