Frequently Asked Questions (FAQ) on Renewable Energy: Presentation Project – Winter 2011/2012
Textbook: Green Electricity, K. Haven, Libraries Unlimitted, 2011.  Engineering graduate student English course at University of Fukui, Japan. Teacher: E. Hitzer. The questions and answers were made by the students after their presentation and are slightly corrected for language. Disclaimer: No guarantee can be given for the accuracy of the information.

Click on a question link to see the answer, or scroll up and down.

6. Hydroelectric Energy  home

6.1 The current use of hydroelectric energy in Japan.  home
Q1. What do you think is the best kind of hydroelectric energy?
Q2. How many Hydroelectric power stations are there in Japan?
Q3. Where is the biggest Hydroelectric power station in Japan?
6.2 What can be done to increase small scale hydroelectric power in Japan?  home
Q1. What kind of generator is the best?
Q2. What kind of buildings use small scale hydroelectric power?
Q3. Do you think that small scale hydroelectric energy can be used in Fukui city? Where?
6.3 Explain how a pump storage system works.  home
Q1. Please explain the usage of pump storage system?
Q2. Do you think it is important to use pump storage system in the future?
Q3. Why is it necessary to use pumps to pump up water?
Q4. What is the efficiency of power conversion to hydroelectric energy using pomped storage systems?
Q5. What is the most important advantage of hydroelectric power from pump storage systems?
Q6. What is the biggest Japanese pump storage facility in slide 7?
7. Ocean Wave Energy  home
7.1 Explain in detail the design of an ocean wave energy power plant.  home  
7.2 Overview of the main ocean wave energy projects worldwide.  home   
Q1. What do you think is the best country for ocean wave energy generation?
Q2. How many kinds wave of energy power plants did you find in your research?
Q3. Wave power is widely used in Asia, who is developing wave energy power in Asia?
Q4. What are the names of the world's major wave energy power plant companies?
7.3 How is ocean wave energy nowadays used in Japan (and Asia)?  home  
Q1. Where are wave energy plants in Japan?
Q2. Is wave energy becoming commercial in Japan?
Q3. What kind of wave energy systems are most efficient?
8. Ocean Tidal Energy  home
8.1 Explain what is ocean tidal energy and how it can be used.  home
Q1. How much does it cost to make an ocean tidal generating station?
Q2. What do you think about the necessity of ocean tidal energy?
Q3. What do you think is the worst disadvantage of ocean tidal energy?
Q4. What do you think about ocean tidal energy help for Japan.
Q5. How much energy can be made by tidal energy in a day?
Q6. What do you think about ocean tidal energy?
8.2 Which company is world leader in ocean tidal energy conversion to electricity? Explain their main product.  home
Q1. How many ocean tidal energy plants does Japan have?
Q2. How much costs a single tidal energy plant?
Q3. Why is France leading in ocean tidal energy projects?
8.3 Explain the research into ocean tidal energy in Japan, and how it is used in Japan.  home
Q1. What about tidal power plants is better than for any other power plants?
Q2. What do you think about the development of tidal power plants in Japan in the future?
Q3. What do you think most is the most important advantage for tidal energy?
9. Ocean Current Energy  home
9.1 Explain what is ocean current energy and how it can be used.  home   
Q1. Is there an Ocean Current Energy plant in Japan?
Q2. Do you think Ocean Current energy is the best clean energy?
Q3. What are the expected costs of an Ocean Current power plant?
9.2 Explain the major ocean currents around Japan and estimate how much electric energy they can deliver in one year.  home
Q1. Do you think that ocean current energy power plant will be built and used in Japan in the future?
Q2. When do you think ocean current energy systems will be completion?
Q3. Which ocean current would be best for ocean current energy power plants in Japan?
9.3 Explain the research into ocean current energy in Japan, and how it is used in Japan.  home
Q1. What is the merit of a Maguro tarbine?
Q2. What is the most difficult problem for this technology?
Q3. What do you think about the relation between warm currents and cold currents?
10. Municipal Solid Waste  home
10.1 Explain what is municipal solid waste and how it should be processed.  home   
Q1. How many power plants use Municipal Solid Waste for fuel in Japan?
Q2. Do you think Municipal Solid Waste can be a new power source?
Q3. Do you think that Municipal Solid Waste will become part of the main power generation?
10.2 Explain the advantages and disadvantages of converting municipal solid waste to electric energy.  home   
Q1. What is the cost of the municipal solid waste (MSW) fuel?
Q2. What do you think is the best advantage of converting municipal solid waste (MSW) to electric energy?
Q3. What do you think about municipal solid waste (MSW)?
10.3 How much municipal solid waste is there in Fukui City, in Fukui Prefecture, and in all of Japan? How  much energy can be made from it? What is the best method?  home
11. Bio Crop Waste  home
11.1 Explain what is bio crop waste and how it can be used.  home   
Q1. What is the most widely used bio crop waste in your research?
Q2. Do you think that energy from bio crop waste will be of major importance in Japan in the future?
Q3. What do you think is the most efficient way to use bio crop waste?
11.2 Explain the advantages and disadvantages of converting bio crop waste to electric energy.  home   
Q1. Where is most bio crop waste used in the world?
Q2. What do you think is the most important advantage of converting bio crop waste to electric energy?
Q3. You introduced us to bio crop waste. Do you think clean energy is the most important for the earth?
11.3 How much bio crop waste is there in Fukui Prefecture, and in all of Japan? How much energy can be made  from it? What is the best method?  home  
Q1. Will you introduce a bio crop waste system for your personal use in the future?
Q2. Which prefecture succeeded using bio generation system for the first time?
Q3. Which prefecture has the lowest amount of bio crop waste in Japan?
12. Energy Crops  home
12.1 Explain what are energy crops and how they can be used.  home   
Q1. Do you think Japanese are using energy crops to generate energy?
Q2. Do you think that energy crops provide is the cleanest source of energy?
Q3. What are the costs for producing energy crops?
12.2 Explain the advantages and disadvantages of converting energy crops to electric energy.  home   
Q1. What is the amount of supply of electric energy from the conversion of energy crops in Japan?
Q2. What is the most important advantage of converting energy crops to electric energy?
Q3. What do you think is the most important disadvantage of converting energy crops to electric energy?
12.3 Which countries are the main producers of energy crops? What plants do they use? What intermediate  products (ethanol, etc.) do they make from it, and in what quantities? What percentage do they export?  home  
Q1. How much does it cost to produce energy from biocrops?
Q2. What are the differences between the various kinds of energy crops?
Q3. Do you think energy crops will become popular in the future? 
13. Electrical Cogeneration  home
13.1 What is electrical cogeneration and how does it work?  home   
Q1. Can cogeneration systems be used in personal homes?
Q2. Power plants transmit electricity power. Cogeneration systems generate power at home. But what are the costs of transporting the primary energy to homes? [e.g. trucks, ships, ... ]
Q3. What is needed to develop the cogeneration?
13.2 Explain the advantages and disadvantages of electrical cogeneration.  home
Q1. What is the most important advantage of cogeneration systems?
Q2. How much does a cogeneration system cost?
Q3. You said the cogeneration system also throws away 30% energy. Do you think a cogeneration system can use energy even more efficiently?
13.3 Explain the current situation of electrical cogeneration in Japan and the future potential of this  technology for Japan.  home
Q1. What is most important to further develop cogeneration in Japan?
Q2. What do you mean with CHP?
Q3. If the cost of a cogeneration system would go down, would you use such a system yourself?
14. Energy Recapture  home
14.1 What is energy recapture and how does it work?  home
Q1. How much does it cost to recapture energy?
Q2. Do you think that energy recapture is the cleanest form of energy?
Q3. How many pump storage systems are there in the world?
14.2 Try to "design" (make suggestions) for an energy recapture system for the University of Fukui. Describe its components and estimate how much energy it could generate (recapture).  home
Q1. Where are solar systems used in Japan?
Q2. Do you think this technology (of energy recapture) will make night electricity cheaper or more expensive?
Q3. What energy recapture systems do you think will use in Japan?
14.3 What energy recapture technologies would work best in Japan? How much energy could Japan generate (recapture) in this way in one year?  home

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6. Hydroelectric Energy
6.1 The current use of hydroelectric energy in Japan.

Q1. What do you think is the best kind of hydroelectric energy?
I think, Pumped-Storage Hydroelectric Energy is the best for storing large amounts of electrical energy for later use. Because this system does not waste resources.
Q2. How many Hydroelectric power stations are there in Japan?
Japan has 4605 hydroelectric since March 2007.
Q3. Where is the biggest Hydroelectric power station in Japan?
The biggest hydroelectric power station in Sakuma power plant in Shizuoka prefecture. The maximum output is 1,830,000 Mwh.
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6.2 What can be done to increase small scale hydroelectric power in Japan?

Q1. What kind of generator is the best?
I think setting up a generator in a stream is the best. Japan has many brooks and much rainfall. Therefore, setting up a generator in a stream is a good match for Japan's environment.
Q2. What kind of buildings use small scale hydroelectric power?
In buildings it can be used to generate power at faucets, toilets and water pipes.
Q3. Do you think that small scale hydroelectric energy can be used in Fukui city? Where?
It can be used at Kuzuryu River, at other streams and brooks, and in buildings. It can be used wherever there is water.
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6.3 Explain how a pump storage system works.

Q1. Please explain the usage of pump storage system?
During the night, water is pumped from a low lake to a high lake. Cheap electricity is used to carry out this process. During the day time the water from the high lake is released in a controlled way and as it descends at high speed, it is used to turn turbines, generating electricity.
Q2. Do you think it is important to use pump storage system in the future?
Yes, it is important. Because in this way large amounts of electricity (e.g. from wind and solar power) can be stored, while at the same time the damage to the environment is kept to a minimum.
Q3. Why is it necessary to use pumps to pump up water?
It is because the pumps can use electricity to pump the water from the lower reservoir to the higher reservoir and thus convert electric energy into potential energy, with a good energy efficiency.
Q4. What is the efficiency of power conversion to hydroelectric energy using pomped storage system?
About 70% - 87%.
Q5. What is the most important advantage of hydroelectric power from pump storage systems?
The time for power generation from start to maximum output is comparatively short, and the output adjustment is easy.
Q6. What is the biggest Japanese pump storage facility in slide 7?
It is the Okutataragi plant of Hyougo prefecture in Japan.
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7. Ocean Wave Energy
7.1 Explain in detail the design of an ocean wave energy power plant.
7.2 Overview of the main ocean wave energy projects worldwide.   

Q1. What do you think is the best country for ocean wave energy generation?
I think France. Because in addition to power generation, France has set goals to promote the creation of nearly 10,000 jobs in this new industry.
Q2. How many kinds of wave energy power plants did you find in your research?
I found four types of ocean wave energy power plants, see for example http://en.wikipedia.org/wiki/Wave_power
Q3. Wave power is widely used in Asia, who is developing wave energy power in Asia?
In Asia, Korea is going to build a wave energy power plant near Takeshima. Hence I think that I am going to work at Takeshima. Also China pushes forward a plan to build a wave energy power plant. Wave energy has been taken up in Asia.
Q4. What are the names of the world's major wave energy power plant companies?
The United Kingdom is THE CROWN ESTATE http://www.thecrownestate.co.uk/energy/wave-and-tidal/pentland-firth-and-orkney-waters/
The United States is OCEAN POWER TECHNOLOGIES company http://www.oceanpowertechnologies.com/
France is DCNS http://fr.dcnsgroup.com/energie/energies-marines-renouvelables/
Australia is OCEANLINX compny http://www.oceanlinx.com/
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7.3 How is ocean wave energy nowadays used in Japan (and Asia)?

Q1. Where are wave energy plants in Japan?
Currently, there are no wave energy plants in Japan. But, Japan is soon going to build one at its Pacific coast.
Q2. Is wave energy becoming commercial in Japan?
Japanese people think, that wave energy is a clean form of energy and an inexhaustable form energy.
Q3. What kind of wave energy systems are most efficient?
In certain devices waves move up and down and cause currents of pressurized air. These currents of air turn turbines to generate electricity. Therefore, I think to improve the generation efficiency is most important for obtaining efficient wave energy systems. Wikipedia (of 28 Feb. 2012) reports: Stephen Salters 1974 invention became known as Salter's Duck or Nodding Duck, although it was officially referred to as the Edinburgh Duck. In small scale controlled tests, the Duck's curved cam-like body can stop 90% of wave motion and can convert 90% of that to electricity giving 81% efficiency. Source: http://en.wikipedia.org/wiki/Wave_power#History
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8. Ocean Tidal Energy
8.1 Explain what is ocean tidal energy and how it can be used.

Q1. How much does it cost to make an ocean tidal generating station?
Construction expenses differ for each plant.For example the La Rance tidal power plant in France had a construction expense of 534,000,000 Euros.
Q2. What do you think about the necessity of ocean tidal energy?
I think that a sufficient difference of low and high tide, a strong enough flow, and a large bay area are necessary.
Q3. What do you think is the worst disadvantage of ocean tidal energy?
I think that the worst disadvantage is the high initial cost.
Q4. What do you think about ocean tidal energy help for Japan.
The differences between high tide and low tide are small in Japan. According to a scientific book (*1), in Japan the biggest place of the tide level difference is 4.9m. Can not easily generate electricity with this tide level difference using existing technology. Therefore, I think that at the moment it cannot be used in Japan. 
(*1) Author : 椹木 亨 (Sawaragi, Toru), Title : 環境圏の新しい海岸工学 (New Coastal Engineering in Global Environment), Publisher : フジ・テクノシステム (Fuji Techno system), Year of publication : Aug.1999, ISBN-10: 4938555700, ISBN-13: 978-4938555702.
Q5. How much energy can be made by tidal energy in a day?
The quantity of annual generation in the French Rance tidal power plant which is the world's largest is 600,000,MWh, and the average output power is 68,000kW. Therefore, it is 1650MWh in a day at one power plant.
Q6. What do you think about ocean tidal energy?
I think that it is a great technology, however the number of places are limited. Furthermore, the flow of tide changes. Even a project in the Gulf of Isahaya, in Japan had sever problems. I think that it is difficult because fishery is prosperous in Japan, which may lead to conflicts of interest.
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8.2 Which company is world leader in ocean tidal energy conversion to electricity? Explain their main product.

Q1. How many ocean tidal energy plants does Japan have?
There are so far no commecially operating plants in Japan, only two test projects.
Q2. How much costs a single tidal energy plant?
For example, the construction cost of the La Rance ebb and flow power station took 620,000,000 French Francs altogether. The construction cost per 1 kWh for the last 44 years of operation is approximately 0.25 JPY.
Q3. Why is France leading in ocean tidal energy projects?
Because the ebb and flow at La Rance posed a good local opportunity.
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8.3 Explain the research into ocean tidal energy in Japan, and how it is used in Japan.

Q1.  What about tidal power plants is better than for any other power plants?
Tidal energy uses renewable energy. So this energy doesn't dry up.
Q2. What do you think about the development of tidal power plants in Japan in the future?
I think that it is difficult for tidal energy to develop tidal power plants in Japan. Because Japan doesn't have a good places with high tides to establish tidal power plants.
Q3. What do you think most is the most important advantage for tidal energy?
The most important advantage of tidal energy is that doesn't emit CO2.
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9. Ocean Current Energy
9.1 Explain what is ocean current energy and how it can be used.   

Q1. Is there an Ocean Current Energy plant in Japan?
No there isn't. However, I think Ocean Current energy plants will be realized in Japan in the near future.
Q2. Do you think Ocean Current energy is the best clean energy?
Yes I think so. Becsuse, the relatively constant flow of the ocean currents carries large amounts of energy that can be captured and converted to a usable form.
Q3. What are the expected costs of an Ocean Current power plant?
I don't know. Because Ocean Current power plants have not been realized yet.
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9.2 Explain the major ocean currents around Japan and estimate how much electric energy they can deliver in one year.

Q1. Do you think that ocean current energy power plant will be built and used in Japan in the future?
Major companies such as IHI and Toshiba are undertaking research and development together now. So I think that ocean current energy power plants in Japan will develop further from now on.
Q2. When do you think ocean current energy systems will be completion?
According to a certain specialist, it will in about 20 years.
Q3. Which ocean current would be best for ocean current energy power plants in Japan?
The result of my research is that the Kuroshio Current would be the best.
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9.3 Explain the research into ocean current energy in Japan, and how it is used in Japan.

Q1. What is the merit of a Maguro turbine?
I think Maguro turbine's merit is its shape. The shape efficiently changes ocean current energy into electricity.
Q2. What is the most difficult problem for this technology?
The most difficult problem is the environmental laod. If this system would disrupt an ocean current, the environment could be damaged. So, it should be studied with caution.
Q3. What do you think about the relation between warm currents and cold currents?
Maybe, this question is "What is the difference between warm current and cold current?" There is no real difference. But, the Japan current is attracting attention. Because there are major cities near it on the Pacific side of Japan.
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10. Municipal Solid Waste
10.1 Explain what is municipal solid waste and how it should be processed.

Q1. How many power plants use Municipal Solid Waste for fuel in Japan?
According to MY research, five waste power plants exist in Japan, they are in "Tokyo", "Saitama", "Shizuoka", "Shimane", and in "Fukuoka".
Q2. Do you think Municipal Solid Waste can be a new power source?
Yes, I think that Municipal Solid Waste can become a new power source.
Q3. Do you think that Municipal Solid Waste will become part of the main power generation?
No, I think Municipal Solid Waste will not become a main power generation source in Japan in the near future. Because, the generation method using Municipal Solid Waste has some problems. For example, Municipal Solid Waste has many kinds, and its separation is a serious issue, which requires effective technology. I think the biggest problem are non-burnable components. Municipal Solid Waste characteristically has several non-burnable components. Therefore the waste-generated electricity may not be as efficient as other forms of thermal power generation.
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10.2 Explain the advantages and disadvantages of converting municipal solid waste to electric energy.   

Q1. What is the cost of the municipal solid waste (MSW) fuel?
The cost of the municipal solid waste (MSW)fuel is almost zero yen because all the fuel is garbage.
Q2. What do you think is the best advantage of converting municipal solid waste (MSW) to electric energy?
I think that the conversion of municipal solid waste (MSW) to electric energy can reduce the landfills of garbage. It can also decrease the emission of harmful gas which originates from landfills.
Q3. What do you think about municipal solid waste (MSW)?
I think that municipal solid waste (MSW) should be converted and used effectively as electric energy.
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10.3 How much municipal solid waste is there in Fukui City, in Fukui Prefecture, and in all of Japan? How
much energy can be made from it? What is the best method?

11. Bio Crop Waste
11.1 Explain what is bio crop waste and how it can be used.   

Q1. What is the most widely used bio crop waste in your research?
Corn (husks, cornstalks) and sugarcane are the most widely used kinds of bio crop waste, because these cereals are cheaper than another crops.
Q2. Do you think that energy from bio crop waste will be of major importance in Japan in the future?
I think it is difficult to say, because the production volume of crops in Japan is less than in other major countries. And I think that the production volume of crops in Japan may not increase dramatically in the future.
Q3. What do you think is the most efficient way to use bio crop waste?
If it is used only to produce other fuels (e.g. from wood waste), I think it will not be very efficient. Because the generative power of such derived fuels may be weaker than that of kerosene, etc.
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11.2 Explain the advantages and disadvantages of converting bio crop waste to electric energy.   

Q1. Where is most bio crop waste used in the world?
The most developed country regarding bio crop waste usage is America. In America a large amount of bio crop waste is used, because America is the biggest country which produces a lot of crops.
Q2. What do you think is the most important advantage of converting bio crop waste to electric energy?
I think "no depletion" (it is fully renewable) is the most important advantage. People use huge quantities of energy. So depletion of energy resources is a serious problem in the future. Therefore, the development of sustainable resources is the most important thing for us and the earth.
Q3. You introduced us to bio crop waste. Do you think clean energy is the most important for the earth?
I think the question is, whether clean energy is most important for the earth. Clean energy is very important for the earth. We have many environmental problems such as global warming, water pollution and so on. Thus, we have to develop new technologies for generating energy as clean as we can.
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11.3 How much bio crop waste is there in Fukui Prefecture, and in all of Japan? How much energy can be made
from it? What is the best method?  

Q1. Will you introduce a bio crop waste system for your personal use in the future?    
I think, I will not use it. Because bio crop waste systems may not become popular in Japan in the near future.
Q2. Which prefecture succeeded using bio generation system for the first time?     
Yamaguchi is the first prefecture that succeeded using a bio crop waste energy generation system in Japan.
Q3. Which prefecture has the lowest amount of bio crop waste in Japan?  
Akita prefecture produces bio crop waste of only 2,800 tons in one year. This is the lowest of all prefectures in Japan.
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12. Energy Crops
12.1 Explain what are energy crops and how they can be used.   

Q1. Do you think Japanese are using energy crops to generate energy?
Japanese companies are currently not used energy crops very much to generate energy.
Q2. Do you think that energy crops provide is the cleanest source of energy?
I do not think so, because biofuel made from energy crops ejects CO2, but on the other hand, the same amount of CO2 is absorbed by newly growing plants, l eading to a closed cycle, with zero net production of CO2.
Q3. What are the costs for producing energy crops?
I'm sorry. I did not research it. But for example switch glass is grown at the expense of 1/4 of that of growing corn in Michigan.
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12.2 Explain the advantages and disadvantages of converting energy crops to electric energy.   

Q1. What is the amount of supply of electric energy from the conversion of energy crops in Japan?
The supply of electric energy from crops is 1.2% in Japan.
Q2. What is the most important advantage of converting energy crops to electric energy?
The most important advantage is the reduction of carbon dioxide emissions.
Q3. What do you think is the most important disadvantage of converting energy crops to electric energy?
I think that it is difficult to secure a stable supply of energy in this way. And the cost (of transport, etc.) are relatively high.
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12.3 Which countries are the main producers of energy crops? What plants do they use? What intermediate
products (ethanol, etc.) do they make from it, and in what quantities? What percentage do they export?  

Q1. How much does it cost to produce energy from biocrops?
In Brazil, for example, sugarcane is converted to bioethanol. It costs about 0.18 dollars per liter.
Q2. What are the differences between the various kinds of energy crops?
The differences are conversion efficiency, growth rate, drought and disease resistance and so on.
Q3. Do you think energy crops will become popular in the future?
Yes, I think so. Energy crops are a very clean energy source. The amount of CO2 emission is 0.
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13. Electrical Cogeneration
13.1 What is electrical cogeneration and how does it work?   

Q1. Can cogeneration systems be used in personal homes?
This system has been developed for personal home use already.
Q2. Power plants transmit electricity power. Cogeneration systems generate power at home. But what are the costs of transporting the primary energy to homes? [e.g. trucks, ships, ... ]
I it is hard to clearly understand this question. I think that the transport costs of primary energy is very large, and ways to transport it are limited. But the situation is different, if for example city gas or natural is used, when a home is already connected to a municipal gas supply network. Then no additional transport costs arise.
Q3. What is needed to develop the cogeneration?
I think that what is most required os a system of support and incentives by the government. Furthermore, the efficiency can be further improved by new technologies.
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13.2 Explain the advantages and disadvantages of electrical cogeneration.

Q1. What is the most important advantage of cogeneration systems?
Recently, we understand how important it is to protect the natural environment from destruction of the Earth's environment. So, the most important advantage of cogeneration is that this way energy can be generated much cleaner.
Q2. How much does a cogeneration system cost?
The price of cogeneration equipment for one family household is nowadays about 3 million yen.
Q3. You said the cogeneration system also throws away 30% energy. Do you think a cogeneration system can use energy even more efficiently?
The cogeneration system is a new system that adds a new energy generation factor to conventional systems. This new factor is using exhaust heat. Therefore, the power generation method itself does not change. So, a cogeneration system can use energy more efficiently than conventional systems and may be further improved in the future. (Some systems already reach an efficiency of up to 90 %.)
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13.3 Explain the current situation of electrical cogeneration in Japan and the future potential of this
technology for Japan.

Q1. What is most important to further develop cogeneration in Japan?
It is a further reduction of the initial cost.
Q2. What do you mean with CHP?
CHP means a "Combined Heat and Power" system.
Q3. If the cost of a cogeneration system would go down, would you use such a system yourself?
Yes, I will. Because I can reduce my electricity bill by using cogeneration.
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14. Energy Recapture
14.1 What is energy recapture and how does it work?

Q1. How much does it cost to recapture energy?
I was not able to confirm the concrete costs of the energy recapture. Because the costs are different with regard to the location, the capability, the type and other aspects.
Q2. Do you think that energy recapture is the cleanest form of energy?
I cannot be sure whether it is the most cleanly energy. But I think it is a very clean form of energy. Because it will not release any CO2 and no fossil fuels are required.
Q3. How many pump storage systems are there in the world?
I researched this question, but I was not able to find the answer, ... I think it is difficult to count the number of pumps storage systems. But they are used widely in the world. Wikipedia (of 27 Feb. 2012) has the following information: In 2008 world pumped storage generating capacity was 104 GW, while other sources claim 127 GW, which comprises the vast majority of all types of utility grade electric storage. The EU had 38.3 GW net capacity (36.8% of world capacity) out of a total of 140 GW of hydropower and representing 5% of total net electrical capacity in the EU. Japan had 25.5 GW net capacity (24.5% of world capacity). In 2010 the United States had 21.5 GW of pumped storage generating capacity (20.6% of world capacity). PHS (Pumped-storage hydroelectricity) generated (net) -5501 GWh of energy in 2010 because more energy is consumed in pumping than is generated. Source: http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity#Worldwide_use_of_pumped-storage_hydroelectricity
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14.2 Try to "design" (make suggestions) for an energy recapture system for the University of Fukui.
Describe its components and estimate how much energy it could generate (recapture).

Q1. Where are solar systems used in Japan?
Solar systems are used by many businesses and private families throughout Japan.
Q2. Do you think this technology (of energy recapture) will make night electricity cheaper or more expensive?
The reason why nighttime electricity is cheaper than daytime electricity is that the nighttime demand of electricity is low compared with the amount of electricity generated at night. So if energy recapture technologies develop, I think nighttime electricity could become more expensive than nowadays.
Q3. What energy recapture systems do you think will use in Japan?
Nowadays, pumped energy storage systems are widely used in Japan. NaS-Battery have been commercialized. I think that Compressed Air Energy Storage systems and flywheel batteries are still in the research and development phase, but these products should be ready for practical use soon.
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14.3 What energy recapture technologies would work best in Japan? How much energy could Japan generate
(recapture) in this way in one year?

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Last update: 29 February 2012. Disclaimer 1: EMS Hitzer is not responsible for the content of external internet sites. Disclaimer 2: No guarantee whatsoever is given for the accuracy of the information in the above FAQ list.