Renewable energy is green energy:

Renewable energy is green energy:

Renewable energy is the energy which is made from resources that Mother Nature replaces, such as wind, water and sunshine. Renewable energy is also called “clean energy” or “green power” because it doesn’t pollute the air or the water. In fact, wind, water and sunshine are the cleanest and most abundant sources of energy we have.

However, these abundant and natural sources of renewable energy have few shortcomings, such as unlike natural gas and coal, we can’t store up wind and sunshine to use whenever we need to make more electricity. If the wind doesn’t blow or the sun hides behind clouds, there wouldn’t be enough power for everyone. Another reason why we prefer fossil fuels like coal and natural gas over natural sources of energy is because they’re cheaper. It costs more money to make electricity from wind, and most people aren’t willing to pay more on their monthly utility bills.

The prominent sources of renewable energy are: (i) Wind power, (ii) Biomass energy, (iii) Hydro power, (iv) Solar power, (v) Geothermal energy.

(i) Wind Power - Here a wind turbine is used to make electricity. Using the wind to create electricity has been around for a long time. When the wind turns the blades of a windmill, it spins a turbine inside a small generator to produce electricity, just like a big coal power plant. To make enough electricity to serve lots of people, power companies build "wind farms" with dozens of huge wind turbines. Wind farms are built in flat, open areas where the wind blows at least 14 miles per hour.

(ii) Biomass Energy - Biomass energy uses natural materials like trees and plants to make electricity. It can also mean waste products like trash. Biomass means "natural material." When biomass energy is burned, it releases heat – just like the wood logs in your campfire. Some of the common material used includes: (a) Leftover wood from sawmills. (b) Leftover paper and wood waste from paper mills. (c) Corn stalks, corn cobs and seed corn from farms. (d) Paper and cardboard that can’t be recycled in other ways. (e) Fast-growing crops and trees etc.

The philosophy behind biomass energy includes:

* Growing energy crops,

* Turning garbage into energy,

* Cow power or power from animal waste.

(iii) Hydro Power - A hydro power plant uses river water to make electricity. In fact, people have used water power for more than 2,000 years. In modern day, people built dams to control the power of the big mountain rivers. Workers can change the amount of water flowing through the dam depending on the weather and how much electricity people need.

(iv) Solar Power - “Solar” is the Latin word for “sun” – and it’s a powerful source of energy. In fact, the sunlight that shines on the Earth in just one hour could meet world energy demand for an entire year. We can use solar power in two different ways: (a) as a heat source, and (b) as an energy source.

Today we use solar collectors for heating water and air in our homes. We can also use solar energy to make electricity. The process is called photovoltaics. It’s difficult and expensive to make a lot of electricity using photovoltaics – the panels cost a lot, and a lot of open land is needed.

(v) Geothermal Energy - The hot lava from a volcano and the hot steam from a geyser both come from underground heat - and we can use that same type of heat in our homes. The system pumps a liquid through the pipes to absorb the heat and brings it back indoors. A device called a "heat exchanger" takes the heat from the liquid and uses it to heat the air inside the home. A geothermal system can cool your house during the summer, too! It just works in reverse, absorbing the heat from the air inside your home and moves it back into the earth. A geothermal heater is also very energy-efficient. Almost none of the energy used is wasted, so it helps keep heating bills very low during the winter.

Adoption of environment-friendly Green Technology in various fields is need-of-the-hour:

Adoption of environment-friendly Green Technology in various fields is need-of-the-hour:

Performance of green products is steadily improving, prices are going down, and tax breaks and subsidies are further helping erode financial barriers. The following list addresses environmental priorities in four broad consumer categories – (a) home, (b) car, (c) lifestyle, and the (d) future; identifying issues that consumers will face and ways they can help reduce the greenhouse gases they produce, minimize the depletion of natural resources, and produce and conserve energy more efficiently.

(a) Home –

1. Think solar panels. In many cases, solar can save you money in the long run. Solar panels also are getting more attractive.

2. Or think solar water. If you don't want to completely outfit your house with solar panels, you can deploy solar technology on an appliance-by-appliance basis.

3. Let the utility control your thermostat. These monitoring-and-control systems can indeed trim your use of peak power and lead to lower bills.

4. Move or remodel. If you're panning to buy a home, homes made from more eco-friendly materials should be given priority.

5. Switch to eco-friendly clothes and furniture.

6. Use green cleaning supplies. This is an important issue, but also one that's relatively easy to address.

(b) Car –

7. Buy a hybrid. Although the tax breaks on these cars can rise and fall, hybrids continue to get good reviews from customers, and the cars get quite a good fuel economy (about 60 miles a gallon).

8. Contemplate buying an electric car. Electric cars aren't perfect. Most barely can go more than 120 miles before needing a recharge and they cost more than their gas-powered equivalents, but advocates say both factors will improve.

9. Think diesel. Bio-diesel made from vegetable oil produces far less carbon dioxide than regular diesel. It can be put straight into conventional diesel cars.

(c) Lifestyle –

10. Swap the lightbulbs. Only about 5 percent of the energy that goes into incandescent lightbulbs turns into light. The rest turns into heat. Fluorescent-bulb manufacturers and light-emitting diode (LED) bulb makers say their products can produce as much light with far less energy.

11. Go organic in the garden. Traditional fertilizers and pesticides are made out of petroleum products and are being phased out by legislation due to concerns that they're causing health problems. Many companies have devised bio-pesticides, which kill fungi and other material with bacteria that's not harmful to humans.

12. Cut down on vampire-power gadgets. PCs, DVD players, televisions (especially some flat-panel models), and other devices can consume a lot of power, even in sleep mode, so unplug when you can.

13. Look for the green products and services such as dry cleaners or personal computer etc.

14. Buy carbon offsets. These arrangements are designed to allow individuals and organizations to reduce emissions directly or by participating in programs that, through various energy-conservation techniques and emissions-trading initiatives, attempt to achieve a net reduction in greenhouse gases.

(d) The future - Not everything will be easy when it comes to alternative energy. Here's a quick list of some other emerging technologies and issues that will likely become more prominent in the future.

15. Consider clean coal. Lung disease, mining accidents, environmental poisoning, these are just some of the associations mankind have with coal. Coal may never be as clean as solar power, but advocates point out the infrastructure already exists to adopt cleaner coal. In any event, phasing out coal will take years, so cleaner coal-burning technologies may as well be adopted.

16. Second and third thoughts on genetically modified (GM) crops. Corn, soy, sugar and other crops that now get converted to ethanol or bio-diesel have one thing in common: they were originally bred for food. To boost fuel production, these crops will likely need to be genetically enhanced.

17. Give up some open space for solar power and wind power. Providing solar power on a broad scale will require dedicating lots of land to power generation. Similarly, wind power often means placing large fields of turbines in the ocean.

18. Going for nuclear power generation in a big way. The nuclear issue is back on the table and will be one of many topics that governments of most of the nations will address when it comes to energy security.

19. Recycled water on tap. Water shortages will likely be the first major impact humans feel when it comes to global warming. China, Australia, and India already face significant challenges. To alleviate the problem, several countries are increasing investments in desalination technologies and purification systems for turning sewage water into drinking water.

20. High taxes. Developing green technologies and getting them into the market will require billions of dollars in grants, subsidies, and tax cuts that will often go to green-tech companies. Clean energy might require direct subsidies, but health care costs and the need for often-costly toxic-waste cleanups will decline.

Wind Energy – Renewable energy by harnessing wind power – Answer for Emission problem:

Wind Energy – Renewable energy by harnessing wind power – Answer for Emission problem:

People try to make many assumptions against wind turbines for generation of wind energy; but the fact remains, wind energy is most suitable form of renewable energy we can have to replace coal fired / nuclear powered / and even oil fired power plants in the near future. In support various points are discussed below:

1. Wind power is a clean, renewable source of energy which produces no greenhouse gas emissions or waste products. Power stations are the largest contributor to carbon emissions, producing tones of CO2 each year. We need to switch to forms of energy that do not produce CO2. Just one modern wind turbine will save over 4,000 tones of CO2 emissions annually.

2. The average wind farm will pay back the energy used in its manufacture within 3-5 months of operation. This compares favorably with coal or nuclear power stations, which take about six months.

3. A modern wind turbine is designed to operate for more than 20 years and at the end of its working life, the area can be restored at low financial and environmental costs. Wind energy is a form of development which is essentially reversible – in contrast to fossil fuel or nuclear power stations.

4. A modern wind turbine produces electricity 70-85% of the time, but it generates different outputs depending on the wind speed. Over the course of a year, it will typically generate about 30% of the theoretical maximum output. This is known as its load factor. The load factor of conventional power stations is on average 50%. A modern wind turbine will generate enough to meet the electricity demands of more than a thousand homes over the course of a year.

5. All forms of power generation require back up and no energy technology can be relied upon 100%. Variations in the output from wind farms are barely noticeable over and above the normal fluctuation in supply and demand.

6. The cost of generating electricity from wind has fallen dramatically over the past few years. Between 1990 and 2007, world wind energy capacity doubled every three years and with every doubling prices fell by 15%. Wind energy is competitive with new coal and new nuclear capacity, even before any environmental costs of fossil fuel and nuclear generation are taken into account. As gas prices increase and wind power costs fall – both of which are very likely – wind becomes even more competitive, so much so that some time after 2010 wind should challenge gas as the lowest cost power source. Furthermore, the wind is a free and widely available fuel source, therefore once the wind farm is in place, there is no fuel requirement or no waste related costs.

7. In future, we will need a mix of both onshore and offshore wind energy to meet the challenging targets on climate change. At present, onshore wind is more economical than development offshore. However, more offshore wind farms are now under construction. Thus, prices will fall as the industry gains more experience.

8. Wind energy is a benign technology with no associated emissions, harmful pollutants or waste products. In over 25 years and with more than 75,000 machines installed around the world, and there is no report of any body has ever been harmed by the normal operation of wind turbines.

9. The evolution of wind farm technology over the past decade has rendered mechanical noise from turbines almost undetectable with the main sound being the aerodynamic swoosh of the blades passing the tower.

10. We need to act now to find replacement power sources - wind is an abundant resource, and therefore has a vital role to play in the new energy portfolio all over the world.

Average onshore turbines discussed here is of capacity 1.8 MW. For many on-going projects at present the capacity over 2 MW turbines are being installed. Offshore, turbines currently being installed are rated at 3 MW, and it is expected that this will rise to a typical 5 MW per machine by 2010.

Sodium-Sulfur (NaS) battery possesses immense advantages to tackle environmental pollution problems:

Sodium-Sulfur (NaS) battery possesses immense advantages to tackle environmental pollution problems:

Until recently, large amounts of electricity could not be efficiently stored. Thus, to tackle the power cut problems industry used to get the services of Diesel Generating (DG) sets. Diesel generating system runs on diesel and, as we know, pollute environment in many ways. Apart, the quality and economy of electricity produced by DG sets are neither upto the standard nor at par with the electricity obtained from state power grid. Moreover, it helps in improving performance of renewable energy plants, specifically wind farms and solar generation plants, by delivering more reliable power.

A new type of large room-size battery, however, may be poised to store energy for the nation's vast electric grid almost as easily as reservoir stockpiles water, transforming the way power is delivered to homes and businesses. In general, the batteries, use for storage of electricity for many purposes, are plagued by limited life spans or unwieldy bulky.

A Sodium-Sulfur battery is a type of battery constructed from sodium (Na) and sulfur (S). This type of battery exhibits a high energy density, high efficiency of charge/discharge (89—92%), long cycle life, and is fabricated from inexpensive, non-toxic materials. Sodium-Sulfur (NaS) batteries are compact, long-lasting and much efficient to handle large power requirements. Using so-called NaS batteries, utilities could defer for years, and possibly even avoid, construction of new transmission lines, substations and power plants. A suggested application is grid energy storage.

The salient features of NaS batteries are:

(a) High energy density (compact);

(b) High charging-discharging efficiency;

(c) Long calendar lifetime;

(d) Environmentally friendly;

(e) Superior operation and maintenance requirements;

(f) Internal operating temperature is nearly 300 degree Celsius.

The advantages of NaS battery are:

(i) Reduce the investment in power plant and transmission and distribution facilities;

(ii) Improve the efficient use of existing power generation and distribution facilities;

(iii) Reduce power transmission losses;

(iv) Improve the reliability of electricity supply;

(v) They make wind power - wildly popular but frustratingly intermittent - a more reliable resource;

(vi) They provide efficient backup power in case of outages.

Above benefits are critical, as power demand is increasing by leaps and bounds everywhere. The NaS battery is the most advanced of several energy-storage technologies. USA and Japan is the leading user of NaS batteries for their power utilities.

Comparison of Sodium-sulfur (NaS) battery with Lead-Acid battery
Properties	NaS battery	Lead-Acid battery
Energy Density (Volume)	170 kWh/m3 (4.2)	40 kWh/m3 (1)
Energy Density (Weight)	117 kWh/ton (5.8)	20 kWh/ton (1)
Charge/Discharge Efficiency	More than 86%	More than 84%
Maintenance	Maintenance free	Regular maintenance
Life	2,500 cycles or more	1,200 cycles

The biggest drawback of NaS bettery, now, is price. The battery costs about $2,500 per kilowatt, about 10% more than a new coal-fired plant. That discourages independent wind farm developers from embracing the battery. Mass production, however, is expected to drive prices down.

Technology: A Sodium-Sulfur (NaS) battery consists of liquid (molten) sulfur at the positive electrode and liquid (molten) sodium at the negative electrode as active materials separated by a solid beta alumina ceramic electrolyte. The electrolyte allows only the positive sodium ions to go through it and combine with the sulfur to form sodium polysulfides.

2Na + 4S = Na2S4

During discharge, as positive Na+ ions flow through the electrolyte and electrons flow in the external circuit of the battery producing about 2 volts. This process is reversible as charging causes sodium polysulfides to release the positive sodium ions back through the electrolyte to recombine as elemental sodium. The battery is kept at about 300 degrees C to allow this process.

Sodium-Sulfur batteries are a possible energy storage application to support renewable energy plants, specifically wind farms and solar generation plants. In the case of a wind farm, the battery would store energy during times of high wind but low power demand. This stored energy can then be discharged from the batteries during peak load periods. In addition to this power shifting, it is likely that sodium sulfur batteries can be used throughout the day to assist in stabilizing the power output of the wind farm during wind fluctuations. These types of batteries present an option for energy storage in locations where other storage options are not feasible due to location or terrain constraints.