By Gloria Smith
Geothermal energy is one of the renewable forms of energy being utilized today in various applications. As a natural resource that is in abundant supply, its usage in the future is expected to grow more.
The term geothermal is actually a combination of two Greek words - geo which means earth and therme meaning heat. As one of earth's resources, geothermal energy is clean and can be sustained for long years.
This alternative energy comes from the earth's heat found underneath its surface. The earth's crust is mainly a result of the past existence of millions of volcanoes and great volumes of magma that did not erupt but rather cooled below the surface. In addition, the earth's core has high temperatures between 50 and 60 degrees Fahrenheit that remain constant throughout the year.
This makes it an ideal source of heat for various purposes. Among its resources include the shallow ground, hot water and hot rock below the earth's surface and molten rock or magma deep down. These resources have two main categories - the high temperature (220 degrees Celsius and above) geothermal resources found in volcanic regions and island chains and the moderate/low temperature found on all continents. The high temperature resources are mostly used in power production.
In extracting hot water for geothermal reservoirs, wells are normally drilled into underground reservoirs for use in generating electricity. The steam from a reservoir is used by some geothermal power plants to power turbine/generator. Other plants use the hot water to boil a working fluid that vaporizes and then turns a turbine.
Hot dry rock, on the other hand, can be found about three to five miles deep down the earth's surface. In certain areas, they can be found at lesser depths. To extract heat from these rocks, cold water is injected down a well which filters through the cracks in the rocks situated in the hot region. Heated water is eventually drawn off from the recovery well. This then flashes into steam upon reaching the surface.
Steam can be used to drive a turbo generator. However, in order to do this, steam must first be purified. In heating homes, it can pass through a heat exchanger to provide heated water.
A hot dry rock system (EGS) reaches at least 10 kilometers down into hard rock. It is estimated that the United States alone has a huge resource of hard rocks that can supply the world's energy needs for some 30,000 years.
Hot water sourced underground can be used in a number of ways such as in generating electricity, heating buildings, growing plants in greenhouses, drying crops, heating water at fish farms. In industrial application, it is used in pasteurizing milk.
Geothermal heat pumps are used in heating and cooling homes and buildings. This type of heating system is made up of a heat pump, ductwork or air delivery system and a loop or a series of pipes buried in the shallow ground near the home or building.
Currently, geothermal power is produced in more than 20 countries. These include the U.S., Italy, Germany, France, The Netherlands, Mexico, Russia, New Zealand, Turkey, China, Japan, the Philippines and Iceland. The first geothermal power plant was constructed at Landrello, Italy while the second was built at Wairekei in New Zealand.
By Simon Harris
The use of propane has greatly increased over the years. There are several factors for this. In some cases natural gas line are not available in certain areas. There are no other options that are available. In some cases propane has become of the fuel of choice. This is especially true when home owners want to avoid an all electric home and cut back on some of the cost of using other fuel alternatives. If you decide to use propane as a fuel source for your home you must consider propane tanks and all of the details that are associated with installation.
Of course propane tanks are necessary to hold and store your fuel source. They are available in many different sizes but all of the construction is just about the same. Most of them are stored above the ground because it is less costly and provides easy access. You can store them under ground but it will cost you more money and the access to the tank becomes a problem in some cases. The homeowner can purchase a tank on average from 500 gallons to 1000 gallons. Keep in mind that a tank can not be filled to capacity. You must leave room at the top for expansion of the propane gas. A good rule to follow is to fill it only to eighty percent of capacity. This will ensure safety and security for your tank.
Make sure to contact your local gas supplier when thinking about using propane. They will be able to provide you will solid and accurate details on the system you will need for propane gas usage. They will give you advice on the size of propane tanks and what you need for your home according to what you are going to use for your system. These professionals offer the best advice as to a plan of action and can provide you with the help you need.
There is no doubt that propane is a good source of fuel and provide many homes with an alternative source of power and energy. Putting in a propane system for your home is not difficult and it is not unreasonable in cost. You can investigate the possibilities for your home with a little research and by talking with your local gas supplier.
Simon Harris writes about Propane Tanks at http://www.propane-prices.org/
By Steven D. Foster
Some people believe that our energy source in the world will soon be depleted. Our massive use of oils and gasoline will eventually diminish not only our lives but also our environment. The oil companies are sending us a clear message that we will always be dependent on their resources and will never exist without it. Do we even know anything about alternative energy? Have we ever considered how important and helpful alternative energy can be? Why are we so reliant in oils and gasoline to run our machines, industries, and markets?
On February 24, 2009, The President of the United States of America, Barack Obama addressed a speech to the joint session of Congress about the use of alternative energy. He said that "To truly transform our economy, protect our security, and save our planet from the ravages of climate change, we need to ultimately make clean, renewable energy the profitable kind of energy."
What is alternative energy?
Basically the term alternative energy is a renewable energy intended to substitute the traditional fuel sources of our world. It is also a fundamental way to relieve the undesirable consequences derived from the use of oils, gasoline, nuclear energy, and fossil fuels. The adverse effects caused by these traditional fuel sources are:
Global Warming. Release of High Carbon Dioxide in the atmosphere. Obscure disposal of harmful Radioactive Waste. And many more unwanted outcomes to our planet.
Alternative energy is the best solution for the unwanted effects of these traditional fuel sources. And the role of "Hydrogen Fuel" as an alternative energy source is very important in achieving positive changes for our environment. It will also provide us sufficient energy sources that will not only power our machines but will also take us to the next significant step in saving our planet.
What is Hydrogen?
Hydrogen is the third most abundant element of the universe. It is a chemical element with an odorless, tasteless, and colorless characteristic. Hydrogen is a highly flammable diatomic gas which has the lightest weight from to all the elements in the world.
When we use hydrogen as a fuel, it burns more cleanly than a regular gasoline. It does not release harmful carbon dioxide that is detrimental to our atmosphere. Here are some positive attributes of a Hydrogen Fuel:
It can be made from different plentiful resources such as coal, natural gas, biomass and water. It can also be created by transferring electrical current through water with a process called electrolysis. When used in an engine or motor, it can emit no harmful gasses. The only waste it produces is water vapor. It has the highest content of energy compared to other kinds of fuels. Disadvantage of a Hydrogen Fuel: Producing Hydrogen Fuel takes a sizeable amount of energy from fossil fuels, and may tend to be more expensive than using traditional kinds of fuels. Some believes that Hydrogen Fuel production is not too economical today.
The Future of Hydrogen Fuel A handful of economist believes that by producing hydrogen fuel from renewable energy like solar and wind power, we may actually lower the cost of making hydrogen fuel. This can also pave the way in producing more alternative energy to power our vehicles, industries and cities. Hydrogen, as an alternative energy For Better Fuel, can actually be our hope for a better and more environment friendly future.
The Solar Battery Charger - Free, Clean, And Renewable Energy
By = David Faulkner
One of the most annoying realities of our electronic lifestyle is that so many of our electronic must-haves are battery operated. And depending on how often we use them, the life of their batteries can be from a single day to a couple of weeks. While a package of disposable batteries, depending on their size, usually costs less than $5, if they are powering an addiction forming device lie a GameBoy, you may burn through them the way a chain smoker burns through a pack of cigarettes.
While TV remotes, flashlights, and smoke detector batteries may only need changing once or twice a year, GameBoys, MP3s, and cell phones are different stories. Not only that; some of the most-used battery-powered devices require not one, but two batteries. The simple truth is, even disposable batteries can make a dent in the entertainment budget.
Not only that; actually disposing of disposable batteries has become an issue, and many landfills are no longer taking them because of the danger they pose to groundwater. Fortunately, many battery manufacturers have been ahead of the environmental curve in addressing this issue, and are now marketing rechargeable batteries to replace disposable ones. And they have gone one environmental step further by creating the solar battery charger.
Advantages Of Solar Battery
A solar battery
charger has two advantages; unlike wall chargers, it does not use energy which you have to pay for to recharge your batteries, and unlike wall chargers, it does not require an electrical outlet. A solar batter charger has built in solar panels which, when placed in a sunny locations, gather the suns rays, which the charger converts to free electricity and feeds to your rechargeable battery or batteries.
As long as you have sun, youll have a way to keep you electronic devices up and running; and a solar battery charger can get your batteries fully recharged in as little as three hours on the brightest days. Most rechargeable batteries are equipped with a light to let you know when they have reached their full charge.
A solar battery
charger is not large; in fact it is easily transportable so that you can move it to whatever location will provide the best sun exposure. With a solar battery charger and rechargeable batteries, you need never worry about running out of power for your electronic device again. And even better, you will be powering them with free, renewable, clean solar energy, stored in rechargeable batteries which require no environmentally-threatening disposal!
Directions for a system that can heat seventy liters of water to sixty degrees Celsius.
Transcript of radio broadcast:
19 April 2009
This is the VOA Special English Development Report.
Solar water heaters are devices that use energy from the sun to heat water. Solar water heating is used around the world.
An example of a rooftop solar water heater
being built in South Africa
The solar water heater described here is based on a design developed some years ago in Afghanistan. Since then, it has been built and used in many countries. It can heat seventy liters of water to sixty degrees Celsius. It can do this between sunrise and noon on a clear day with an average outside temperature of thirty-two degrees Celsius.
There are two parts to the solar water heater. One part is made of a sheet of metal painted black. This metal surface, placed in contact with the water, will heat the water. Black-painted surfaces that receive the sun's heat become hotter than surfaces of any other color.
The black metal plate is called a collector. There are several kinds of metal sheets that can be used for the collector. Metal sheets that have raised sections will work very well. These corrugated sheets often are used to make the roofs of houses.
Once the water is heated, it is kept hot with material called insulation. This allows the water to stay warm for a long time.
The second part of the solar water heater holds the water for the system. This storage tank can be a container that holds about one hundred liters. Two rubber pipes are attached to the water storage tank. One pipe lets water flow into the system. The other lets water flow out.
When the water heater is working correctly, water will flow from the storage tank to the collector and back again. You can use the hot water at the top of the tank for washing and cleaning. You can change the flow of water so that the temperature is hot or warm as desired.
This solar water heater is easy to build and operate. It will last about two years before the rubber pipes need to be replaced.
There is also something else you will need to make the solar water heater work -- the sun. As you might expect, the heater will heat water only on sunny days.
You can get more information about projects like solar water heaters from EnterpriseWorks/VITA. This nonprofit group works to fights poverty in many countries. The Web site is enterpriseworks.org. Choose the link for News & Resources, then click on Publications.
Transcripts, MP3s and podcasts of our reports are at voaspecialenglish.com.
And that's the VOA Special English Development Report. I'm Steve Ember.