How come the water that is piped into your house is so cold (colder than it seems like it should be)?
The reason I ask is that it seems like our society could be much more energy efficient if the water we’re pumping into our houses wasn’t as cold as it is. Perhaps we could heat it all a few degrees on a massive scale using geothermal, before it gets to people’s houses?

A small geothermal power plant in Europe uses hot water from the ground as a high
temperature reservoir and the outside air as the low temperature reservoir. Hot
ground water enters the plant at a temperature To and leaves the plant at a slightly
lower temperature Tf. Waste hest is ejected to the environment at a temperature Tc.
How ground water of mass m kg is pumped through the power plant each second.
How much heat is supplied to the power plant energy second? (hot
groundwater is cooled from To to Tf).
b. What is the theoretical maximum efficiency of the geothermal plant, if the
temperature of the hot reservoir is taken to be the average of To and Tf)?
c. What is the maximum power output of the geothermal plant?
d. At this geothermal plant, 5.8kg per second of hot groundwater enters the
plant at To =79.6°C and leaves the plant at 79.4°C. In winter the temperature
of the outsid air is Tc = ?0.4°C. Calculate the theoretical power output of the
geothermal plant.

1. Limitless resources include:
A.coal
B. oil
C. natural gas
D. none of the above
2. The energy transfer represented when a hair dryer is in use includes:
A.electrical to heat, mechanical, and sound
B. heat only
C. electrical to mechanical
D. electrical to radio
3. Location is the major factor in the following alternative energy usage:
A. geothermal
B. tidal energy
C. OTEC
D. all of the above
4. The form of energy characterized by the force of moving objects is:
A. mechanical
B. sound
C. radio
D. light
5. Which of the following is NOT true:
A. the earth only intercepts a very small part of the sun’s output
B. wind energy is just another form of solar energy
C. wind has only recently been used to pump water and grind grain
D. biomass can be used as an energy source
6. The energy of electrons moving through a conductor is:
A. light
B. heat
C. electrical
D. nuclear

When people think about electricity, different things come to mind. One person may think about household appliances, another might find himself wondering about lightning, and electricity could conjure up thoughts of Thomas Edison, or his famous invention, the electric light, in yet another person. Yet all agree that electricity has become an essential, irreplaceable part of all our lives and its discovery is one of the most important breakthroughs of modern man. It seems that almost everything that we use in our daily lives runs on electricity, including mom’s stove and oven, dad’s laptop computer and wristwatch, and your cell phone and video games. Even some of our most advanced technology, including supercomputers, satellites, and the latest spy technology, have at least one basic need – electricity. Without it, modern civilization cannot function. Communication over long distances, which is vital to our lives, would be paralyzed, and the comforts of our present environment would be rendered unfeasible. Man himself would be virtually helpless without electricity.
Electricity is used in all kinds of diverse ways and is produced from numerous sources. Some sources of electricity are fossil fuels. In a power plant, fossil fuels (mainly coal) are burned. The heat is used to heat water and create steam to turn turbines to generate the electricity. Coal produces about 40% of the electricity used on earth. Another source is water. The electricity, called hydroelectric power, is generated by turbines. Water behind a dam flows into a channel in the dam called a penstock and turns the turbine, which generates electricity. 25% of the electric energy on earth used by humans is hydroelectric. About 16% of the energy in the world is nuclear power. Uranium or plutonium atoms split in the core of a nuclear reactor, producing intense heat. Water, under high pressure, is pumped into the reactor and comes out extremely hot. The water heats more water in a tank, producing steam to turn turbines. Other minor sources of electric energy include the sun (solar energy), wind (wind power) heat from the earth’s interior (geothermal energy), and biomass (energy release by bacteria in cow manure). Batteries also supply electricity. Unfortunately, renewable sources still account for only 12% of the United States’s supply of electricity.
Humans have been trying to harness the great powers of electricity for a long time. The ancients wondered what lightning was, and attributed different gods to thunder and lightning. Thales, a Greek philosopher, noted that rubbing a piece of amber caused bits of straw to stick to it. (This phenomenon is known today as static electricity). By performing his famous experiment with a silk kite and a metal key, Benjamin Franklin proved that lightning was indeed electricity in 1750, two millennia later. 21 years later, in 1771, Luigi Galvani made an interesting discovery when he found that a dead frog would twitch if touched by two pieces of metal, copper and iron. An electric charge traveled through the animal, which caused the movement. This occurrence would be called galvanism, after Galvani. His associate, Alessandro Volta, used this information to develop the voltaic pile, a forerunner of the battery that produced a steady electric current. The volt, a unit of measurement used to measure electric power, was named after him. Finally, Sir Humphrey David connected some voltaic piles and invented the first battery. Modern batteries are similar to this design.
Modern life is helplessly dependent on electricity. Production of electricity has become an indispensable piece our daily lives as we hope to find more renewable and efficient ways to produce it for its many significant purposes.

1) a nuclear power plant generates_________energythat boils water to produce steam.
2) the spinninggenerator of a nuclear power plant converts ________ energy into electrical energy.
3) Why is nuclear energy considered a nonrenewable resorse?
4) How does a hydroelectric dam change kinetic energy into electrical energy?
5) Wind turbines convert energy of air in to ___________ by turning a generator.
6) the thermal energy caused by the heating of earth’s crust is called__________.
7) some geothermal power plants pump water underground next to hot__________.
organic matter that can be burned to realease energy is called_________.
9) Name one disadvantage of fossil fuels.
10) Why can’t solar energy br used to meet the energy needs of large cities?
11) Why is hydroelectric energy not always a disirable energy resource?
thank you in advance. appropriate answers only. thanks again.

The Pac-Car is the world record holder for fuel efficiency, now standing at 5,134 kilometres per litre of petrol. This converts to roughly 14,502 MPG!!!
Working prototype: 100 MPG+Plug-in Toyota Prius
We have Solar and wind alternative energy
we had the electric car which the oil companies killed
Geothermal heating
Wave power which is the energy of ocean surface waves and the capture of that energy to do useful work – including electricity generation, desalination, and the pumping of water (into reservoirs)
Just because the politicians are in the back pockets of the oil companies, does not mean we do not have the technology to be energy independent.
Do your research before you speak, think before you buy the arguments from big oil

What causes global warming?
Carbon dioxide and other air pollution that is collecting in the atmosphere like a thickening blanket, trapping the sun’s heat and causing the planet to warm up. Coal-burning power plants are the largest U.S. source of carbon dioxide pollution — they produce 2.5 billion tons every year. Automobiles, the second largest source, create nearly 1.5 billion tons of CO2 annually.
Here’s the good news: technologies exist today to make cars that run cleaner and burn less gas, modernize power plants and generate electricity from nonpolluting sources, and cut our electricity use through energy efficiency. The challenge is to be sure these solutions are put to use.
Is the earth really getting hotter?
Yes. Although local temperatures fluctuate naturally, over the past 50 years the average global temperature has increased at the fastest rate in recorded history. And experts think the trend is accelerating: the 10 hottest years on record have all occurred since 1990. Scientists say that unless we curb global warming emissions, average U.S. temperatures could be 3 to 9 degrees higher by the end of the century.
Are warmer temperatures causing bad things to happen?
Global warming is already causing damage in many parts of the United States. In 2002, Colorado, Arizona and Oregon endured their worst wildfire seasons ever. The same year, drought created severe dust storms in Montana, Colorado and Kansas, and floods caused hundreds of millions of dollars in damage in Texas, Montana and North Dakota. Since the early 1950s, snow accumulation has declined 60 percent and winter seasons have shortened in some areas of the Cascade Range in Oregon and Washington.
Of course, the impacts of global warming are not limited to the United States. In 2003, extreme heat waves caused more than 20,000 deaths in Europe and more than 1,500 deaths in India. And in what scientists regard as an alarming sign of events to come, the area of the Arctic’s perennial polar ice cap is declining at the rate of 9 percent per decade.
Is global warming making hurricanes worse?
Global warming doesn’t create hurricanes, but it does make them stronger and more dangerous. Because the ocean is getting warmer, tropical storms can pick up more energy and become more powerful. So global warming could turn, say, a category 3 storm into a much more dangerous category 4 storm. In fact, scientists have found that the destructive potential of hurricanes has greatly increased along with ocean temperature over the past 35 years.
Is there really cause for serious concern?
Yes. Global warming is a complex phenomenon, and its full-scale impacts are hard to predict far in advance. But each year scientists learn more about how global warming is affecting the planet, and many agree that certain consequences are likely to occur if current trends continue. Among these:
Melting glaciers, early snowmelt and severe droughts will cause more dramatic water shortages in the American West.
Rising sea levels will lead to coastal flooding on the Eastern seaboard, in Florida, and in other areas, such as the Gulf of Mexico.
Warmer sea surface temperatures will fuel more intense hurricanes in the southeastern Atlantic and Gulf coasts.
Forests, farms and cities will face troublesome new pests and more mosquito-borne diseases.
Disruption of habitats such as coral reefs and alpine meadows could drive many plant and animal species to extinction.
Could global warming trigger a sudden catastrophe?
Recently, researchers — and even the U.S. Defense Department — have investigated the possibility of abrupt climate change, in which gradual global warming triggers a sudden shift in the earth’s climate, causing parts of the world to dramatically heat up or cool down in the span of a few years.
In February 2004, consultants to the Pentagon released a report laying out the possible impacts of abrupt climate change on national security. In a worst-case scenario, the study concluded, global warming could make large areas of the world uninhabitable and cause massive food and water shortages, sparking widespread migrations and war.
While this prospect remains highly speculative, many of global warming’s effects are already being observed — and felt. And the idea that such extreme change is possible underscores the urgent need to start cutting global warming pollution.
What country is the largest source of global warming pollution?
The United States. Though Americans make up just 4 percent of the world’s population, we produce 25 percent of the carbon dioxide pollution from fossil-fuel burning — by far the largest share of any country. In fact, the United States emits more carbon dioxide than China, India and Japan, combined. Clearly America ought to take a leadership role in solving the problem. And as the world’s top developer of new technologies, we are well positioned to do so — we already have the know-how.
How can we cut global warming pollution?
It’s simple: By reducing pollution from vehicles and power plants. Right away, we should put existing technologies for building cleaner cars and more modern electricity generators into widespread use. We can increase our reliance on renewable energy sources such as wind, sun and geothermal. And we can manufacture more efficient appliances and conserve energy.
Why aren’t these technologies more commonplace now?
Because, while the technologies exist, the corporate and political will to put them into widespread use does not. Many companies in the automobile and energy industries put pressure on the White House and Congress to halt or delay new laws or regulations — or even to stop enforcing existing rules — that would drive such changes. From requiring catalytic converters to improving gas mileage, car companies have fought even the smallest measure to protect public health and the environment. If progress is to be made, the American people will have to demand it.
Do we need new laws requiring industry to cut emissions of global warming pollution?
Yes. The Bush administration is promoting an initiative in which energy companies cut emissions only if they choose to do so. As the past 10 years have clearly shown, though, voluntary programs do not stop the growth of emissions. Proposals to cap emissions of carbon dioxide and other heat-trapping pollutants from America’s largest sources — power plants, industrial facilities, and transportation fuels — are gaining support in Congress.
Stricter efficiency requirements for electric appliances will also help reduce pollution. One example is the 30 percent tighter standard now in place for home central air conditioners and heat pumps, a Clinton-era achievement that will prevent the emission of 51 million metric tons of carbon — the equivalent of taking 34 million cars off the road for one year. The new rule survived a Bush administration effort to weaken it when, in January 2004, a federal court sided with an NRDC-led coalition and reversed the administration’s rollback.
Is it possible to cut power plant pollution and still have enough electricity?
Yes. First, we must use more efficient appliances and equipment in our homes and offices to reduce our electricity needs. We can also phase out the decades-old, coal-burning power plants that generate most of our electricity and replace them with cleaner plants. And we can increase our use of renewable energy sources such as wind and sun. Some states are moving in this direction: California has required its largest utilities to get 20 percent of their electricity from renewable sources by 2017, and New York has pledged to compel power companies to provide 25 percent of the state’s electricity from renewable sources by 2013.
How can we cut car pollution?
Cost-effective technologies to reduce global warming pollution from cars and light trucks of all sizes are available now. There is no reason to wait and hope that hydrogen fuel cell vehicles will solve the problem in the future. Hybrid gas-electric engines can cut global warming pollution by one-third or more today; hybrid sedans, SUVs and trucks from several automakers are already on the market.
But automakers should be doing a lot more: They’ve used a legal loophole to make SUVs far less fuel efficient than they could be; the popularity of these vehicles has generated a 20 percent increase in transportation-related carbon dioxide pollution since the early 1990s. Closing this loophole and requiring SUVs, minivans and pick-up trucks to be as efficient as cars would cut 120 million tons of carbon dioxide pollution a year by 2010. If automakers used the technology they have right now to raise fuel economy standards for new cars and light trucks to a combined 40 m.p.g., carbon dioxide pollution would eventually drop by more than 650 million tons per year as these vehicles replaced older models.
For more information on hybrid vehicles, see NRDC’s hybrid guide.
What can I do to help fight global warming?
There are many simple steps you can take right now to cut global warming pollution. Make conserving energy a part of your daily routine. Each time you choose a compact fluorescent light bulb over an incandescent bulb, for example, you’ll lower your energy bill and keep nearly 700 pounds of carbon dioxide out of the air over the bulb’s lifetime. By opting for a refrigerator with the Energy Star label — indicating it uses at least 15 percent less energy than the federal requirement — over a less energy-efficient model, you can reduce carbon dioxide pollution by nearly a ton in total.

A power plant taps steam superheated by geothermal energy to 505 K (the temperature of the hot reservoir) and uses the steam to do work in truning the turbine of an eletric generator. The steam is then converted back into water in a condenser at 323 K (the temperature of the cold reservoir), after which the water is pumped back down into the ground where it is heated again. The output of the generator is 84MW. Calculate:
The maximum efficiency at which this plant can operate.
The minimum amount of rejected heat (in MJ) that must be removed from the condenser every 24 hours.
Would appresiate if you showed working with the answer so i can work though it myself, but just the answer is fine. Cheers

A power plant taps steam superheated by geothermal energy to 505 K (the temperature of the hot reservoir) and uses the steam to do the work in turning the turbine of an electric generator. The steam is then converted back into water in a condenser at 323 K (the temperature of the cold reservoir), after which the water is pumped back down into the ground where it is heated again. The output power of the generator is 84 MW. Calculate:
1) The maximum efficiency at which this plant can operate
2) The minimum amount of rejected heat (in MJ) that must be removed from the condenser every 24 hours
3) Express your answer to (2) in TJ and in PJ.
(Quick question – what would TJ and PJ mean? Terra joules and Peta joules or something?

So I’m having to make a cardboard house for a science project that runs only on alternate energy sources. I’m using geothermal as a source, and nuclear. However, our sources can only be based for our homes, and not for several. So for geothermal, I’m using a ground source heat pump, and for nuclear, Toshiba’s micro nuclear reactor. However, I can’t figure out how the reactor circulates heat through the home, and I’m so confused! I understand the gist of how the liquid lithium-6 triggers the reaction, but I don’t know how that relates to heating the home, and how. Could you please help me? Thank you so much!