Introduction
With growing concerns and evidence of global warming and the effects of climate change, significant attention has been shifted to alternative energy sources. These renewable sources of energy, the most well-known of which are solar, wind, and hydro energy, have the potential to fulfill society’s energy needs without environmental damage. This report will examine alternative energy sources and discuss their use in the context of sustainability.
Solar Power
Solar power uses sunlight to convert energy into electricity through a variety of means. It is one of the most common types of alternative energy sources due to the availability of sunlight in most places on the planet. The amount of energy from sunlight reaching Earth in a matter of an hour exceeds that of humanity’s energy needs for a whole year, making solar power an attractive alternative. The challenge remains in the process of conversion of sunlight to usable energy, most often electricity.
The two developed methods are using photovoltaics or concentrated solar power. Photovoltaics transfers light into an electric current by exposing a specialized material which creates a chemical photoelectric effect resulting in voltage which is then stored, a method more fitting for small and medium scale applications. Meanwhile, concentrated solar power which utilizes mirrors and lenses to redirect sunlight into a beam to focus on a targeted receiver located in a tower in the middle of the solar panels. Sunlight is then converted into heat and stored as thermal energy to power an engine which generates electricity (Weinstein et al., 2015). Either technology remains inefficient economically at this point unless deployed on a large scale, requiring further research and development.
Wind Power
Wind alternative energy depends on the use of airflow to rotate mechanical wind turbines which stimulate electric generators to produce power. Wind power is one of the oldest alternative energy sources as windmills used to work on a similar principle. The wind turbines are connected to a unified electric network which transfers and stores electricity from the small individual generators in each structure. Wind power is extremely clean, with minimal environmental impact to manufacture, establish, and maintain the turbines. However, the drawbacks of severe noise, as well as the circumstantial presence of wind, makes this a less popular alternative energy source despite being economically viable. With government incentives, industry experts expect wind energy to provide a third of global energy needs by the mid-21st century (Zhao, Wu, Hu, Xu, & Rasmussen, 2015).
Hydropower
Hydropower, also known as hydroelectricity, is the process of converting the flow of water into electricity. Using the natural movement of water in any natural or artificial body of water, as well as the renewability of the water cycle, hydropower seeks to adapt this into electricity. Moving water, generating mechanical energy, spins rotors in a turbine which is connected to an electromagnetic generator. There are two types of hydroelectricity plants, impoundment facilities are built into artificial dams that generate electricity as water is transferred in large volumes from the dam. Run-of-river facilities are rarer, built on natural water flows and diverts that into generators, being subject to variability in water flow depending on season or tide. Currently, hydropower is the most used alternative energy source, contributing nearly 7% to global electricity production (Zarfl, Lumsdon, Berlekamp, Tydecks, & Tockner, 2014).
Renewability and Sustainability
The sources of alternative energy discussed in this report are considered renewable, as they are naturally replenished at a rate which is greater than it is used. Renewable energy sources must have a low environmental impact and be widely available. However, fossil fuels can technically be characterized as such, albeit the renewability of rate of fossil fuel formations is millions of years where solar, wind and hydro energy is currently a continuous and consistently renewing cycle in nature.
In addition to the argument that alternative energy is much cleaner and not directly associated with concerning environmental issues such as climate change, the concept of sustainability becomes relevant. It is sustainability which is driving innovation towards alternative sources as sustainable energy can meet the demands of society without compromising neither the demand needs nor the safety of future generations as is the case with fossil fuels. Sustainability is determined based on three simple pillars of whether energy is naturally replenished, its energy efficiency, and availability in the long term (Kumar et al., 2017). Based on current knowledge and understanding of nature and science, the alternative sources described will exist abundantly on the planet as long as life continues to exist on Earth.
Renewable and sustainable energy are terms used interchangeably while there are significant differences. Renewability implies a replenishment of a resource, which applies to these alternative sources. Meanwhile, the sustainability of energy indicates its ability to be used as an energy source for a defined period of time, something that depends on several factors including available technology, resource type, and supply demands. Renewability and sustainability of energy are not interchangeable since even renewable sources can become unsustainable if used faster than the ability to regenerate, and non-renewable resources can become sustainable if used in moderation (IGS, n.d.). For example, fossil fuels will eventually regenerate if humanity stops using them, but a full transition to hydroelectricity (which uses mostly freshwater) may lead to shortages of these resources. Another context to consider is nuclear energy, which is technically renewable, but unsustainable in the current state of technology due to its persistent dangers and high level of radioactive waste. Therefore, these concepts are critical to consider when examining the adoption and development of alternative energy sources to replace fossil fuels.
References
IGS. (n.d.). Sustainable and renewable energy: What’s the difference? Web.
Kumar, A., Sah, B., Singh, A. R., Deng, Y., He, X., Kumar, P., & Bansal, R. C. (2017). A review of multi criteria decision making (MCDM) towards sustainable renewable energy development. Renewable and Sustainable Energy Reviews, 69, 596–609. Web.
Weinstein, L. A., Loomis, J., Bhatia, B., Bierman, D. M., Wang, E. N., & Chen, G. (2015). Concentrating solar power. Chemical Reviews, 115(23), 12797-12838. Web.
Zarfl, C., Lumsdon, A. E., Berlekamp, J., Tydecks, L., & Tockner, K. (2014). A global boom in hydropower dam construction. Aquatic Sciences, 77(1), 161-170. Web.
Zhao, H., Wu, Q., Hu, S., Xu, H., & Rasmussen, C. N. (2015). Review of energy storage system for wind power integration support. Applied Energy, 137, 545-553. Web.