Renewable Energy, Renewed Earth?

Following on from the last post, this post will focus on the benefits and costs of utilising renewable energy. The science behind renewables and the viability of them are considered.

It is of vital importance to determine the viability of utilising renewable forms of energy to divest away from fossil fuel efficiently and the consequential greenhouse gas effect on the planet. Greenhouse gasses released by fossil fuel emissions absorb infrared radiation from the earth and re-emit radiation in all directions, including towards the earth (Figure 1). Leading to a warming of the planet infamously known as the ‘greenhouse gas effect’ (Marquis and Tans 2011).

Figure 1. Greenhouse Gas Effect on the Planet (Source: https://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-1-3-figure-1.html     

As a finite source, it is inevitable that supply of fossil fuels will run out. Currently, proven reserves for coal, oil and gas are 576.8 thousand Mtoe, 223 billion tonnes and 180 trillion cubic metres respectively. To restrain warming to 2°C, of CO₂ emissions must be confined to 1,100 gigatonnes (from 2011 and 2050) – ‘to have at least a 50% chance’ to attain the 2°C target (McGlade and Ekins 2015). However, of the current reserve, estimated emissions would transgress the 1,100 gigatonnes limit by three times. An unfeasible scenario is then created: utilising all known reserves and attaining the 2°C target, neither one can happen in the presence of the other.

We reach an impasse.

Renewable energy is one part of the solution to dissolve this impasse.

There are various forms of renewable energies: solar, wind, marine and geothermal are the widely known forms. By highlighting these examples, I aim to emphasise the effect renewable energy will have as a collective on climate change. Table 1 outlines the way these energies work in brief.

Table 1. Renewable Energy Forms

Renewable Energy:	The Science:
Solar	Photovoltaic and concentrating solar power (CSP) are the widely known forms of utilising solar radiation. Energy is created through the absorption of solar radiation (Ginley et al 2011).
Wind	Wind energy is converted to electricity through Wind Turbines, these large convertors are found onshore and offshore. The turbines initially harness mechanical energy through force of lift – of which the generator converts into electricity. (Manwell et al 2009)
Marine	Energy harnessed from wave and tidal action. One example is The LIMPET, one of the first wave energy convertors, rated at 500kW which drives a central turbine to generate electricity. The LIMPET is the first to be connected to the main network. (Mueller and Wallace 2008)
Geothermal Energy	Geothermal energy is derived from the decay of uranium, thorium and potassium. Current worldwide geothermal energy utilisation is present in 80 countries (Ingvar 2001). Geothermal energy is available through the presence of molten rock intrusion bringing up a significant amount of heat, as well as ascent of groundwater that has been heated as well as the heating of shallow rock by radioactive decay (World Energy Council 2013).

Viability of Utilising Renewables

There are various costs attached to implementing renewable energies. Considering Marine renewable energies, there are costs stemming from uncertainty in predictability of interaction that wave and tidal climate will have on the devices implemented to harness energy. Whether these devices can be installed cost-effectively with the least environmental costs and how operations will be controlled thereafter to ensure the system ‘survives’ reliably and whether they are affordable (Mueller and Wallace 2008). Often these barriers exude a negative narrative, preventing implementation. These barriers are relevant to all forms of renewable energies.

Solar energy requires a significant technological breakthrough in order for it to be commercially viable and thus a significant component in producing energy on a scale that renders fossil fuel energy inadequate (Guillemoles 2011).

Onshore wind energy has been harnessed by some countries to a great success, generating more than 10% of the energy in the regions of Sweden, Denmark and Germany (Henederson et al 2003). With urban areas so well built it is almost impossible to initiate wind turbine generation and is unfeasible, the dependence on the countryside for wind farms is thus created. But wind farms in pretty areas cause chaos. The presence of large wind turbines has led to outrage for some communities: leading to the rise of NIMBYISM (Not in My Back Yard –ism).  Offshore wind energy is then relied upon, but this has a few barriers to entrance itself, there is a need for a much greater machine and thus generators. This itself relies on the expansion of the market.

Energy Utilisation of Geothermal activity is limited to where there is a carrier, primarily this is water – either in a liquid or vapour form. This limits the potential to harness this energy. But the potential for Geothermal energy has been utilised sufficiently in many cases. (World Energy Council 2013). The most prominent is Iceland. Renewable energies provide for 85% of Iceland’s primary energy, of which geothermal supplies 66%. This is a vast amount, of course the potential of utilising such energy is based on geographic location for such geothermal activity. Yet where it is present, there is a vast potential for it to be a viable source of renewable energy (National Energy Authority n.d.)

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The post has outlined the environmental benefits of harnessing renewable sources. The question of whether they are viable? I believe they are, technologically we have been able to create new ways to utilise natural energy.  There are several barriers in the way of renewable sources of energy, namely the over-reliance of fossil fuels. I also believe that the climate change arena is dominated in an economic perspective predominantly concerned with peak supply. Subsequently, the idea that we shouldn’t be utilising the reserves we have as it causes more harm, is being marginalised.