Science TEKS 5.7.C
ExploringEnergy Sources Activity Sheets
Group 1 – Wind
Proposals Would Turn Highways into Wind Farms
By Darren Murph posted April 30th 2007 10:04AM
Clogged highways and frustratingly waiting while your gas needle plummets to empty usually doesn't conjure up thoughts of green, but it seems like these very roads could become the source of a lot more energy. Several recent student designs have proposed that major roadways be retrofitted with various forms of wind energy collection devices, ranging from overhead turbines that collect energy from quickly-moving cars below to barrier panels (pictured after the jump) that harness the wind from closely passing vehicles moving in opposite directions. Ideally, the wind energy could then be sent back out to the grid to power nearby communities, light-rail transportation systems, or even intelligent billboards. Of course, most of these ideas are still in the research phase, and even if proven feasible, we can't imagine the up-front costs (or inconveniences of installing these things) to be minor, but we're sure that government subsidies should be able to lend a helping hand.
Jay Leno Builds a Wind Turbine on His Green Garage
Jay Leno is making plans with the team from PacWind to install the state-of-the-art Delta II turbine on the roof of his Green Garage.
Recently, Jay had a chance to meet up with the folks from PacWind, a company that makes vertical-axis wind turbines like the 500-watt Seahawk they brought by the garage. Drag-type vertical turbines such as these move a lot like those three-cup anemometers commonly used for measuring wind speed. But the PacWind design is unique in that its foils utilize the forces of lift, too, making them more efficient.
The Seahawk was just one example of Pacwind's turbines--and Jay was impressed. But for the 17,000-sq-ft. garage, which uses, um, quite a bit of energy each month, the PacWind team recommended their brand-new, top-of-the-line Delta II turbine. It can produce 10 kw at around 28 mph and has a cut-in wind speed of 6 mph. These turbines don't need a braking mechanism and can self-start at very low wind speeds--something similar designs in the past could never do. Generating usable wind power can be quite tricky, since wind is fickle and performance can vary from place to place. But according to Pacwind, Jay's garage looks like a very suitable spot.
A few more neat things about these vertical turbines: They take up very little space, they're virtually silent, and multiple units can be placed within feet of one another. Delta II units can also be stacked vertically up to 50 kW. We wouldn't be surprised to see quite a few of these 9-ft., 500-lb. turbines lining the upstairs of the Green Garage very soon.
Group 2 - BioFuel
Jatropha oil – The Next Aviation Fuel
New findings suggest that an oil-producing but inedible plant, Jatropha curcas, holds the future of renewable aviation fuel production in Latin America, Boeing said Thursday.
Citing details of research into the plant's properties, Boeing said the Jatropha curcas, freely grown in tropical and subtropical conditions in Central and South America and other parts of the world, showed significant potential as a major future source for sustainable aviation fuel.
Boeing has been looking into ways of producing “green” aviation fuels in response to global concerns over issues such as air travel contributing to climate change — an implied threat to Boeing as a major manufacturer of aircraft.
Biofuel research and production has also alarmed food lobbyists amid indiscriminate switchovers in some areas from food crops to crops producing feedstock for biofuels.
The greatest factor in the defense of Jatropha-curcas is that it is poisonous, not edible, and easily grown without an adverse effect on food agriculture.
The plant grows as a semi-evergreen shrub or small tree, reaching a height of up to 20 feet in right conditions and resistant to aridity and therefore suitable for arid areas in Central and South America.
Boeing, like many other interested parties, is keen to develop a commercially viable, renewable source for aviation fuel so as not to have to face lobbyists and lawmakers who see reduced air travel as the best step forward.
If cultivated properly, Jatropha curcas can deliver strong environmental and socioeconomic benefits in Latin America and greenhouse gas reductions of up to 60 percent when compared to petroleum-based jet fuel, the research showed.
A 747 on BioFuel
At the Eco-Aviation Conference in Washington, Air New Zealand’s Chief Pilot Captain David Morgan announced the company’s findings on a test flight from last December. Powered by a combination of biofuel and jet fuel, the test resulted in a fuel savings of 1.2%. It also cut CO2 emissions by over 60%!
While a 1.2% fuel savings doesn’t seem like much, that is over 1 ton of fuel!
The test was conducted using a commercial 747-400 fitted with Rolls Royce engines. Rolls Royce had certified the fuel — a 50:50 blend of standard Jet A1 fuel and synthetic paraffinic kerosene derived from Jatropha oil.
Group 3 – Solar
Solar Panels Keep Buildings Cool
ScienceDaily (July 19, 2011) — Those solar panels on top of your roof aren’t just providing clean power; they are cooling your house, or your workplace, too, according to a team of researchers led by Jan Kleissl, a professor of environmental engineering at the UC San Diego Jacobs School of Engineering.
In a study in an upcoming issue of the journal Solar Energy, Kleissl and his team published what they believe are the first peer-reviewed measurements of the cooling benefits provided by solar photovoltaic panels. Using thermal imaging, researchers determined that during the day, a building’s ceiling was 5 degrees Fahrenheit cooler under solar panels than under an exposed roof. At night, the panels help hold heat in, reducing heating costs in the winter.
“Talk about positive side-effects,” said Kleissl.
As solar panels sprout on an increasing number of residential and commercial roofs, it becomes more important to consider their impact on buildings’ total energy costs, Kleissl said. His team determined that the amountsaved on cooling the building amounted to getting a 5 percent discount on the solar panels’ price, over the panels’ lifetime. Or to put it another way, savings in cooling costs amounted to selling 5 percent more solar energy to the grid than the panels are actually producing— for the building researchers studied.Data for the study was gathered over three days in April on the roof of the Powell Structural Systems Laboratoryat the Jacobs School of Engineering with a thermal infrared camera. The building is equipped with tilted solarpanels and solar panels that are flush with the roof. Some portions of the roof are not covered by panels.The panels essentially act as roof shades, said Anthony Dominguez, the graduate student lead on the project. Rather than the sun beating down onto the roof, which causes heat to be pushed through the roof and inside the ceiling of the building, photovoltaic panels take the solar beating. Then much of the heat is removed by wind blowing between the panels and the roof. The benefits are greater if there is an open gap where air can circulate between the building and the solar panel, so tilted panels provide more cooling. Also, the more efficient the solar panels, the bigger the cooling effect, said Kleissl. For the building researchers analyzed, the panels reduced the amount of heat reaching the roof by about 38 percent.
Although the measurements took place over a limited period of time, Kleissl said he is confident his team developed a model that allows them to extrapolate their findings to predict cooling effects throughout the year.For example, in winter, the panels would keep the sun from heating up the building. But at night, they would also keep in whatever heat accumulated inside. For an area like San Diego, the two effects essentially cancel each other out, Kleissl said.
Group 4 – Hydroelectric
What if the Hoover Dam broke?
by Katherine Neer
Introduction to What if the Hoover Dam broke?
The Hoover dam is one of those miracles of the modern world that almost defy explanation. When you stand next to it, the size is unbelievable. It is more than 700 feet high (imagine a 70-story building). The top of the dam is more than 1,200 feet long. At the base, it is an amazing 660 feet thick and at the top it is 45 feet thick. The water on the lake side is more than 500 feet deep, and the lake holds a total of 10 trillion or so gallons of water -- enough water to cover a state like Connecticut 10 feet deep.
Let's say the Hoover dam broke. This is difficult to imagine, given its thickness. No conventional bomb would have an effect on a dam like this. It is difficult to imagine even a nuclear bomb having an effect, unless it were an extremely powerful one and it were inside the dam at the time of explosion. But let's say that some sort of tremendous earthquake or an asteroid strike or some other natural disaster were to somehow eliminate the Hoover dam in one fell swoop. What would happen?
The first thing that would happen is that 10 trillion gallons of water would move as quickly as it could out of the lake and down the river in a huge tsunami of water. The Hoover dam is located in a desert area that is not hugely inhabited below the dam, but there are still some sizeable populations. Lake Havasu City, population 40,000, is about the biggest town in the United States along the river. Bullhead city, population 30,000 is also close to the dam. Needles, California; Blythe, California; and Laughlin, Nevada all have populations of around 10,000 people as well.
Where the water would do immense damage is in the lakes below Hoover dam. It turns out that below Hoover dam is another large lake called Lake Mohave, which is held in place by Davis dam, and below that is Lake Havasu, held in place by Parker dam. These are smaller lakes and smaller dams. For example, Lake Havasu only holds about 200 billion gallons of water.
Damage to the Dam
As the water released by the Hoover Dam moved through these two lakes, it would likely destroy them and their dams as well. That's where the real impact would be felt, because these lakes affect a huge number of people. The water in them produces hydroelectric power, irrigates farmland and supplies drinking water to cities like Los Angeles, Las Vegas, Phoenix and San Diego.
The Hoover dam produces roughly 2,000 megawatts of power. Davis and Parker dams produce less, but together they might all produce 3,000 megawatts. That represents about one half of one percent of the total electrical power produced in the United States. If you eliminated a sizable amount of generating capacity like that, especially in that area of the country (near Los Angeles and Las Vegas, for example), it would definitely cause problems.
The destruction of irrigation water supplies would also have a huge effect on farming in the region. Farmers in the Imperial Valley get most of their water from the Colorado River, and these irrigation systems would collapse. Prior to irrigation, the Imperial Valley was a barren desert. Today it is the home of more than half a million acres of farmland and produces more than a billion dollars in fruits and vegetables every year.
There would be large effects as well from the loss of drinking water. For example, Las Vegas gets 85 percent of its drinking water from Lake Mead -- the lake behind Hoover dam. With the loss of water and the loss of power, Las Vegas would become uninhabitable, and that would displace 1.5 million residents and empty more than 120,000 hotels rooms and the casinos, bringing the multi-billion-dollar gambling industry in this city to a halt.
Isn't it amazing how much commerce, and how many people, depend on that one dam?
Group 5 - Geothermal
Japan's Geothermal Resources Get a Closer Look
By Robert Crowe | May 11, 2011
In wake of nuclear crisis, experts say time has come to tap into Japan's underground heat.
Kyushu, Japan -- For centuries, the Japanese have enjoyed relaxing in abundant hot springs, or "onsen," which are heated by the volcanic and tectonic activity that makes East Asia prone to major earthquakes.
Similar geothermal resources along the Pacific Rim’s “ring of fire” have attracted billions of dollars in foreign investment to Indonesia and the Philippines as those countries develop hundreds of megawatts of power plants that generate electricity with natural steam.
Japanese companies play key roles in the worldwide geothermal boom, yet development is conspicuously absent within Japan due to cultural reverence for hot springs, a lack of incentives and the historical reliance on nuclear power and fossil fuels for electricity. Since the 9.0-magnitude earthquake and tsunami on March 11 crippled the Fukushima Dai-ichi nuclear reactors, causing radiation leaks and blackouts, there have been renewed calls to develop Japan’s abundant geothermal fields.
“With regard to geothermal, this is absolutely an untapped resource that could benefit Japan and all of the Asian region,” said Julia Nesheiwat, a Council on Foreign Relations fellow studying energy policy for U.S. Department of State.
A typical geothermal plant takes five to 10 years to develop, so Japan will have to turn to wind and solar for immediate renewable energy sources, Bronicki added. The Climate Change Policy Division of Japan's Ministry of Environment estimates that Japan possesses 1,900 GW of potential wind energy, according Climate Connect.
None of the country’s wind farms were damaged by the tsunami or earthquake, although some power lines were damaged. Many wind turbines near the hardest-hit coastlines continue generating electricity today.
Evaluation
Student instructions: Design a city that uses only alternative energy sources. Make a diagram of your city and label all the parts and sources of energy. Also, write an informative article about your city for the local newspaper.
Rubric for Alternative Energy CityPossible Points / Self Score / Teacher score
Diagram is neat and colored / 4
All sources and uses of energy are labeled / 4
Uses at least 4 different alternative energy sources / 4
Article is informative – includes all the energy sources used in the city / 4
Article is at least one page in length / 4
Article is neat and uses good grammar / 4
Total / 24