Bangladesh is now staring at a situation when misleading perception of the past decades on abundance of natural gas reserves has suddenly disappeared. Even in a short term perspective, it is unlikely that the country can come out of the quandary of enormous and complex proportions. The situation is further compounded by the fact that electricity related undertakings entail large investment, a long gestation period and an ensured supply of fuel for 30+ years of life of a plant. Our hopes are limited by our capacity to resolve these issues on a fast track, and a bleak future is a more realistic scenario. We have to have patience and learn to make sacrifices for some more years to come even if we resolve to learn and apply the tricks of comprehensive and programme based planning. In this backdrop, the importance of a proper generation-mix assumes overwhelming importance. The imaginary perception of reserves of indigenous primary energy resources has to be replaced by evolution of a realistic fuel-mix that can help develop the energy sector in keeping with the goals of socio-economic advancement. The alternatives include oil, coal and nuclear—each having a separate set of relative advantages and disadvantages.
Discussions are now focused on coal as one of the options. It now accounts for about 41% of global electricity. In some countries, coal fuels a higher percentage of electricity. For example, its share in total generation is 94% in South Africa, 76% in Australia, 68% in India, 93% in Poland, 49% in USA, 81% in China. Even a cursory analysis would show that these countries depend on indigenous reserves and thus take into account the question of sustainable energy security. In Bangladesh, the total deposit is not so significant that we can attain that level of security of supply. Naturally, the government is contemplating importing coal to fuel some future power plants. The combined capacity of such plants is reported to be 2000-3000 MW, according to various open sources of information. It is encouraging to see that the decision makers are looking beyond a contingency plan of energy supply.
Before jumping into the environmental dimensions or the economics of this solution, it is worthwhile to look at the other important issues like logistics of transportation and handling of imported coal. A 300-MW coal-fired plant, operating at a plant factor of 75%, would require about 900,000 tons of coal annually, which is equivalent to a daily average uninterrupted supply of about 2,500 tons. Do we have such a capacity in place? If not, then do we have a plan in place as an integral part of the solution?
In the past, when the requirements were much lower than what we plan for coal as fuel for thousands of megawatts of coal fired plants, ocean going vessels used to berth at River Mooring at Chittagong Port. It had a daily handling capacity of about 2000 MT. The alternative to this is to discharge from a larger mother vessel at the outer anchorage to lighter vessels of capacity to carry 1500 -2000 tons each. There used to be a dumping lot for coal near the Marine Academy Jetty, which had a holding capacity of about 30000 MT, which can possibly still be restored as the coal dumping yard. Even this storage capacity can cater for five days’ supply to a 300 MW power plant. Another alternative is to use conveyor belts for discharge of coal. In that event every lighterage vessel has to have its own conveyor system to unload. By doing so, the unloading capacity could be increased to 6000 MT for the River Mooring of Chittagong. Thus, it may be possible to have a maximum of 600 MW of coal-fired plants with coal imported through the Chittagong port. Another limitation is that due to draft restrictions, ships carrying a maximum of 25000 MT of coal can be berthed depending on the tide. Turn around time for such a vessel would be 4-5 days. In case of Mongla, the draft restriction will allow vessels with a maximum capacity of 10-12,000 MT, meaning that each ship could carry 4-5 days’ requirements of fuel for a 300 MW plant. One could imagine the stresses on the channels by movement of coal cargo. Moving coal upcountry from the port area is almost impossible, especially during the lean months. Thus, such plants have to be built close to the Chittagong port. This proposition, if implemented, would have little impact to supply of electricity to the energy-starved western zone of the country, where per capita availability of electricity is half of what is supplied in the east zone.
The problems can be resolved subject to limitations, like handling and transportation of imported coal. Even, then the maximum capacity of generation with imported coal cannot possibly exceed 500-600 MW. And even for achieving this, a careful planning of handling has to be made and infrastructure for this developed.
Burning coal produces about 9 billion tons of carbon dioxide each year which is released to the atmosphere, about 70% of this being from power generation. Other estimates put carbon dioxide emissions from power generation at one third of the world total of over 25 billion tons. Development of new “clean coal” technologies is addressing this problem. The ultimate aim is to achieve “zero emissions”. Burning coal gives rise to a variety of wastes which must be controlled. So-called “clean coal” technologies aim at resolving environmental concerns, including that of global warming due to carbon dioxide releases to the atmosphere. This includes, among others, coal cleaning by ‘washing’ which reduces emissions of ash and sulfur dioxide when the coal is burned, electrostatic precipitators and fabric filters for removing fly ash from the flue gases, flue gas desulphurization (FGD) for reducing emission of sulfur dioxide, use Low-NOx burners to reduce nitrogen oxide emissions, increasing efficiency of plant to reduce emissions per kwh, advanced technologies such as Integrated Gasification Combined Cycle (IGCC) and Pressurized Fluidized Bed Combustion (PFBC) for increasing thermal efficiencies, ultra-clean coal (UCC) such as Gasification, including underground coal gasification (UCG) in situ, etc. for reducing ash and sulfur.
Another dimension of burning coal is waste coal ash (85 tons of ash from burning of 100 tons of waste coal). Mercury and other toxic contaminants enter a waste coal burner, which are concentrated in the highly toxic ash that ultimately threatens the groundwater wherever this ash is dumped. Waste coal burners have cleaner air emissions than antiquated coal plants due to their better pollution controls. Waste coal ash is dumped in communities not far from the waste coal burners, threatening the groundwater with leaching lead, mercury and other poisons. Power plant waste is allowed to be dumped without the basic protections (landfill liners).
Some of the measures mentioned are still to reach a level of maturity that would allow their use on a commercial scale. Often, even matured technologies are ignored to improve economics of electricity generation. Years ago, I saw a comment in a report by a reputed consulting firm which said that incorporation of FGD would increase cost of a coal-fired plant and that the coal option would result in a loss of at least a part of its economic advantages over the alternatives. I had politely asked the foreign consultant whether such a comment would be acceptable in his country. The answer was something between yes and no. This was in the 1980s. The scenario has changed since then, especially in the backdrop of universal concern for climate change. Ideas are floated now on carbon trading, carbon tax, low carbon path of development. If a consensus is reached on mitigation of Green House Gas emission, there would not be short cut available to mitigate emission-it is important to realize that retrofitting for improving technological performance, including making a power plant responsive to environmental and climate change mitigation regime will be costly, time consuming and even impossibility.
It is likely that development of the energy sector with coal as one of its important components would require investments by the local and expatriate entrepreneurs. And the regulatory regime should be comprehensive and exhaustive. Required codes and standards should be developed in consultation with the experts so that non-responsive technologies are automatically excluded. This should be true for power plants to be built both by the public and the private sectors. Infrastructure for handling and transportation should be developed so that the issues are resolved well ahead of time. All these aspects should be reflected in the coal policy or alternatively in a separate document on establishment of coal-fired plants.
We need a secured and rugged energy-mix that would help sustainable growth of electricity sector. Coal is a viable proposition. Problems are diversified, but technological solutions are also available. All we have to do is be careful and prepare for all the likely pitfalls of coal-fired power plants with the risks minimized. A surprise appearing a few years down the line would fail to provide us with a reliable supply of coal based electricity.