Alternative Energy

Alternative Energy

  • Deinsam Ogan added an answer:
    Could someone help me in biogas plant installation??

    I am building a biogas plant and I want to know if it is always necessary to introduce microorganisms to digest the waste or it can be efficient naturally. And also I will like to know some of the microbes that are introduced.

    Deinsam Ogan

    Hi Nestle,

    Remember there are many options, but a combination of methods may sometimes appear to be be more sustainable. I believe you will find these materials very useful.


    Also, see attached.


    + 1 more attachment

  • Johan K. Fremerey added an answer:
    Is the suface current, in a rare earth permanent magnet, an example of room temperature superconductivity?

    Rare earth permanent magnets are completely unlike earlier iron or Alnico magnets, in that their bodies have a relative permeability of unity, the same as air or free space.  Their analysis depends on assuming an unwavering, permanent current at their surface.  Is this a real current?  Does it represent superconductivity?  Can it be made to perform a useful function, beyond the magnetic one?

    Johan K. Fremerey

    Referring to Figure 4 of my above cited paper the peripheral (tangential) current of a permanent magnet is made up of circulating currents on an atomic scale. As these are locally bound to the crystal lattice they are, in fact, not suited for electron transport over distances such as along an extended electric conductor. But I wouldn't term the circulating currents and the resulting peripheral "envelope" currents of a permanent magnet as "purely hypothetical".     

  • Roberto Calisti added an answer:
    Could pit latrines be the answer to domestic air pollution in developing countries?

    During the recently concluded CAHRD Meeting held in Liverpool (UK), one of the issues discussed was the prospect of reducing domestic air pollution (from burning biomass) and its negative health consequences, which particularly affects women and children.

    I frequently come across papers reporting the success of domestic and public pit latrines designed to double up as bio digesters to produce bio gas for cooking and lighting purposes.

    My questions are: Could this be the way forward for developing countries? How feasible is it to be scaled up?

    Roberto Calisti

    Dear Colleague,

    in the past, in Italy pit latrines were largely (and partly are still now) diffused in the countryside and in any area where sewers didn't exist.

    It deals of an excellent alternative to spreading on the open terrains (that was often used by old farmers in the aim to manure the fields),  a very useful option to avoid pollution  of drinking water sources and of vegetables and to reduce burnings. 

    The simplest kind of pit latrines, known as "black pit", was static and had to be cleared  out at regular intervals.

    A more complex, largely more useful and today still used model of pit latrines is named "IMHOFF PIT"; it  is based upon two sequenced chambers connected by a pipe and having a final drain to remove the cleared sewage. 

    If you are interested in "IMHOFF PITS", I'll send yo some documents (texts and drawings).

    Best regards

    Roberto Calisti

  • Kenneth M Towe added an answer:
    How can manmade global warming trends be reversed?
    Right now and in the foreseeable future, civilization and even our physical survival is being threatened by extreme, erratic and shifting weather patterns. These in turn are caused by the Earth’s oceans becoming warmer, which in turn is being caused by the increasing amounts of CO2 in the atmosphere.

    The primary and ultimate cause of all of these effects is our burning of fuels.

    These changes are amplifying themselves because of various positive feedback mechanisms, thus accelerating these processes.
  • Fasial Baig added an answer:
    Do we really have an energy and resource crisis?

    There is a renewed debate on how “real” the energy and resource crisis is in the world. Some say it is based on faulty science and politics and the reality looks different. It seems that we have enough renewable energy which helps use to handle our limited resources of raw materials when using intelligent concepts of reuse after lifetime of our products.

    Fasial Baig

    crises are there. but its about changing our habits. and necessity is the mother of invention. together we all can work this out.

  • Ljubomir Jacić added an answer:
    Is it possible to generate enough electrical power using all the three types of alternative energy to replace conventional energy sources?

    A good amount of work is being carried to tap solar, wind and geothermal energy so as to replace facile fuel. With present day state of art is it possible to generate enough power to meet ever increasing demand of power?

    Ljubomir Jacić

    Dear @Rasbindu, I find this fine article by my respected colleague Branko Terzic as very inspiring. 

    Thanksgiving to Energy!

    "Today, we are thankful for the improvements in human condition provided by fossil fuels.

    But we are also newly informed as to the consequences of 200 years of combustion of fossil fuels producing greenhouse gases which raised the concentration of carbon dioxide in the atmosphere above levels which nature can recycle and stabilize at the levels which produced modern civilization.

    Allow me to suggest, that where fossil fuels have enabled improvement in the human condition, fossil fuels have also produced great wealth in much of the world. Thus, this same wealth, according to such reports as the Stern Review on the Economics of Climate Change, can also fund the transition to carbon free or carbon controlling technologies.  For this we should be thankful as well."

  • Samuel Tesema Lakew added an answer:
    Modelling 100% renewable electricity in Sub-S. Africa by 2030. Any software recommendations?
    As part of my thesis, i am looking at the best possible mix and the lowest cost option for providing 100% renewable electricity in Sub-Saharan Africa by 2030. I have been researching modelling tools that are specific to the power sector when I stumbled across this forum. Any help will be appreciated.
    Samuel Tesema Lakew

    Dear Avery, 100% renewable energy hybrid system is not cost effective but you can model it. I have a book on how to model such systems as high penetration renewable energy for African case specially Sub-Saharan Africa like Ethiopian Somali Region. I used Homer software for preliminary analysis. Refer to my publications. For S.S.A You may have a combination of Solar PV/Wind/Solar Thermal/Geothermal/Biomass etc. Good luck with your thesis !

  • Samuel Tesema Lakew added an answer:
    Could Sound energy be utilised as a source of Energy for light loads?
    I am trying to use the heavy traffic noise (on a busy highway) for street lighting or other lighter loads. but my concern is its feasibility. Any suggestions?
    Samuel Tesema Lakew

    Of course it is possible for small loads like low power lighting, smart phones and electric vehicles though the density of energy acquired is small. You need a transducer for energy conversion. But you can generate a better power on a busy street using the weight or pressure exerted by people or cars.

  • Harry ten Brink added an answer:
    How valid are climatic models and IPCC results?

    Cornelis Van Kooten (2012) believes "the truth has been sacrificed for political expediency" (Page 96). In a high critical scientific manner, he explains why so-called Global Climate Models (GCM) and Regional Climate Models (RCM) do not have factual temperature and rainfall outputs (e.g. by comparing actual data to predicted data). More interesting, he also scrutinizes the results of Intergovernmental Panel on Climate Change (IPCC) and questions its assessment reports.

    Now, I'm not certain about applying GCM and RCM models and use the results of IPPC as well. Is there another option to consider more realistic scenarios? 

    Reference:Van Kooten, G. Cornelis. Climate Change, Climate Science and Economics: Prospects for an Alternative Energy Future. Springer, 2012.

    Harry ten Brink


    Same with me about the water levels in estuaries that you explained in another question

  • Manuel José Serafin Plasencia added an answer:
    How detailed does an AHP hierarchy need to be?


    I was asking myself the above question when structuring a hierarchy to find out where businesses in the industry like to invest in optimization measures.

    The hierarchy is attached.

    The five alternatives are: Energy efficiency, optimization measures for processes, quality, technology and supply chain.

    Now I would be able to break down the criteria especially the quantitative ones into additional sub-criteria. For Example: Net present value in 0.15 - 0.3%, 0.3 – 0.5%, 0.6 - 1%, 1 - 2.8%, 2.8 - 5%, > 5% or payback period in static and dynamic and then in years (e.g. 0 - 1.5 years, 2 years etc.).

    But is that really necessary?

    Thanks in advance for any help you can provide. I also appreciate any comment regarding the hierarchy.

    Manuel José Serafin Plasencia

    Dear Anton I just note your question I hope that my answer remains useful to you at this late time.

    You don't have and I strongly recommend do not break down more your hierarchy adding levels because it is enough developed. The experts have to make judgements to fill up twelve 5x5 matrices each one corresponding to the alternatives judged respect each of the criteria and two more one 5x5 and one 7x7 to judge the within criterias. In theory there is another 2x2 comparison between qualitative and quantitative but that will be spurios in my opinion. You could fix equitative weigth between both kind of criteria.

    Remeber that you must fill all the upper triangular matrix that means n*(n-1)/2 paired comparisons. Then you have 20 comparisons for 5x5 matrices (adding up 130 in your current hiearachy) plus another 21 for the 7x7 matrix. A questionnaire so long will get tired to any one that acept to help your research.

    Best wishes

  • Gerro Prinsloo added an answer:
    Can anyone help me to get articles on bio-battery?

    One of my student have interested in bio battery as an eco friendly power production

    Gerro Prinsloo

    Dear Mophin

    Very good presentation on bio battery technology on this link



  • Osman Abbas added an answer:
    How can you remove Systematic Bias from Demand Forecast?
    Correcting bias in power forecast
    Osman Abbas

    Have a look at this link :

    • [Show abstract] [Hide abstract]
      ABSTRACT: This chapter examines the use of mathematical programming to remove systematic bias from demand forecasts. A debiasing methodology is developed and applied to demand data from an actual service operation. The accuracy of the proposed methodology is compared to the accuracy of a well-known approach that utilizes ordinary least squares regression. Results indicate that the proposed method outperforms the least squares approach.
      No preview · Article · Nov 2011
  • Daniela Plana added an answer:
    What are the problems of using urine specifically in Microbial Fuel Cells to generate electricity?

    I am having some difficulty in identifying what are the operational parameters for using urine in Microbial Fuel Cells to generate electricity. I have read articles that this type of technology can be implemented in toilets at refugee camps to help power lighting. There are many articles regarding the problem in the material used for MFCs, but not so many on the fuel source. So what are the factors that are considered when using urine as the fuel source? 

    Daniela Plana

    Although I don't know all the details, I know there is plenty of work in this area at UWE... here is a link to their website, where I'm sure you can find plenty of information or can contact them directly:

  • Mohamad Kharseh added an answer:
    1000 W/m² seems to be a general expression to make life easier for calulations - what if this value was much higher in reality?

    1000 W/m² solar irradiation on average on the planet's surface as a reference to the electromagnetic wavelengths coming through our orbital spheres in the forms of UV, visible light and IR.

    In photovoltaics only photons (as particles) are beeing used to explain the transformation of energy while in solar thermic energy transformation IR or heat is beeing harvested (without using particles as explanatory "variables").

    One of the great theoretical physics scientist, Victor Weisskopf, once said "There are no real one-particle systems in nature, not even few-particle
    systems. The existence of virtual pairs and of pair uctuations shows that
    the days of xed particle numbers are over."

    Shouldn't it be possible by widening the "efficiency ratio" paradigm to improve already existing PV technology to harvest usable end energy for example also from Bosons?

    By introducing the idea of availability and computability of more than one particle wouldn't we have to recalculate our real solar irradiation values and maybe come up with a much higher scale than the 1.000 W/m²?

    Mohamad Kharseh

    The standards are given to make the comparison between different brands easy.  They give thumb approximation for the required area. But however, in detailed study the local data must be used.

  • Peter Baker added an answer:
    How could I get water from air by using a friendly environmental condenser?

    I live in a regular huminity area, and I would like to know if there is any kind of friendly environmental condenser without using a lot of energy (from an outlet). I'm thinking of using a alternative energy if it requires.

    Thank you very much for your advice.

    Peter Baker

    Fog nets?

    Klemm et al., AMBIO 2012, 41:221–234

  • Chrysi Karagiannaki added an answer:
    "Magnus effect" can it be used as one of the renewable sources of energy?

    i have seen many videos and articles on this magnus effect usage! even ships are made to run by this magnus effect! so, is there any potential for developing this effect so transportation dependence on this may increase? if so, what are the drawbacks of this magnus effect usage?

    Chrysi Karagiannaki

    That is true Jaydeep. Using spinning cylinders instead of wings you can actual increase the lift but yes, they would generate more drag as well (way more) so i guess for airplanes it is impractical.
    For ships there were designs using Flettner rotors instead of sails (they deflected cross wind to move the ship forward, again cross wind!) but you can check why they didn't become "popular". (i guess because they have to rotate constantly, and their size should be an issue... but not sure)

  • Anurag Pandey added an answer:
    Energy, where we are going ?
    We are about 7.2 billion and the expectation is 9.6 billion in 2050.

    The coal, oil and natural gases are low, the shale gas exploitation is killing our drinking water resources. Green bio fuel seems to be less green if all the production aspects are counted. Solar energy conversion to electricity or hot water still has very low efficiency and can not be used everywhere. Wind conversion involve high costs and technological difficulties besides disturbing noise. Tidal power is still insufficient and the climatic changes are heavily affecting those power plants.
    After 60 years of nuclear energy it seems this is not exactly the right way (only ~13% of the world's electricity in 2012).

    We are talking too much about energy harvesting (using our electromagnetic pollution - the electro-smog, or the noises we are creating running our cars, trains and our mouths) but everything seems to be just a joke. We are using efficient bulbs (with doubtful efficiency) replacing the Edison's one in the name of energy savings, but do not give up our cars, burning fuel every day.

    Which do you think will be the energy of the future? Green energy, alternative energy or even "free energy" ? Which is your experience in this field of research?

    sponsoring the International Journal of Practical Electronics:
    win 200 euro for best paper accepted:
    Anurag Pandey

    Renewable energy is the option. but its not possible only solar and wind. Support of multi purpose system can help the energy system. Like we use car,laptop and other things other hand we have roads, machines etc. so, generation of electricity can be increased due to this roads, machines and other system if we put some arrangement for that.

  • Sudharshan K added an answer:
    Can anyone tell me the energy equivalent of wood-based panels such as particleboard and medium-density fibreboard?

    MJ per kg or m3

    Sudharshan K

     also you can contact Dr.Muthukrishnan achary who is in public pages with LInkedIn social network, he is doing govt project under India who can address you query....

  • Fabrice Auzanneau added an answer:
    What about generating energy by driving on a highway?
    I think it should be possible to generate energy just by driving a car on a highway. Imagine that the car is equipped with a permanent magnet under its base, just between the wheels, and the highway has some electrical wires inside, not too far from the surface. Then, by passing over the wires, the car and its magnet will generate a current in the wires which can be collected and stored in some batteries. Multiply this by the number of cars passing on the highway, this would lead to a high energy generation.
    Of course, our cars do not have magnets underneath, but they could be placed when entering the highway, just for the time you drive on it. The highway manager would gain money by selling the current, then they would decrease the fare if you accept to bear the magnet.
    Do you think this would be possible, and cost-effective?
    Fabrice Auzanneau

    Yes, you're right, Michael, but there will be magnets in electric cars also, maybe smaller though. But we can reverse the process : put the magnets inside the road and generate electricity to charge the battery of the electric car, thus increasing its range.

  • Russell Barton added an answer:
    Feasibility of low scale hydrogen fuel cells to avoid the use of batteries in PV applications?
    The cost economic and to the environment of the use of batteries in the PV applications at low scale (residential) is high. The problem is that the demand of PV energy in this kind of applications ins during the night.
    Now, one remedy is avoiding the use of batteries and connecting directly the PV bank to the net. But in isolated applications this principle is not feasible. Then, the alternative to store the energy obtained during the sun hours in hydrogen, may be attractive. The question is, the cost of a hydrogen fuel cell for low scale application is high? Anybody know some bibliography or commercial information about this possibility?
    Russell Barton

    Almost any battery will return over 80% of the watt hours you charge it with.

    Decomposing water over the day, and turning it back into electricity at night will never return even 1/2 of the power you start with. Seen that way, the more costly batteries are an investment in efficiency.

  • Negin Minaei added an answer:
    On water evaporation control, anyone aware of studies/reports on evaporation rates for floating solar platforms, solar water blanket or water covers ?

    Conducting environmental impact research on cleantech floating solar systems for sustainable agriculture at vineyards and wineries, in particular water savings in terms of water preservation and evaporation reduction due to installation of over water  floating solar systems on lakes, dams, irrigation ponds reservoirs, agricultural and mining ponds, hydroelectric reservoirs and canals. 

    Would really appreciate links to reports where evaporation rates had been monitored or measured, or forecasted with mathematical modelling or environmental monitoring models are used to model or predict water evaporation rates on irrigation ponds or rivers or water canals.

    Negin Minaei

    You may find this project interesting, Roots Up's Dew Collector greenhouse provides veggies and water in Ethiopia

  • Behnaz Rezaie added an answer:
    What is the best psychological variable to measure people's perception about sustainable behaviour in energy consumption?

    I'm working on research about energy consumption in passiv houses in Luxembourg. I need some suggestions about variable(s) that could measure people's perception about sustainable behaviour in energy consumption. Thanks in advance!

    Behnaz Rezaie

    The factors are not the same for all communities. I would say, you have to determined the community, then based on perception of that community find out the important factors related to useing renewable energy. For example people in Norway have different attitude toward renewable energy in compare with people in Egept.

  • Mahinda Henegedara added an answer:
    Can someone give an outline of a good business or economic model for hydrogen fuel cell technology in developing countries?
    Recent news says that the economic potential for hydrogen fuel cells will increase to USD2bil by 2018 in Asia alone. Let's not miss the boat.
    Mahinda Henegedara

    Practical Action (Former Intermediate Technology Development Group ) Has conducted lot of studies and projects in this regard. Try to contact Practical Action (UK) or Sri Lankan office.

  • Amin Bennouna added an answer:
    How does the variation in power output of a solar module depend on the temperature?

    References says the power output of the  PV module will decrease when the temperature increases. This is due to the reduction in Voc.

    But the equations which relating to the temperature coefficient beta and Voc is like this

    Voc= Voc+ beta*(Toperational-T reference)

    So this equation says when temperature increases Voc increases.

    Guys,can any one help me with this?

    Or suggest me a reference.


    Amin Bennouna

    With temperature:

    - current increases, with a temperature coefficient aI around +0.1% per K

    - voltage decreases, with a temperature coefficient aV around -0.5% per K

    As P =  V.I, it comes that (dP/P) = (dV/V) + (dI/I) and power decreases, with temperature coefficient aP around -0.4% per K.

    The "per K" refers to the increase of the cell temperature from the reference of standard test conditions (STC) temperature (25°C):

    As (dP/P)=aP (supposed constant), it comes that the power can be written as:

       P=PSTC(1-aP)(tc-tSTC) of which 

       P=PSTC[1-(tc-tSTC)*aP] is an approximation when aP is small ennough

    The cell temperature can be calculated from ambient (tamb), solar intensity (S) and module normal operating cell temperature (NOCT, typically 45°C):

       tc°C = tamb°C + [(NOCT°C-20°C)/800W/m²].S

    The values of aV, aI and NOCT given here are for crystalline or polycrystalline glass to plastic silicon solar modules.

  • M.Azizul Moqsud added an answer:
    Is it necessary to use plexiglass for making the MFC?

    Is it plexiglass the only acceptable material for making MFC?

  • Michael Issigonis added an answer:
    What are the possibilities of meeting the entire global energy requirements from renewable energy sources?

    Please discuss the possibilities, technologies required, changes required in energy utilisation methods and other related issues.

    OR is it foolish to think this way?

    Michael Issigonis

    It is not foolish at all to ask and there are excellent possibilities. It should have been that way to start with. No air pollution should have been allowed in the beginning. It was a criminal act to pollute the air/water/oceans and hide the effects from the public for so long.

  • Srikanth Reddy added an answer:
    How can I calculate trombe wall efficiency?

    Solar wall or trombe wall efficiency especially if it built for ventilation 

    Srikanth Reddy

    The following presentation may help you:

  • Frank Veroustraete added an answer:
    Calculating Solar radiation on a tilted solar panel?
    I am trying to calculate the incident radiation on a tilted solar module. It is a fixed module and the angle is manually changed three times a year. I have the longitude and latitude of the location. I also have the TMY data provided by NREL. Since it is not my specialty (I am an Electrical/Industrial Engineer), I would appreciate if someone can help me with this.
    Frank Veroustraete

    Hi Haidar,

    Please find the relatioships you need,



  • Hugo Valdés added an answer:
    What is the difference between 'Energy harvesting' and 'Energy scavenging'?
    When we are discussing our research, we often come to meet difficulties in defining the sources of surrounding energy. What is your definition?
    Hugo Valdés

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