14 votes

Which solar power technology has the highest energy return on investment (EROI aka EROEI)?

TLDR; cadmium telluride panels have the highest EROI of the mentioned PV panels (around 34.2) EROI estimates vary widely. This is because of differences in the method of calculation, scope of the ...
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  • 14.1k
11 votes
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Transmit solar over multiple time-zones?

Yes, we can. Estimates vary of the losses in long-distance HVDC (high-voltage direct current) transmission, but they're around 3-4% per 1000 km. Now, those operate at far higher voltages than you've ...
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  • 14.6k
10 votes
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What causes photovoltaic (solar) cells to degrade?

The rate and types of degradation differ a bit depending on the panels. Common to all types is water ingress within the panel itself, causing corrosion of the wiring. Monocrystalline silicon (aka ...
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  • 14.6k
7 votes

How much irradiation from the sun is required to generate solar power?

Solar Irradiance The amount of energy striking the earth from the sun is about 1,370W/m2 (watts per square meter), as measured at the top of the atmosphere. This is the solar irradiance. The value at ...
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  • 11.3k
6 votes

Converting from W/m² to kWh/m²/day

If your data is minute-by-minute then that's exactly what you need to do. Adding all the minute-by-minute W/m² figures for a day (you should have 1440 of them, so use a spreadsheet or script) will ...
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  • 2,037
6 votes
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Solar PV panels - Worth the cost of more efficient panels?

Rooftops are pretty much the only place where efficiency matters for PV panels, because surface area is typically a constraint there, but almost nowhere else. And the structure of UK feed-in tariffs ...
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  • 14.6k
6 votes
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Can solar energy be too focused onto a solar cell?

Yes, if the photovoltaics aren't designed for operating as concentrated PV, it can shorten the life of the cell: the additional thermal stress can be huge; the cell will operate at a higher ...
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  • 14.6k
6 votes
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Are green roofs more sustainable than roofs with photo voltaic?

The two are not mutually exclusive, and in fact installing PV panels over a green roof improves PV performance anywhere from 1 to 10% due to the cooling effect of the green roof. From the presentation ...
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  • 11.3k
5 votes
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How much energy costs do portable solar panels save in a house?

I'm afraid these little mini solar kits are much smaller in scale than rooftop panels. They can be great for charging gadgets when away from mains electricity, but they're not an economic substitute. ...
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  • 3,621
5 votes

How to consume all my photovoltaic electricity locally?

Maybe my answer is naive, but have you thought about a battery like the Tesla Powerwall? Storing energy during daylight and using at night increases dramatically the auto-consumption rate (~98%).
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  • 598
5 votes

Solar charging an e-bike's lithium battery while riding

Before you worry about charging, consider this: It takes about 85W to propel a 75kg cyclist at 20km/h under ideal conditions. Thin film (i.e. flexible) solar panels have an efficiency of ~9% and when ...
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  • 2,744
5 votes
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What is the energy payback time of portable solar panels, in hours?

Given that static, thin-film photovoltaic panels, exposed to the sun all day every day, might pay themselves off in 3 years (according to NREL in 2004), there is an extremely high probability that a ...
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  • 2,744
4 votes

How much energy costs do portable solar panels save in a house?

The Goal Zero PV panel is rated at 20 Watts. Specifications here Here is the average insolation figures for Houston The line in the 4th chart titled "Insolation, kWh/m²/day" gives the kWh per square ...
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4 votes

Solar Panel short section of string due to obstacle

You must open circuit the panels you're not using, do not short circuit them. Open circuit is fine, the panel just sits there and no current flows. You'll see quite a high voltage on the terminals (it'...
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  • 3,755
4 votes

How do I keep my solar panels clean?

I work and attend classes at a University in Florida. Our 100kW system has been installed for more than five years without a single cleaning. I have walked the solar field several times and can ...
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  • 51
4 votes

How to consume all my photovoltaic electricity locally?

For the case where feed-in is forbidden, you need a zero export mechanism (see this answer for options). In addition, since you want to consume all your electricity locally, it must include a demand ...
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  • 449
4 votes
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PV system: Which to upgrade first: panels, inverter, batteries?

I agree with LShaver's number-crunch, although I reach a slightly different conclusion. I agree you have plenty of inverter. Your are covered not only for routine loads, but also for startup ...
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4 votes

Do solar PV roofs make sense for semi trucks?

Taking a single semitrailer as the load you have approximately 12.5m long by 2.5m wide of top surface, or 31.25m². With 20% efficient panels you might get as much as 6kW from the semitrailer, or 6kWh ...
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  • 3,755
3 votes

Can I connect an inverter directly after an MPPT controller, with no battery?

Yes this is very much possible. While purchasing the Inverter , look for " BATTERY-LESS ", and you will have your desired product. Just a suggestion, a Taiwan based company has such model of ...
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3 votes

Can I connect an inverter directly after an MPPT controller, with no battery?

Generally speaking, the answer to your question is yes: there are many examples of irrigation systems employing a pump powered directly by solar power, with no battery energy storage. A quick search ...
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  • 11.3k
3 votes

What exactly is Potential Induced Degradation in PV panels?

In very simple terms, current leaks from the solar cells to the structure of the panel. This happens when a combination of heat, water and the generated electricity cause the material the panel is ...
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  • 3,755
3 votes

Feeding hotwater into modern appliances

I am not aware of any modern washing machines (at least in the UK) that still have a hot water feed. One reason is that modern machines don't actually use that much water, so even if you had it ...
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  • 367
3 votes

Apply solar energy solutions at our apartment?

I'm not an expert on the topic but I have been doing similar research for the past several months as I'm planning to build an off-grid home and, obviously, renewable energy is critical for me. As ...
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  • 166
3 votes
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What is the typical embodied energy of a solar photovoltaic panel?

According to the Wikipedia article on EROI, 585 kWh/m2 is a median value for the embodied energy of a photovoltaic panel, rated based on surface area. The "energy invested" critically depends on ...
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  • 2,749
3 votes

What is the typical embodied energy of a solar photovoltaic panel?

Energy payback in 1-6 years Taking manufacturing variables into account basically gives you a range of time from 1.25 - 6.5 years based on 5 sunny days out of seven and an average of 6-8 hours of sun ...
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  • 86
3 votes

PV system: Which to upgrade first: panels, inverter, batteries?

To give you specific recommendations to address your issue, you'll likely need to have a qualified electrician out to look at your system, or talk to the system vendor. However, here are a few general ...
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  • 11.3k
2 votes

What advantages (any?) has water heating via photovoltaic system over solar thermal system?

Regarding directly feeding a tank with a series string of panels. Don't have the figures at hand but basically figured the math on this once (maybe it was 3400 btu's per kwhr?) and remember that 1500 ...
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2 votes

How can I monitor a PV system's performance?

As there are already two excellent answers I would just like to add what I found useful to monitor: As Nate's answer suggests the energy produced per month is a good metric for keeping track of the ...
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  • 476
2 votes

Solar PV panels - Worth the cost of more efficient panels?

The maximum rated power is not the only thing to consider. You should also look at how your panels are going to perform in low light conditions. Cloudy days, early mornings and late afternoons etc. ...
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  • 321

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