Calculating The Size Of Your Solar Pv System
Now you know how much power you typically use and the times of day you use it. What capacity will your solar PV system need to be to cover your power usage?
First, we’re assuming you’ll have a grid-connected system. This is by far the most common type and it simply means you have solar panels generating electricity during the day, and a grid connection to supply electricity when the solar panels aren’t generating enough . See grid-connected vs off-grid for more.
How much electricity can you expect per kW of solar panels?
Solar PV systems are rated in watts or kilowatts . You’ll see systems described as 4kW, 5kW, 10kW and so on.
1kW of solar panels = 4kWh of electricity produced per day .
For each kW of solar panels, you can expect about 4kWh per day of electricity generation. So a 6.6kW solar system will generate about 26.4kWh on a good day .
It’s just a general rule the actual amount of electricity generated per kW of solar panels depends on your location, the time of year and the amount of sunlight you’re getting, the quality of the system, the orientation of the panels, how old they are, and so on. In southern regions such as Hobart it could be as low as 3.5kWh per day, while the same 1kW of panels in Darwin could generate 5kWh.
How Much Electricity Can I Generate With Solar Panels
There are a number of factors that can affect how much electricity you will generate from any solar panels installed.
Some of these are controllable, such as the size, number and position of panels on the home however, others are less predictable, like the number of hours of daylight .
Determining the amount of electricity that you may generate on your property must be done on a case by case basis, and it will largely depend on the kind of panel you have and its rating.
The standard solar panel has an input rate of around 1000 Watts per square meter, and the majority of solar panels available have around 15-20%. Therefore, if your solar panel was 1 square meter in size, then it would likely only produce around 150-200W in good sunlight.
To calculate how much power you can expect your own solar PV system to produce, take a look at our detailed guide.
How Many Kwh Does A Solar Panel Produce Per Month
First, it is important to note that not all solar panels are created equally.
Presently, the range of efficiency, that is, how much of the suns energy hitting the solar cell is converted into electricity averages 18 percent, but can vary depending on the quality of the solar panel. A premium panel, manufactured with more expensive materials will cost more and be more efficient.
A solar panel operating at 20 percent efficiency produces around 265 watts of power per hour .
Manufacturers are required to label the panels with the number of kilowatts they can power per hour during ideal conditions, i.e. direct sunlight on a cloudless and sunny day. This number is called a Standard Test Condition rating and will be for example 265 if the panel produces 265 watts of power.
So, how much energy does a solar panel produce per day?
If for example, the solar panel has a rating of 250 watts of power, and the panel received a full hour of direct sunlight, and no other factors diminished the power, then you would get 250 watt-hours of electricity.
On average, one such panel would produce one kilowatt hour per day and 30 kWh per month.
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Editors Note: This Is An Overview On How To Understand How Much Energy Your Solar System Will Produce And Overall Solar Panel Output
We always advise speaking with at least a few certified solar installers to understand how all the factors will affect solar panel output for your system.
Solar panels indicate how much power they intend to produce under ideal conditions, otherwise known as the maximum power rating.
But how much electricity your solar panels produce depends on several factors.
- Does intermittent shading obscure direct sunlight from hitting the roof?
- How much sunlight does your roof get on average?
- How big are the solar panels, and how efficient are the solar cells at converting energy?
Because the seasons and weather conditions affect the amount of sunlight hitting your roof, and the amount of sunlight also varies on the time day, you cant use just the solar panel ratings to predict how much power youll get. However, your location will allow you to do some math and determine how well a solar panel works where you are.
Solar Power Systems: The Numbers Explained
Now you know how solar power works, but what about all those numbers? What do they actually mean?
A watt is a unit of electricity. So when you see a solar panel described as 360W, or a system described as a 1kW solar system, that refers to the total wattage. Its the overall amount of power the panel or system can put out.
Generally, solar panels are rated to create between 250-400W of electricity. The more panels you add, the more total power you can generate.
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Ology And External References
Solar production potential was calculated using the mean daily global insolation ) in Natural Resource Canadas photovoltaic potential and insolation dataset spreadsheet .
- We used values for a south-facing tilt where the installation angle equals degree latitude -15°.
- A 25% efficiency loss factor was then applied before getting the final kWh/kW/yr number.
- The top five populated cities from each province were used to calculate province and territorial averages.
While the data presented on this page is accurate to three digits, the maps here are intended to be illustrative representations rather than a precise geographic information system.
NRCan has an ArcGIS web mapping application which can be used to lookup data for any municipality in Canada, and an additional list of solar resource data sources here.
Factors Affecting Solar Panels Generation
Before we dive deep into calculating the power generation of one solar panel there are three major things that we need to understand which affects the power generation of solar panels.
So now we know the parameters that play vital role in solar panels generation, we can calculate the power generation of one solar panel.
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The Electricity Produced By One Solar Panel
The energy output of a solar panel varies based on the size of the panel you have and its efficiency.
On average a modern solar panel produces between 250 to 270 watts under ideal sunlight and temperature conditions. This is the power equivalent to lighting 84 compact fluorescent bulbs for 1 hour a day . Such panel consists of 60 solar cells. One solar cell generates 5 watts, with the efficiency between 15 to 18 percent. The size of the panel in this case is around 65 inches in length and 40 inches in width .
But you can have also panels generating as much as 325 watts. You should know, though, that panels with higher output are more expensive and are usually installed when free space is a limiting factor.
Solar Panels: How Much Energy Do They Generate
Youve begun researching solar panels, but all you can see is numbers. So many numbers.
5kW solar system, 300W solar panels, 230W output.
Why does choosing a solar system have to trigger flashbacks to maths class?
Unfortunately, you need to understand the numbers to work out how much energy the solar panels you choose will generate. Then this, in turn, helps you decide on the best solar power system for you.
So do your best to push down the memory of Mr Lawsons algebra tests, and lets demystify all those numbers.
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Key Takeaways On Solar Farm Land Requirements
Farmers, ranchers, and landowners in search of a predictable way to receive passive income should determine if they meet the solar farm land requirements for leasing a solar project on their property.
The advantages gained from satisfying the minimum of 6-8 acres of solar-ready land per megawatt needed to construct the smallest of community solar farms may outweigh any disadvantages as detailed in this article.
One hundred sixty or more acres would satisfy the solar farm land requirements for a larger utility-scale solar power station.
But each case is unique. Search out legal advice before going all in.
With our top 7 tips for farmers concerning solar leasing after youve met the solar farm land requirements, youll be well on your way as a partner in a quintuple win/business opportunity for you, the solar developer, the public utility, consumers, and the planet.
How Much Solar Power Will You Need
To determine your homes average energy requirements, look at past utility bills. You can calculate how many solar panels you need by multiplying your households hourly energy requirement by the peak sunlight hours for your area and dividing that by a panels wattage. Use a low-wattage and high-wattage example to establish a range . Note that the size of your roof and how much sunlight your roof gets are factors as well.
If you work with an experienced solar installer, they will handle all these calculations for you. If youre searching for a calculator to figure out how many solar panels do I need?, look no further. You can use SunPower Design Studio to estimate your own system size, monthly savings, and the actual appearance of a solar array on your own roof. This interactive tool provides a solar estimate in just a few seconds and can be done on your own or on a call with a SunPower 786-7693.
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Importance Of The Hours Of Sunshine
It is evident that this calculation is an approximation to the amount of energy that a solar panel can produce, since it will not be the same to live in southern areas such as Malaga or Seville than in northern cities such as Bilbao or Santander. Keep in mind that when we look at the watts of the solar panel and see 200 W or 300 W, the manufacturer refers to the power generated by the solar panel in optimal conditions , which is obviously not going to be given every day of the year.
In summer we can have the same number of hours of sunshine in Bilbao or Malaga, but the hours of sunshine are actually very different. The incidence of the sun is more powerful in warm areas so it is more than likely that the solar panel approaches the optimal power more often. The good news is that constant advances allow solar panels, even on a cloudy day, to be able to extract energy.
As a summary, when it comes to knowing how much power a solar panel actually generates, we should take into account three aspects : power, hours of sunshine, and the incidence of the sun in the place of residence.
Putting It All Together
With those variables in mind, we can roughly estimate the number of solar panels for home that you’ll need. In this example, we’ll use the average annual energy consumption, solar panel wattage and hours of sunlight that we mentioned earlier.
Let’s say that your property receives four hours of sunshine each day, and you’re purchasing 325-watt solar panels. In that case, each panel can generate 1,300 watt-hours per day . Assuming that your energy usage is in line with the average of 29 kWh per day, you’d need 23 325-watt panels to create enough electricity for your home.
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What Are Watts And Kilowatts
To understand how much electricity a solar panel can produce, we first need to get comfortable with some units of power and energy.
If youve been reading about solar panels, youll have noticed some specific units being mentioned: watt and kilowatt , plus watt-hours and kilowatt-hours . Watt and kilowatt are units of power, and indicate how much power a solar panel can provide 1,000 watts = 1 kilowatt .
Watt-hour and kilowatt-hour are units of energy, and are used to show how much work can be completed in one hour 1,000 watt-hours = 1 kilowatt-hour .
Is Geographical Location A Factor
Location, location, location. The effectiveness of solar panels is strongly influenced by where you live. The US states with the most sunshine and the clearest skies are the best places to install solar panels. But that doesnt mean that you cant get good returns in other states.
Studies show that the most productive states in terms of the energy collected by solar panels are Arizona and New Mexico. In these states, a 1 kW solar setup will generate nearly 5 kWh of power per day on average. But if you install the same panels in Washington State, you can expect just 3 kWh per day and only 2.8 in Minnesota.
Wherever you live, you can use solar panels to make a real difference in your energy costs. If youre in a cloudier, more northern state, you will need to install more panels to push up the energy output.
This is because in places with less direct sunlight, you need to spend more money on a larger solar panel set up to get the same energy youd get from a small setup in a sunnier place.
Solar power is more economical in places with a lot of direct sunlight.
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How Much Electricity Does A Solar Panel Produce Per Day
Of all the factors that affect how much electricity your solar panels produce in a day, the area you live will have the most impact.
This comes down to a figure called peak sun hours: a measure of how much solar energy is available throughout the day in your area. And you can use this number to work out how much electricity your solar system can supply.
The Bureau of Meteorology collects readings that will tell you the average peak sun hours in your area.
Lets look at an example.
Say you live in Sydney, NSW, and install a 360W panel.
Sydney gets an average of 4.6 peak sun hours per day.
So your panel would generate 4.6 hours x 360 watts = 1,656 watt-hours .
To take 15% off for the efficiency loss, you multiply it by 0.85 . So your 360W panel will typically produce 1.66kWh x .0.85 = 1.41kWh per day.
Thats for one solar panel. If you installed 10 panels to make a 3.6kW system, youd multiply your result by 10.
So your entire system would then generate 1.41kWh x 10 panels = 14.1kWh per day on average.
No matter what size system you want to install 1kW, 3kW, 5kW, 6.6kW, 7kW, 10kW or some other size your calculation will be the same:
Peak sun hours x Size of system x 0.85 = Estimated amount of power produced by your system
Discover how to calculate how many solar panels youll need here.
Solar Panel Power Output Calculator
So far Ive shown the theoretical solar panel production, but real-life isnt like that. A solar installation has losses, both due to design and environmental factors.
These losses can amount to 20% of the overall production capacity and so this calculator uses that figure to give realistic output values of various installations.
Infographic shows typical losses reducing power produced from solar panels
Infographic embed code:
PDF download of Infographic: 10 main losses in domestic PV system
Go to the Global Solar Data, enter your location by city or GPS, and note the value for direct irradiance
It will be between 3 to 6 kWh/m2/day, which is also called the peak-sun-hours and will be used in the calculator to find the power you can expect to be produced by your system
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Calculating Solar Power Costs
Once the above costs and benefits are determined, a solar system can theoretically be evaluated using the discounted cash flow method. Outflows at the beginning of the project would consist of installation costs , and inflows would arrive later in the form of offset electricity costs .
Rather than using DCF, the viability of solar power is usually evaluated by calculating the levelized cost of electricity , then comparing it to the cost of electricity charged by the local utility. The LCOE for household solar will typically be calculated as cost/kilowatt-hour – the same format commonly used on electricity bills. To approximate the LCOE, one can use the following equation:
LCOE = Net Present Value of the Lifetime Cost of Ownership / Lifetime Energy Output
The useful life of a PV solar module is generally assumed to be 25-40 years. The cost of ownership includes the maintenance costs, which must be discounted to find the NPV. The LCOE can then be compared to the cost of electricity from a utility remember, the relevant price is that which occurs during times at or near peak PV solar production.
