Questions tagged [renewables]
a resource that can be created or used over and over again without depleting the materials from which it is made.
64
questions
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3answers
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What's the average efficiency of pumped hydroelectric energy storage facilities?
Pumped hydroelectric storage has, to date, been the most scalable way to store electricity (in this case, in the form of gravitational potential energy), allowing us to spread the time between when ...
9
votes
2answers
171 views
How worthwhile is it to use energy during daylight to take advantage of grid-based solar power?
Common sense is telling me to try to do things like vacuuming, laundry and cooking at times of maximal sunlight during the day so that more of the electricity I use comes from solar power generators ...
9
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2answers
3k views
How renewable is diatomaceous earth? (How much is left on earth?)
I've read a lot about diatomaceous earth being useful for organic gardening, animal raising, pest control, intestinal parasite treatment, etc. However I am somewhat conflicted about the material ...
8
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3answers
160 views
Is pellet fuel a sustainable energy source in the way it's used now?
Pellet fuel is considered a sustainable energy source. But the way it's used now seems to produce air pollution which I think should not happen in case of sustainable energy source. So is pellet ...
8
votes
1answer
308 views
Transmit solar over multiple time-zones?
I heard that at big voltages (10 000+V) the energy loss along a wire is very small. Unfortunately I've got little electrical knowledge, but this sparked up a question:
Considering that peak ...
8
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3answers
154 views
How the grid is managed in markets with high renewable energy penetration
As many people know, many of the renewable energy technologies generate fluctuating power dependent on availability of the power generating source e.g. wind and solar et al. Balancing power must be ...
7
votes
3answers
140 views
Is “renewable” a proper term for both solar and hydro power?
The common definition for renewable energy sources includes at least:
Wind
Solar
Biofuels
Hydro
Geo-thermal
However, the common definition of renewable makes this grouping a bit awkward. Webster ...
7
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3answers
5k views
Why the world is using non renewable resources?
According to Wiki,
A renewable resource is an organic natural resource which can replenish to overcome usage and consumption, either through biological reproduction or other naturally recurring ...
7
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3answers
1k views
Is solar energy the best renewable source of energy?
Here is my thinking on renewable resources. Biomass is the absolute worst way to go because it releases CO2 and damages habitats.
Geothermal is not far behind but is for a different reason. ...
7
votes
1answer
303 views
What is the number 1 country by global installed wind capacity: the United States or China?
In the following graph:
We see that China surpassed every single country in wind energy production, except the United States.
But these statistics are up to 2009 only.
So my question is: what about ...
7
votes
1answer
68 views
How are readings from the wind sensors mounted on wind turbines influenced by the blades' wakes?
Utility-scale wind turbines have various sensors mounted on the nacelle, to ensure the power generation is optimised.
How are readings from the wind sensors mounted on wind turbines influenced by the ...
7
votes
2answers
933 views
What are the physical limits on wind turbine size?
Wind turbines just seem to keep growing. Predictions a few years ago that a 120-metre diameter rotor was going to be the maximum, have turned out to be wrong, and 154-metre rotors are being installed ...
7
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1answer
97 views
What scope is there for price reductions in photovoltaic inverter costs?
In almost all of the world (except the USA, which has specific local cost challenges), system photovoltaic (PV) costs have come down a lot, to about €2 per installed watt. A large part of the ...
6
votes
1answer
106 views
Are there different types of water-source heat pump?
I have heard multiple names for water-source heat pumps. What's the difference between something called a water-to-water heat pump, and a seawater heat pump? Are they just different names for the same ...
6
votes
1answer
186 views
Where are the world's wave resources, beyond the UK and Portugal?
Are there maps of the global resource for near-coast (<200km or so) wave power? I know that the UK has a particularly good resource - the kinetic energy in the waves in UK waters amounts to an ...
6
votes
1answer
76 views
How quickly can the offshore-turbine supply chain expand?
To date, there were until recently just a few players in the manufacture of multi-megawatt scale offshore-wind turbines, though with the entrance of new Chinese manufacturers, that's been expanding ...
6
votes
1answer
1k views
How long does it take to construct a new port suitable for offshore wind construction?
How long does it take to construct a new port suitable for offshore wind construction?
I'm thinking about the whole period: the design and planning, construction, and commissioning?
I'd value real-...
6
votes
2answers
339 views
Are RECs (Renewable Energy Certificates) an effective method to “green” industry?
Chris Goldie's answer to a question on sustainable web infrastructure brought this question up.
From the US Environmental Protection Agency:
A renewable energy certificate, or REC (pronounced: rěk)...
5
votes
1answer
104 views
Is electricity used at night more likely to be renewable?
Discussing charging my electric car with a colleague recently I argued that since (in Ireland) our renewable energy sources are mainly wind and hydro, since I charge my car at night the mixture of ...
5
votes
1answer
139 views
Hydro-electric generation from roof-collected rainwater
Can electricity be produced from running water by the use of dc motors?
For example rainwater collected from from the roof of a very tall house say 15m high is directed through a pipe and at it's exit,...
5
votes
3answers
271 views
Can The UK Be Powered Practically By 100% Renewables?
Taking into consideration the landmass of the whole of the United Kingdom, areas of open country where windfarms could be placed, areas of country designated as wildlife havens and also areas of ...
5
votes
3answers
67 views
Cost benefit analysis of a PV array with racking to set optimal angle, vs a larger array
I'm thinking of installing some panels on the roof. It's unshaded but only pitched at 5 degrees on long run roofing iron.
Would I be better off racking at an angle to optimize for winter sun, or just ...
5
votes
2answers
132 views
Is an incrementalist approach to decarbonisation feasible?
There seem to be two broad approaches to the climate crisis.
One centres around technological progress, where efficiencies, a gradual switch to renewables, and CCS enable a broadly similar model of ...
5
votes
1answer
71 views
Is there an “energy returned on materials invested” index for energy sources?
We already try to measure how much energy is invested (EROEI) in the production of energy, but I have a hard time finding numbers on the materials invested.
For example: What is the total energy a ...
5
votes
1answer
70 views
What's the applicability of biochar?
Could the cost of biochar production ever be less than that of coal extraction? Is the thermal potential good enough?
I have seen certain articles (sorry, no links) that point to its applicability ...
5
votes
1answer
60 views
What is the % of energy produced per year which is renewable energy (including hydropower, biomass, …) in the U.S. and in the whole world?
I would like to know what is the % of energy produced per year which is renewable energy (including hydropower, biomass, wind, geothermal, solar) :
in the United States
in the entire world
.
And ...
5
votes
2answers
51 views
I'm on mains gas and live in England, am I eligible for the domestic RHI?
The domestic Renewable Heat Incentive is about to launch, in different formats, to different constituent countries of the UK.
It is an incentive to install particular accredited renewable heat ...
5
votes
1answer
89 views
What metrics are usually used to quantify forecasted power error for weather-dependent renewables?
What metrics are usually used to quantify forecasted power error for weather-dependent renewables such as wind or PV?
I guess that there are at least two kinds of errors: where the magnitude of the ...
5
votes
1answer
33 views
How accurate are consultant pre-construction energy assessments?
For power plants where the energy that could be generated is driven by exogenously variable factors, such as wind farms, PV power plants, and run-of-river hydro, which are all driven by weather, how ...
5
votes
0answers
70 views
Calculating wheel and motor size for run-of-river hydroelectric generator [closed]
I am a student designing a hydro electric generator used on rivers to collect kinetic energy from horizontal water flow, rather than potential energy from vertical water drops.
My idea is to turn a ...
5
votes
0answers
30 views
Which part of the process of estimating wind resource has the potential greatest benefit from further research?
Estimations of the potential generation resource of wind power happens at all scales from very coarse global estimates, to detailed estimates at individual sites based on specific locations and ...
5
votes
0answers
168 views
What are the advantages and disadvantages of using lidars over sodars for wind resource assessment?
The process of wind resource assessment has used a variety of methods over the years; more recently, lidar - radar-style sensing using lasers; and sodar (similar, but using sound) have come to ...
4
votes
5answers
21k views
What is the difference between “hydro” and “tidal/wave”? And what is the difference between “solar (heat)” and “solar panels”?
In the following graph:
What is the difference between "hydro" and "tidal/wave"?
And what is the difference between "solar (heat)" and "solar panels"?
4
votes
1answer
64 views
How much land needed to dispose of blades from wind turbines?
I saw a news article saying that Wind Turbine Blades Can’t Be Recycled, So They’re Piling Up in Landfills. This is definitely unfavourable, but I really want to get a better sense of the scale of the ...
4
votes
1answer
42 views
Shading percentage to cause hot spots
I'm designing a solar plant over the roof or a huge building for my company. Now the roof has a lot of obstacles, Shafts, pillars, AC equipment etc. I have a couple of questions that I could really ...
4
votes
1answer
74 views
Solar Panel short section of string due to obstacle
Recently I have installed a set of 10 panels connected in series with 1 single Inverter. I have realised that for the first 2 hours 2 PVs have a cast shadow on them from a neighbourhood tank (that ...
4
votes
2answers
50 views
Is there a simple on-line tool for estimating wind turbine power output?
The back-and-forth in the comments on this answer sent me searching for a simple tool that would enable a user to put in a location, wind turbine size, and a few other parameters, in order to estimate ...
4
votes
1answer
528 views
What does the P90 of a wind resource mean?
I've heard that investors use the P90 of a wind resource when considering an investment. What kind of measure is it, what does it actually mean, and how is it calculated?
4
votes
1answer
91 views
Which measure of solar irradiance is needed to calculate the energy output of PV systems?
According to "E = A * r * H * PR" global formula to estimate energy generated, the solar irradiance value is needed. I have Horizontal irradiance, Tilted irradiance, and Normal irradiance values but ...
4
votes
1answer
415 views
Will natural gas or propane generators also run off of methane?
I'm looking at building a sustainable energy project that will convert biogas (methane) into electricity. I haven't found any biogas or methane electric generators for sale. It seems that there are ...
4
votes
1answer
102 views
Is there a recent study that shows how accurate wind turbine wake models are?
Wind-turbine wake models are used in the design of wind farms, to optimise the choice of turbine model, and the layout of the turbines. They're also sometimes used in the operation of wind farms, to ...
3
votes
3answers
281 views
Are trees more productive than wind turbines?
Tree farm assumptions:
250,000 square meters (m2) tree farm
A 1 ton tree contains 1 MWh of energy
Each tree takes 10 m2 of space
Total energy for this farm is thus 25 GWh
Wind farm assumptions:
5 ...
3
votes
1answer
103 views
Should we leave all fossil fuels in the ground and not use them?
I get the feeling that there is such a strong backlash against fossil fuels that there is an irrational movement to purge them completely. Maybe because people are transferring their worries about ...
3
votes
2answers
70 views
Will negative power pricing counteract the growth in solar PV capacity?
In California, the real-time electricity prices routinely go negative. Here's pricing for the four load aggregation points for California on April 1, 2020 (source):
This is due to the large amount of ...
3
votes
1answer
104 views
What is a good database containing wind speed and direction?
I am pursuing a science project involving wind power, and am looking for some data on wind speeds, directions, and ideally turbulence and shear.
Do you know where I could find this? I would need to ...
3
votes
1answer
129 views
What are the biggest supply-side logistical constraints on the expansion of offshore wind?
Offshore wind is a booming industry, and in particular the UK has an enormous theoretical potential to generate 2TW mean power from offshore wind, as I wrote on my blog.
And whereas there's a lot of ...
3
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0answers
32 views
How much renewable energy is curtailed around the world?
CAISO, the California electric grid operator, provides daily and historical reports on wind and solar curtailment:
I started looking for similar data from MISO, the grid operator where I live, ...
3
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0answers
66 views
Are there any articles that describe to correlation between the forecast errors for renewable energy resources, depending on the distance?
In an article by Zhang et al., the authors describe how the (normalized) forecast errors of different renewable energy sources (like solar panels and wind mills) are correlated. To that end, they ...
2
votes
2answers
113 views
Why do some people say that biofuels are renewable energy source if producing biofuels requires nitrogen fertilizers?
Why do some people say that biofuels are renewable energy source if producing biofuels requires nitrogen fertilizers that are produced from natural gas (and energy output of biofuels is less than that ...
2
votes
1answer
190 views
How many vessels does it take to build an offshore wind farm?
How many vessel-days does it take to build an offshore wind farm, per turbine or per megawatt? I notice that when an offshore wind farm is being built, there are quite a few vessels milling around: ...
