With the realities of climate change and the depletion of fossil fuels, renewable energy is now in the spotlight. Currently, wind and solar power have been in the news, but there are also many other sources of energy that would benefit the environment and the developing world. These sources include wave and tidal power in addition to small hydro. In China and India, small hydro is quite popular and there are also a few projects in Pakistan; however, the government could do much more to promote water power.
This article will first examine wave and tidal power with reference to its applicability in Pakistan. This will include an analysis of the history of these technologies, the conditions needed for successful projects and the benefits and drawbacks. The second part of the article will look at small hydro and why it is the best option for Pakistan at this time. Wave and tidal power are good technologies; however, the benefits of small hydro are much greater, especially for Pakistan’s developing economy.
An Explanation and History of Wave Power
Many companies have developed different ways of using wave power, but the two basic principles behind the designs remain the same. The first design involves the waves moving into a chamber where the water rises and falls. At the top of the chamber, there is a hole out of which air is forced, which drives a generator. The other type of design involves a long tube with hinges, which moves up and down due to the motion of waves. This motion moves hydraulic fluid, which drives a generator. A power cable then moves this electricity to where it is needed. The first design was used for the very first commercial wave power station, which is situated on Islay island in Scotland. This project began producing power in November 2000 and provides enough power for 400 homes, according to Nayyer Alam Zaigham, Professor & Director, Institute of Environmental Studies, University of Karachi. The second design was used for the Pelamis, which was also developed in Scotland, but the first project will soon be installed off the coast of Portugal. The Pelamis produces enough energy for 1500 Portuguese homes, as can be found using the Pelamis wave energy converter. Pelamis was developed by the student of Professor Salter at the University of Edinburgh.
Wave power began in France in 1799 with a patent that used wave power to drive heavy machinery; however, it was not until the 1970s when wave power was taken seriously. At the University of Edinburgh, Prof. Salter developed what is known today as Salter’s Duck. Salter’s Duck looked like very large boxes that were attached to the ocean floor. As the waves moved them back and forth, the mechanical energy became electrical energy, which drove a generator. Salter’s Duck was able to capture 90 percent of the wave motion and 90 percent of that could be turned into electrical energy, which is very impressive. In addition, at the time the Duck was completed, the cost of the electricity was the same as nuclear power; however, the nuclear power industry was able to lobby the government to cancel financial support for wave power in 1982, as stated in an article on Economist.com. This set back the cause of wave power for many years; however, other forms of energy such as tidal have shown promise.
Tidal Power
Tidal power is potentially very useful because tides are very reliable. However, only 40 sites in the world have been found that are suitable because there must be a five meter difference between high and low tides.
There are two types of tidal power stations: the first is built across an estuary and looks similar to a dam. Inside the dam, there are tunnels that the water passes through. The water then turns a turbine. The other type of tidal power station looks like underwater wind turbines, but the size is usually limited to 25 to 50 megawatts (MW), according to the Pembina Institute which works to advance sustainable energy solutions in Canada. The largest tidal power station was built in northern France in 1966 and it produces 240 MW of electricity.
Benefits of Wave and Tidal
Power Wave and tidal power have many benefits. A 40 MW wave power station, which is being proposed off the coast of Cornwall, England, will save 300,000 tons of carbon dioxide over 25 years. In addition, the net potential for both wave and tidal power is greater than wind and solar because water is 850 times denser than wind, which pushes the turbines faster, according to the Ocean Energy Council (OEC).
Also, because many cities are situated in port areas, the power can be used right where it is needed. This is important because, as electricity moves through transmission systems, some of the power is lost and cannot be recovered. Both tidal and wave power are fairly inexpensive to maintain and tidal power is very predictable. Tidal power cannot harm any marine life because underwater animals can often sense turbine movement and their sound. In addition, because tidal power requires a high current, there will never be any animals feeding in those areas because plants cannot grow.
Challenges of Wave and Tidal
Power Wave and tidal power also have many challenges that need to be resolved in order for these types of powers to be successful.
Generally, the best waves are situated in temperate zones, which means that Pakistan is not suitable for wave power. This is because west winds are often found in the temperate zones, which are the best for wave power. Also, strong winds over large areas as well as a location near the continental shelf are much more favourable for wave power because it ensures a disparity between wave height and wave length.
Sites such as these are very rare, as mentioned above. Wave power is also much younger than wind or solar power and the cancellation of the UK wave power programme did not aid that. The fact that wave power is young also means that the power generated costs more than other sources of power. Currently, wave power costs approximately 7.5 cents per kilowatt hour (kWh) compared to 3 cents for natural gas, according to the OEC. Tidal power also faces many challenges. One of the main problems is that shore birds depend on the tide to uncover mud flats in order for them to feed; tidal power changes this quite drastically. The cost of tidal power per kWh is 12 cents, which is quite high. This cost would take many years to recover, which is not attractive for the developing world. Lastly, according to the OEC, tidal power has a very low capacity factor of 20 to 35 percent whereas nuclear power stations experience a 90 percent capacity factor, says E. Michael Blake in an article published in the Nuclear News magazine of the American Nuclear Society.
Thus, although nuclear power is a more questionable energy source, capacity factor is very important because if the capacity factor is higher, it ensures that power will be produced more frequently. The reason why tidal power has such a low capacity factor is that tides are only predictable for part of the day and thus, there is no constant supply of energy.
Small vs. Large Hydro
Due to the challenges just mentioned, Pakistan is not suitable for wave and tidal power. However, Pakistan has had some experience with small hydro and there is a continuing interest in the technology. Currently, Pakistan has 108 MW of small hydro, which consists of nine projects. There are also 10 MW under construction and 180 MW planned, according to the International Energy Agency. However, Pakistan has the potential for 46,000 MW of hydroelectricity, which includes large and small installations; at present, only 6459 MW are installed, states engineer Abdul Waheed Bhutto. Furthermore, he states that many people now realize that large dams are not suitable for the environment, economy and people because dams cause the flooding of villages and towns, which means that the overnment must spend money to resettle people; the Kalabagh dam, for example, will cost the government Rs. 2 billion in resettlement costs.
In addition, because reservoirs often contain decaying biomass, greenhouse gases are emitted. Large hydro is often accompanied by corruption, which is discussed in the next section.
Forms and Effects: What Corruption in Hydropower Looks Like
Grand corruption can occur in the form of bid-rigging and illicit payments, which are often disguised by channeling them through agents or subcontractors. Irregularities with environmental impact assessments can arise during the planning phase. In India, an accounting firm commissioned to conduct an EIA for two dams was caught in 2000 copying large sections of an EIA for another project 145 kilometers away. After a civil society watch group spotted the plagiarism and posted the information on its website, the contractor said it would rewrite the document. Vulnerabilities continue during project operation and maintenance. These can include corruption related to service access and provision, misappropriation or misuse of fees, illegal connections, failure to honour social and environmental mitigation commitments, patronage and abuse of funds in resettlement activities, and failure to honor benefit-sharing. If these vulnerabilities were addressed, the bene-fits that would flow to people and the environment would be considerable. Direct cost savings may start at US$ 5-6 billion annually if contractor bid prices decreased by 10 percent, which was suggested by Transparency International.
If corruption leads to cost overruns that eat into funds originally earmarked for maintenance, proper functioning may be put at risk, reducing the long-term benefits. Corruption can also hamper the expansion of electricity ser-vices in developing countries by driving up costs, delaying projects and lowering service quality and reliability, especially in rural areas considered low priorities. The table, printed in the Global Water Corruption 2008 report by Transparency International, summarizes the impact of corruption on hydropower.
How Small Hydro Works
Most small hydro systems work on the same principle known as run of river. One of the main benefits of this is the absence of a
reservoir, which means no towns are flooded. The water at the high point of the river is fed through a pipe, which turns a small
generator. After this, the water re-enters the river, which means that there are no environmental consequences and the system needed is fairly small.
These systems last for about 25 years and very little maintenance is needed. Small hydro has three different categories: pico, mini and micro, which are below 5 kilowatts (kW), 1 MW and 100 kW respectively, explain Taylor, Dr. Upadhyay and Laguna (Project Manager, European Small Hydro Association) in a review on small hydro in developing countries published on Renewable Energy World.
Vietnam is one of Asia’s leaders in pico hydro where a 300 watt unit costs $20 and produces enough power for one family.
Benefits of Small Hydro
Small hydro has many benefits, both for the environment and for Pakistani society. Small hydro produces no greenhouse gas emissions after it is built. In addition, unlike tidal power, the ecosystem is not adversely affected. Pico hydro only requires a 1-metre rop in height, which means the technology is guaranteed to work more of the time than wave power, which depends on very large waves.
With regards to society, mall hydro guarantees that there will be electricity available more of the time, which means that children can study at night and women can also make handicrafts ormarkets, which gives them more economic power in society. In addition, women are given even more free time because they do not have to collect firewood anymore.
Pakistan can also benefit from the experience and knowledge of its neighbour India, which has 1694 MW of small hydro installed. Lastly, it is very mportant to note that many people in rural Pakistan do not have electricity and small hydro is very well suited to many of these areas because it does not have to be connected to the grid. Another option is to build grids that only cover one village or town, which is a very popular option in China, India and Vietnam because smallhydro can easily be connected to this type of grid, state Taylor, Upadhyay and Laguna.
Thus, small hydro is by far the best option available for Pakistan due o the presence of many rivers, the environmental and societal benefits as well as the drawbacks of wave and tidal power. It is now up to the government to put in lace policies that would allow people to purchase these systems cheaply. If Pakistan is able to independently produce power, this would greatly increase the umber of jobs and the benefit to society.
References:
Nayyer Alam Zaigham and Zeeshan Alam Nayyer “Prospects of Renewable Energy Sources in Pakistan”
<http://www.energy.com.pk/>
Wikipedia “Pelamis Wave Energy Converter”
http://en.wikipedia.org/
The Economist “The Coming Wave”
<http://www.economist.com/>
Pembina Institute “Energy Source: Tidal Power”
<http://re.pembina.org/>
Ocean Energy Council “Wave Energy”
<http://www.oceanenergycouncil.com/>
E. Michael Blake “U.S. Capacity Factors: A small gain to an already large number”
<http://www.ans.org/>
International Energy Agency “International Small Hydro Atlas: Pakistan”
<http://www.smallhydro.com>
Abdul Waheed Bhutto “Small Hydro-power Units for Remote Villages”
<http://my.reset.jp/>
Simon Taylor, Drona Upadhyay and Maria Laguna “Flowing to the East: Small Hydro in Developing Countries”
<http://www.esha.be/>
THANKS FOR THE KIND INFORMATION, YOU PROVIDED