Solar Photovoltaic (PV)
Solar Photovoltaic (PV) systems are composed of solar panels and inverters that work to generate electricity. This is done by converting the energy emitted by the sun into electrical energy that can be used to power appliances, lights, charge batteries etc.
Sunlight is made up of photons. When these strike semi-conductor crystals embedded in solar cells they create a Direct Current (DC). The DC current is converted to an Alternating Current (AC) by an inverter which then allows electricity to flow into a home or business to be consumed.
Solar systems can be installed ‘off-grid’ meaning that all electricity is consumed at the site of generation or connected to the grid. Connecting to the grid allows surplus electricity to flow back into the grid to be consumed elsewhere. This surplus energy is sometimes paid for by the network in the form of a Feed in Tarriff (FiT). Payment of this is dependent on the network and state the solar system is located in.
Before installing a solar PV system, households and businesses should contact their retailer to ensure the network they are connected to has the capacity to absorb flows of electricity back into the grid. This is especially important in areas where many homes or business have solar PV systems or in rural areas.
Solar is well placed to reduce critical peak demand during hot summer days when millions of Australians are using air-conditioners. Energy emitted from the sun which heats buildings causing occupants to run air-conditioners, can be instead used to cool it by using the sun’s energy converted to electricity to run air conditioners. This results in less electricity extracted from the grid during times of increased demand.
In October 2012, Clean Energy Regulator stated that over three-quarters of a million Australians have installed solar PV systems, which equates to 2 gigawatts (GW). This number is predicted to hit one million during 2013.
An incentive for the installation of solar PV comes in the form of Small-Scale Technology Certificates (STCs) that are attached to solar PV systems, as well as solar hot water and heat pumps. STCs are tradable certificates created under the Renewable Energy Target (RET) that can be sold at market rates. The generating capacity of a solar system dictates the amount of STCs awarded to a system. Further incentives come from Solar Credits which multiply the amount of certificates awarded to a solar system.
Wind turbines catch the wind blowing past their blades, which turns a rotor and powers a generator. This process transforms natural kinetic energy from the wind into electricity. Because of its minimal operating costs, wind is considered the cheapest renewable technology at approximately 5 cents per KW. Modern turbines range in capacity from 3MW to 7MW. In order to maximize generation, wind turbines are grouped together in the same location and connected together in formations known as wind farms.
The Macarthur Wind Farm is Australia’s largest wind farm and is located near Macarthur, Victoria. With 140 turbines it has an installed capacity of 420MW and is jointly owned by AGL and Meridian Energy. The largest wind farm in the world is the Alta Wind Energy Center in California, US. It consists of 342 turbines and has an installed capacity of 1,020MW, with plans to expand to 1,320MW. China is currently building the world’s largest wind farm called the Three Gorges of Wind. Once installed it will have a capacity of 20,000MW.
Concentrated Solar Thermal
Also known as Concentrated Solar Power, utlises mirrors to concentrate the sun’s heat onto a central area. Housed in this area is usually water that is heated to approximately 1000°C to create steam. This steam is then used to power a turbine, in much the same way as a coal thermal plant. The arrangement of reflecting devices varies, but the premise of collecting solar energy, concentrating it to a central point and heating liquid is the same.
Concentrated solar thermal towers have been installed or are under construction in Spain, Mexico, Chile, South Africa, Algeria, Morocco, France, Germany, Italy, Egypt, China, Saudi Arabia, India, Thailand, the US and Australia. While the capacity of solar thermal plants remains small compared to other technologies, arrays of single solar thermal plant have achieved capacities of coal or gas comparable levels. The Solar Electric Generation Station (SEGS) project, which consists of nine concentrating parabolic trough plants in California’s Mojave Desert, has a capacity of over 350MW.
Cogeneration or Combined Heat and Power is the method of producing electricity and heat in the one operation from the one fuel source. Whilst many fuel sources are used in cogeneration natural gas forms the predominant primary fuel source.
Cogeneration systems use either a reciprocating engine, a steam turbine or a gas turbine. The heat produced from the electricity generating process is recovered and redirected to other processes. Two (forms of energy) for the price of one.
Cogeneration offers dual benefits of reduced energy costs and reduced greenhouse gas emissions. Thermal efficiencies can be more than doubled and CO2 emissions reduced by up to two thirds when compared with electricity generation from a conventional coal fired power station.
Cogeneration units come is a range of sizes from 100’s of kWs to hundreds of MWs. Processess that use large amounts of heat, hot water, steam or chilling water can benefit from cogeneration.
Typical examples would be in an industrial environment where the electricity generated can be used provide power for the industrial process and the heat can be used to provide process steam or hot water.
Similarly cogeneration can be applied to commercial buildings where again the electricity would be used for general light, power, mechanical services etc and the waste heat used to produce cooling water for air conditioning via absorption chillers. Hotels, abattoirs, paper plants, shopping centres, universities, and chemical plants can all benefit from cogeneration.
Improved quality and/or reliability of supply can also be achieved as the electricity supply for critical parts of a process can be met by the cogeneration plant and these processes can then be effectively isolated from the local electricity supply network where power quality problems are often generated.
The economics of cogeneration depend upon 4 key elements :
- Heat or hot water load
- Electricity load
- Gas cost
- Electricity cost.
Wave Power converts the kinetic energy of ocean surface waves into usable electricty. As the surface of the ocean oscillates up and down the energy in this movent can be harnessed and used to power a generator. This can be achieved in a number of different ways. Most commonly, a wave power device will use the motion of waves to pump a hydraulic fluid through a generator to convert into electricity. Another method is to have a linear generator which - unlike a conventional generator that revolves around an axis - uses the up-down motion to generate electricity.
To date, a number of problems have restricted the success of wave power, these include:
- High capital cost of installation
- High operating expenses - as servicing requires ships and/or submersive equipment
- Corrosion and aquatic life build-up are troublesome
For further info call T&O Consulting on (03) 9602 2181 or email to firstname.lastname@example.org.