Csi Epbb Design Factor Calculator: Fill & Download for Free

I suggest using the CSI-EPBB, a website built to calculate the California solar rebates, but still useful now that the rebates are gone.First, convert the 1000 square feet into panels. A 250 watt (STC) panel is about 39” by 65”. Let’s add an inch to each dimension, for installation wiggle-room, then multiply those numbers together, and divide by 144 to get the panel’s area, in square feet:39 by 64 => 40 by 6540 x 65 = 2600, divided by 144 = 18 square feet.So 1000 sq ft can hold 55.55 panels. Let’s call it 55 panels.Now go to CSI EPBB CalculatorThis site requires that you know the hardware you’re using. Don’t bog down, it doesn’t make that much of a difference. I suggest that you use a microinverter like the Enphase M215-60-2LL (so that you don’t need to know string-sizing; just use “55” for the number of inverters) and that you use a typical 250-watt- panel like Canadian Solar’s CS6P-250p. (Read a more detailed explanation of the steps involved in using the CSI-EPBB at www.HowManyPanels.com .)Here are the inputs I've used:The power of the CSI-EPBB site is two-fold:It calculates production based on your zip code, not just ‘Southern California.”It calculates production based on the orientation and tilt of the panels. Look at the chart below to see how important orientation and tilt are:When you hit Go, the CSI outputs a bunch of information. The key figure is at the top of the second page, the annual kilowatt-hours: 21,468 kilowatt-hours.Hope this helps!

Great question. The simple answer is when LCOE < average utility rate(over the same period of time). The LCOE essentially calculates the cost / kWh that you'll pay over the life of the system (levelized cost of energy = total predicted energy production / total cost of the system). It's important to make sure both costs are compared in terms of present value since the solar investment has a cost that is presumably born up-front (unless the system is being financed) whereas the payments to the utility will have a longer duration since you'll be making monthly payments.Note that there exist PPAs (power purchase agreements) in many states where you agree to buy the energy produced by your system at a certain $/kWh over the life of the system (often with an annual escalator). For example you could sign up for $0.12/kWh with a 2% annual escalator. In this case, the LCOE calculation is taken care of for you and all you need to do is determine whether the PPA rate is lower than your current cost of electricity and whether the escalation rates are comparable. It's worth pointing out that with these PPAs your PPA rate will be higher than the LCOE (less direct savings for the consumer) because the solar provider finances the system through a bank in order to achieve its margin immediately rather than accumulating it over 25 years or whatever the duration of the PPA agreement may be. As a result, the bank takes an additional cut on the margin and so the financing is not as attractive as it would be under a cash purchase of a system. The upside is that with a PPA the risk is shifted back onto the solar provider since the consumer is only required to purchase the energy that is actually produced. Compare this to a situation where a consumer buys the system outright and the system may underperform leaving the consumer unhappy and with less savings. If the PPA-financed system underperforms, the bank and solar provider are on the hook and will take measures to maintain the system and improve its performance since the bank is relying on these monthly energy purchases to pay off the initial investment in the system.Now if your question is asking about what is the optimal time to "go solar" (to maximize savings) then, unfortunately, I don't think there is a definitive, empirical answer or equation to determine when it "makes sense" because of the complex incentive structures that are required to make solar feasible in certain locales, but we can dig a little deeper into how these factors come into play.Currently, for solar to be "make sense" there needs to be a solid incentive structure built around it. Take California for example: CSI (California Solar Incentive) was set up as a PBI (performance-based incentive) which steps down over time. There's a bit of jargon in there, but basically this means that you receive monthly payments based on your system's actual production (energy in kWh). The stepping down part means that there are discrete steps where this base incentive level drops over time (e.g. $0.13/kWh down to $0.11/kWh). These "steps" are taken once a certain quantity of solar has been registered / installed / financed with CSI, the incentive program. The logic behind this incentive structure is the following: early on there will be a lot of soft costs associated with solar in addition to the fact that the technology itself will be more expensive, so these early adopters need a larger incentive in order to "go solar." Later on as the technology / manufacturing leads to cheaper costs (and prices seen by the consumer) the incentives no longer need to be as large for someone to decide to "go solar." There is also the LBD (learning-by-doing) externality by which installers become more efficient and reduce labor to install, etc. Anyway, the point of that is to say that policy makers tried to structure the incentive such that "going solar" was more or less equally attractive throughout the duration of the incentive program. On top of this local incentive there is also the 30% ITC (investment tax credit) and local / state tax rebates, utility incentives, etc... which complicate the problem and make the answer a little bit different for each state. The answer will also vary slightly based on the size of the system (residential 2-5 kWp system vs. commercial 1+ MW system). I hope that was useful and not too complicated.

I agree - it's messy. And some panel manufacturers probably like it that way, since they can then select a dimension that they rank well in.At home, you consume different amounts of electricity over different lengths of time. One 100-watt bulb on for one hour means that you've used 100 watt-hours. Two 100-watt bulbs on for one-half hour also equals 100 watt-hours. Sixty 100-watt bulbs on for one minute equals... 100-watt-hours. At the end of the month, your utility sends you a bill stating that you've used 5000 kWh... 5000 kilowatt-hours. Note how important the "hours" is; energy consumption requires a time dimension.- - -Let's talk energy production. A certain solar panel will be described as a 270-watt panel.. On the one hand, that seem fair, since a 100-watt bulb is described as a 100-watt bulb. But the energy that comes into a solar panel varies throughout the day. And the efficiency of a solar panel depends on its temperature. So the 270 watts is performance under a lab condition known as STC. Unfortunately, this condition is like testing a car's miles per gallon on a stretch of downhill road... it's pretty meaningless. So there's a slightly better test, PTC, where the panels are tested while a bit warmer. But it still doesn't reflect the reality of production on a hot roof in suburbia.At this point some distractions can appear in the marketing materials. A company might write about its panel's efficiency. OK, if one brand's panel needs to be 30% larger than the next brand's, to produce 270 watts STC, efficiency matters, but otherwise, efficiency is a distraction.- - -In the first paragraph, I gave an example where a household's monthly bill was 5000 kWh. Let's say your electricity consumption climbs in the summer (air con) and drops in the winter (your heating is gas, not electric), but averages 5000 kWh/month.If you're trying to eliminate your average bill, that's your target production: 5000 kWh/month. Note how energy production also requires a time dimension - hours per month in this case.- - -Here in California our tax dollars have produced a sun-hours map. (See a portion of it at Weather Considerations .) For many cities and towns, the average amount of sun (summer and winter) has been captured in a single number. A number like 5.8 means that Orange, California has 5.8 hours of midday-level sun, on average, over 365 days. Multiply 5.8 times the PTC rating for a panel, and now you're getting somewhere! (Note how we've brought the time dimension into the calculation once again.)I've skipped over some aspects of solar PV nomenclature - the loss converting DC to AC, for example - but the above should be a good start to understanding the terms. If you're in California, our tax dollars paid for another remarkable tool, an online calculator, called the CSI-EPBB. CSI EPBB Calculator This site was designed to calculate government rebates a half-decade ago, but is still a remarkable device. I explain how to use it here: How Many Solar Panels Do I Need