PV Gap

Ethel Said:

Is Earth a closed system? How does one add/remove excess thermal energy?

We Answered:

ha ha i thought about that, 'why not build giant solar panels in space to block off the sun, since our polar ice cap just isn't cutting it anymore'. we dont have the technology simply put.

theres probably a huge matter of safety in transfering the energy if it was possible.

we need to focus getting heat from the sun away from our planet as it is. worrying about substituting energy wont help us at this point.

Rose Said:

What thoughts on mass scale geo thermal energy?

We Answered:

Geothermal energy in the United States continues to be an area of considerable activity. The USA is the world leader in online capacity of geothermal energy and the generation of electricity from geothermal energy.

According to 2005 state energy data, geothermal energy provided approximately 16 billion kilowatt hours (kWh) of electricity -- 0.37% of the electricity consumed in the U.S. As of May 2007, geothermal electric power was generated in five U.S. states: Alaska, California, Hawaii, Nevada, and Utah. According to the Geothermal Energy Association's recent report, there were 75 new geothermal power projects underway in 12 states as of May 2007 . This is an increase of 14 projects in an additional three states compared to a survey completed in November 2006.

The most significant catalyst behind new industry activity is the Energy Policy Act of 2005. This Act made new geothermal plants eligible for the full federal production tax credit, previously available only to wind power projects. It also authorized and directed increased funding for research by the Department of Energy, and gave the Bureau of Land Management new legal guidance and secure funding to address its backlog of geothermal leases and permits.

If heat recovered by ground source heat pumps is included, the non-electric generating capacity of geothermal energy is estimated at more than 100 GW (gigawatts of thermal power) and is used commercially in over 70 countries.

During 2005, contracts were placed for an additional 0.5 GW of capacity in the United States, while there were also plants under construction in 11 other countries.

Resources

Estimates of exploitable worldwide geothermal energy resources vary considerably. According to a 1999 study, it was thought that this might amount to between 65 and 138 GW of electrical generation capacity 'using enhanced technology'.

A 2006 report by MIT that took into account the use of Enhanced Geothermal Systems (EGS) concluded that it would be affordable to generate 100 GWe (gigawatts of electricity) or more by 2050, just in the United States, for a maximum investment of 1 billion US dollars in research and development over 15 years.

The MIT report calculated the world's total EGS resources to be over 13,000 ZJ, of which over 200 ZJ would be extractable, with the potential to increase this to over 2,000 ZJ with technology improvements - sufficient to provide all the world's energy needs for several millennia.

The key characteristic of an EGS is that it reaches at least 10 km down into hard rock. The MIT report estimated that there was enough energy in hard rocks 10 km below the United States to supply all the world's current needs for 30,000 years. At a typical site two holes would be bored and the deep rock between them fractured. Water would be pumped down one and steam would come up the other. There seems no reason why the steam should not feed an existing coal, oil or nuclear fired generating plant.

Drilling at this depth is now routine for the oil industry (Exxon announced an 11 km hole at the Chayvo field, Sakhalin. Lloyds List 1/5/07 p 6). The technological challenges are to drill wider bores and to break rock over larger volumes. Apart from the energy used to make the bores, the process releases no greenhouse gases. Compared to the difficulties of developing other forms of energy supply (nuclear, wind, wave, solar etc)EGS seems to be well worth encouragement.

Although geothermal sites are capable of providing heat for many decades, eventually specific locations may cool down. It is likely that in these locations, the system was designed too large for the site, since there is only so much energy that can be stored and replenished in a given volume of earth. Some interpret this as meaning a specific geothermal location can undergo depletion, and question whether geothermal energy is truly renewable, but if left alone, these places will recover some of their lost heat, as the mantle has vast heat reserves. The government of Iceland states It should be stressed that the geothermal resource is not strictly renewable in the same sense as the hydro resource. It estimates that Iceland's geothermal energy could provide 1700 MW for over 100 years, compared to the current production of 140 MW.

Power plants

Three different types of power plants - dry steam, flash, and binary - can be are used to generate power from geothermal energy, depending on temperature, depth, and quality of the water and steam in the area. In all cases the condensed steam and remaining geothermal fluid is injected back into the ground to pick up more heat.

Dry steam

A dry stream power plant uses hot steam, typically above 455°F, to directly power its turbines. This is the oldest type of power plant and is still in use today.

Flash steam

Flash steam power plants use hot water above 360°F from geothermal reservoirs. As the water is pumped from the reservoir to the power plant, the drop in pressure causes the water to vaporize into steam to power the turbine. Any water not flashed into steam is injected back into the reservoir for reuse.

Binary-cycle

The water used in binary-cycle power plants is cooler than that of flash steam plants. The hot fluid from geothermal reservoirs is passed through a heat exchanger which transfers heat to a separate pipe containing fluids with a much lower boiling point. These fluids, usually Iso-butane or Iso-pentane, are vaporized to power the turbine. The advantage to binary-cycle power plants is their lower cost and increased efficiency. These plants also do not emit any excess gas and are able to utilize lower temperature reservoirs, which are much more common. Most geothermal power plants planned for construction are binary-cycle.

Distribution

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The largest dry steam field in the world is The Geysers, 72 miles (116 km) north of San Francisco. The Geysers began in 1960, has 1360 MW of installed capacity and produces over 750 MW net. Calpine Corporation now owns 19 of the 21 plants in The Geysers and is currently the United States' largest producer of renewable geothermal energy. The other two plants are owned jointly by the Northern California Power Agency and the City of Santa Clara's municipal Electric Utility (now called Silicon Valey Power). Since the activities of one geothermal plant affects those nearby, the consolidation plant ownership at The Geysers has been beneficial because the plants operate cooperatively instead of in their own short-term interest. The Geysers is now recharged by injecting treated sewage effluent from the City of Santa Rosa and the Lake County sewage treatment plant. This sewage effluent used to be dumped into rivers and streams and is now piped to the geothermal field where it replenishes the steam produced for power generation.

Another major geothermal area is located in south central California, on the southeast side of the Salton Sea, near the cities of Niland and Calipatria, California. As of 2001, there were 15 geothermal plants producing electricity in the area. CalEnergy owns about half of them and the rest are owned by various companies. Combined the plants have a capacity of about 570 megawatts.

The Basin and Range geologic province in Nevada, southeastern Oregon, southwestern Idaho, Arizona and western Utah is now an area of rapid geothermal development. Several small power plants were built during the late 1980s during times of high power prices. Rising energy costs have spurred new development. Plants in Nevada at Steamboat near Reno, Brady/Desert Peak, Dixie Valley, Soda Lake, Stillwater and Beowawe now produce about 235 MW.

Geothermal power is very cost-effective in the Rift area of Africa. Kenya's KenGen has built two plants, Olkaria I (45 MW) and Olkaria II (65 MW), with a third private plant Olkaria III (48 MW) run by geothermal specialist Ormat. Plans are to increase production capacity by another 576 MW by 2017, covering 25% of Kenya's electricity needs, and correspondingly reducing dependency on imported oil.

Geothermal power is generated in over 20 countries around the world including Iceland (producing over 50% of its electricity from geothermal sources in 2006), the United States, Italy, France, New Zealand, Mexico, Nicaragua, Costa Rica, Russia, the Philippines (production capacity of 1931 MW (2nd to US, 27% of electricity), Indonesia, the People's Republic of China and Japan. Canada's government (which officially notes some 30,000 earth-heat installations for providing space heating to Canadian residential and commercial buildings) reports a test geothermal-electrical site in the Meager Mountain–Pebble Creek area of British Columbia, where a 100 MW facility could be developed.

Water injection

In some locations, the natural supply of water producing steam from the hot underground magma deposits has been exhausted and processed waste water is injected to replenish the supply. Most geothermal fields have more fluid recharge than heat, so re-injection can cool the resource, unless it is carefully managed.

Benefits

Geothermal energy a number of advantages over traditional fossil fuel based sources. From an environmental standpoint, the energy harnessed is clean and safe for the surrounding environment. It is also sustainable because the hot water used in the geothermal process can be re injected into the ground to produce more steam. In addition, geothermal power plants are unaffected by changing weather conditions. From an economic view, geothermal energy reduces reliance on foreign fossil fuel imports. Given enough excess capacity, geothermal energy can also be sold to outside sources such as neighboring countries or private businesses that require energy. It also offers a degree of scalability: a large geothermal plant can power entire cities while smaller power plants can supply more remote sites such as rural villages.

Environmental concerns

There are several environmental concerns behind geothermal energy. Construction of the power plants can adversely affect land stability in the surrounding region. For example, increased seismic activity can occur because of well drilling and land subsidence can become a problem as older wells begin to cool down.[9]. Dry steam and flash steam power plant also emit low levels of carbon dioxide, nitric oxide, and sulfur, although at roughly 5% of the levels emitted by fossil fuel power plants!!!!!!!!!

Stacey Said:

What are some real, effective, and reasonably priced energy saving systems for a new construction house?

We Answered:

Ever been in a basement that's not heated in the winter time? It's cool, but not unbearable. How about a basement that's not air conditioned in the summer? It's generally not as hot as the rest of the house.

I'm not saying build your house underground. That doesn't meet your standards. The concept of having a 2 story home with a basement comes to mind though. The way it would work is your first floor would be 1/2 underground 1/2 above. The basement of course would be under it, and the second level would be above the first of course. It would be preferred that a home like this be built on a hill, and the second floor would make it not look weird.

In the US, most homes are built using 2X4 wall beams. It would cost some extra coin, but switching that up to 2X6 wall beams would give room for more insulation. More insulation will increase the efficiency dramatically. A minor problem arises in purchasing doors for the home. This problem isn't a problem though because the door openings can be reduced to 2X4, or your contractor will probably know where to get doors that fit. Windows are designed different from doors so this wont be a problem for them. This also allows for larger ductwork through the walls. This will reduce the load on your central heating/cooling system's blower saving some coin. Use of 2X6 framing also opens a new avenue for adding custom features like in-wall shelving.

It's fairly common to see a room with a switch by the door controlling an outlet for a lamp to be plugged into. Having switches like this installed all over your house to cut off power to things like TVs when no-one is in the room would save some nice coin. You will need outlets that are not switch controlled too for things like clocks, and cable boxes/satellite receivers that have interactive services like TV Guide and battery chargers. That's your chance to learn from my mistake. I converted my home so that all the outlets ran on switches, and purchased battery powered clocks. I had to undo some of it so my cable box would work right.

Often less is more, and more is less. I purchased an air conditioner rated for the size of room I have, and it didn't cut it. It never was cool in the room, and my power bill went up by $100 a month. I decided to upgrade it, and bought one 3 times the size for $200 more. This reduced my electric bill by $50 a month from what the first cost me. In 4 months it paid for itself.

Installing multiple lighting systems in each room can save you big money if used right. It can also be more comfortable to the eyes. A low power lighting system for regular use, and a task lighting system for when you need the extra light. I use just a 10 watt bulb in my hallway for normal everyday traffic. I can see well enough to get through it. When I need to vacuum the hallway though I turn on a 100 watt bulb, and can see it very well. This system is also very good to have in the bathroom because when someone is making use of the toilet, they don't tend to need extra light. When they are using the mirror though they want a lot more light. It applies very well in the kitchen too. Under cabinet lights can give the task based lighting needed to cook, and over-head lighting will allow a person to pass through the kitchen without stubbing their toe on a cabinet, or stepping on that fork someone dropped.

A switch at every door! Some rooms have multiple doors, and often is the case that someone will walk into the room on one side, and turn the light on, then as they walk out on the other side there is no switch so the light gets left on. It doesn't cost much to install a multiple switch situation.

Having all the plumbing in a home in one central area can be a big savings also. Not so much in energy as in water which also costs money. In some homes, you turn on the water in the bathroom or kitchen, and have to wait for hot water to come out. The closer everything is together the shorter the wait, and the less water wasted.

Having a closed in porch can save you big too. In the winter when it's windy, you will open the porch door, and enter, and while you take the step across the porch to the front door of your house the porch door will close behind you blocking the wind as you enter your home.

Whether or not to install a geothermal HVAC system in your home will depend on what it costs in your area to install. It may not be a viable option. LED Lighting can be an option, but I suggest you try it in your current home before investing in a whole house system. You may or may not like it, or may only want it in certain rooms/situations. On demand hot water systems are efficient for 2-3 people living in a home. If you have more, then the system will use more power heating the water than the older system using a tank. This is because it takes a lot of power to heat water right now. The older system instead uses less power to heat it over a period of time.

Appliance placement can save you money too. Most washers and dryers are set up side by side. Well most people wash their clothes in cold water, and the dryer uses heat to dry the clothes. Washers and dryers are not insulated. Separating them will keep the cold water from sucking the heat out of the dryer, so the dryer wont have to work as hard. A simple insulated wall between the 2 the height of the washer and dryer can make a huge difference. Insulating the walls around your hot water heater can make a difference when you are using the air conditioning. Everything in this paragraph is not common even in new homes.

When choosing your appliances remember less is more once again. Less features like digital controls means less power used. That microwave with the digital clock sitting in your kitchen, well it uses power 24/7 whether you are using it or not. The time with a timer that you turn the knob to use doesn't. When it's off, it is off. Gas cook stoves that use electronic ignition instead of a pilot lighting system don't sit there generating heat when your air conditioning is on, and using gas. Refrigerators with through the door ice and water avoid constantly opening the freezer to get ice out. If someone in your home bakes a lot, then an in-wall double oven system will probably make them happier, and since they can use both at once, the heat from 1 will make the other more efficient. They will also spend less time using 2 at once rather than using 1 longer. This will help cut down on cooling bills in the summer.

Insulating all the pipes in your home can help too.

Holly Said:

Avatar: Natrium as an energy metal boycotted, unresearched, forgotten?

We Answered:

I am not sure if you are asking a question or just proselytizing. The necessity of salt in everyday lives is well known, as well as the dangers of too much salt.

Since it is the 6th most common element on Earth, I can see why you think it should be utilized more and in a more efficient manner. Have you any ideas as to what uses you would like to see it used for?