Month: March 2016

The four exhibits at the museum of science were concrete proof of some of the laws, theories, and concepts that were discussed in class.  Though we have done experiments, written about, and researched wind power, energy, solar energy, and heat conservation, the exhibits were able to offer not only additional, but very specific information that were very interesting.

Catching the Wind:

The “Catching the Wind” Exhibit explained how wind power is a natural and clean resource generated by wind turbines to perform tasks or convert wind into usable electricity.  It mentions how humans have been catching the wind for thousands of years, and have continued to perfect wind power technology.  the exhibit goes into further detail and explains that wind is actually a form of solar energy.  Sunlight hitting the Earth heats the air unevenly which creates a temperature difference.  This difference starts moving the air, as warmer air rises and cooler air moves in to take its place.  The exhibit also states that wind power is measured in kilowatts (kW), which is equal to one thousand watts.  I can also be measured in megawatts (mW), which is equal to one million watts.  Wind power can additionally be measured in energy generated per hour using the units kilowatt-hour (kWh) or in megawatt-hour (mWh).  The exhibit states that one kilowatt generated at a steady rate for an hour can power 66 energy efficient light bulbs for an hour.  The most impressive part of the exhibit was the display of how much wind power is necessary to spin a wind turbine.  According to exhibit, a wind turbine only needs wind of speeds of 6-12mph to spin the turbine’s blades.  Surprisingly, this is the speed of a gentle breeze!  Lastly, I was surprised to find that the MOS uses five different wind turbines on their roof and a display of how much energy is generated by each turbine.

Energized!:

Energized was the second exhibit at the MOS related to topics we have studied in class.  This exhibit explains the potential of solar energy.  It states that wherever there is sunshines, solar energy could be harnessed to generate electricity.  The sun provides the about a thousand times more energy than the world needs, yet solar technology currently generates only about 1% of the world’s energy.  This gap exists because sunshine is inconsistent and because it takes large areas to harness useful amounts of power.  Despite these challenges, solar energy has enormous potential and is the fastest-growing power-generation technology in the world.  It is projected to increase 30-fold in the next 25 years.  The exhibit mentions various methods of capturing and using available sunlight.  Aside from the regular solar panels, there are solar collectors that do not use photovoltaics.  They use mirrors to focus sunlight at a central point and generate heat.  From there, the process for creating electricity is essentially the same as a power plant where the heat produces steam and the steam is used to spin turbines.  According to the exhibit there are three main types of solar collectors: towers, troughs, and parabolic dishes.  Energized! also had an interactive display that showed at what time of day solar panels would be most efficient due to the sun’s movement.  At the end of the interactive display, it was clear that solar panels are most efficient in the afternoon where solar energy can be captured for a longer period of time.

Investigate:

Investigate was a relatively simple exhibit compared to the others as it involved the conservation of heat through the use of  styrofoam and warm water.  The exhibit display asks which cup keeps drinks at their starting temperature longest and if blowing on a hot liquid makes it cool off faster.  The experiment itself involved pouring hot water in a styrofoam cup and in a plastic cup and gauging the temperature in both.  My hypothesis was that the styrofoam cup would keep the water heated longer because styrofoam is widely used to conserve heat in many instances.  The result of the experiment were as I expected as the styrofoam cup keep the temperature at 75 degrees Fahrenheit for a longer period of time.  The plastic cup’s heat retention was far less and the image below shows that the liquid’s heat was at 74.1 degrees Fahrenheit.  Blowing on the hot liquid did also decrease its heat much faster than if it were left alone.

Conserve @ Home:

Conserve at Home was an exhibit on the simple changes that can be made at home in order to conserve energy.  The interactive display on lightbulbs allowed people to power different types of light bulbs such as LED and incandescent.  The LED light bulb was an 8 watt light bulb and it was able to light up a room relatively easily.  The 40 watt incandescent bulb was very difficult to light up and barely provided any light.  The exhibit also mentioned the importance of recycling and how humans produce 4.4 pounds of daily waste without recycling and 2.9 pounds after recycling.  Though these measures do not eliminate waste, they are able to reduce waste by a significant amount when you take the entire population into account.

 

Pandora’s Promise is essentially a portal into a world that environmentalists, past and present, unanimously fear due to previous incidents such as the Chernobyl disaster and most recently the Fukushima Dai-ichi disaster.  The movie is produced in a way that attempts to eliminate the growing concerns that environmentalists, but more specifically, anti-nuclear activists have over the use of nuclear energy.  Its central argument is that nuclear power is, in fact, a safe method of generating clean energy and that it can mitigate the global warming problem we face today.  The movie’s use of several notable individuals, some of whom were once vehemently opposed to nuclear power but who now speak in favor of it, is a wonderful way to begin the documentary.  It offers environmentalists, the target audience, well-known people with a scientific background who shared the same concerns they do.  Though once opposed to the use of nuclear power, these people now support it and use modern evidence to dispel anti-nuclear advocate concerns.

Many environmentalists bring up the point that there is not enough safety surrounding the nuclear power plants and use major examples such as Chernobyl, 3-mile Island, and Fukushima Dai-ichi as supporting evidence for these facts.  Though the advocates for nuclear power admitted to the failures in the past due human error, negligence, poor safety standards, and lack of a well-designed plant, they claim that these mistakes shall never happen again.  The advancement of technology has allowed people to move away from the use of poorly designed reactors, such as Chernobyl, and proper protocol and fail safe measures have been put into place to prevent disasters such as Fukushima Dai-ichi from ever happening again.

Anti-Nuclear Advocates also bring up the point that radiation leaks have a negative effect on people and on the environment.  They make strong claims that even if radioactivity is kept under control that the radioactivity surrounding nuclear plants will still be harmful.  The environmentalists turned supporters explain how radioactivity is present in many areas of the world where reactors are not found.  They are present in small quantities in nature itself.  By visiting different locations and testing them, the documentary makes it clear that humans are surrounded by radioactivity and that in small quantities it is not harmful to the body.  The documentary shows that radioactivity in U.S cities is roughly the same amount as radioactivity found in reactors.  Pandora’s Promise also shows how radiation levels due to cosmic radiation at higher altitudes equal more than that found at plants.

Finally, environmental concerns are discussed in the documentary as the storage and nuclear waste is brought up.  The advocates for nuclear energy state that the use of breeder reactors instead of light water reactors reduce nuclear waste due to its ability to recycle nuclear material many times over.  The unrealistic views of environmentalists concerning solar and wind power are also mentioned.  Due to excessive costs required to build, maintain, and use these methods, nuclear energy is still considered a better resource.  Nuclear energy advocates mention that nuclear energy may, in fact, be the only way to reduce CO2 levels.  The production of nuclear energy produces less CO2 than the production of solar panels and wind turbine components.  Ultimately, the nuclear energy advocates bring up France’s nuclear success story and how after its switch to nuclear energy in the 70’s it has enjoyed access to cheap energy and far less carbon emissions than Germany, a leader in the use of solar energy.

Overall, Pandora’s promise makes a clear statement: through trial and error, humanity now has the resource to vastly reduce emissions through the means of nuclear energy.  The notable individuals who once opposed the use of nuclear energy put aside their pride and admitted that they were wrong.  If the production of safe nuclear energy is indeed the method that will reduce carbon emissions, it is important that environmentalists come to an understanding of how nuclear energy is beneficial and how their concerns have been addressed.

Exactly five years ago today on March 11th, 2011, Japan’s Fukushima Dai-ichi Nuclear Plant went through a series of equipment failures, nuclear meltdowns and releases of radioactive materials at the Fukushima, Nuclear Power Plant, following the Tohoku Tsunami on 11 March, 2011.  It is the largest nuclear disaster since the Chernobyl disaster of 1986 and only the second disaster (along with Chernobyl) to measure Level 7 on the International Nuclear Events Scale (INES).

Japanese officials are still trying to understand all the factors that contributed to the meltdowns at the Fukushima Dai-ichi nuclear power plant.  Officials came to the conclusion that the plant was not designed to withstand the 40-foot tsunami that hit it which was caused by a magnitude 9.0 earthquake.  Within days, three of the plant’s six reactors had suffered severe fuel damage—and possibly even melted down—raising fears of radiation dispersal in Japan and around the world.  When the tremors rattled the plant, control rods automatically scrammed the reactor as they were designed to do, cutting off the fission process. Then the plant lost electricity from the grid and the diesel generators kicked on, only to be swamped and disabled by a 30-foot tsunami within the hour.

With no power to keep coolant flowing, the energy from radioactive decay began to build up, raising the pressure within the reactor vessel. Tokyo Electric Power Company (TEPCO) reported on March 12 that safety valves had been triggered in the reactor vessel, and pressure inside the containment structure had increased to double the design limits. Fearing that the containment structure itself might fail, the utility made the calculated decision to vent it through filters and out to the environment (beyond the support building), albeit at the risk of releasing small amounts of radioactivity—mainly the isotopes created by the decay, including iodine-131 and cesium-137.

Over the next few days, it became obvious that the fuel was damaged. The question became whether it would melt, and if it did, whether it would melt through the reactor vessel and into the containment structure. While all of the specifics are not yet known, the fuel certainly suffered severe damage, and at least part of it likely melted. During this time, the spent fuel stored in pools in the support building surrounding the containment structure was also overheating. This presented a grave dilemma: If that spike in temperature wasn’t stopped, the spent fuel, which wasn’t surrounded by a safety barrier, could release radioactivity directly into the environment.

Despite the failure of the first and second barriers and the venting of radioactive water and steam, a truly major release of radioactivity has been averted—a “major release” being a Chernobyl-style accident in which a large fraction of the fission products escape the plant.

The Chernobyl Nuclear disaster is widely considered to have been the worst power plant accident in history, and along with Fukushima Dai-ichi, is one of only two classified as a level 7 event on the International Nuclear Event Scale.The battle to contain the contamination and avert a greater catastrophe ultimately involved over 500,000 workers and cost an estimated 18 billion rubles.

The Chernobyl disaster was attributed to a flawed system along with human error.  The operating crew on the nuclear plant was planning to test whether the plant’s turbines could produce sufficient energy to keep the coolant pumps running in the event of a loss of power until the emergency diesel generator was activated.

To prevent any interruptions to the power of the reactor, the safety systems were deliberately switched off. To conduct the test, the reactor had to be powered down to 25 percent of its capacity. This procedure did not go according to plan and the reactor power level fell to less than 1 percent. The power therefore had to be slowly increased. But 30 seconds after the start of the test, there was an unexpected power surge. The reactor’s emergency shutdown (which should have halted a chain reaction) failed.

The reactor’s fuel elements ruptured and there was a violent explosion. The 1000-tonne sealing cap on the reactor building was blown off. At temperatures of over 2000°C, the fuel rods melted. The graphite covering of the reactor then ignited. The graphite burned for nine days, churning huge quantities of radiation into the environment. The accident released more radiation than the deliberate dropping of a nuclear bomb on Hiroshima, Japan in August 1945.

With events such as these, society will demand increased safety standards, more rigorous planning, careful checklists, and increased transparency in the whole nuclear political system.

Nuclear security is the most essential element of safe nuclear. According to the International Atomic Energy Agency (IAEA) nuclear security plan can be achieved through “prevention, detection of and response to malicious acts, and Information coordination and analysis.  The Fukushima incident has called for increased transparency in the public and private sector, as the plant’s operator Tokyo Electric Power (TEPCO) received severe scrutiny from the international community because of the problems at the reactor.  Aside from these two important measures, it is also important to have specific protocols and fail proof designs that will hedge or completely eliminate the risk of nuclear disasters occurring from malfunction or unexpected natural disasters.

 

Sources:

http://www.world-nuclear.org/information-library/safety-and-security/safety-of-plants/safety-of-nuclear-power-reactors.aspx

http://www.world-nuclear.org/information-library/safety-and-security/safety-of-plants/chernobyl-accident.aspx

http://www.world-nuclear.org/information-library/safety-and-security/safety-of-plants/fukushima-accident.aspx

Normally, geothermal energy is hard to come across due to the amount of drilling is required to reach the required heat and steam to produce geothermal energy.  There is, however, one country whose geographical positioning makes it perfect for extracting geothermal energy.

Iceland is a young country geologically. It lies on either side of one of the earth’s major fault lines, the Mid-Atlantic ridge. This is the boundary between the North American and Eurasian tectonic plates. The two plates are moving apart at a rate of about 2 cm per year. Iceland’s location is a hot spot of unusually great volcanic productivity.

During the course of the 20th century, Iceland went from what was one of Europe’s poorest countries, dependent upon peat and imported coal for its energy, to a country with a high standard of living where practically all stationary energy is derived from renewable resources.  The main reason for this enormous change in the country’s energy resource is due greatly to the volcano activity.

Iceland is currently a pioneer in the use of geothermal energy for space heating and the generation of electricity. Generating electricity with geothermal energy has increased significantly in recent years and geothermal power facilities currently generate 25% of the country’s total electricity production.

In 2014, roughly 85% of primary energy use in Iceland came from indigenous renewable resources and 66% was from geothermal resources.  The use of geothermal energy has many direct utilizations from bathing and recreation to snow melting to space heating.  Many pools in Iceland are heated using geothermal energy.  Most of these pools are public, but many school pools are also heated by these means.  Only about 8% of these pools are heated using electricity or fossil fuels.  Geothermal energy is also used to heat fish farms as the fish raised in these farms require the water to be in a specific temperature range for them to survive.

Some of the other direct utilizations of geothermal energy include space heating and snow melting.  After World War II, Iceland carried out a lot of research and development , which has led to the use of geothermal resources for heating in the 89% of households in the country.  The relative share of energy resources used to heat households has changed since 1970. The increase in geothermal energy is clear, but after 1985 it has been relatively small. The proportion of the population using geothermal energy is, however, still increasing. Overall, the share of oil for heating continues to decrease and is at present at about 1%. The share of electric heating is about 10%.

Snow melting with geothermal water has also increased during the last two decades and now most new car parking areas in regions enjoying geothermal district heating are provided with snow melting systems.  Interestingly enough, the water used in space heating does not go to waste, but is actually used to deice sidewalks.  The water used in space heating returns at roughly 35 degrees Celsius and is sometimes mixed with hotter water to melt the ice or snow found on streets and sidewalks.

Generating electricity with geothermal energy has increased significantly in recent years in Iceland. As a result of a rapid expansion in Iceland’s energy intensive industry, the demand for electricity has increased considerably.  The use of geothermal power plants in Iceland has helped reduce the amount of fossil fuels to produce electricity by a huge magnitude.  The geothermal power plants are able to harness the steam produced through the geothermal process to spin steam turbines which ultimately produces electricity.

Due to its geographical positioning, Iceland has been able to make use of its access to geothermal energy.  They continue to improve on and decrease the amount of fossil fuels they use to generate heat or electricity and are on their way to becoming self sustaining energy wise.

 

Thermoelectric devices, such as generators, take a temperature difference and are able to turn it into electrical power.  Amazingly, thermoelectric devices can also be run in reverse!  If power is put into a thermoelectric generator a temperature difference is created.  Small mini-fridges, for just a few sodas, use thermoelectric generators to efficiently cool a few drinks.

To understand how thermoelectrics generate the electricity from a temperature difference, it is important to know how electrons move in a metal.  Metals are good conductors because electrons can move freely within them, similar to a fluid in a pipe.

The best way to explain thermoelectrics is imagine a pipe full of water and you raising one end.  The water will flow down the pipe from the high end to the low end.  This is because when the pipe was raised the potential energy was increased and the water wanted to flow to the lower point.  In a thermoelectric material the same general concept applies where fluid-like electrons want to move from one point to another.

Heating one end of a thermoelectric material causes the electrons to move away from the hot end toward the cold end.  When the electrons go from the hot side to the cold side an electrical current is formed.  The larger the temperature difference, the more electrical current is produced and therefore more power generated.

The tricky part about thermoelectric devices, such as generators is that as one side is heated, the other side, or the cold side of the generator heats up too.  In order to generate power with the a thermoelectric generator it is necessary to have both a heat source and a way of dissipating heat in order to maintain a temperature difference across the thermoelectric materials.

An example of a thermoelectric device is known as the power pot.  It essentially is a generator that creates electricity with water and a variety of  heating sources, such as fire or propane.  The power pot is essentially able to limit how hot the cold side can get because water itself cannot get any hotter than 212 degrees Fahrenheit, the point at which it boils.  Because the power pot has no moving parts and only requires a heating source and a cold source, it is a great way to provide electricity to communities or people that do not have access to it through a grid.  Essentially, it is yet another step to providing power for everyone.

 

Sources:

https://www.alphabetenergy.com/how-thermoelectrics-work/

http://thermoelectrics.caltech.edu/thermoelectrics/history.html

http://ocw.mit.edu/courses/mechanical-engineering/2-997-direct-solar-thermal-to-electrical-energy-conversion-technologies-fall-2009/audio-lectures/MIT2_997F09_lec02.pdf