Lemonade Award

I was nominated with an award - the Lemonade Award and this is my first award as a blogger (well, this is also my first blog). So, I would like to thank Eco Mama, Its all about our home, the Earth! and Goal For The Green for awarding me with it, and assure you that I really appreciate this acknowledgement! I think that making lemonade out of lemons can be an interesting endeavor, and besides, I like both lemons and lemonade :)

The Lemonade Award is passed to bloggers for showing great Attitude and/or Gratitude and now it's my turn to pass it to ten other blogs.

And here are my nominations :

SolReka
Environmental Chaos
Passionate Green
Chasing The Wind
Green not Mean
Eco-Blogical
Bulgarian Slivatree
Newton's Ocean
Life on a Southern Farm
Teddy Tour

The rules of this award for recipients:

1. Put the logo on your blog or post.

2. Nominate at least 10 blogs which show great Attitude and/or Gratitude!

3. Be sure to link to your nominees within your post

4. Let them know that they have received this award by commenting on their blog.

5. Share the love and link to this post and to the person from whom you received your award.

Solar Energy and Solar Power

Solar energy and solar power are two terms that are often used interchangeably but actually they are not the same thing. They both mean to receive and use solar rays, but more specifically solar power refers to electricity generated from the sun's light.

Solar energy is a more generic term and it describes all the uses of the light and heat from the sun. That includes solar power generation, but also solar thermal for water heating, space heating and cooling, and heat for industrial processes. Solar energy includes also passive solar energy that uses building orientation, design and materials to heat and cool buildings. 

Solar power is generated directly using photovoltaic (PV) technology. Solar PV panels (made from a semiconductor material) harness sunlight to create electricity to run appliances and lighting in your home. The electricity created by the solar system is direct current (DC), and the electricity we use in our homes is alternating currents (AC). Thus solar systems need an inverter which changes the DC current into useable AC current.

There are also concentrating solar power systems. They concentrate the sunlight using mirrors or lenses onto a receiver to produce heat. Then the heat can be used to generate electricity through steam turbines.

Solar energy is clean, environment-friendly, and most abundant renewable energy source we can use. In my next few posts, I will write about producing your own solar electricity by installing solar PV panels on the rooftop of your house, and what basic information householders need to know at the beginning.

Solar Heating Panels on the White House Roof

Still under the impression of the USA 2008 Presidential vote (although I am not an American) I found this information interesting to be published now.

Did you know that way back in 1979 (during the second US oil crisis) the American President Jimmy Carter installed solar heating panels on the roof of the White House West Wing? I personally didn't know that curious fact! And it seems that the Nobel Prize winning President Carter was quite a visionary.

In July 1979, President Carter outlined his plan for achieving energy independence and improving energy efficiency in his "Crisis of Confidence" speech. In an effort to set an example for the nation, he installed solar panels on the White House roof. They were more as a symbol of a new strategy to reduce America’s dependence of foreign sources of energy and a move designed to support Carter’s solar institute, which he had “created to spearhead solar innovation.”

Carter called for 20 percent of American energy to come from solar power by the year 2000. He even had very generous tax reductions implemented for people who installed solar panels at home.

The solar-energy system that President Carter installed consisted of 34 solar collectors which were used to heat water for the staff eating area and some other areas of the White House.

At the time, President Carter warned "a generation from now, this solar heater can either be a curiosity, a museum piece, an example of a road not taken, or it can be a small part of one of the greatest and most exciting adventures ever undertaken by the American people; harnessing the power of the Sun to enrich our lives as we move away from our crippling dependence on foreign oil." (It turns out Carter's warning was at least partially correct: One of his solar panels is now museum piece.)

In 1986, President Reagan had the solar panels removed during a roof in repair and put them into a federal storage facility. Actually, the solar panels were supposed to be reinstalled but they never were.

In 1991, the environmentally-minded Unity College of Maine, found the panels in a government warehouse in Franconia, Va., bought them for peanuts and installed them to use for the generation of hot water in the student dining hall.

By 2004, the solar panels had worn out. Unity College kept one of the panels for “historical significance,” donated another panel to the Smithsonian Institute and offered the rest for sale.

Even a documentary film has been made about the solar panels, using them as a backdrop to explore American oil dependency and the political lack of will to pursue alternative energy. Swiss directors Christina Hemaner and Roman Keller follow the route of the panels in the hour-long film "A Road Not Taken."

In 2003, the National Park Service, which manages the White House complex, installed a nine kilowatt solar electric or photovoltaic panels, on the roof of the main building used for White House grounds maintenance. Solar thermal systems were also installed to heat water: one for landscape maintenance personnel, the other for the presidential pool and spa.

Cellular Base Stations Powered by the Sun

It seems that the mobile industry is another technology field where solar power soon can play an important role in reducing costs and ensuring a reliable power supply.

In a new study ABI Research analysts predict that the future mobile phone base stations will be sun powered. They say that over 335,000 base stations worldwide will be using solar power by the end of 2013, with around 40,000 of those being completely autonomous and off-grid. The research firm explained that improvements in photovoltaic cells have meant that solar energy is now a viable option for supplying power to charging stations.

"The market for autonomous solar powered cell sites looks set to grow from extremely modest levels today to over 40,000 renewable energy sites by the end of 2013. A further 295,000 base stations are expected to supplement on-grid power usage with solar," said Stuart Carlaw, vice-president of ABI Research.

Still, the majority of these cellular base stations will use diesel or mains electricity to supplement their solar panels, especially in areas where population density and less solar energy require it.

Probably the developing countries will be the biggest winners as remote communities will receive phone coverage and Internet connections for the first time. According to some UN figures half of the world is still not able to make a phone call.

Other alternatives to normal electricity for base stations being considered are wind power, fuel cells and even compressed air.

Source: Market Watch

Thin-film Photovoltaic (PV) Cells

In some of my previous posts I have mentioned thin-film photovoltaic cells and in this article I'll give a brief overview of them.

Solar panels based on the photovoltaic effect have been used for more than thirty years and have traditionally been built using wafers of crystalline silicon, which requires expensive processing and results in ridged, heavy and fragile solar panels.

Crystalline silicon PV cells are still the mainstream products in the PV cell market because they have high conversion efficiencies. However, their output is increasingly being bogged down by shortage of raw material, high production cost and difficulty of processing. These factors have given rise to rapid development of second generation PV technology known as thin-film PV technology.

Thin-film solar cells are generated by coating a substrate (glass, thin flexible metal or plastic substrate) with layers of conductive and semi-conductive materials of a few micrometers in thickness. The individual layers of material are deposited by various processes.

The key materials for the thin-film solar cells are semiconductor elements such as amorphous silicon (a-Si, still silicon, but in a different form), cadmium telluride (CdTe) and copper indium (gallium) diselenide (CIS or CIGS).

Amorphous silicon (a-Si) was the first thin-film material to be commercialized, although, the PV cells built from amorphous silicon are invariably less efficient than crystalline PV. These PV cells have low efficiency and limited lifetime (approximately 10-15 years). Initially, a-Si was mostly used in consumer items such as calculators. Amorphous silicon is the most widely used for the creation of thin-film solar panels. It has a sun energy conversion rate as high as 9%.

Cadmium telluride (CdTe) is a highly useful material in the making of solar cells. Cadmium telluride PV (CdTe PV) is the first and only thin-film photovoltaic technology to surpass crystalline silicon PV in the marketplace in terms of lower system price for a significant portion of the PV market – large (multi-kW) systems.

CdTe PV cells structure includes a very thin layer of cadmium sulfide that allows most sunlight to pass through to the CdTe layer. These characteristics provide the potential for high-efficiency modules with low-cost manufacturing processes. CdTe cell efficiencies are over 16% in the laboratory; commercial module efficiencies are likely to be in the 9% range in the first manufacturing plants.

Copper indium gallium diselenide (CIGS) cells create more electricity from the same amount of sunlight than does other thin-film PV and therefore has a higher "conversion efficiency". Besides that, CIGS conversion efficiency is very stable over time, meaning its performance continues unabated for many years.

CIGS cells use extremely thin layers of semiconductor material applied to a low-cost backing such as glass, flexible metallic foils, high-temperature polymers or stainless steel sheets. They are of interest for space applications and the portable electronics market because of their light weight. CIGS cells are also suitable in special architectural uses, such as photovoltaic roof shingles, windows, siding and others. CIGS thin-film solar cell recently reached 19.9 percent efficiency, setting a new world record for this type of cell.

Thin-film PV technology has attracted a lot of interest in the recent years. The main reason for this interest is that thin-film PV cells are less expensive than other PV systems. Rather than being manufactured laboriously piece by piece, thin-film can be mass-produced in cheap rolls like packaging - in any colour. Thin-film PV cells also can harvest as much energy from the sun with far less semiconductor material. They can be made with flexible substrates which allow them to be used in more locations than silicon cells, such as clothing and sails. A number of applications are being pursued using thin-film PV technologies, including roof-top applications (such as rooftop shingles, roof tiles), building-integrated photovoltaics (BIPV), the glazing for skylights or atria, and utility-scale applications.

Thin-film PV cells represent the most promising technology for providing more affordable solar cells for residential and other uses in the future. According to NanoMarkets, the thin-film photovoltaics (TFPV) market will produce 26GW by 2015, generating over $20 billion in revenues.