Hello again, to whoever may read this blog! I have been taking a break for a while from writing in this since I graduated from Western this past June. I’m entering the frightening and difficult world of finding a job as a recent college grad.
The summary of the article is this: scientists at MIT have found a way of better storing solar energy for later use. Awesome. We need to advance the technologies of solar energy or people will continue to dismiss it as an unreliable alien method of energy capable of only powering one measly light in your home if you’re lucky and the sun is shining hot and bright. The method that scientists have found is to use carbon nanotubes combined with a chemical compound called azobenzene. And this got me thinking about where I have heard of chemicals containing Benzene. Benzene compounds are used in soft drinks, agricultural pesticides, and various other things. They are known carcinogens and have been connected to organ failure and disruption of the endocrine system. I’m not entirely sure from the article how this chemical would be stored, what the risk of exposure to humans would be, but it doesn’t seem like a very environmentally friendly method for trying to enhance a form of energy designed to reduce our impacts upon the ecosystem. Another issue would concern disposal. If this chemical were to be contained in a battery like storage device, most likely, that device does have an expiration date. So what happens to that product when it is no longer usable? Into the dump? Will this chemical leach out of its container and contaminate the surrounding ecosystem?
Now, I’m no expert (yet!), so I couldn’t go making suggestions for what to do. I just feel strongly about certain things NOT to do. Maybe with more research and education I could begin to hypothesize my own method of storing solar energy. Because there is no arguing that it is a vital piece in allowing us to better use energy derived from the sun. I know that scientists do their best, but surely this isn’t the right direction in “green chemistry”.
This is my last section on alternative energy. I know this has taken forever to get up – I had a lot of background research to do, and it make much more sense to do this all in one full post rather than a few smaller ones. I might elaborate on some of these issues in later posts, since this topic such a large one. There are so many cool things being done in the area of solar energy, it’s hard to keep up sometimes!
Projections for energy use estimate that by 2030, the entire globe will be consuming 16.9 trillion watts of power, compared to our current amount of approximately 12.5 TW (trillion watts). If energy production were acquired solely through non-fossil fuel sources, the amount of energy needed would actually decrease to approximately 11.5 TW. This is because renewable energy is used to create electricity, which is a more efficient source of power. An example of this can be seen in cars, where only 17-20% of the energy is actually used, where as the rest is expelled as waste energy in the form of heat. An electric car would utilize 75-86% of that electricity to power the vehicle. Similarly, generating electricity through burning coal is inefficient. If energy demand continues to rise while we are using fossil fuels only, thousands of new plants will be needed to meet this demand, and could cost upwards of $10 trillion. While creating an infrastructure for new solar and wind energy production could be costly, the benefit lies in the fact that we would be investing in a source that would not become outdated. If we invest trillions of dollars in coal plants, those plants are useless once coal is gone. If we stay reliant upon fossil fuels, then as energy demand increases, we will need to build more plants. Solar power plants and wind turbines constitute an infrastructure that needs no expansion once established. Many scientists believe that in the switch to alternative energy, combining both solar and wind power will create a sufficient supply. The two are complementary sources, since solar power is not generated at night, but strong winds can power turbines during the night instead. The article in Scientific American that I referred to in the first part of this section on alternative energy outlines the various facilities to supply the globe with enough energy without using fossil fuels. Using a combination of WWS sources, solar would constitute 40% of the global power supply through solar power plants and solar panels on rooftops of homes and commercial buildings. 90,000 solar power plants producing 300 megawatts of electricity each would be needed. The solar panels not located on buildings would take up only .33% of the planet’s land. If we continued to use coal, then 13,000 new plants would be needed. These take up considerably more space than solar panels and solar power plants. The additional space-saving benefit to solar energy also comes from onsite energy production, which is the ability for individual houses to get electricity directly from the solar panels that are on the roof or surrounding property. More and more city and state governments are offering incentives and tax cuts to residents who install renewable energy sources like solar panels.
Personally, I feel strongly that there is great potential in solar energy as prices continue to drop, efficiencies increase, and number of materials that can be used to create solar panels expands. Once built, solar panels need very little maintenance and have very little downtime. The average US coal plant is actually shut down for about 12.5% of the year due to planned and emergency maintenance procedures. In comparison, photovoltaic systems are down less than 2% of the year. Combined with other alternative energy sources, this would mean that we could have power generated by systems hardly ever shut down for maintenance. There are also hopes that in 10 or so years, the cost of photovoltaic energy will be comparable to conventional sources. In 2007, the average cost of power was 7¢ per kWh (kilowatt hour), and it is estimated it will increase to 8¢. By this same, photovoltaic power will hopefully by about 10¢ per kWh.
There are several issues of concern expressed by the public, environmentalists, and scientists. While I accept these concerns as valid, I do not think they should be reasons to not invest in solar technology and further research in alternative energy. The idea of disrupting the status quo is very scary to many people, but I feel confident this is largely due to a lack of education about the environmental issues and the real solutions. Much of the public does not understand the real crisis of continuing our reliance upon fossil fuels, and they think that environmental issues are incredibly blown out of proportion. People go about their lives not thinking about where their power comes from, not thinking about the global consequences of their actions. Things like solar technology are actually viewed by many people still as being some futuristic science fiction technology still in experimentation. Solar power has been in use since around 1970s, and while experiments to increase efficiency and find safer or more abundant materials to use is still being explored, the basic solar power technology is long past the experimental stage. Some of the concerns I’ve seen people express about solar power are these:
How the hell does it work?
How efficient is solar technology?
It’s expensive and unreliable
The materials used are still possibly dangerous and environmentally hazardous
Solar panels only work in consistently bright and sunny areas like the Southwest desert of the US
How does solar power work?
Solar energy works by taking light from the sun and converting into electricity.
Solar panels are made up of things called photovoltaic cells. Multiple cells are connected through wires upon a substrate of some kind, and a number of these modules are placed on a larger panel to create an array. The most common associate people have are the large, reflective flat solar panels arranged in rows in the middle of the desert.
Photovoltaic cells are made of semiconductor materials that exhibit the photovoltaic effect. The photovoltaic effect happens when an electrical current is created in a material when it is exposed to sunlight. A related term is photoelectric, which refers to when electrons are simply emitted from a material that is exposed to sunlight with high enough energy.
The most common material used in PV cells is silicon, which is classified as a metalloid on the periodic table of elements.
It is the most common metalloid on the earth. (For reference to those not versed in chemistry, one form of silicon is silicon dioxide, which is sand). Three forms used in different types of photovoltaic cells are monocrystalline silicon, polycrystalline silicon, and amorphous silicon. Crystalline silicon is named as such because of its structure.
A silicon atom has 14 electrons and 14 protons. The electrons are constants moving around the nucleus of the atom at different distances from the nucleus based upon their energy level. The four outermost electrons, called valence electrons, have the highest energy level. The crystalline structure of silicon is formed when multiple silicon atoms form covalent bonds.
When light hits a photovoltaic cell made up of crystalline silicon, what we see occur is called the Compton scattering Effect. When high-energy photons from sunlight collide with a material, this releases electrons from the outer shell of the atom. These outer shell electrons are the valence electrons and have the loosest bonds. These freed electrons move, creating a charge, which can be directed a certain direction using an electric field on the PV cells. This flow of electrons in a certain direction creates a current, which can be drawn from the cell using metal contacts on either side of the cell. This electric current can then be directed to power various things.
Often times, silicon is “doped” with other chemicals to make it easier to free those valence electrons. This doping process creates impurities, and while impurities are usually a bad thing, in this sense it creates a substance that requires less energy to free electrons. Less energy needed means it is more efficient and the photovoltaic effect occurs during a wider range of conditions. Silicon is commonly doped with Phosphorous, which bonds with silicon and has one unbounded electron around it. Silicon doped with phosphorous has more free carriers, which are those electrons freed due to the Compton scattering effect. This is a basic explanation of how PV cells work, but there are variations of this system that are being explored today. These variations include different materials from silicon, or using nano-scale silicon particles. Different materials for substrates of panels are being researched along with flexible thin-film photovoltaics. That brings us to the issue of….
How efficient is solar technology? And isn’t it expensive and inefficient?
This depends upon many factors, but the general assessment of photovoltaics is that they have a conversion efficiency somewhere between 12-18%. Most universities are investing in solar technology to create PV cells that have efficiencies of 40%. A company in San José has developed PV cells with a conversion efficiency of about 19.5%, which is relatively efficient. If you think about it from the standpoint of how many gathering sources are needed, even if solar technology is less “efficient” than burning coal, it is more efficient in the sense that for the amount of energy gathered, there is less energy loss in transmission to the end user. Let’s say you get less energy from the sun due to how much that panel can gather; more of that energy gathered is going to be given to you, the consumer. Coal on the other hand, can be produced only in large processing plants, so electricity will take longer to get to you and the energy loss between that plant and your home will be greater. You also have to think of the impacts of mining and transportation of a physical energy source that needs to be moved from its original locations to a plant. As solar technology advances, we can have almost every surface turned into a generating station. There can be small solar energy stations and large ones. With coal, it’s incredibly inflexible. The efficiency of coal plants sits at about 30%, with the most efficient being around 45%. As I stated earlier, in my mind, it’s important to look at the big picture in the fact that, although they are more efficient, there are many factors that must be taken into account when assessing the impact of energy. These include environmental and human impacts of mining, transporting, and pollution from coal combustion.
Currently, the method of producing silicon wafers for solar panels is labor intensive, wasteful of materials, and expensive to do. Wafers are made by sawing a rod of silicon, similar to cutting a slice of cheese for a sandwich from a larger block. Thin film solar panels are made by coating a substrate with amorphous silicon, but these are still difficult to cost-effectively mass produce. What many solar energy proponents are pushing is the idea of basic economics – that as consumer demand increases, and more people are buying solar panels made from cheaper material, production costs and cost per kWh will decrease. The efficiency of thin film solar panels is about 8% on average, which is lower than the crystalline wafer ones. The benefit of thin-film is that they can be applied to a wider range of surfaces, and opens up the possibility of flexible substrates. This means that one could potentially have curtains that can gather solar energy.
Experiments in new materials will potentially help in lowering costs and increasing efficiencies. Thin film PV cells made from Copper Indium Diselenide (CIS), and these have an average efficiency of about 11%. Solar panels made from CdTe (Cadmium Tellurium) have an efficiency of 11% also, but have a lower cost of manufacturing. In 2000, this technology was successfully tests in the US on a large scale. The safety of these new materials is another issue being explored, since dealing with certain chemicals can be potentially dangerous. The health issues of handling Cadmium is under scrutiny right now, and this makes me think about the fact that what is bad for humans is usually bad for the environment. If the concentrations of this chemical are high enough to produce health risks, could the environmental impact be of concern also once these panels came to the end of their lifespan?
Materials: expensive and possibly dangerous?
As addressed above, there have been some questions over the materials. This is mostly a speculative issue right now for me, because there are so many different technologies being produced. In general, though, I wonder how much of the materials needed can be made, or must be mined, and if they were made, would this be a dangerous chemical intensive process? Silicon is a very safe material, but the costs of it keep rising. There are more promises in polymer based solar technologies, and if those polymers are made from naturally occurring and abundant materials, rather than being petroleum-based (like many plastics now are), then I think that could be a very good alternative.
Solar panels only work in very sunny areas:
This is the biggest myth in solar technology, while unfortunately having a tiny hint of truth. Solar panels DO work in cloudy weather, but they do not work as efficiently. Solar panels work when photons hit them and break those electrons free. The electromagnetic spectrum is made up of various radiation types and energy waves.
The light that we see is only one part of the spectrum, classified as visible light waves. There are many different types besides visible light, such as radio waves, infared, and ultraviolet. Many photovoltaic cells have decreased efficiency in cloud cover because they are made to absorb energy from only visible light. Efficiency can be increased by making solar cells that can take other wavelengths and produce electricity.
Another form of solar energy I didn’t mention above is thermal, which takes heat energy to produce electricity. Photovoltaic cells are actually impaired by heat, since they gather energy from light, and not heat. PV cells are not as efficient in high temperature locations. Wake Forest University is experimenting with a new polymer based hybrid solar device to capture both heat and light. This device captures solar infared radiation to generate heat. Testing has shown a conversion efficiency of about 30%, with the additional benefit that this device is designed to capture light energy at angles, which is one problem solar panels have.
So, this, despite its length, is a very basic and brief summary of how photovoltaic systems work. It seems when I talk to many people, they don’t realize the potential of solar technology, and the fact that this technology has been around since the 1970s and is not some new and mysterious method of producing energy. The roadblocks are in price, efficiency and materials. A combination of consumer support, and advances in technology and manufacturing processes will allow us to overcome these roadblocks.
Ok, I last left off talking about alternative energy and I discussed the problem of fossil fuel reliance. The best options for energy would be wind, solar, geothermal, tidal or hydroelectric. These sources are grouped together and abbreviated as WWS, since they are all created by wind, water or sunlight. Personally, I think the most potential is in solar energy; solar and wind combined would be ideal. There is a myth that only sunny places can utilize solar power effectively, but actually, solar panels can be effective even on cloudy days. Wind power seems like it would be a good complimentary power source. The idea with alternative energy is combining sources, so that each source contributes to the system as a whole to maintain a constant sufficient energy supply. I’m going to give an overview of the various alternative energy sources scientists are exploring today and analyze their potential pros and cons.
Many questions begin bubbling in my mind when it comes to alternative energy – and specifically in comparing its environmental impacts to fossil fuel.
What would the cost and time be to create an infrastructure for this new type of power supply?
What would we have to change in the following areas/places: manufacturing processes, factories, office buildings, and homes?
What would the individual costs be i terms of the utilities bill?
Where would this energy source be located? Would it affect the ecosystem?
How easily integrated into society could it be? As in, could we take this technology and apply it to things that already exist?
What would the scale need to be to generate enough electricity? (A source of energy would still be impractical and inefficient if it had to be massive in size and it took space away from other necessary parts of life such as forests or farmlands.)
From a cradle-to-cradle perspective: what are the materials being used? How are they made? How much energy is required to produce these materials? Are these materials renewable or non-renewable? What is the waste impact – are they biodegradable or would they fill a dump and leech toxic chemicals into the air and soil?
The first renewable energy source I want to explore is tidal energy, since I have never even heard of this option before. I would guess it’s not very well known, but from my research, I’m finding that it is actually more reliable than solar and wind power options; the problems have been cost and the very few places on the earth where this could work.Advances in technology and design have opened doors more recently to developing this method further. Tidal energy is created by gravitational forces between the sun, moon and earth that causes each coast to have two high tides and two low tides within a 24-hour period. In order for the energy to be gained from this source, the difference in the high tide and the low tide must be at least 16 feet. While tides are predictable and their size can be reasonably well estimated, there are not many places on earth where the 16 feet difference happens consistently. There are two types of methods for capturing tidal energy, and this is where the biggest problem occurs with tidal energy. These methods of using tides to create electricity extremely affect the ocean’s ecosystem.
The first method of capture is called a barrage or dam. There are only three barrages in the world currently, with France’s Rance Tidal Plant (built in 1966) being the largest in the world. In a barrage, water is forced through a turbine to create electricity. This happens when the water level on each side of the barrage has reached a great enough difference. Gates open to allow water to flow through, activating the turbines. The barrage is like a dam, but on a much larger scale. It sits at the opening of a bay to catch water as it moved in and out with the tides.
Barrages have extreme environment and economic impacts that must be accounted for in considering them as an alternative for energy. Barrages are expensive to build initially, although they don’t require expensive maintenance once constructed. They also take a long time to construct, and in the meantime the area has to deal with increased traffic, road blocks and
construction noise. The Rance barrage took five years to build. Although barrages can be useful as roads across a bay, unless they have a feature allowing them to swing open like Seattle’s 520 floating bridge, boat access to the bay is cut off. This could possibly have social and economic impacts upon the coastal town or city. More significant is the environmental impact of barrages. A barrage affects both plant and animal life as it alters the natural flow of the water in and out of an estuary or bay. Fish can easily get killed in the turbines, and the bay’s water quality can decrease as a result of the barrage acting as a road block to the dispersal of contamination. The Rance plant is a good example of the environmental damage that can occur. Because of the barrage, sandbanks disappeared and many species lost their habitat. Other species moved in actually, which changes the diversity of the ecosystem. It is easy for us to disregard changes in diversity and species, but it is one of the biggest environmental impacts humans have and it must be better understood. Changing an ecosystem has profound and last impacts, and regardless of how much people alter their surrounding and separate themselves from the natural environment, we have to understand that we are actually a part of the greater environment, and destruction or changes to nature will eventually impact us.
The second method of tidal energy capture is tidal turbines. Underwater turbine technology is much newer than tidal barrages, and they are similar to wind turbines. These are placed at the entrances of bays or rivers where there are fast currents to move the turbines. Since water is denser than air, more energy can be extracted through spinning turbines with water than with wind. These turbines need to be in water about 60-120 feet deep, and in an offshore or estuary location with winds of at least 5-6 miles per hour. An underwater turbine farm was constructed in 2006 in the East River of New York City, and they are hoping for expansion of that project that will have a generating capacity of 10 megawatts. That would generate enough power for several thousand homes in the city. While turbines are less environmentally destructive than barrages, they are still taking up permanent space in the ocean that aquatic flora and fauna should have free range of. There have also been concerns about the machines being overrun by barnacles and other sea life of that nature.
While tides are reliable and predictable, tidal energy can only be captured during the high and low tides, which totals about 10 hours each day. From that standpoint, combined with the large scale and serious ecosystem impacts, I don’t see tidal energy as a viable solution to clean energy. It is my personal opinion that we should opt to find energy solutions that can be utilized on various scales of size and not alter the environment this much. In finding alternative energy sources, I think it’s important to find one that doesn’t take up undeveloped space. This is why I am hesitant that developing turbines are barrages in water is a good idea, since it expands our development even further, rather trying to incorporate energy production into already developed areas like cities. I think that we should look to solar energy for meeting our needs of the future. And my next post will explore this option!
I know I haven’t had a good post in a while, and I’m going to try to pick up my pace over the next few weeks. Life has been hectic, and I’m finding it more difficult to formulate topics for blog posts as this is my first crack at a project of this nature. Here’s a more serious post than my past few entries.
Today I wanted to examine some options in renewable energy sources, which will hopefully replace fossil fuels as the main source of energy in the near future. The health of the environment and its inhabitants is heavily dependent upon us converting to renewable and pollution-free sources of energy. Currently, our energy consumption, especially in the United States, is higher than ever. According to the U.S. Energy Information Administration, electricity consumption in 2009 was 13 times higher than in 1950, amounting to almost 3,741 billion Kilowatthours used in that year alone. As the rate of consumption climbs, we are continuing to tap into sources of energy from natural deposits in the earth that are soon to run dry.
So to begin with, what are fossil fuels exactly? And what is so bad about them? Fossil fuel sources are coal, oil, and natural gas that is mined and drilled from the earth and burned to extract energy. These fossil fuels were formed over millions of years from animal and plant remains decomposing under heat and pressure. Petroleum, a natural gas, is used in cars and to produce plastics. Natural gas and coal are both burned to generate electricity for heating buildings. In 2009, it was recorded that almost half of the electricity produced in the United States was generated from burning coal (See diagram to the side). Fossil fuels must be burned to extract energy, a process that consequently pollutes the environment with harmful chemicals like sulfur, nitrogen, and carbon. Those three main pollutants alone have far-reaching consequences from contributing to global climate change (carbon dioxide) to causing acid rain (chemicals bond with water vapor molecules to form acidic compounds).
Burning fossil fuels is harmful to humans as well as the environment. They contribute to increased temperatures in cities, creating a phenomenon known as the “urban heat island effect”. Smog, also known as ground level ozone, is commonly found on some of the hotter days in cities, and is caused by Nitrogen Oxides interacting with volatile organic compounds in the presence of heat and sunlight. Heat and smog cause general discomfort, heat stroke, respiratory problems, and even death.
Side note: One of the problems I have noticed in the whole debate over climate change, the environment, etc, is that people fail to understand two crucial points. One: the human-environment interaction. Two: the compounding consequences of our actions upon all aspects of life. What is bad for the environment is bad for humans. So, it’s not just about trying to help the environment and saving nature, it’s also about protecting our health and the health of our children. When I hear people say they don’t care about the environment, I always want to tell them they better not have children, because it would be a cruel thing to do. The state of this planet will impact the health of our children, so why bring a child into the world to make it suffer in a world full of pollution and disease-causing chemicals. The second point I want to raise is that people naturally have difficulty understand far reaching consequences. The conflict we’re dealing with in the modern age is that our brains are still quite primitive and unable to understand consequences on a global scale; we do much better with direct cause and effect that is obvious. While our brains are still stuck on that scale, our actions have expanded to have global consequences. An example of this is air conditioning. Yes, it is hot, so you turn on the air conditioning. This requires electricity, which means fossil fuels are burning. Fossil fuels contribute to increased temperatures in the area you are trying to cool. This doesn’t happen immediately like the cold air you feel from the air conditioning, it occurs slowly over years, each summer hotter than the previous. The urban heat island effect also impact water quality by sending large amounts of hot water directly into streams and lakes, causing a rise in water temperatures. This impacts the ecosystems, contributing to large oxygen depleting algae blooms in water, massive dead zones in lakes where no plant or animal life can survive, and deteriorates overall water quality. So, most likely, when you turn on the air conditioning, this is not what you think about. All you do is flip a switch or press a button without thinking twice.
Okay, back to before that rant — the use of fossil fuels began with the Industrial Revolution in the 1700s. Coal was, and still is, a cheap and abundant source of energy. Coal and oil are resources that will eventually become depleted, and the big challenge right now is pushing forward new technologies for renewable energy immediately and not waiting until we’ve actually depleted our fossil fuels completely. Coal companies began several years ago toting “clean coal” as a way of reducing carbon emissions from coal plants. This is done by carbon capture, which involves catching the carbon dioxide by-product from burning coal and literally storing it underground. This solution is a dangerous one. Many coal plants are not geographically able to store carbon dioxide, and it is also very risky to have large stores of carbon dioxide underground in the event of an earthquake or other disaster. This is not a viable solution in my opinion, since the consequences of a leak seem to great and at the bottom line, coal is still being burned to generate electricity. Another problem with burning fossil fuels is the lack of efficiency. As these sources are quickly depleted, more energy must be put into extracting them from the earth. If more energy is put into extracting coal and oil than we are getting from them., it is an inefficient energy source. Burning coal for electricity is also inefficient because of the lost energy in conversion and distribution. Coal plants generate electricity that is distributed to a network of electricity lines; during the transfer some energy is lost. Alternative energy sources are more efficient because there is not as much lost energy in production and conversion, and the possibility of on-site electricity production is a viable option.
The most promising options for renewable energy sources are sun and wind power. Technological advances in photovoltaics, solar panels and wind mills would be able to provide the world with all the energy it needs. There was an article published in Scientific American in 2009 detailing how we actually switch to 100% renewable energy production through using all forms of renewable energy. The article can be found online at Scientific American; its long, but it’s a good read and they make some very valid points to support their argument.
So, this is getting quite long, so I have decided to make it a two-parter. Part two will focus on the options for renewable energy sources and the monopoly big coal and oil companies have on the energy production market.