This is the first series of a two-part article on power plants.

The government is planning to build a 300-megawatt coal-fired power plant near Lahad Datu, on the east coast of Sabah. In point of fact, the proposed site is at the Malaysian edge of the Sulu-Sulawesi Marine Ecoregion (SSME), and very close to the Tabin Wildlife Reserve, a protected area of primary rainforest providing critical habitat for numerous endemic and endangered species, including orang utans, Sumatran rhinos, Bornean pygmy elephants and several species of primates and hornbills.

The proposal was greeted with mostly negative reactions from politicians on both sides, NGOs and Sabahans. The Ministry of Natural Resources and Environment are coming up with a report to look into the viability of constructing such a power plant and environmentally-friendlier alternatives to the fossil fuel types for Lahad Datu. Presented here are facts on various types of power plant including the coal-fired type proposed to be built on a area that is said to be too close for comfort to one of the country’s precious wildlife sanctuaries.

Solar Power

Solar power is the generation of electricity from sunlight. This can be direct as with photovoltaics (PVs), or indirect as with concentrating solar power (CSP), where the sun's energy is focused to boil water which is then used to provide power.

A solar power plant in Arizona, U.S.A.

Various technologies such as the Stirling engine dishes, which use a Stirling cycle engine, are used to power a generator. PVs were initially used to power small and medium-sized applications, from the calculator powered by a single solar cell to off-grid homes powered by a PV array.

Solar power plants can face high installation costs, although this has been decreasing due to the learning curve. Developing countries have started to build solar power plants, replacing other sources of energy generation.

Wind Power

Wind power is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electricity, windmills for mechanical power, wind pumps for pumping water or drainage or sails to propel ships.

A 'Wind Farm'

As such, large-scale wind farms are connected to the electric power transmission network; smaller facilities are used to provide electricity to isolated locations. Utility companies increasingly buy back surplus electricity produced by small domestic turbines. Wind energy, as an alternative to fossil fuels, is plentiful, renewable, widely distributed, clean, and produces no greenhouse gas emissions during operation. However, the construction of wind farms is not universally welcomed because of their visual impact and other effects on the environment.

Nuclear Power

Nuclear power is produced by controlled nuclear reactions. Commercial and utility plants currently use nuclear fission reactions to heat water to produce steam, which is then used to generate electricity.

Nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts (lighter nuclei), often producing free neutrons and photons in the form of gamma rays.

A Nuclear Power Plant

Nuclear reactors generally have automatic and manual systems to shut the fission reaction down if unsafe conditions are detected.

There are many different reactor designs, utilising different fuels and coolants and incorporating different control schemes. Some of these designs have been engineered to meet a specific need. Reactors for nuclear submarines and large naval ships, for example, commonly use highly enriched uranium as a fuel. This fuel choice increases the reactor's power density and extends the usable life of the nuclear fuel load, but is more expensive and a greater risk to nuclear proliferation than some of the other nuclear fuels.

A number of new designs for nuclear power generation, collectively known as the Generation IV reactors, are the subject of active research and may be used for practical power generation in the future. Many of these new designs specifically attempt to make fission reactors cleaner, safer and/or less of a risk to the proliferation of nuclear weapons. Passively safe plants are available to be built and other designs that are believed to be nearly fool-proof are being pursued.  Fusion reactors, which may be viable in the future, diminish or eliminate many of the risks associated with nuclear fission.

Coal Power

A conventional coal-fired power plant produces electricity by the burning of coal and air in a steam generator, where it heats water to produce high pressure and high temperature steam. The steam flows through a series of steam turbines which spin an electrical generator to produce electricity.

The exhaust steam from the turbines is cooled, condensed back into water, and returned to the steam generator to start the process over.

A Coal Power Plant

Conventional coal-fired power plants are highly complex and custom designed on a large scale for continuous operation 24 hours per day and 365 days per year. Such plants provide most of the electrical energy used in many countries. Most plants built in the 1980s and early 1990s produce about 500MW (500•106 watt) of power, while many of the modern plants produce about 1000MW. Also, the efficiencies (ratio of electrical energy produced to energy released by the coal burned) of conventional coal-fired plants increased from under 35 percent to close to 45 percent.

Coal generates 54 percent of our electricity, and is the single biggest air polluter in the US’ typical (500 megawatt) coal plant burns 1.4 million tons of coal each year. There are about 600 US coal plants.

Biomass

Biomass is a renewable energy source where biological material derived from living, or recently living organisms, such as wood, waste, hydrogen gas and alcohol fuels. Biomass is commonly plant matter grown to generate electricity or produce heat. In this sense, living biomass can also be included, as plants can also generate electricity while still alive.

A Biomass Power Plant

The most conventional way on how biomass is used however still relies on direct incineration. Forest residues for example (such as dead trees, branches and tree stumps), yard clippings, wood chips and garbage are often used for this. However, biomass also includes plant or animal matter used for production of fibres or chemicals. Biomass may also include biodegradable wastes that can be burnt as fuel. It excludes organic materials such as fossil fuels which have been transformed by geological processes into substances such as coal or petroleum.

Industrial biomass can be grown from numerous types of plants, including miscanthus, switchgrass, hemp, corn, poplar, willow, sorghum, sugarcane, and a variety of tree species, ranging from eucalyptus to palm oil. The particular plant used is usually not important to the end products, but it does affect the processing of the raw material.

Although fossil fuels have their origin in ancient biomass, they are not considered biomass by the generally accepted definition because they contain carbon that has been "out" of the carbon cycle for a very long time. Their combustion therefore disturbs the carbon dioxide content in the atmosphere.

Plastics from biomass, like some recently developed to dissolve in seawater, are made the same way as petroleum-based plastics. These plastics are actually cheaper to manufacture and meet or exceed most performance standards, but they lack the same water resistance or longevity as conventional plastics.

 Sources: Wikipedia and citizendium.

  

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