The basic technology involved in burning coal to generate electricity using a steam turbine is more than one-century old and the optimum power plant configuration, materials and operating conditions are extensively documented. From the standpoint of the simple boiler and steam turbine plant burning pulverised coal, behaviour is predictable and the technical risks minimal.
Power plant performance will depend on the exact type of coal to be burned and the nature of the fuel must be taken into account. This will generally mean designing a plant around a particular type of coal, often from a single source. Here factors such as the extent and reliability of the supply must be carefully weighed too. Later adaptation to a different coal from a different source is possible but it will affect generating costs.
Also critical from the design standpoint are the environmental regulations that exist when the plant is to come into service, and any possible changes to these regulations in the future. New plants constructed in most developed countries will require extensive emission-control systems. In some developing countries the existing regulations are often less stringent but this is a position that is likely to change. It would be wise to at least make provision for the addition of flue gas treatment systems in any new plant.
The more advanced coal-burning technologies such as FBC and IGCC are relatively recent innovations. Atmospheric FBC systems have been extensively demonstrated in power generation applications and their reliability is generally proven. Risks should be minimal and these plants offer the added flexibility of being able to burn different coals with ease. This takes some of the risk out of fuel supply.
Pressurised FBC plants and IGCC plants are still in a relatively early commercial stage. Long-term reliability has to be established and some component development remains. Commercial implementation of these technologies must be considered to carry an additional risk to that attaching to the more established technologies for burning coal.
Aside from the technology, the second source of risk associated with coal-fired power plants relates to fuel supply and cost. Both have remained relatively stable in the last 20 years, though there have been some price peaks (see below). Where coal is abundant, and particularly where it faces competition from natural gas, this situation appears likely to continue for the immediate future. Over the lifetime of a new coal-fired plant, prices will show an increase but with several major sources around the globe, no dramatic move is likely. This situation should allow for firm planning of fuel costs.
The situation may not prove so straightforward where a plant is built to exploit a local source of coal. Fuel costs under these circumstances are likely to be lower but that advantage could be counterbalanced by less security of supply and less price stability. In order to ensure that the project is to remain viable over its lifetime, a secure fuel supply agreement is vital. And in a country where the fuel delivery might be unreliable, some form of guarantee should be sought.
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