The International Union for Conservation of Nature surveyed 47,677 of animal and plant species this year, ultimately listing 17,291 of the count under Red’s List of endangered species.

The Switzerland-based environmental group conducts a yearly examination of plant and animal species and 2009’s list topped last year’s by 2,800. However, the group admitted that the list is incomplete, and there remain millions of other specimens yet to be surveyed.

Rabb’s fringe-limbed tree frog

Among the new animals to be included in the list is Rabb’s fringe-limbed tree frog, discovered merely four years ago. It is but one of the 1,895 amphibians that could soon die out like the Kihansi spray toad of southern Tanzania (pictured above) which is known to be extinct in the wild. In fact, the fringe-limbed tree frog is threatened by the same fungal disease that killed off the Kihansi spray toads. This disease called chytridiomycosis is thought to have spread and reached Panama through international trade and global warming.
Source: Simply Green

Solar roof tiles

What is the true cost of solar power? The answer to this question may determine whether or not you decide to install solar panels on your home or business. In fact, in the current economy, everyone is worried about investments, and whether they make sense long term.

How does the cost of solar power factor in?

In order to accurately determine solar energy cost, you’ll need to consider a range of factors. Get your pencil out… you should write these down:

1. Current utility bills, averaged on a monthly basis
2. Projected future utility bills, over your estimated years of ownership of the property
3. Amount you may save annually in electricity bills
4. State and provincial solar energy tax rebates and other incentives, such as no money down
5. Type of solar panel system you want to install: PV Panels or Solar roof shingles
6. Other potential energy savings, through energy efficient bulbs, shutting off lights, adjusting thermostats
7. Other potential energy retrofitting measures, including windows, insulation, Energy Star appliances, etc.

When you consider the fact that solar power is free, once you install the panels, it may be worth it to consider converting now.

Case in point

Let’s say that your solar panel system will cost you R20,000.  Now, consider that your monthly electricity bills average R600 a month, which is R7,200 a year. That alone would be about a 3-year return on investment, but wait! What about the increase in value of your home? If you can save the entire R7,200 a year, multiply that figure by 20 which is the typical loan period you get R144,000.   That’s right: R144,000 in additional property value!

Eskom tarif hike

Now, add in the rising electricity rates that you won’t have to worry about. Oh, and the cost of continued global warming – you are doing your part you know… priceless!

You see, it just takes some focused arithmetic to determine the true cost of solar power. Think beyond your initial investment/outlay, and I’ll bet you will soon see that solar energy is the way to go, without requiring you to break the bank.
Source: Solar Panel | Green Power

1. Choosing the right solar panel for your needs is like choosing a battery.

In the same way that a bigger battery will provide more power for longer, a larger Solar panel will collect more energy in less time. The right size of panel will depend on variables such as the power required by the appliance, the length of time you want to use it and how much sunshine you get at the time of year.

2. There are three things to consider when choosing a solar panel or creating a solar system.

You need to know what appliances you will be using and how much energy they require, how much energy your battery can store and which solar panel will replenish your ‘stock’ of energy in the battery in line with your pattern of use.

3. How much energy will your appliance(s) use over a period of time?

The power consumption of appliances is given in Watts (e.g. 21” fluorescent light, 13W). To calculate the energy you will use over time, just multiply the power consumption by the hours of use.  The 13W light fitting, on for 2 hours, will take 13 x 2 = 26Wh from the battery.  Repeat this for all the appliances you wish to use, then add the results to establish total
consumption.

4. How much energy can your battery store?

Battery capacity is measured in Amp Hours (e.g. 17Ah). You need to convert this to Watt Hours by multiplying the AH figure by the battery voltage (e.g. 12V).  For a 17Ah, 12V battery the Watt Hours figure is 17 x 12 = 204Wh.  This means the battery could supply a 13W fluorescent for 15 and a half hours, 204W for 1 hour, or 102W for 2 hours, i.e. the more energy you take, the faster the battery
discharges.

5. How much energy can a solar panel generate over a period of time?

The power generation rating of a solar panel is also given in Watts (e.g. STP010, 10W).  To calculate the energy it can supply to the battery, multiply Watts by the hours exposed to sunshine, then multiply the result by 0.85 (this factor allows for natural system losses).  For the solar 10W panel in 4 hours of sunshine, 10 x 4 x 0.85 = 34Wh. This is the amount of energy the solar panel can supply to the battery.

Source: GreenWeld

During the initial years of electricity distribution, Edison’s direct current was the standard for the United States^[1] and Edison was not inclined to lose all his patent royalties. Direct current worked well with incandescent lamps that were the principal load of the day, and with motors. Direct current systems could be directly used with storage batteries, providing valuable load-leveling and backup power during interruptions of generator operation. Direct current generators could be easily paralleled, allowing economical operation by using smaller machines during periods of light load and improving reliability. At the introduction of Edison’s system, no practical AC motor was available. Edison had invented a meter to allow customers to be billed for energy proportional to consumption, but this meter only worked with direct current. As of 1882 these were all significant technical advantages of direct current.

From his work with rotary magnetic fields, Tesla devised a system for generation, transmission, and use of AC power. He partnered with George Westinghouse to commercialize this system. Westinghouse had previously bought the rights to Tesla’s polyphase system patents and other patents for AC transformers from Lucien Gaulard and John Dixon Gibbs.

Several undercurrents lay beneath this rivalry. Edison was a brute-force experimenter, but was no mathematician. AC cannot be properly understood or exploited without a substantial understanding of mathematics and mathematical physics, which Tesla possessed. Tesla had worked for Edison but was undervalued (for example, when Edison first learned of Tesla’s idea of alternating-current power transmission, he dismissed it: “[Tesla's] ideas are splendid, but they are utterly impractical.”^[3]). Bad feelings were exacerbated because Tesla had been cheated by Edison of promised compensation for his work.^[4][5] Edison would later come to regret that he had not listened to Tesla and used alternating current.^[6]

Source: Wikipedia

In 1887 direct current (DC) was king. At that time there were 121 Edison power stations scattered across the United States delivering DC electricity to its customers. But DC had a great limitation — namely, that power plants could only send DC electricity about a mile before the electricity began to lose power. So when George Westinghouse introduced his system based on high-voltage alternating current (AC), which could carry electricity hundreds of miles with little loss of power, people naturally took notice. A “battle of the currents” ensued. In the end, Westinghouse’s AC prevailed.
Source: PBS