Carbon Emissions from Desalination Plants and How to Reduce It in Saudi Arabia - Case Study Example

Cаrbоn еmissiоns frоm dеsаlinаtiоn рlаnts аnd hоw tо rеduсе it аt sаudi Аrаbiа Name Institution Date Cаrbоn еmissiоns frоm dеsаlinаtiоn рlаnts аnd hоw tо rеduсе it аt sаudi Аrаbiа Desalination usually involves cleaning of dirty water either from the sea, ground water or even river water. This method of achieving clean water supply for industrial as well as domestic use is gaining a lot of demand as a source of sustainable water supply. In fact, it is being adopted all over the world in areas where increased demand for water is experienced beyond sustainable supply (Western Australia Water Corporation 2006, p.1). It is also a source of water in areas with water sources that are fragile or even overdrawn as well as experiencing adverse effects of climate change while trying to make previously reliable sources unreliable. Desalination can also be carried out on waste water that is already treated and has been returned to the environment to a quality level which is higher for use within the industry or for mining processing (Pacific Institute 2006, p.1). Desalination of water has many benefits to the users. It is a process that takes into consideration the industrial demands of water from public water supplies. It also reduces the volume of treated waste water that is disposed to the environment. Desalination of water for major public supply has already been extensively adopted in various areas of the world including; the Middle East, North Africa, Southern Europe, China, Singapore, USA and the Caribbean. Desalination plant Desalination of water is usually done using a desalination plant. The work of a desalination plant is to separate saline water into two water courses including; the fresh water stream as well as the concentrate or brine stream. The fresh water stream is one that has a low concentration of dissolved salts while the concentrate stream is one that contains the remaining dissolved salts. The reason for using desalination as a method of sustainable water supply is that, it is more economically viable with the improvement of technology. In Saudi Arabia, desalination plants have been employed for the purpose of water supplied for the large cities as well as for irrigation. Even though desalination plants come with many benefits of water supply and the provision of energy, they have various negative environmental impacts such as; discharge of the concentrated saline solution as well as the energy use that emits greenhouse emissions or carbon emissions (Einav et al, 2002; Höpner and Windelberg, 1996). Our concern in this paper is carbon emissions from desalination plants in Saudi Arabia and how to reduce it. Saudi Arabia is well known to have been facing a severe fresh water scarcity problem. The construction of desalination plants for the purpose of extracting salt as well as other minerals from sea water became a practical plan so as to provide the country with a solution for safe drinking water for industrial and domestic use as well as the provision of low cost energy (Picow 2009, p.1). The three main desalination plants in Saudi Arabia include; the Al-Juail, Al-Khobar and the Shoaiba desalination plants. The three plants provide the cities in Saudi Arabia with a total capacity 400 million gallons of fresh water per day (Danoum 2007, p.6). More details are provided in Table 1 below. Appendix 1 presents different images for the desalination plants. Table 1: Desalination Plants in Saudi Arabia Desalination Plant Al-Jubail Shoaiba Al-Khobar Capacity million gallon per day 246.7 107.3 50.7 Constructed date 1988 2001-2003 2002 Geographical Position Eastern Coast Western Coast Eastern Coast Danoum (2007, p.54). The assignment will major on two case studies of desalination plants in Saudi Arabia and compare them based on carbon emissions and how to reduce it. The two desalination plants in our case study will be the Al Jubail desalination plant and the SAWACO North Obhor water desalination plant. Al Jubail desalination plant The Al Jubail desalination plant was constructed for the purpose of producing energy and providing a sustainable water supply to the people of Saudi Arabia (Riyadh, 2013). It is located at the new Jubail II Industrial zone within the Kingdom’s Eastern Province. The Al Jubail destination plant creates 800,000 cubic meters of water for cities within the Eastern Province, and generates 2,750 megawatts of electricity. This desalination plant in Saudi Arabia has proved to be a solution to the water needs within the country. The plant has brought diversification to the economy that has been highly dependent on petroleum among other benefits. Figure 1: A Satellite Image of the Al Jubail Desalination Plant Source: Danoum (2007, p.41) With the provision of enough supply of water to the people of Saudi Arabia, the Al Jubail desalination plant has an impact to the environment through its electricity production. According to Younos (2005), the electricity production that is required to power desalination is usually responsible for the increased greenhouse gas emissions. Therefore, carbon emissions from the plant are as a result of electricity use in powering the desalination plant. Some of these carbon emissions from the desalination plant include; carbon monoxide (CO), carbon dioxide (CO2), nitrogen dioxide (NO2), nitric oxide (NO), and sulfur dioxide. The Al Jubail desalination plant produces 100,000m3/day to service the city of Al Jubail together with it related industrial complex. It is the largest water supply to the city when compared to the other desalination plants. The plant uses different technology of desalination including; the two multistage flash desalination plant as well as a three reverse osmosis facilities that produce a combined capacity of 84,000 cubic meters a day. The plant desalinates both sea water using the MSF plants and water from wells within the Al Jubail area is fed using reverse osmosis (ACCIONA 2012, p.1). SAWACO North Obhor water desalination plant The SAWACO North Obhor water desalination plant is a sea water desalination plant that is located in the North Obhor in Jeddah, Saudi Arabia. It is approximately 45 kilometers away from the city center. The size of the plant is 14,400 m2. It started its operations in the year 2001 and currently it is serving more than 6,000 customers within a day. It was established for the purpose of producing energy as well as desalination of sea water that would provide clean water supply for the people. The plant produces a maximum of 13,350 m3/day supply of portable safe drinking water for domestic and industrial application. The treatment technology that is used in the plant is Micro filtration system and a reverse osmosis membranes. Carbon emissions from the plant come from the energy used in powering the desalination plant. Figure 2: SAWACO Water Desalination Plant Source: SAWACO Water Desalination 2015 Comparison of the two desalination plants The two plants have differences in water capacity and energy production. However, in terms of electricity generation, the two plants do generate power energy. It is through the high energy use during desalination that consequently increases carbon emissions. It is evident that, carbon emissions are a big concern with desalination that need to be addressed. Source of Carbon Emissions The sources of carbon from the two desalination plants are different. Carbon emissions from the Al Jubail desalination plant come from the corrosion as well as material selection. It is clear that, corrosion in desalination plants usually cause undesirable consequences such as the emission of carbon from carbon steel as well as cast irons, titanium and stainless steels (Malik & Kutty 1992, p.653). Corrosion causes leaks of carbon to the air and contamination of products and leading to serious personal hazards. In SAWACO desalination plant, carbon emissions are also caused by the dissolving of carbon dioxide and hydrogen sulphide due to high chemical use (Fleming Gulf Conferences 2011). Carbon Emissions and pH According to Uddin (2014, p.116), the carbon emissions are a bottom sediments in the Arabic waters since they are sensitive to pH variations. These emissions have a likeliness of sequestering within the waters hence leading to acidification of the country. Marine ecosystems are usually sensitive to carbon dioxide enrichment. Carbon dioxide mediated acidification also influences the carbonate chemistry within the marine environment. As presented below, the pH levels in the sea water decreases as a result in carbon dioxide emitted from desalination plants (Figure 2). Figure 2: pH measurements in Sea water in the Gulf Source: Uddin (2014) Desalination Carbon Emission levels and costs Considering that desalination directly contributes to the pollution of the environment through fossil fuel energy consumption as well as brine plus chemical discharge. There is fossil fuel energy consumption in the two plants in our case study that have the effect of polluting the environment through carbon emissions. The energy that is required for desalination in the plants is usually obtained from burning fossil fuels that are responsible for air pollution as well as green gas emissions. This increases desalination costs within the plants also known as the emission costs. Emission costs are usually calculated using the emission product known as the carbon dioxide since the effects of carbon dioxide to the environment are usually global and are highly associated with their point of origin. Therefore, the pricing of carbon emissions (CO2) is usually calculated without regard to the location. This means that, based on our case study, the cost of carbon emission for the two plants does not have difference in calculation irrespective of their locations. Various researches have been done with regard to the societal costs of carbon. According to the Stem Review which is known to be among the best reviews of carbon economics, calculates the price of carbon at $85 per ton (Stern 2006, p.1). Another study done by the National Council in the United States of America, that undertook various studies on pricing of carbon revealed that, the average cost of carbon is approximately $30 per ton (National Research Council 2009, p.1). Carbon emissions and the technology used in the plants The technology that is used in the two plants is different hence achieving different levels of carbon emissions. The Al Jubail desalination plant uses two multistage flash desalination plant as well as a three reverse osmosis facilities that produce a combined capacity of 84,000 cubic meters a day. The MSF plant is used to desalinate sea water while the reverse osmosis is used to desalinate water from wells. The technology that is used at SAWACO North Obhor water desalination plant is the Micro filtration system as well as a reverse osmosis membranes. The different technology used in desalination plants produces different levels of carbon emissions. The following table presents different technologies with their respective different levels of carbon emissions. Table 2: CO2 Emissions for Different Desalination Technologies Source: Darwish (2007, p.311) Reducing Carbon Emissions In order to reduce carbon emissions in the desalination plants in Saudi Arabia, various measures need to be undertaken. Carbon emissions from desalination plants usually have an effect on climate change. This means that it is necessary to seek ways that can reduce carbon emissions from desalination plants. There are various ways through which carbon emissions that are associated with desalination plants. Some of these methods include; reducing the total energy requirements of the plant, powering the desalination plant with the use of renewable energy and purchasing carbon offsets (Cooley & Heberger 2013, p.1). Increasing Energy Efficiency Energy efficiency can be increased by coupling the desalination plant with a power plant. This method has been used in both plants under our case study. The two desalination plants have power plants that serve to increase energy efficiency. These setups usually allow the exhaust gases from the power plant to be used in desalinating water in the distillation plant or even heating the incoming feed water. This serves as a way of cogeneration in the desalination plants which is more energy efficient that in desalination plants that are set alone (Hamed 2007, p.207). The combination of a thermal desalination unit as well as a single pass RO unit into a hybrid plant is also a good method of increasing energy efficiency in desalination plants. It is evident that, only the Al Jubail desalination plant in our case study does utilize this method. The Al Jubail desalination plant combines the MFS and RO technologies that serve to increase energy efficiency. However, the SAWACO desalination plant only uses MF and RO technologies. The MF does not use energy, therefore, increased energy efficiency is not experienced in this plant. Hence, carbon emissions are not controlled in any way. Cheaper Energy Sources There are other methods that can be used to reduce carbon emissions in the desalination plants including; cheaper energy sources like renewable energy of solar energy, nuclear energy and wind energy for generating energy for the desalination plants (Kamal 2008, p.269). This works to reduce carbon emissions from the desalination plants. Figure 3: Example of a Solar Still Unit for water desalination Source: Corrosion Control Carbon emission from corrosion of metals in the Al Jubail desalination plant needs to be controlled through effective selection and corrosion control by safe operations of the plant. 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Western Australia Water Corporation, 2006, Desalination, paper prepared for the 2006 Australian State of the Environment Committee, Department of the Environment and Heritage, Canberra. Appendices Appendix 1: Images of Desalination Plants, Shoaiba and Al-Khobar Read More