Author: Jerdayne Hayles
The worldwide changes in climate and the environment have become a key focal point for society as of recently, with small scale movements initiated to combat these disturbances. Fast-tracked global warming, in particular, makes it increasingly difficult for regions to adapt and mitigate effectively. The burning of fossil fuels largely contributes to global warming through excessive concentrations of greenhouse gases (GHGs) such as carbon dioxide being released in the atmosphere at a rate higher than natural carbon sequestration. However, we are tremendously dependent on fossil fuels for life on Earth; and it is imperative that we find alternatives to offset further environmental degradation. A more sustainable and eco-friendly energy alternative is geothermal energy.
What is Geothermal Energy?
Geothermal Energy, a renewable resource, essentially is the heat that is generated from the sub-surface of the Earth, found beneath the crust in materials such as rocks (low enthalpy) volcanoes and geysers (high enthalpy). Geothermal energy can be harvested for human consumption through no direct conversion or using geothermal power plants to generate electricity using hydrothermal resources. To harness geothermal energy as a means of electricity generation, wells (around a mile or two in depth) must be dug into underground reservoirs to access extremely hot steam or water, which is then used to propel turbines connected to electricity generators.
Presently, there are three basic types of geothermal power plants:
1. Dry Steam: The earliest form of geothermal engineering, uses steam directly from the ground to drive generator turbines.
2. Flash Steam plants: The most operated geothermal plants, utilizes high-pressure hot water from the Earth which is converted into steam that propels the generator turbines. When the steam cools, condensation occurs and the water formed is channeled back underground to be reused.
3. Binary Plants: Here, heat is transferred from geothermal hot water into another liquid which has a lower boiling point, the reaction from the heat and the liquid generates steam which drives the turbine generator.
Geothermal energy is perceived as one of the most rewarding sources of energy, presently outperforming several traditional energy sources.
Advantages of Geothermal Energy
- With geothermal energy being directly harnessed from the Earth’s subsurface, power plants practically produce roughly one-sixth of carbon emissions and little if any nitrous oxide or sulfur-bearing gases than that of fossil fuel energy plants. This makes it a sustainable environmentally friendly generator of electricity. Furthermore, binary geothermal plants essentially produce zero emissions. To add, a whopping 70 to 80 percent of consumption savings should occur from the transition of traditional energy sources to geothermal energy.
- In comparison to other sources of renewable energy such as solar or wind, geothermal energy is a constant and reliable source, available year long. Geothermal power plants can efficiently provide enough electricity to meet demand and be responsive to changes to demand with adjustments.
- Geothermal energy also reduces both foreign exchange spent and importation of oil used in the generation of electricity.
- Much like solar energy, geothermal energy is not limited to large scale energy plants. An efficient way to utilize heat from the Earth’s subsurface is with a Geothermal Heat Pump (GHPs) designed for residential and/or commercial use. Unlike geothermal power plants, the heat pumps are more advantageous as they make use of low-temperature geothermal reservoirs, which are available virtually anywhere.
Disadvantages of Geothermal Energy
Much like any source of energy, geothermal is not without its disadvantages.
- While it is true that under normal circumstances, geothermal plants do not emit greenhouse gases, it is undeniable that drilling into the Earth’s surface releases gases into the atmosphere that are stored. Although the exchange of gases occurs naturally overtime, the rate increases though the emission rate is far less than that of fossil fuels energy generation.
- Geothermal energy plants are associated with the implication of triggering earthquakes as a result of the alterations undergone to the Earth’s structure. Subsequently, the risk is more ubiquitous with enhanced geothermal power plants where water is forced into the Earth’s crust opening fissures solely to unlock a greater potential. Contrary, geothermal plants are not located in areas that are densely populated therefore the consequences of a higher earthquake frequency are quite slim.
- Geothermal energy plants have a high start up cost ranging anywhere from $2-$7 million for a plant with a capacity of 1 megawatt. While it is an expensive resource, the return on investment and the environmental impact is far greater than the costs.
- Furthermore, geothermal energy plants are location restricted, as they require areas where energy is obtainable to exploit the resource.
Feasibility in Jamaica
The Jamaican Government is currently screening renewable energy projects repositioning the energy dynamics targeting to integrate 30 percent of greener energy alternatives by the year 2030
In 2013, geologist Krishna Vaswani and partners presented a project aimed to generate energy from heat trapped underground in Jamaica at the Jamaica Stock Exchange. He remarked that while Jamaica is not an active tectonic area, faults do run throughout the island which indicate potential to tap into this resource. The Petroleum Corporation constructed a list of potential geothermal hotspots are: Guava River Spring, Bath Spring, Mt Felix Spring and Garbrand Hall Spring – all in St Thomas; Rockfort Spring in Kingston; Ferry Hill Spring in St Catherine; Salt River Spring and Milk River Spring in Clarendon; Black River Spring in St Elizabeth; Windsor Spring and Yankee River Spring in St Ann; and Buxton Spring in Westmoreland.
He approximated the project cost of US$15 million for geothermal energy, and proposed the construction of a 15 Megawatt plant with an anticipated start year of 2016, however the research conclusion would be the final determinant of the project.
As Jamaica relies on the importation of oil for the generation of electricity, and with constant fluctuations and uncertainty in oil prices, investing in a geothermal energy plant may be favourable in the long run for the Jamaican population and economy at large.
Although Jamaica is unlike Caribbean territories such as Montseratt, which have more geothermal potential due to their active volcanoes, this should not deter the Government from pursuing this initiative as an energy alternative.
With discussions of energy alternatives and diversification underway, tapping into geothermal potential in the near future could not only be beneficial to the Jamaican economy as well as ensuring a sustainable future for the generations to come. However, intensive research and development as well resource and investment allocation is needed before a possible geothermal plant is erected.