15

You have to get several numbers: payments how much will you pay to obtain the PV system how much will you pay on taxes, recycling fees from the PV system etc. returns how much will you get back from produced power how much will you save on your electricity bill (price of electricity is rising) how much will you be payed from incentives (if any) ...


15

If you are in the U.S. in particular, I would recommend the National Renewable Energy Laboratory's PVWatts calculator, which will provide both likely solar gain (the defaults are reasonable, but you can tweak them to your situation) and potential savings on electricity. For installation costs, again for a US case, LBNL has a great report on installed costs (...


14

If your want to calculate your own Insolation figures then I would highly recommend having a look at the gaisma website, which provides sunrise, sunset, dusk and dawn times for thousands of locations all over the world. For our purposes though, it also provides details of average Insolation (kWh/m²/day), along with Clearness, Temperature, Wind speed, ...


13

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 study, installation location, assumed lifespan of a panel, etc. This also makes it relatively easy to manipulate EROI calculations. Pessimistic The most ...


12

Exergy PV is generally superior to solar thermal because it produces a higher-quality energy: electricity rather than low-grade heat: 1kWh of electricity has more exergy than 1kWh of low-grade heat. As you say, PV's efficiency tends to be significantly lower than solar thermal, in straight watt-for-watt terms, which means less power per unit roof area. ...


11

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 mentioned: you wrote of 10 000 V, which is also written as 10 kV. HVDC runs at 100-800 kV, i.e. 10 to 80 times higher (100 000 to 800 000 V). The idea of using ...


10

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 mono-Si) is very stable, chemically and mechanically; so, to a slightly lesser extent, is polycrystalline silicon (aka multi-Si). The individual cells can have the ...


9

I will answer your question from a different approach, which is practicality rather than raw efficiency. You asked if there are advantages to heating water using solar PV instead of direct solar hot water. The first potential advantage is how the variation throughout the year can be handled. In a modern grid-tied solar PV system, you can bank electrical ...


9

If you compare a MC (monocrystalline) and PC (polycrystalline ) PV (photovoltaic) panel with the same full-sun efficiency in each case, there is very little difference in efficiency as light level falls, between the MC & PC panel. For the same full-sun efficiency monocrystalline are slightly better in low light conditions but the difference is liable ...


9

Photovoltaic system's performance parameters belong to two categories: energy generation (electricity units like Volts, Amperes, Watts and Watthours) and supplemental (some other units). Although you don't mention it, to make the answer complete, I add energy storage category (if you had a battery storage attached). A PVE system can be in one of these ...


8

Generally, no they're not. For a combination of several reasons the tracking system itself has a high capital cost. static PV systems are extremely low maintenance. Tracking PV systems are not. adding a tracker means bigger spacing between groups of panels, so that they don't shadow each other The net additional energy yield isn't that high: for PV, ...


8

I only have one anecdote and avague idea: An agrarian schooling center (Haus Düsse) in Germany clean their PV System once a year, and clean/dirty means a difference of 10% effectiveness. However, as this is basically a small farm with lifestock, different grain treatments, lots of diesel vehicles etc. you would expect far more dust there than at a lot of ...


7

There shouldn't be a big difference in annual energy production between mono and poly in general. The three main factors that influence energy production of solar panels in real life are temperature coefficients (given at the data sheet) the efficiency at low light conditions (should be given at the data sheet as the drop against nominal efficiency at 200 ...


7

This is a bit specific to each solar PV installation, but I'll give it a shot. Short Answer For a 4kW array, the actual power output you see is likely to be around 3kW if your system is operating properly, assuming the array isn't too old. For more, read on ... Proprietary Monitoring Software First of all, many home solar installations now are done by ...


6

There are two parts to the answer. One is enlarging the geographic area of capture of wind and solar across diverse climates, to smooth out the exogenous variations. The other is is storage. Span more climates Back in the early noughties, Gregor Czisch built a massive optimisation model to look at how to balance a 100% renewables grid at lowest cost, ...


6

Short Answer Does it need an equator-facing roof? No. Does it help to face the equator? Yes, but probably not as much as most people might think. Elaboration Solar panels are surprisingly productive, even if they're not oriented optimally. If your primary goal in installing home solar is a desire to produce renewable energy (for environmental reasons),...


6

I think the best tool freely available at the moment is the System Advisor Model (SAM) by the National Renewable Energy Laboratory (NREL) of the US. For Europe/Afrika a good starting point is PVGIS.


6

I can think of one big advantage, in certain instances, to using PV to drive a resistance heating element: ease of transmission. I can run a cable up, down, sideways, etc. with little difficulty, provided that it is large enough for the anticipated current. To do the same thing with pipe can be tricky, especially where you have to deal with extreme ...


6

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 usually means it's best to go for the maximum ~3.86 kW installation. However, a 40% cost increase (I'm assuming that's the increase in price of the total system ...


6

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 give you the number of Wmin/m² incident radiation. So then divide by 60,000 to get kWh/m² for that day. You might as well use the "average" value unless you ...


6

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 the earth's surface varies around the globe, but the maximum measured at sea level on a clear day is around 1,000W/m2. The loss is due to the fact that some of ...


5

Broadly speaking, there are no pros to PV windows. The point of a window is to let light in, and they're usually vertical. The point of PV is to capture as much light as possible, turn as much of that as possible into electricity, and are angled towards the sky to capture as much light as possible (specific angle will depend on latitude). Added to that, ...


5

For small systems, go with the central inverter, assuming it's lower cost (they usually are, at the moment), unless your system is going to suffer from partial shading during the day, in which case micro-inverters are probably the way to go. PV system suppliers should be able to offer you simulations of the options, but bear in mind they'll be optimising ...


5

There are three broad approaches to dealing with variable generation: Diversity of supply: Both through building a grid covering a wide area (see EnergyNumbers' answer for details) and by using different sources of generation. As an example of the latter, consider a grid powered by both wind and solar sources: these are likely to provide peak output at ...


5

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 temperature, as it can't dissipate heat that quickly. This can crack the encapsulant, leading to moisture ingress and the corroding of the cell and/or its contacts. ...


5

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. Let's make some assumptions: You have three mobile phones in your household. Each phone has a battery with a capacity of 2Ah (2000mAh) at 5V One of these ...


5

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%).


5

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 deployed as an overhead canopy would likely deliver no more than 50W/m² in mid-latitudes. To generate the required 85W you thus would need a panel 1.7m² in ...


5

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 portable solar panel — used relatively infrequently and under sub-optimal conditions — would never pay for itself. If it takes (3*365=) ~1100 days at full ...


4

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 confirm that no significant dust has collected. (The angle of inclination is about 27 degrees.) But, Florida rains a lot and that helps keep everything clean. I ...


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