PDS APES 5th Period 2009-10

http://www.bynon.cc/blog/atmosphere.jpg

In class, we dicussed what made up “good air” and how it was defined.

First things first, we talked about how in Environmental Science, we mostly focus on the troposohere and the stratosphere. There are several differences between the two, but they both hold very important roles in providing “good air”

Trophosphere vs. Statosphere

Trophosphere = the air we breathe, where weather occurs, and is made up of 78% Nitrogen, 21% Oxygen and 1% “other” (more about that later), global warming, and the danger of ozone at this level.

Stratosphere= global winds and higher levels of O3, ozone thinning an issue, ozone= global sunscreen-necesary to block UV rays.

Overall, air in the trophosphere is comprised of 78% Nitrogen, 21% Oxygen and the 1% “other” made mostly of Co2, methane, water vapor and argon. Too much of one of these gases causes what we call “bad air”.

Here is today’s presentation. While biomass is valued for being essentially carbon-neutral, you cannot ignore all the potential drawbacks to agriculture (erosion, fertilizer, pesticides, feedlots, etc…).

When you think “Modern Wind Technology”, think of Power Plants.

http://www.duurzamevoetafdruk.nl/en/cms/selplaatje.asp?id=223

These power plants include wind turbines that are powered by the wind in order to turn a turbine that powers a generator, and creates electricity that can be used and stored.

http://visual.merriam-webster.com/images/energy/wind-energy/wind-turbines-electricity-production/nacelle-cross-section.jpg

To understand the parts of a turbine and how it works, check out the following websites:

http://guidedtour.windpower.org/en/kids/intro/intronac.htm

http://guidedtour.windpower.org/en/kids/intro/index.htm

One wind turbine generates approximately 2 MW of power.

Wind is less than 1% of the commercial energy market.

Positives:

-No emissions (CO2)

-Multiple land use because of small footprint

-Could go longer than solar power (because of night and day)

-Renewable Energy

Negatives:

-Noise pollution (from the blades)

-variable wind supply (need storage and backup)

-Aesthetics

-Some habitat laws (birdstrikes-birds sometimes fly into them)

This is a funny video from class : ) :

http://www.youtube.com/watch?v=6IjUkNmUcHc

1. Power

Power is the rate at which Energy is used or being created. Its base unit is in Watts where 1W=(1Joule)/(1second). Power is the basis for rating the amount of energy appliances use over time, like a 100 Watt light bulb will use twice as much energy at any period of time than a 50 Watt bulb.The equation for Power is:

P=E/t

This equation can also be rearranged to find Energy produced: P*t=E

2. Heat transfer

The most common method of turning any Energy in heat, is to transfer heat into steam which will turn a turbine and generator shaft. We can use Heat transfer equations to show how much Energy we need to boil water.

The heat equation uses several variables: Q=Heat energy(calories/BTU’s); m=Mass(grams);c=specific heat, the higher the harder to heat up a material [cal/(J*C)]; and T refers to the change in Temperature. The equation goes like this:

Q=mcT

(remember T is change in temperature!)

3. Price

Calculating Price is the same process as calculating Power, minus the  science! Instead of power we refer to number units bought(units), individual price($/unit) to get the total Price($). Instead of power, price uses a ‘price rate’ or the individual price. Equation:

#Units*Individual Cost= Total Cost

4. Efficiency

Last but not least, we need to be able to calculate efficiency. It doesn’t matter how much Energy we use, if we aren’t using it properly, thats what efficiency is about. Sadly, due to reality all appliances aren’t a 100% efficient so we need to see how much energy we are wasting. For efficiency, we focus on the Input energy, the total energy we put into say a light bulb, multiply that by the efficiency to get an output, an alternate form of energy from what we started (say light/heat). The equation is straight forward:

Input*%efficiency=Output

Today we took a brief look at solar power. Solar makes up a tiny fraction (<1%) of the commercial energy market, but it is doubling every two years. I tried to distinguish between solar electricity technologies and solar thermal (heat) technologies.

When considering solar electricity, it can be done on a small scale (homes/buildings) and a large scale (solar tower power plants). Most folks are familiar with solar panels, or photovoltaic panels, made from two layers of silicon and divide into solar “cells.” These panels can be bolted on existing structures or built into the roof (as shingles). When light hits the panels, electrons are freed from silicon and flow in wiring for immediate use or storage in batteries. Battery storage is critical, since solar incidence (amount of sunlight energy) varies by season and location and of course, since there is no sunlight at night. Small bolt-on systems are a great solution for homes that are off an electrical grid. A good basic explanation of PV technology is in your text, or at HowStuffWorks.com:
http://www.howstuffworks.com/solar-cell.htm

Folks are less familiar with large-scale solar-thermal power plants, like the one seen in the video below from Spain:

A huge field of mirrors follows the sun and focuses the sunlight on a central tower where water is heated to make steam, to turn a turbine, to turn a generator, to make electricity. There are a quite a few of these in the US and other countries.

As for solar thermal technologies, they focus on capturing the sun’s heat (infrared radiation). Unfortunately this year we will not get to tour a local home that incorporates both these techniques. In years past, I’ve taken APES classes to the home of Jeff Martin up at Lake Norman. From the front, Jeff’s home looks like a normal house, but if you walk around back you can see his huge solar roof:

Local Solar Home

Jeff designed the home, not just to produce electricity (the lower 3/5 of that roof) by PV cells, but also to take advantage of passive and active solar thermal technologies.

• Passive techniques: The rear of the home (and the panels) faces south to maximize the sun’s light and heat. Also, the amount of window space is maximized on the south face of the home. A large overhang blocks the more intense, higher sun in the summer but is designed to let the lower winter sun in completely. The home also has concrete floors (with nice wood on top) to absorb the sun’s heat to heat the structure. Finally, the house is super-insulated to retain all this warmth.
• Active techniques. The top 2/5 of the roof (see picture above) has copper sheets with water piped through them via a pump in the basement. The water is heated by the sun, then piped back down to the basement for storage in a huge insulated water tank. This heated water not only provides almost unlimited hot showers, but it can also be circulated through tubing in the concrete floors to provide radiant heating for the structure.

Between all these technologies, Jeff and his family have a house that is heated and lighted in a super efficient fashion. He further works to maximize energy efficiency with Energy Star rated appliances, super insulation, and CFL bulbs. Of course, one of the downsides is the cost–not everyone can afford the technology on this scale. Regardless, solar technologies are becoming more and more prevalent in the USA and enjoy even greater popularity in Japan and Germany.

Wednesday in class we talked about the common fuels that we use. The three most commonly used fuels include Coal, Oil (Crude Oil), and Natural Gas. When comparing the percents of total energy use in the world to total energy use in the US, 76% of the world’s energy use requires fossil fuels while 85% of the US’s energy requires fossil fuels.

http://www.tehrantimes.com/index_View.asp?code=200268

COAL:

Coal is made up of decayed ancient swamp material which tends to be solid hydrocarbons. Coal can also contain Carbon, Sulfur, Magnesium, and Nitrogen. The top three reserves for coal include 1) USA (27%) 2) Russia (17%) , and 3) China. After coal is mined and extracted from the earth, it is primarily used for electricity generation and steel production. Advantages include: Ample supplies, high net energy yield, low cost, well-developed technology, and air pollution can be reduced with improved technology. Disadvantages include: Severe land disturbance, air pollution, and water pollution, severe threat to human health when burned, environmental costs not included in market price, large government subsidies, high Co2 emissions when produced and burned, and radioactive particle and toxic mercury emissions. Coal is projected to last 200-900 years.

http://unclemeat.wordpress.com/2009/09/17/end-of-peak-oil/

Crude Oil:

Oil is a liquid mix of hydrocarbons and decayed remains of ocean plants and animals. Oil is also known as Petroleum. The top three reserves that we drill oil from are 1) Saudi Arabia (25%), 2) Canada (15%), and 3) Iran (10%). After the oil is extracted from the earth, it is primarily used for transportation and sometimes asphalt and plastics. Advantages to using oil include: Ample supply for 42-93 years, low cost, high net energy yield, easily transported within and between countries, low land use, technology is well developed, and efficient distribution systems. Disadvantages include: Need to find substitutes within 50 years, large government subsidies, environmental costs not included in market price, artificially low price encourages waste and discourages search for alternatives, pollutes air when produced and burned, releases Co2 when burned, and can cause water pollution. Oil is projected to last for 42-93 years (less than 100 years).

http://nedgrace.wordpress.com/2009/03/28/natural-gas-prices-drop-to-lowest-level-in-6-years-on-weak-us-economy/

Natural Gas:

Natural gas is a gas mixture of hydrocarbons that comes from oil and coal. 50-90% is methane along with some propane and brutane. The top three reserves for natural gas includes 1) Russia (27%), 2) Iran (15%), and 3) Qatar (14%). After natural gas is retrieved from the earth, it is primarily used for heating spaces and for cooking. Advantages to using natural gas include: ample supplies, high net energy yield, low cost, less air pollution than other fossil fuels, lower Co2 emissions than other fossil fuels, easily transported by pipeline, low land use, and good fuel for fuel cells and gas turbines. Disadvantages include: it’s a nonrenewable resource, releases Co2 when burned, government subsidies, environmental costs not included in market price, methane can leak from pipelines, difficult to transfer from one country to another, can be shipped across ocean only as highly explosive LNG, and sometimes it is burned off and wasted at wells because of low price. Natural Gas is projected to last 62-125 years.

Today in class, we discussed the properties of Uranium, as well as how it is used in nuclear power plants.

Of all the naturally occurring atoms on Earth, Uranium is the largest in size.  Because of its large size, Uranium is very unstable, and very reactive.  In order to stabilize itself, Uranium (and any other large, unstable atoms) must release matter and/or energy.  There are two types of matter an atom can release: alpha and beta.  Alpha Decay occurs when an atom releases a proton or neutron to stabilize itself, and Beta Decay occurs it releases electrons.  An atom can also release energy, or Gamma Rays.  Unstable atoms naturally release one, two, or all of these three, causing the atom to decay over time.  Given time, Uranium will naturally decay until it becomes the stable lead atom.  An atom is considered radioactive when it constantly releases matter or energy.

A Half Life of an atom is the time period that it takes for half a sample of that atom to decay into a nonradioactive, or stable state.  Uranium 235 has a half life is 710 million years.

Because Uranium is the largest atom, and therefore the most likely to decay, it is also the most radioactive of all the atoms.  This comes in handy with nuclear power plants, which use Nuclear Reactors to create energy from Uranium.

When finding the Uranium to use in nuclear reactors, the only isotope of Uranium that can be used is Uranium-235.  An Isotope is an atom that has the same number of protons, but a different number of neutrons.  The number that follows the atom name (235) is the number of neutrons that the particular isotope has.  Although Uranium-235 is the main source of fuel used, it is also one of the smallest Uranium amounts found in nature (less than 1%).

Nuclear Fission is the atomic process that powers nuclear reactors.  Nuclear fission occurs when the nuclei of a large atom is hit by a neutron, and therefore split, producing a split atom and another free neutron.   A Nuclear Fission Chain Reaction occurs when the neutron that was produced by the original nuclear fission hits another atom’s nucleus, producing more free neutrons, and therefore the chain continues.

The Chain Reaction produces a LOT of heat, which is used to power the nuclear reactors.  In nuclear reactors, Fuel Rods (Uranium) and Control Rods (neutron control) are placed in a containment building.  The fuel rods are placed in a huge vat of water, and when the chain reaction occurs (the speed of which can be controlled by the control rods, which absorb or release neutrons) the water is heated.  The water in the vat then boils, turning into steam.  The steam is sent through Steam Pipes/Heat Exchangers, which use the steam to spin a Turbine, creating energy.  All the steam then travels to the cooling tower, where excess heat is vented through steam stacks.  There are no pollutants released from nuclear Power plants. Here is a cite explaining nuclear reactors in more detail:  http://www.howstuffworks.com/nuclear-power.htm

http://electricalandelectronics.org/wp-content/uploads/2008/10/nuclear-power-plant.jpg

After fuel rods are used, they are still very radioactive, and must be placed securely in storage for hundreds of years.  If not placed in storage, radioactivity can be very harmful to human health.  Released alpha particles are not strong enough to get past the outer layer of human skin, but can cause skin cancer.  Beta particles are a little stronger, and can pass to the epidermal, or inner layer of skin.  Gamma Rays are nasty, and can pass through any type of tissue, bone included.  This is useful for treating diseases like cancer, but harmful in any other way.

I hope this helps!

For those who missed the first day of our energy unit, here is the kick off:

I tried to give you a sense of just how destructive surface mining can be to habitats and biodiversity. I’ve also found a great slideshow by a photographer named Daniel Shea on NPR. There are only 15 slides, and it is worth the 30 seconds of your time to take a look at the impact of mountaintop removal on rural Appalachia. This has really become an environmental justice issue in West Virginia and Kentucky. If you want to read great (but depressing) book on the issue sometime, try Lost Mountain, by Erik Reese.  For folks who live near these mining sites, it is very hard to believe in such as thing as “clean coal.”

Mountaintop removal/valley fill coal mining in southern West Virginia in May 2003 Photo by Vivian Stockman, May 30, 2003

http://www.ohvec.org/galleries/mountaintop_removal/007/

The EPA has been taking a hard look at destructive mountaintop removal mining practices. A federal judge in West Virginia took steps to block some types of permits for the practice in the last year. NPR has a short report on this legal action too.

If all this is too serious, check out this recent Colbert Report on mountaintop removal:

Funny, yes, but do you think Mr. Colbert should make a joke of the issue? Is that his message?

Subsurface coal mining has its own set of issues. If you have time check out this 40 minute episode of “30 Days” with Morgan Spurlock (the “Supersize Me” guy) on Hulu. *Note: Hulu is blocked at school.

Hey, several folks were curious about the material the book, Cradle to Cradle: Remaking the Way we Make Things, is made from so here is a little more info on it: http://www.mbdc.com/features/feature_may2002.htm

Also, here is a 20 minute TEDTalk by William McDonough (from 2005)on some of his design ideas if you want to know more:

Seems idealistic, but you have to realize this is ALREADY changing BIG businesses (like Nike, Ford) in positive ways.  If we do focus on good design (redesign) and refuse to use toxins in production, we can prevent a great deal of waste (esp. hazardous waste) and spend less money on/spend less time worrying about trash and recycling it.  Will McDonough is a champion of a new set of Rs and if his revolution succeeds, we’ll no longer have a “grave.”  Notice this puts a greater burden on engineers and product designers to eliminate waste, and lesser burden on the consumer to dispose of it.

I forgot to name a scribe today so, I’ll handle the duty again. In fact, I’ll try to scan and post a top-quality version of the material-flow economy diagram in “the box” soon. I must admit I borrowed a good bit of my concept for the diagram from The Story of Stuff project. You can see the 20 minute video below:

*They’ve even got a brand-new one out on bottled water. See it here.

The group that made this obviously has an agenda. There is much true in the video, but it does oversimplify some issues. This video has been widely circulated over the last few years. Some folks have reacted strongly to it. Check out this 4 minute Fox News bit hosted by conservative commentator Glen Beck:

I used it because I wanted you guys to think through the often invisible “upstream” portion of the waste stream and how the 3 R’s impact it. Folks will always debate ecology/health versus economy. I’d like to think it is not about who is right or wrong, rather it is about tradeoffs…what do you think?