14

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 ...


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 ...


7

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 ...


7

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 ...


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

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. ...


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, across ...


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

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 "Interaction between PV-systems and extensive green roofs" given at the Fifth Annual Greening Rooftops for Sustainable Communities Conference, Awards ...


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

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

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

This isn't a complete answer but I would avoid buying PV panels built in countries with poor environmental regulations. That would be a good place to start. For example China. Then if possible avoid companies that mine the materials they're built from in places like China or Africa. Again, the regulations allow much more pollution than places like Europe ...


4

Cost is a big advantage; if you already have a hot water tank with space for an immersion heater then it is a lot cheaper to add a small photovoltaic panel then a full solar thermal system. The payback time can be very short for this. No control system is needed, as the immersion heater will just cut out when the tank gets too hot – the GCH can be set to ...


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 ...


4

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 meter per day ~= hours of equivalent full power sun. You'll see that Houston average about 4 kWh/m^2/day. That means that an eg 20 W panel will produce about 4 ...


4

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'll be listed on the panel data sheet as "maximum open circuit voltage". If you short the panels you'll get up to "maximum short circuit current" which risks ...


4

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 management feature. I know of the following devices that fulfill both requirements: Circutor Dynamic Power Controller CDP-G. Includes an electricity meter, ...


4

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 surges. The inverter has a charge controller built into it. It's perfectly fine, but it is merely there for convenience, so on a small system you don't have to ...


4

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 every 100km/60 miles on the highway (which is also where good solar access is most likely). It's tricky to find energy consumption figures for heavy electric ...


3

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 made of to break down at a very low level, and start conducting electricity where we don't want them to. It's hard to balance "how, exactly" with "not too ...


3

My 40 gal electric HW heater was dying (18 years old - time to go, even for a Sears Kenmore). I had EIGHT 220 watt PV panels left from an installation (at my office), and I wanted to use them to heat water (much more efficient use than sitting in my shed for a year! Right? ). 220 x 8 is only 1760 watts. I found a new "Brand X" 50 Gal Electric HW heater ...


3

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 indicates there are numerous suppliers and types/scales of systems, and even a few youtube videos with DIY-guides to setting such a system up. Specifically, it ...


3

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 Inverter with in-built MPPT controller. Google for INVEREX INFINI


3

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 connected to a hot tap, it would be filled mainly with the cold water that's been standing around in your pipes, unless you have a particularly short pipe run to your ...


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