Tidal Wave and Wind Power as renewable energy for Bangladesh
Currently the total demand for power in Bangladesh is about 5,500 MW (megawatts), while renewable energy covers only 30 MW of total production of 3,525 MW, according to one estimate.
It is believed that the demand is likely to grow almost 50% per cent in the next 15 years and Bangladesh needs to increase the capacity to more than 8,000 MW by 2015, according to one estimate.
At present the country’s energy is 90% gas-based and the shortfall of energy in the country during this summer stands around 1,975 MW. There have been frequent electricity disruptions in day and night (load-shedding) in the country.
Bangladesh has to explore the source of energy from renewable resources that are easily available in Bangladesh, such as, solar, tidal waves, wind power and biomass at an affordable cost.
The government in its budget statement in June of this year has said that the Renewable Energy Policy has already been prepared and by 2015, it has targeted to produce 5% per cent of total power generation and 10% per cent by 2020 from renewable energy, such as air, waste and solar energy. An agency called “Sustainable Development Agency (SEDA) has been set up to develop renewable energy sector.
Solar energy is being given priority in Bangladesh as green energy. Already the Prime Minister’s Office has installed solar energy for its electricity and other government offices are being planned to have solar panels for their needs.
It is reported that solar energy has revolutionized the life style of many businessmen in the countryside as their daily income has increased by 50 per cent with the use of solar energy, provided by Grameen Shakti and Infrastructure Development Company Limited (IDCOL).
The government is encouraging private sectors to go for green and renewable energy. As part of its effort the government has designated a Purchase Plan, known as Feed-In-Tariff (FTT). In its simplest terms, FTT is the preferential rate paid for electricity fed back into the national grid from a renewable energy generator by private sectors.
It is noted that 64 countries adopted FTT. The concept of FTT came first in the US in 1974 when the government urged the private sector to come forward to solve the power crisis.
Chinese private sectors have been utilising from wind power and it is rising every year. India has adopted FTT for renewable energy. In calculating FTT India used some fixed cost components that may be useful for Bangladesh.
The components are return of equity,interest on loan capital, depreciation, interest on working capital, operating and maintenance expenses. Infrastructure Development Company Limited (IDCOL) of Bangladesh submitted a proposal to the government on FTT.
Tidal Energy:
Bangladesh is fortunate to have access to the sea and tidal energy can be obtained from the changing sea levels. Generation occurs when the water is flowing both in and out, with the change in rotation occurring during low and high tide. It is a direct result of tide shifting from low to high.
The tides rise and fall due to the gravitational tug-of-war between the Earth, the Moon and the Sun and if energy can be obtained it is inexhaustible.
Tidal energy is being utilized by Portugal, France, Russia, Canada and China. Britain is planning in the Severn Estuary the biggest ever project for 8,640 MW.
Experts say tidal energy can be obtained from three types:
• Tidal Barrage
• Tidal Fence
• Tidal Turbine
Bangladesh has a long coastal belt of 740 kilometers and the coastal area. The normal tidal wave that rises and falls in the coastal region of Bangladesh is between two and eight meters.
Some of the coastal areas are protected by embankment and sluice gates from flooding. Bangladesh has some large tidal sites and many channels of low tidal sites where barrages and sluice gates already exist. Analysis of given sites according to a report indicates that Sandwip has a very good prospect of tidal energy. The 5-metre tides experienced at Sandwip are ideally suitable.
Researchers say that Bangladesh may harness energy from tidal waves by application of two technologies:
• Low head tidal movements (2-5 m head)
• Medium head tidal movements ( 5 m or over)
They argue that low head tidal movements could be applied in coastal areas, such as Khulna, Barisal, Bagerhat,Satkhira and Cox’s Bazar regions with sluice gates and levees. Since these areas are protected by embankments the infrastructure needed for sluice gates is already present in the region. Only “tidal wheel” in the sluice gates is necessary.
The most favourable location of this type of technology is Sandwip Island where the mean spring tidal height is about 5.73 metres. The tides in Sandwip demonstrate 5- hour “in” and 7-hour “out” cycle.
The installation of 75KW turbines, generating 80% of full capacity for 23 hours per day, according to a study by researchers at the International University of Chittagong, equates to the production of about 1,380KW-hr per day and the cost of the installation for one site is about Taka 3.5 million (US$50,000).
Wind Energy:
The strong south/south-westerly monsoon wind, coming from the Indian Ocean enter into the coastal areas of Bangladesh from March to October. This wind enhances speed onwards V-shaped coastal regions in Bangladesh, as research stated.
Based on last 16 years wind speed records at 20m above the ground, assembled by the Bangladesh Meteorological Department, it is known that average wind-blow in many areas has been between 5.5 to 9.50 m/s almost throughout the year. This speed has been proved as appropriate for setting up commercial and non-commercial level wind power plants, power experts explained.
With the increasing total demand of energy, it is imperative that Bangladesh may look for using wind, solar and tidal sources of energy. Bangladesh’s survival is dependent on appropriate policies of adaptation and mitigation of threats of global warming and the use of renewable energy is to be boosted as soon as possible.
By Barrister Harun ur Rashid
Former Bangladesh Ambassador to the UN, Geneva
