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Selected renewable energies (RE) resources and technologies


We are championed and promoting the awareness education in the sustainability of the various energy resources and the colossal effects to the economy, social and environment

*IEA data and analysis


Bio-Energy

Bio-energy Technologies:-

Technology Overview

  1. Biomass power plant: heat produced by direct biomass combustion in a boiler can be used to generate electricity via a steam turbine. Cheapest and most reliable technique to produce energy from biomass. However the efficiency is much lower than fossil-fuelled plant.
  2. Waste-to-energy: High cost due to the needs of rigorous control and robust technologies over the emissions. Low efficiency.
  3. Gasification: thermochemical process converts the biomass into a mixture of several combustible fuel gases. Good for small scale plant 5-10 MWe. The improvement yet to reliase and under research.
  4. Anaerobic digestion: biological degradation of biomass in oxygen-free conditions to form methane-rich gas. Compatible with pollution control policy and relies on cheap/or free feedstock. Low efficiency.

Cost and trends:-

Depends on technologies, operational scales and also quality and/or types of feedstocks. Cost of investment is high, US$2600-4100/KW. Cost reduction is Limited.

Biofuels:-

Technology Overview

Produced by well-developed and commercially processes. The produced fuel can be blended with diesel and gasoline in conventional vehicles.

Cost and trends:-

Despite the well-developed processes, it have few crucial controversial issues to deal with, i.e. competition between fuel and food supply; greenhouse gasses for the production and the usage of the fuels. Too much depends on the quality of feedstock and its prices make it not competitive. The most advances biofuels still under research and yet to commercialise.


 

Geothermal Energy

Technology Overview

Geothermal technologies use energy stored in rock and in trapped vapours or liquids such as water or brines. These resources can be used for generating electricity and to provide heat. Power generation typically relies on geothermal resource temperatures of over 100°C.

Types of Geothermal energy plant:-

  1. Flash steam plant: water-domainted reservoirs with tempretaure higher than 180 0C. 2/3 of current installed capacity.
  2. Dry steam plant: Utilising dry steam piped from production wells to the plant and then to the turbine. Easy in controlling the flow for regulating the rate of power generation. ¼ of current facilities.
  3. Binary plant: Much prevalent and fastest growth technologies. Utilising both low-to-medium temperature resources.

Cost and trends:-

Only applicable to those area with high temperature geotherma. Building cost is high. Approximate US$2000-5000/KW.


Hydro Energy

Technology Overview

Hydro power derived from energy in flowing water, from rivers or man-made installation reservoirs. Turbines placed in the water flow extract its kinetic energy and convert it to mechanical energy. The amount of energy is depends on the flowing rate and the vertical distance that water falls. Hydro power is a fully commercial and well?established mature technology

 

Cost and trends:-

One of the cheapest resources, however it has significant impact on ecology systems, environmental issues, and distinction of wildlife species, as well as Diversities. It also cause death of rivers.


Ocean Energy

Technology Overview

Five different ocean energy technologies under development aim to extract energy from the oceans, including:

Tidal power: the potential energy associated with tides can be harnessed by building a barrage or other forms of construction across an estuary.

Tidal currents: the kinetic energy associated with tidal (marine) currents can be harnessed using modular systems

Wave power: the kinetic and potential energy associated with ocean waves can be harnessed by a range of technologies under development.

Temperature gradients: the temperature gradient between the sea surface and deep water can be harnessed using different ocean thermal energy conversion (OTEC) processes.

Salinity gradients: at the mouth of rivers, where freshwater mixes with saltwater, energy associated with the salinity gradient can be harnessed using the pressure?retarded reverse osmosis process and associated conversion technologies.

Cost and trends:-

None of these technologies is widely deployed as yet. The largest plant is at South Korea (254 MWe). Estimated cost will be US$ 289/MWh by 2020. Cost reduction is about to reach maturity.


Solar Energy

Solar photovoltaics

Technology Overview

Direct conversion of solar energy into electricity via photovoltaic (PV) processes. The PV module is a semiconductor base and typically up to 200-500 W. The modules can be integrated into a systems consisted inverters, batteries; links of these systems can offers power to MW. Mainly silicon based PV cells.

Cost and trends:-

Cost around US$ 11.3-48.6/KWh for ground mounted systems, and US$13.8 68.8/KWh for roof mounted system. Cost expected continues to falls for next two decades owing to the heavily funding in researches. Intermittency in supply and only serve as secondary energy load. Heavily depends on needs of rare-earth Elements in doping the silicon in improving efficiency which led to not so green as claims. Organic polymer PV cells are under research but will needs extra maintenance in replacement owed to its low glassy transition temperature.

Concentrating solar power

Technology Overview

Concentrating solar thermal power and solar fuels technologies produce electricity and possibly other energy carriers (“fuels”) by concentrating solar radiation to heat various materials to high temperatures. A concentrating solar power (CSP) plant comprises a field of solar collectors, receivers, and a power block, where the heat collected in the solar field is transformed into mechanical energy, then electricity. In between, the system must include one or several heat transfer or working fluids, possibly heat storage devices and/or back?up/hybridisation systems with some combustible fuel. A cooling system, wet or dry, completes the description of the plant CSP plants come in four different versions: parabolic trough, linear Fresnel, tower and parabolic dish systems.

Cost and trends:-

Not competitive due to only in isolated locations such as remote islands etc. Intermittency supply


Wind Energy

Technology Overview

A proven and mature renewable energy resources. Wind turbines extract kinetic energy from moving air flow (wind) and convert it into electricity via an aerodynamic rotor, which is connected by a transmission system to an electric generator. Today’s standard turbine has three blades rotating on a horizontal axis, upwind of the tower, with a synchronous or asynchronous generator connected to the grid. Two?blade and direct?drive (without a gearbox) turbines are also available. Typical onshore commercial wind turbines offers 1-3 MW and meets its limits due to weights and size. The greenest energy technology discover so far.

Cost and trends:-

Cost will around US$40-160/MWh. However it is only applicable to locations with significant strong wind, thus have limitation to certain countries. Intermittency supply.


Fossil Energy


Coal Energy

Technology Overview

Coal is a sedimentary organic rock that is highly combustible. Steam coal is used in power stations to generate electricity. Coal is first milled to a fine powder and is blown into the combustion chamber of a boiler where it is burnt at high temperature. The hot gases and heat energy produced converts water into steam and is passed into a turbine.

Cost and trends:-

As of 2013, coal provided approximately 41% of the world’s electricity needs. However, coal has many negative environmental impacts. It creates harmful greenhouse gases. Sulphur dioxide, nitrogen oxide and carbon dioxide emissions causes acid rain, smog and global warming respectively.


Gas Energy

Technology Overview

Natural gas, a fossil fuel consisting mainly of methane, is used to generate electricity. There are two approaches to generating electricity from natural gas: using a steam turbine or using a combustion turbine. By the first method, the natural gas is fired to create heat, which then converts water to steam. The steam turns the steam turbine, which generates electricity. The other, and more common, approach is to burn natural gas in a combustion turbine. Some electricity generation plants also use combined cycle technology, which uses both approaches.

Cost and trends:-

Natural gas burns cleaner than other fossil fuels, producing half the carbon dioxide as coal and about a third less than oil. It also emits fewer amounts of toxic chemicals like nitrogen oxides and sulfur dioxide. As with other fossils, there is a finite supply


Oil Energy

Technology Overview

Three technologies are used to convert oil into electricity:

  • Conventional steam - Oil is burned to heat water to create steam to generate electricity.
  • Combustion turbine - Oil is burned under pressure to produce hot exhaust gases which spin a turbine to generate electricity.
  • Combined-cycle technology - Oil is first combusted in a combustion turbine, using the heated exhaust gases to generate electricity. After these exhaust gases are recovered, they heat water in a boiler, creating steam to drive a second turbine.

Cost and trends:-

Global oil production levels are dependent on the production policy of OPEC. Burning oil for electricity pollutes the air, water and land but some of the worst environmental woes associated with oil are linked to drilling, transporting and refining. Like other fossil fuels, this liquid is the end-product of millions of years of decomposition of organic materials. Since the ultimate amount of oil is finite -- and cannot be replenished once it is extracted and burned


Nuclear Energy

Technology Overview

In current civil nuclear reactors, heat is produced by fission of fissile nuclear materials like uranium-235. Heat generated associated in fission processes is used to raise steam, which runs through turbines, which in turn powers the electrical generators, like in any other thermal power plant. To avoid overheating, the plants incorporate cooling systems

Cost and trends:-

Nuclear power is one of the most reliable and cheap massive energy resources, and serves as one of the best in limiting greenhouse gas emissions behind the wind energy. However it needs rigorous engineering management practises, as all the nuclear catastrophes are cost by human negligence.

 

 
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