GENERATING ELECTRICITY THROUGH DESALINATION
TARIQ AHMED SAEEDI
Nov 29 - Dec 5, 2010
Desalination is considered a novel idea in the world for its usefulness to make water drinkable as well as to generate electricity, through its cost is likeably weighed against benefits it gives. Desalination is costly when the operation is powered by fossil fuel, however, thanks to science technologies are out there to take water as fuel for running generators!
In recent historical development, Independent Natural Resources was planning to put in the waters of Gulf of Mexico wave-powered generation facility to produce electricity and desalinate seawater. It has significant upfront capital costs but amazingly no operating power costs.
The desalination plant in Karachi was inaugurated on February 2008. With electricity generation capacity of 84 MW and potable water making capacity of three million gallons per day, the plant was established by a joint venture of DHA and Messrs Sacoden (Pvt) Ltd of Singapore. The plant was erected on 10 acres land in DHA-VIII with a total cost of 115 million dollar. It is connected to Karachi electric supply company's grid while desalinated water meets the needs of local population in the area. Defence housing authority, managing an area 8,797 acres in the southern part of the country's financial and business hub Karachi, was set up to serve serving and retired officers of armed forces. It has population of more than 60,000. The power plant is fuelled by both gas and steam. It was not a first desalination plant in Pakistan, but converting brackish into drinkable water has been popular for decades in the country. However, the process was carried on small scale and to meet particular project's requirements. For example, desalination plants in Saindak copper mines in Balochistan, at Hubco power station, and at Kanupp's facility were to meet operating requirements.
Nationwide electricity demand and supply shortfall is somewhere near 5000 megawatt while in Karachi optimal supply is just little over 1900MW contrary to the seasonally variable demand of 2100 MW. Power load shedding is hampering the industrial growth. The government is taking short-term measures to resolve energy crisis, but such measures will have adverse impacts on the economy.
Recently, the world's largest ship-mounted power plant berthed at the port of Karachi, and will add 232-megawatt electricity to the national grid for Karachi from next month. Turkish based Karkey Karadeniz Electrik Uretim A.S. owns the power generating ship, Kaya Bey. It is first of its kind power plant in Pakistan rented by Pakistan electric power company (Pepco) to meet the massive electricity shortfall of 200 to 300 MW in Karachi reportedly. "The project will provide a significant support to the KESC system," a press statement quoted minister of water and power Raja Pervez Ashraf as saying during contract awarding ceremony. Government of Pakistan awarded the contract to Karkey last year in April. It is worthwhile to note that at present Pepco supplies 600 to 700 MW to the privately managed KESC. It is feared supply from other sources may allow Pepco to cut supply to Karachi and divert the saved electricity to other distribution companies in the country. Generally, people from all walks of life criticise commissioning of rental power plants for their reliance on thermal sources, which make electricity tariffs for consumers unaffordable in addition to cause flight of money on import of furnace oil. Minister Ashraf told reporters that during a ceremony at the port, prevalent electricity tariff would not be affected after addition of electricity to the grid from the floating plant.
Desalination plant provides two advantages at the same time: electricity and potable water. Unfortunately, Pakistan is facing the shortage of both water and electricity. While electricity crisis is being highlighted from all public forums, water scarcity is what people are least bothered about. A senior official at water development company was not exaggerating while expressing his fear of impending water riots in the overcrowded city of Karachi where demographic change is alarming. He said that government was not realising the gravity of the situation, else, it must have taken steps on war-footing basis. Karachi is facing population burst and worst expansion in urban slumps with political parties supporting unplanned shantytowns at the prospect of enriching vote bank. Such mushroom settlements have created problems on every civic front and become nightmares for city planners to tackle. Water shortage assumed alarming proportions in Karachi with 350 million gallons per day shortfall.
Water supply authority in Karachi is unable to expand its service to un-served and underserved localities because of outdated water allocation estimate prepared in 1980s. Let alone clean drinking water, present freshwater supply in one of the most populous metropolises of the World is not sufficient to meet domestic and industrial demands leaving majority of people with two choices: buy water or reduce water needs, besides putting fate of eleven industrial development projects into jeopardy.
In number of areas, water is supplied once in every two to three days while there are several localities which remain disconnected from supply line for months, according to a government official.
Present supply in the city is around 650 million gallons per day (mgd) contrary to the demand of 1000 mgd. Main sources are River Indus and Hub. After the completion of KIII water project in 2006, which brought to an end quota of 1200 cusecs (650 mgd) allocated to the city by the provincial government, a mega water project KIV was conceived to meet the needs of population growing at a pernicious rate of four to five per cent per annum. Karachi water and sewerage board (KWSB) claims it is waiting for increment in quota and ready to submit PC-1 of the project to the provincial authority.
Desalination project is out of the horizon of urban developments at the moment, as the government is looking for cost-effective means to generate electricity. But, given the rising demands of water for industrial developments and of energy, seawater-powered energy generation will result in a win-win situation.