Alternative Energy: Solar Power

First, I’ll start by saying it was not the easiest thing to find information related to this subject that wasn’t from a solar energy information site, people trying to sell panels, etc. I didn’t want to use those, they seemed kind of biased, but the majority were those types of sites, so not all the questions are answered and not all the disadvantages and advantages are pointed out. With that being said, I split this up into two parts. The first part will talk about how solar panels work. Then the second will talk about the differences between the two types and the pros and cons.

Every hour the sun beams onto Earth more than enough energy to satisfy global energy needs for an entire year. Solar energy is the technology used to harness the sun’s energy and make it useable. Today, the technology produces less than one tenth of one percent of global energy demand.

There are two ways to get solar energy.

Concentrated Solar Thermal systems (CSP) are not the same as Photovoltaic panels; CSP systems concentrate radiation of the sun to heat a liquid substance which is then used to drive a heat engine and drive an electric generator. This indirect method generates alternating current (AC) which can be easily distributed on the power network.

Photovoltaic (PV) solar panels differ from solar thermal systems in that they do not use the sun’s heat to generate power. Instead, they use sunlight through the ‘photovoltaic effect’ to generate direct electric current (DC) in a direct electricity production process. When sunlight hits the cells, it knocks electrons loose from their atoms. A module is a group of cells connected electrically and packaged into a frame (more commonly known as a solar panel), which can then be grouped into larger solar arrays. As the electrons flow through the cell, they generate electricity.The DC is then converted to AC, usually with the use of inverters, in order to be distributed on the power network.

­Photovoltaic cells are made of special materials called semiconductors such as silicon, which is currently used most commonly. Basically, when light strikes the cell, a certain portion of it is absorbed within the semiconductor material. This means that the energy of the absorbed light is transferred to the semiconductor. The energy knocks electrons loose, allowing them to flow freely.

Silicon has some special chemical properties, especially in its crystalline form. An atom of sili­con has 14 electrons, arranged in three different shells. The first two shells — which hold two and eight electrons respectively — are completely full. The outer shell, however, is only half full with just four electrons. A silicon atom will always look for ways to fill up its last shell, and to do this, it will share electrons with four nearby atoms.That’s what forms the crystalline structure, and that structure turns out to be important to this type of PV cell.

The only problem is that pure crystalline silicon is a poor conductor of electricity because none of its electrons are free to move about, unlike the electrons in more optimum conductors like copper. To address this issue, the silicon in a solar cell has impurities — other atoms purposefully mixed in with the silicon atoms — which changes the way things work a bit. We usually think of impurities as something undesirable, but in this case, our cell wouldn’t work without them. Consider silicon with an atom of phosphorous here and there, maybe one for every million silicon atoms. Phosphorous has five electrons in its outer shell, not four. It still bonds with its silicon neighbor atoms, the phosphorous has an extra electron. It doesn’t form part of a bond, but there is a positive proton in the phosphorous nucleus holding it in place.

When energy is added to pure silicon, in the form of heat for example, it can cause a few electrons to break free of their bonds and leave their atoms. A hole is left behind in each case. These electrons, called free carriers, then wander randomly around the crystalline lattice looking for another hole to fall into and carrying an electrical current. However, there are so few of them in pure silicon, that they aren’t very useful.

But our impure silicon with phosphorous atoms mixed in is a different story. It takes a lot less energy to knock loose one of our “extra” phosphorous electrons because they aren’t tied up in a bond with any neighboring atoms. As a result, most of these electrons do break free, and we have a lot more free carriers than we would have in pure silicon. The process of adding impurities on purpose is called doping, and when doped with phosphorous, the resulting silicon is called N-type (“n” for negative) because of the prevalence of free electrons. N-type doped silicon is a much better conductor than pure silicon.

The other part of a typical solar cell is doped with the element boron, which has only three electrons in its outer shell instead of four, to become P-type silicon. Instead of having free electrons, P-type (“p” for positive) has free openings and carries the opposite (positive) charge.

B­efore now, our two separate pieces of silicon were electrically neutral; the interesting part begins when you put them together. That’s because without an electric field, the cell wouldn’t work; the field forms when the N-type and P-type silicon come into contact. Suddenly, the free electrons on the N side see all the openings on the P side, and there’s a mad rush to fill them. Do all the free electrons fill all the free holes? No. If they did, then the whole arrangement wouldn’t be very useful. However, right at the junction, they do mix and form something of a barrier, making it harder and harder for electrons on the N side to cross over to the P side. Eventually, equilibrium is reached, and we have an electric field separating the two sides.

This electric field acts as a diode, allowing (and even pushing) electrons to flow from the P side to the N side, but not the other way around. It’s like a hill — electrons can easily go down the hill (to the N side), but can’t climb it (to the P side).

When light, in the form of photons, hits our solar cell, its energy breaks apart electron-hole pairs. Each photon with enough energy will normally free exactly one electron, resulting in a free hole as well. If this happens close enough to the electric field, or if free electron and free hole happen to wander into its range of influence, the field will send the electron to the N side and the hole to the P side. This causes further disruption of electrical neutrality, and if we provide an external current path, electrons will flow through the path to the P side to unite with holes that the electric field sent there, doing work for us alo­ng the way. The electron flow provides the current, and the cell’s electric field causes a voltage. With both current and voltage, we have power, which is the product of the two.

There are a few more components left before we can really use our cell. Silicon happens to be a very shiny material, which can send photons bouncing away before they’ve done their job, so an antireflective coating is applied to reduce those losses. The final step is to install something that will protect the cell from the elements — often a glass cover plate. PV modules are generally made by connecting several individual cells together to achieve useful levels of voltage and current, and putting them in a sturdy frame complete with positive and negative terminals.

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A Trip to The iFactory

I found this article this morning and it’s pretty intense. It’s long, so I only copied the first few paragraphs to give of feel for what it’s about, but it goes a lot deeper than this, so I’ve given you the link below and I encourage you to read it. Also for those who don’t want to read it, it will be on Nightline TUESDAY, Feb. 21 at 11:35 p.m. ET/PT

http://news.yahoo.com/trip-ifactory-nightline-gets-unprecedented-glimpse-inside-apples-001926196–abc-news.html

“Okay.” “Okay.” “Okay.”

The voices are robot feminine and they never shut up, each chirp a surreal announcement that another new iPad is about to be born.

“Okay.” “Okay.” “Okay.”

The factory floor is spotless under the bright fluorescent lights and with hypnotic rhythm, thousands of hands reach into a conveyor belt river, bringing each gliding gadget to life one tiny piece at a time.

“Okay.” “Okay.”

A supervisor will bark the occasional order in Mandarin, but on this line the machines do most of the talking while the people work in silence.

Their faces are blank as they insert a chip or wipe a screen or plug in a diagnostic cable to hear that everything is “Okay.”

And they will repeat that motion and hear that fembot voice a few thousand more times before lunch.

It is just an average day at Foxconn.

 

Spoon

So…yesterday, I got an abundance of spoons. I found my new favorite stash.

It was just a normal day, I had just gotten out of class which means my next stop was Cherry Berry. I had to wait for a couple of people to go away, so I could get to the trash mostly unseen.  Once I got there, I realized something. There were not any spoons. There were three green spoons which I got, but they weren’t the kind I need now. There are two types of Cherry Berry spoons. The green ones which are thicker and therefore not the kind that will work for this project or the pink ones which are still thicker than your average plastic spoons. For my current project, I need the pink ones.

I had already made up my mind to get 17 pink spoons and once I make up my mind, there is no going back. Cherry Berry is in this strip mall type of a place and I knew in the alley way behind all the stores would be their trash, so slowly and apprehensively I drove to the back to see what was there.

I saw boxes everywhere and shipping pallets, small dumpsters (perfect for diving), huge dumpsters (not so perfect for diving) and I saw medium dumpsters (okay for diving). I saw all dumpsters and assessed them as quickly as I could. Then I saw these cut little trash bags filled with spoons and cups and lots of wasted frozen yogurt. I finished driving to the end of the stores because I thought I was going to come back later and get them, but there was no exit so I had to turn around and drive by the spoons again.

I stopped by them, I heard them calling. I knew I had to get those spoons. I came to get spoons and by golly I was going to get them. I quickly thought threw my options. I could either dig through the trash there and risk being caught or I could take the trash with me and risk getting all over my car and also risk being caught. I chose the latter. Luckily, I had a trash bag from my last trip to the recycle center, so it in there. Then I drove away. It was quite intense

My mom said she was surprised that I did that. I’m not sure why. It was easier than digging in the in front of the store. It was probably a little riskier because I could have been caught without an excuse like ‘I dropped my cell phone in here’ or something. But no one was around and unless someone came out one of the store doors, no one would even know I had been there.  My biggest fear is still getting caught. I would be a lot more productive if I didn’t have that fear, but I’m working on that.

So yes, I got my 17 spoons and a lot more.  Was it scary? Yeah. Do I feel a little crazy? Yep. Does my car still smell like Cherry Berry?…welllll… Was it totally worth it? Absolutely.

More than crazy, I feel like a drug junkie. You know the kind that do whatever it takes to get their stuff. I’m so addicted to the process that I’ll do whatever it takes to get it.

But then there is the haunting image of the trash that I saw. I couldn’t possibly use it all, not for the reason that I couldn’t find something to do with it, but because I simply don’t have the time. It’s overwhelmingly frustrating because I could take a whole semi truck full and it wouldn’t even make a dent. I could find a way to take it all, but then it would just be there again tomorrow. All those wasted boxes, clothes, electronics just ruining our land. We waste so many resources to even get the stuff then we just throw it away. I don’t understand why those places can’t recycle those boxes at least. I understand why businesses won’t give their stuff away for free. Even if it’s selfish, I still understand. I don’t understand why they can’t recycle. It’s so irresponsible. America is so irresponsible. Anyways, thanks for reading and happy diving.

E-waste

eWaste is the popular term for discarded electronic products such as computers, VCRs, cameras, cell phones, keyboards, handheld devices, and the associated peripheral devices that are frequently discarded or replaced due to upgrades or changing technology standards.

It’s to recycle E-waste for several reasons.

First, when electronics are thrown into landfills it releases toxic chemicals, carcinogens and heavy metals like lead, mercury, cadmium, chromium, chlorinated solvents, dioxins and brominated flame retardants, into the air, water and soil. When some of these toxins are burned at low temperatures they create more toxins such as halogenated dioxins and furans – some of the most toxic substances known to humankind. These toxins can cause different kinds of cancers, reproductive disorders, and many other health problems.  Most of these toxins are made up of elements which means although they change forms they will never disappear. Instead they will accumulate in the biosphere and in the food chain.

Second, recycling reduces greenhouse gas emissions, pollution, saves energy, and saves resources by extracting fewer raw materials from the earth.

To add to that problem, most companies that claim to recycle don’t do it responsibly.

According to Basel Action Network (BAN)  (http://e-stewards.org/the-e-waste-crisis/) An estimated 70-80% of the e-waste that’s given to recyclers is exported to less developed countries. Once there, primitive technologies such as open air burning and riverside acid baths are used to extract a few materials. The rest of the toxic materials are usually dumped. Unlike other countries in the world, the U.S. sends a significant portion of its hazardous e-waste to U.S. prisons to process in less-regulated environments without the worker protections and rights afforded in the private sector. Moreover, such operations amount to government subsidies, undermining the development of responsible private-sector recycling infra-structure and distorting the economics of recycling.

The Solution?

Find a responsible recycler that has been certified by e-stewards http://e-stewards.org/find-a-recycler/

I got the following statistics from www.dosomething.org

1. The nation now dumps between 300 million and 400 million electronic items per year, and less than 20% of that e-waste is recycled.

2. E-waste represents 2% of America’s trash in landfills, but it equals 70% of overall toxic waste. The extreme amount of lead in electronics alone causes damage in the central and peripheral nervous systems, the blood and the kidneys.

3. Because computer processing power doubles roughly every two years, many old computers are being abandoned. Only 15% recycle their computers, which means the other 85% end up in landfills.

4. It’s energy efficient to rebuild old computers, but only about 2% of PCs ever find their way to a second user.

5. About 50 millions cell phones are replaced worldwide a month, and only 10% are recycled. If we recycled just a million cell phones, it would reduce greenhouse gas emissions equal to taking 1,368 cars off the road for a year.

6. Flat panel computer monitors and notebooks often contain small amounts of mercury in the bulbs used to light them.

7. Cathode ray tubes in older TVs and computers typically contain about 4 lbs of lead and sometimes as much as 7 lbs.

8. The European Union banned e-waste from landfills in the 1990s, and current laws hold manufacturers responsible for e-waste disposal.

9. Large amounts of e-waste have been sent to countries such as China, India and Kenya, where lower environmental standards and working conditions make processing e-waste more profitable. Around 80 % of the e-waste in the U.S. is exported to Asia.

10.             E-waste legislation in the United States is currently stalled at the state level. Just 24 states have passed or proposed take-back laws. However, as of January 1, 2011, covered electronics are completely banned in West Virginia.

11.             Electronic items that are considered to be hazardous include, but are not limited to:

  • Televisions and computer monitors that contain cathode ray tubes
  • LCD desktop monitors
  • Laptop computers with LCD displays
  • LCD televisions
  • Plasma televisions
  • Portable DVD players with LCD screens.