SolarSolar energy is renewable because the sun never stops shining. Humans do not have to create any input in order to receive energy from the sun. The sun is available anywhere on earth, but only if the infrastructure is available to capture it. The earth receives enough energy from the sun in a single day to meet the energy needs of the entire world for one year (Switch Energy Project, 2012). Most solar panels are only able to turn about 15% of the suns energy into usable electricity year (Switch Energy Project, 2012). The cost of solar panels, which would be needed for the infrastructure, is one prohibiting factor for generating more energy using the sun as a source. It would be possible to use it as a base-load source, but it would take a considerable amount of space to build an array of solar panels large enough to supply those needs. Therefore, the cost of doing such would probably not be feasible. In addition, the output of solar system is not steady, declining on cloudy days and at night year (Switch Energy Project, 2012). This would be a problem in a base-load energy source. Solar energy is the cleanest energy source available, at zero omissions with the exception of steam from steam powered generating plants (Penn State College of Agricultural Sciences, 2016).
Geothermal energy is renewable because the earth continually produces heat which can be used to generate energy. Geothermal reservoirs are replenished naturally and it is not possible to exhaust these resources (Maehlum, 2013). There is massive potential for generating 2 TW of energy on a global scale. Yet, it is suitable for single household use (Maehlum, 2013). The infrastructure is partially underground and has a small footprint, but can be scaled up to large-scale power plants (Maehlum, 2013). There is an initial cost that may be prohibitive in the ability to make geothermal mainstream. There is enough energy available to have the potential for serving as a baseload source, but only if the infrastructure can be built to do so (Maehlum, 2013). Compared to coal, geothermal energy produces 1/8 of the carbon emissions at an equivalent of 122 kg CO2 per megawatt hour of electricity (Maehlum, 2013).
Biomass energy is renewable because living organisms continually generate organic waste. They do this through excretions and through decomposition when they die. It is used to feed boilers where it is burned to generate steam to turn turbines that generate electricity. It is widely available in abundant supply on a local level. Scaling it to a global level would involve many local level generators linked together. It could be supplied on a global basis in a similar manner to the current grid system (Siegel, 2012). Biomass is relatively low cost compared to other renewable energy sources. It is lower carbon than fossil fuels, but it is not easily scalable as a base load source (Siegel, 2012). It requires large amounts of land and a considerable amount of water to grow. Some sources of fuel are not available all year around (Siegel, 2012). Even though it is lower carbon than fossil fuels, it omits some methane during production, and has been a source of respiratory issues in people surrounding local plants (Siegel, 2012).
- Maehlum, M. (2013). Geothermal Energy Pros and Cons. Energy Informative. Retrieved from
- Penn State College of Agricultural Sciences (2016). Solar Energy. Retrieved from http://extension.psu.edu/natural-resources/energy/solar-energy/
- Siegel, R. (2012). Biomass Energy: Pros and Cons. Triple Pundit. Retrieved from
- Switch Energy Project. (2012). “Renewables – Solar.” Video. Retrieved from http://www.switchenergyproject.com/education/energy-lab#solar