Energy is the capacity of a physical system to perform work.
Energy exists in several forms such as heat, kinetic energy, light, chemical potential energy, elastic potential energy, electricity, or other forms.
Ways to conserve electricity:
Lighting
Lighting accounts for 8% of a typical household’s energy bills: cutting your lighting bill is one of the easiest ways to save energy and money in the home.
- ALWAYS turn the lights off when you leave the room. You will save energy by turning them off even for a few seconds.
- Most light bulbs will last longer if you don’t switch them on and off repeatedly throughout the day. But you won’t save money by leaving any type of light on for a few minutes to make it last longer. Just turn it off when you don’t need it and turn it back on again when you do.
- Try and arrange light switches so that it’s easy to turn them off. Make sure you can do this wherever it will help, usually at every door to a room or corridor. Otherwise you may be tempted to leave the light on for later.
- Use the right light for the job in hand. If you’re watching television you probably only want low level background lighting, but if you’re reading a book you will want something bright but local.
- Having a range of lights in a room, all with separate switches, will make it easier to achieve the lighting you want and need, whenever and wherever you want it. And you’ll save more energy than you would by using a single dimmer switch for the whole lot.
- Size matters, the most efficient products come in small packages
Energy ratings labels on appliances are generally given to products based on size categories. The idea is to enable you to compare between two similarly sized products.
This means two differently sized appliances with the same energy rating may use quite different amounts of electricity. For instance an four star rated 180-litre fridge freezer could cost only about $60 a year to run whereas a larger 525-litre fridge freezer with a better five star rating would cost about $90 a year to run.
In trying to save energy it is therefore best to look for the product with the best energy rating for the size of product you require.
Kitchen appliances
Fridges, freezers and fridge-freezers are switched on 24 hours a day, 7 days a week, so it's well worth finding models that are energy efficient. Choosing a new energy efficient model over the market average will save you around 390 kg of carbon dioxide over the lifetime of the product. Look for the right size and the logo. Energy labeled refrigeration appliances must all have an five star or four star energy rating. You can compare the total energy consumption of appliances by looking for their yearly energy consumption in kWh / annum displayed on the bottom right of its energy label.
Tumble dryers: Drying clothes outdoors on a washing line or indoors on a rack costs nothing and uses no energy so it is the ideal way to dry your clothes. But if you need to use a tumble dryer, they use a great deal of energy, so choose one with the Energy label and it will cost less to run, helping you to reduce your energy bill. Choose one that has a sensor that tells when your clothes are dry enough, preventing your clothes from being over dried and the dryer running when it doesn’t need to.
- Gas tumble driers are one of the cheapest and most environmentally friendly type of drier to run. But this type of drier can be slightly more expensive to install as it needs a gas connection.
- Electric heat pump tumble driers are also very efficient as they recycle the heat from the ventilation tube back into the drier, but take away the water vapour from the air.
Washing machines: An energy efficient machine will save you money on to your electricity bill and, if you have a meter, your water bill too. All our recommended washing machines are rated the best in class for energy efficiency, spin efficiency and wash performance.
Home entertainment
Digital television recorders: Recording your favourite shows doesn’t have to cost more in energy bills. In most homes, entertainment equipment accounts for about 20% of your electricity bill.
- HD and 3D TV: Many homes now have cable HD TV and most televisions on the market nowadays are HD ready. HD TVs have more pixels per square inch of screen area and therefore tend to consume more energy than SD (Standard Density) televisions. Buying a smaller SD TV is likely to use less energy than an HD TV, but with the move towards HD broadcasting you might wish to consider how long into the future you are happy to continue using an SD TV.
- LED, LCD and plasma screen are most common forms of flat-screen TVs on the market. LED and LCD TVs are not as good for seeing the screen from sideward angles, but otherwise there is little difference between the picture quality of these and plasma screen TVs. However, plasma screen TVs tend not to come in smaller sizes, and generally use more energy than similar sized LED or LCD TVs.
Computer equipment
Household computers, printers, monitors and laptops on average make up around 13% of electricity around the home. Choosing an energy-efficient computer can have a real impact on your carbon dioxide emissions and your energy costs.
Desktop and laptop PCs: Laptops typically uses 85% less electricity over a year than desktop PCs do, so they're already the more energy-efficient choice. If your computing needs are met by a laptop, then why not consider one as an alternative to a desktop PC? With smaller components and screens, laptops use much less electricity than desktop computers. If you do need a desktop computer, choose a PC that uses less energy in 'sleep' and 'standby' too, not just when it's running.
Inkjet printers: Whether it's a single-function or multi-function inkjet printer that copies, scans and faxes too, there's an energy saving choice.
Renewable Energy
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Ocean Energy
The ocean can produce two types of energy: thermal energy from the sun's heat, and mechanical energy from the tides and waves.
Oceans cover more than 70% of Earth's surface, making them the world's largest solar collectors. The sun's heat warms the surface water a lot more than the deep ocean water, and this temperature difference creates thermal energy. Just a small portion of the heat trapped in the ocean could power the world.
Workers install equipment for an ocean thermal energy conversion experiment in 1994 at Hawaii's Natural Energy Laboratory. Credit: A. Resnick, Makai Ocean Engineering, Inc.
Ocean thermal energy is used for many applications, including electricity generation. There are three types of electricity conversion systems: closed-cycle, open-cycle, and hybrid. Closed-cycle systems use the ocean's warm surface water to vaporize a working fluid, which has a low-boiling point, such as ammonia. The vapor expands and turns a turbine. The turbine then activates a generator to produce electricity. Open-cycle systems actually boil the seawater by operating at low pressures. This produces steam that passes through a turbine/generator. And hybrid systems combine both closed-cycle and open-cycle systems.
Ocean mechanical energy is quite different from ocean thermal energy. Even though the sun affects all ocean activity, tides are driven primarily by the gravitational pull of the moon, and waves are driven primarily by the winds. As a result, tides and waves are intermittent sources of energy, while ocean thermal energy is fairly constant. Also, unlike thermal energy, the electricity conversion of both tidal and wave energy usually involves mechanical devices.
A barrage (dam) is typically used to convert tidal energy into electricity by forcing the water through turbines, activating a generator. For wave energy conversion, there are three basic systems: channel systems that funnel the waves into reservoirs; float systems that drive hydraulic pumps; and oscillating water column systems that use the waves to compress air within a container. The mechanical power created from these systems either directly activates a generator or transfers to a working fluid, water, or air, which then drives a turbine/generator.
Nuclear Energy
Nuclear energy is energy that comes from a nucleus, the core of an atom. Atoms are particles that make up every object; and there exists a lot of energy (binding forces) which holds these atoms together. Nuclear energy can be used to make elecricity, but for this to happen the energy has to be released from atoms. There are two ways energy can be released from an atom: nuclear fusion or nuclear fission (which are exact opposites). Nuclear fusion means that atoms combine to fuse into a larger atom (which is how the sun produces energy). Nuclear fission means that the atom splits into smaller atoms releasing energy. Nuclear power plants use nuclear fission to create electricity. The fuel that nuclear power plants use for nuclear fission is uranium. Unlike solar power and wind energy, uranium is a non-renewable resource. Inside the nuclear reactor, where fission takes place, a particle called a neutron hits the uranium atom, which then splits the uranium atom releasing a great amount of energy as heat and radiation. In a boiling-water reactor (BWR) heat is used to boil water, produce steam and the steam then turns a turbine. So nuclear power plants use the heat during the fission process to produce electricity. In a pressurized-water reactor (PWR) the water passing through the reactor is not transformed to steam as it is kept under intense pressure. It remains liquid. The PWR has a steam generator on the side and channels its radioactive water to this steam generator. The uranium fuel produced is formed into ceramic pellets the size of a capsule but each one produces the same amount of energy as 675 litres of oil. Nuclear energy is highly efficient but also has highly toxic waste as a byproduct, however nuclear power plants do not release any CO2 emissions.
Wave Energy
Waves are generated by the wind as it blows across the sea surface. Energy is transferred from the wind to the waves. Wave energy is sometimes confused with tidal energy, which is quite different. Waves travel vast distances across oceans at great speed. The longer and stronger the wind blows over the sea surface, the higher, longer, faster and more powerful the sea is. The energy within a wave is proportional to the square of the wave height, so a two-meter high wave has four times the power of a one-meter high wave.
It is distributed across the globe and thus offers many countries the benefit of security of supply
Generated over large areas of ocean and, once generated, travel immense distances with only small energy losses.
Can be anticipated one or two days in advance through direct satellite measurements and meteorological forecasts which provide a high level of predictability and hence good network planning.
Good seasonal load-following for regions where electricity demand peaks in winter given heating and lighting requirements.
Although wave energy is a concentrated source of wind energy, as it has often travelled very large distances it is regularly out of phase with the local wind conditions. Wave energy can therefore help to balance output variability from other renewable sources and maximise the efficient use of electricity networks
Waves effectively average out the wind that generates them over large areas which results in a high level of consistency compared to wind or solar. Only on very few days per year are waves too weak to generate electricity.
Kinetic energy (movement) exists in the moving waves of the ocean. That energy can be used to power a turbine. The wave rises into a chamber, the rising water forces the air out of the chamber, the moving air spins a turbine which can turn a generator. When the wave goes down, air flows through the turbine and back into the chamber through doors that are normally closed. Most wave-energy systems are very small. But, they can be used to power a warning buoy or a small light house.
Tidal Energy
When tides comes into the shore, they can be trapped in reservoirs behind dams. Then when the tide drops, the water behind the dam can be let out just like in a regular hydroelectric power plant. In order for this to work well, you need large increases in tides. An increase of at least 16 feet between low tide to high tide is needed. There are only a few places where this tide change occurs around the earth. Some power plants are already operating using this idea. One plant in France makes enough energy from tides to power 240,000 homes.
Geothermal Energy
The source of geothermal power is the heat contained inside the Earth; heat so intense that it creates molten magma. There are a few different types of geothermal energy that can be tapped. Some geothermal systems are formed when hot magma near the surface (1,500 to 10,000 meters deep) directly heats groundwater. The heat generated from these hot spots flows outward toward the surface, manifesting as volcanoes, geysers, and hot springs . Naturally-occurring hot water and steam can be tapped by energy conversion technology to generate electricity or to produce hot water for direct use. Other geothermal systems are formed even when no magma is nearby as magma heats rocks which in turn heat deeply-circulating groundwater. In order to maximize the energy gleaned from these so-called "hot dry rocks," geothermal facilities will often fracture the hot rocks and pump water into and from them in order to use the heated water to generate electricity.
The concentration of geothermal energy at any given location must be quite high in order to make heat extraction feasible, and not all geothermal sites are created equally. Regions that have well-developed geothermal systems are located in geologically active areas. These regions have continuous, concentrated heat flow to the surface. The western United States has the best geothermal regions in the country, while Iceland , New Zealand , the Philippines , and South America , are some of the more prominent global "hot spots." In Iceland , geothermal energy, caused by the constant movement of geologic plates coupled with the volcanic nature of the island, is used to heat 95% of all homes.
Unfortunately even good geothermal areas are a non-renewable. "The Geysers," the world's largest geothermal facility, is a working model on how not to approach a so-called "renewable" geothermal resource. Built in the 1950s on a steam field in Northern California , the facility was established on the apparent assumption that geothermal resources were infinite at that location. However, by the late 1980s, steam decline became noticeable and sustained. Depletion occurred because steam was being extracted faster than it could be naturally replaced. According to a report by Pacific Gas and Electric, "because of declining geothermal steam supplies, the Company's geothermal units at The Geysers Power Plant are forecast to operate at reduced capacities." In response, "plant operators and steam suppliers continually seek new operating strategies to maximize future power generation coupled with daily injection of millions of gallons of reclaimed municipal wastewater." Even though improvements in efficiency and conservation are being implemented and in 1996 The Geysers was still producing enough electricity to supply the power demand of a city like San Francisco , it is projected that the steam field will be defunct in 50 years or so. To prevent this sort of thing from happening elsewhere, geothermal facilities can use a closed-loop system at all times, or the re-injection of water back into the system for constant steam generation, as PG&E is now implementing at The Geysers.
Despite the fact that geothermal energy is able to reduce our dependence on imported fuels, the fact remains that fields of sufficient quality to produce economic electricity are rare. In addition, many of those that are known are located in protected wilderness areas that environmentalists want to preserve. Unless research and technology join forces to "harvest" geothermal power through non-traditional means, such as deep-crustal drilling or the acquisition of heat from magma, the tapping of geothermal energy is limited to a handful of locations. Environmental concerns also taint the issue of geothermal energy. Although no combustion occurs, some applications produce carbon dioxide and hydrogen sulfide emissions, require the cooling of as much as 100,000 gallons of water per megawatt per day, and dispose of toxic waste and dissolved solids.
Another type of geothermal energy being used commercially is Earth energy, extracted through heat pumps. Heat contained in shallow ground is used to directly heat or cool houses since the temperature inside the ground tends to stay at the yearly average. Therefore, in the winter the ground is warmer than the air and can be used to heat a building, and in the summer the ground is cooler than the air and can act as an air conditioner. Researchers know that "no active technology for home cooling is more efficient than the geothermal heat pump." This technique reduces the reliance on other resources and can be utilized anywhere, resulting in significant environmental benefits and reduced energy costs.
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Solar Energy
Solar power is produced by collecting sunlight and converting it into electricity. This is done by using solar panels, which are large flat panels made up of many individual solar cells. It is most often used in remote locations, although it is becoming more popular in urban areas as well.
The two main types of solar power systems are grid connect and off grid (stand alone/remote power).
With a business or residential grid connect system, your house or property is still connected to the mains power supply, so battery storage is not required. A grid connect installation ensures you have the electricity you need, whenever you need it - automatically and regardless of conditions.
An off grid solar power system is completely separated from mains power and utilises a deep cycle battery bank for storing electricity generated by solar panels. Off grid installations are most common in rural and outback areas of where the mains grid simply isn't available, or prohibitively expensive to connect to.
Other applications for solar energy include hot water systems and solar powered pumping.
Biomass
Biomass is biological material derived from living, or recently living organisms. In the context of biomass for energy this is often used to mean plant based material, but biomass can equally apply to both animal and vegetable derived material.
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Biomass is carbon based and is composed of a mixture of organic molecules containing hydrogen, usually including atoms of oxygen, often nitrogen and also small quantities of other atoms, including alkali, alkaline earth and heavy metals. These metals are often found in functional molecules such as the porphyrins which include chlorophyll which contains magnesium. The carbon used to construct biomass is absorbed from the atmosphere as carbon dioxide (CO2) by plant life, using energy from the sun.
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Plants may subsequently be eaten by animals and thus converted into animal biomass. However the primary absorption is performed by plants.
If plant material is not eaten it is generally either broken down by micro-organisms or burned:
These processes have happened for as long as there have been plants on Earth and is part of what is known as the carbon cycle.
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Fossil fuels such as coal, oil and gas are also derived from biological material, however material that absorbed CO2 from the atmosphere many millions of years ago. As fuels they offer high energy density, but making use of that energy involves burning the fuel, with the oxidation of the carbon to carbon dioxide and the hydrogen to water (vapour). Unless they are captured and stored, these combustion products are usually released to the atmosphere, returning carbon sequestered millions of years ago and thus contributing to increased atmospheric concentrations.
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Categories of biomass materials:
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http://www.renewableenergyworld.com/rea/tech/ocean-energy
http://www.energymatters.com.au/renewable-energy/nuclear-energy/
http://www.pelamiswave.com/
http://inventors.about.com/od/tstartinventions/a/tidal_power.htm
http://www.renewableenergyworld.com/rea/tech/hydropower
http://www.altenergy.org/renewables/geothermal.html
http://www.alternative-energy-news.info/technology/solar-power/
http://www.energymatters.com.au/renewable-energy/solar-power/
http://www.biomassenergycentre.org.uk/portal/page?_pageid=76,15049&_dad=portal
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