Questions tagged [renewable-energy]

Questions related to energy produced by renewable systems such as solar, wind, water and geothermal.

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29 views

How energy intensive is creating artificial islands in the IJsselmeer?

The City of Amsterdam is building a series of artificial islands for new housing. One of them is Centrumeiland. Its size is 13 ha. (130,000 m2). Its creation requires 800,000 m3 of sand (Source), i.e. ...
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14 views

TSR of a wind turbine

I wanted to ask that if we are given the ratio of rotor length to radius to be 2 and asked to find the TSR for a 3 blade rotor, will we use the following expression: $$ \lambda_{optimal} = \...
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2answers
68 views

Can lithium ion batteries solve the world's energy storage problem? [closed]

This questions boils down to the following important questions: Do we physically have enough materials in the earth's crust to make enough lithium ion batteries to support global storage demand? Can ...
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14 views

Shadow flicker validation

I am currently trying to validate a shadow flickering algorithm against some data generated by Openwind. The goal of this validation is to have a code that we know that is correct and modify it to ...
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1answer
20 views

Capacity credit vs capacity factor

What is the difference between capacity factor and capacity credit? I know that capacity factor = annual generation / (installed capacity * 8760) but I don't understand how capacity credit is ...
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1answer
30 views

Why Do Airborne Wind Energy Systems Use Kites And Not Balloons?

Title says it all, Why are AWE-companies like Makani spending years and millions of dollars developing drones, rather than simply using a balloon-based design? Wouldn't it be easier and faster to get ...
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1answer
36 views

Advantages of hydrogen gas turbine over fuel cell

In the setting of large-scale electricity generation, I was wondering why one would want to burn hydrogen in a gas turbine instead of using it to power a fuel cell. Aren't fuel cells more efficient ...
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0answers
8 views

Increase in target emission rate (TER) when using a air source heat pump (ASHP) in standard assessment procedure (SAP) calculation

I am running a SAP calculation on a proposed building which will be utilising a 8.5 kW ASHP for space and water heating. I am also running a comparative analysis against a mains gas boiler to show the ...
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2answers
38 views

What is and how do you calculate the wind velocity design for wind turbines?

I am finding it difficult to get consensus on the definition of design wind speed for aeolic turbines. I thought it was the velocity that corresponds to the maximum power output, but I have already ...
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7answers
7k views

Why is hydro-electric power still scarce in some places?

70% of the Earth's surface is covered in water, why can't a hydroelectric power plant be set up on each and every river? Is it that its too expensive? Why is electricity still a problem in countries ...
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4answers
177 views

Why aren't gravity batteries everywhere?

The problem of energy storage, especially with regard to renewables, remains unsolved. Or at least there do not seem to be any popular solutions. Why not gravity batteries? I love the idea, and they ...
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1answer
36 views

How to estimate wind generation using power curve?

I am trying to verify windfarmer generation estimates manually. To do so I am trying to manually calculate the estimated energy production (kWh) of a wind turbine. The information I have available is ...
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4answers
119 views

Wind turbines with down tower power units. Why aren't they more common?

Concerning the big megawatt wind turbines, if there is such a big trouble with gearbox bearings failing much earlier than expected and costly maintanence or replacement of huge gearboxes, what is ...
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1answer
46 views

Clutch role in a micro hydropower

I've recently visited an old (about 60 years old) micro hydroelectric standalone installation. Total electric power is about 3 kW A/C. A local told me between generator + fly-wheel and turbine there ...
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1answer
38 views

Get electricity generation data for Europe [closed]

I am looking for electricity generation data (hourly at least) including renewable energy generation, for European countries. From as many years back as possible to the present. Where can I find this ...
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2answers
72 views

Can a bridge's towers be used as wind turbines?

I come from a fairly remote island where we need a 150 min ferry ride to reach the mainland. While the island has few resources that would encourage a government to investigate the possibility of a ...
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100 views

Can a Tesla Powerwall 2 be rate limited?

Can a telsa powerwall 2 be rate limited (discharge/charge)? I have access to realtime electricity rates (30 min update interval) and also access to 12 hour predicted look ahead. So I wish to limit ...
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2answers
116 views

Why vertical wind turbine don't be half covered

I think it would be more efficient for a vertical wind turbine to have a covered funnel about half of it Something like this figure It would protected the turbine from opposite wind and also ...
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0answers
36 views

Designing a piston pump for windpump

I am designing a savonius type wind pump for low wind speeds(avg speed = 2.7 m/s), with these speeds and rotor area of about 2 m2. Acc. to my calculations, I am getting a volume flow rate of ...
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0answers
25 views

Hybrid Energy Monitoring Systems

I have been doing research on renewable energy systems and I must admit that I am a newbie in this specific area. I have noticed that stand-alone systems have their own specific monitoring system ...
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1answer
29 views

Qualitatively how does the O-wind turbine function?

Recently the O-wind turbine won the James Dyson award for innovation, the item is essentially a compact wind turbine which unlike traditional wind turbines can harness wind from multiple directions, ...
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1answer
41 views

Solar Thermal heat gain formula converted to CO2e and trees saved

We have invented a solar thermal heating system with interseasonal storage, recently patented. I want to display the trees saved and carbon offset on the control display based on temperatures coming ...
2
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1answer
64 views

Converting grams of fuel per kWh of energy

Is there a database showing how many grams of a particular fuel generates how many Kilowatt hours of electricity?
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1answer
38 views

Why do pumped storage hydroelectric facilities use bent pipes? [closed]

When a reservoir is used to store water for electricity, it's pipes are usually laid in several segments on the ground to reach its source, such as a lake. It seems that if the pipes went directly to ...
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2answers
475 views

How is the energy production of solar and wind compared with the prospect of nuclear fusion? [closed]

I am trying to find reliable information and comparisons about the energy production of renewable energy technologies, specifically, how solar and wind alternatives compare to nuclear fusion. Why is ...
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1answer
552 views

CUF v/s PLF of power plants

What is the difference between capacity use factor (CUF) of solar power plant and plant load factor (PLF) of coal based power plant? Can we compare both since they seem analogous?
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1answer
305 views

How do you calculate the Enthalpy of a geothermal resource?

Enthalpy seems to be commonly used to characterize geothermal reservoirs, but how is it calculated? I have an example here where the enthalpy is cited as 800 $kJ kg^{-1}$ for a reservoir with a ...
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1answer
63 views

Feedback on idea for a power station

Hi there, When I was very little I came up with this idea for a power station and I recently remembered it and was curious about the viability. The way it works theoretically is that a voltage supply ...
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4answers
178 views

Are abandoned nuclear smoke stacks strong enough to be filled with water (for pumped storage)?

I noticed that there are a growing number of abandoned stacks of this type: Image source. I wonder if they are physically strong enough to hold water, for use in pumped storage:
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1answer
52 views

How many batteries can I charge and how long would it take?

Using a hydro generator which gives an output of 4.838KW, I am trying to figure out how many batteries I can charge and how long it would take. I am doing the calculations based on 12V, 17Ah ...
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2answers
109 views

Can you use the kinetic energy of air to power a car?

In my fluid mechanics class, I've learned that a fluid traveling in a pipe will generate a force when the exit area is smaller then the entrance area. Suppose a pipe is attached to a car that will use ...
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1answer
90 views

Generating power from fruit

Is it possible to generate power from fruit juice, using a device with a simple circuit which charges a battery using juice from fresh oranges? If so what would be the ratio between emf emitted and ...
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1answer
58 views

What is the exact definition of renewable energy [closed]

I was wondering, in laymen terms, what is the exact definition of renewable energy and what are its various forms, which ones are better and in what situations can they / can they not be used. How do ...
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4answers
2k views

What is the theoretical maximum energy efficiency of hydro turbines?

From what I've read it seems that hydro turbines can theoretically achieve 100% energy conversion from kinetic to electrical energy. However, I just wanted to double check if this was true.
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37 views

Parameter effects on kinetics of esterification for bio-diesel production

I want to discuss the effect of parameters on the kinetics of esterification for bio-diesel production. In esterification process, temperature effect and molar ration are two important parameters. ...
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2answers
653 views

Why don't we just build a giant wind turbine?

The power generated by a wind turbine is given by: $$\mathrm{Power} = \frac{1}{2}C\rho AV^3$$ Where: $\rho = \text{Air density}$ $C = \text{Coefficient of performance}$ $A = \text{Frontal area}$ $V ...
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1answer
116 views

What theoretical efficiencies can wind / hydro turbines achieve? [closed]

The high water has some energy E = mgh. In the basic school, we were told that hydropower plants extract the energy of "falling water". Now, that banned principle says that if your water falls upon ...
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7answers
5k views

What are the disadvantages of concentrated solar thermal power?

Concentrated solar power looks on the surface to be an excellent source of grid power. It's sustainable, has no obvious waste products to deal with either during construction or operation, and with ...
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2answers
3k views

Relationship between wind velocity, turbine rotor diameter, and power output

I'm trying to understand and identify the equations to use in defining the relationship between wind velocity, turbine rotor diameter, and power output for a wind turbine. To simplify my question, ...
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1answer
154 views

What is the power and max flow rate required to rotate a 300 W wind turbine?

I have purchased a wind turbine with a power of 300 W, the start up wind speed is 2.5 m/s, rated wind speed is 11 m/s, and the survival wind speed is 45 m/s, and what I'm going to do is to make an ...
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1answer
568 views

How to get the maximum power point from I-V curve for Organic Photovoltaics (OPV)?

I am taking organic solar cell course on Coursera, and I have a question about I-V curve for a certain solar cell. The question asks for the solar cell characteristics such $V_{oc}$, $P_{max}$ and $FF$...
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1answer
85 views

To what degree are wind and water turbines exchangeable?

Assuming maximum efficiency is not the primary concern (but net positive efficiency is), to what extent could a wind turbine operate in water and vice versa? How do the different turbine types fare ...
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1answer
85 views

Could future fusion energy exist without the input of any petroleum or natural gas products?

Given a successful deuterium-tritium fusion reactor such as that conceived by ITER, could the world's energy needs theoretically be met without the input of any petroleum or natural gas products? ...
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1answer
134 views

Calculate energy (kW, or kJ) from Vapour Expander Generator

I'm a student of Integrated Water Management, and looking at a geothermal bore that is producing potable water for a town's water supply. The bore water reaches the surface at $50$ $^oC$, and flows ...
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2answers
833 views

Is the fill factor of a photo-voltaic cell constant?

An important factor in specifying the efficiency of photo-voltaic (PV) cells is called the fill factor (FF). It is defined as the ratio of the maximum power of the cell to the product of the open-...
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5answers
7k views

Why don't hydroelectric plants use cascades of turbines instead of single turbines?

In a gas turbine engine there're multiple sets of blades - one set after another and combustion products pass all the sets and each set of blades gets some of the power. This increases utilization of ...
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1answer
114 views

Do regulations in the United States limit the size of aerial wind turbines?

What with all the work done by the FAA recently on regulating drone usage, I thought it would be nice to turn my eyes to the sky for another, less-known type of aerial denizen: the aerial wind turbine....
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2answers
258 views

How to correctly size the blades for a small educational wind turbine?

I want to design a small wind turbine that can be easily carried out of the classroom into the sports field in relatively low-wind conditions (5-15km/h) that can power a small ultra-bright 5V LED - ...