Why Are Solar Systems Sold In Kw And Not Kwh
As you know, all manufacturers rate their solar systems depending on their power rating . The reason for this lies around the fact that a solar systems rating only refers to its potential maximum output.
During solar system production, every panel manufactured undergoes thorough testing under optimum conditions before being released to the market. The maximum power achieved during testing then defines the solar systems power rating.
This means that since your rooftop will rarely receive the ideal sunlight conditions, your solar systems output might always be slightly lower than its rating.
Moreover, different solar panels use different materials and technologies, and their locations receive different sunlight levels. Therefore, the amount of energy the panels produce each day will vary, making it impossible to sell a solar system in kWh.
What is the relationship between energy consumption and time?
Energy defines the total power consumed over a given time. It can be broken down into:
Energy = Power x Time
From the equation above, we can conclude that energy is directly proportional to power and time. Without time, the energy only shows the quantity of energy consumed or produced without specifying how much time it took.
For instance, a 1.5kW solar system can generate 20kWh of power, just like a 5kW system would. However, the difference between the two will be the time it takes them.
Therefore, time makes the rate of energy consumption quantifiable.
When Will Pv Solar Reach Grid Parity
There is no one cost number that defines utility grid parity. There are different levels of parity depending on what the generation system is. Solar has already penetrated the most expensive generator – the “peaking plant”, also known as a “peaker”. Peakers are rather small plants, ranging from 50 MW to 500 MW in size, normally about 100 MW. Peakers are mainly used in the summertime during “peak” electrical use for air conditioning late in the afternoon. They are normally single-cycle natural gas generators, meaning no boiling water burning natural gas directly fuels the turbine. Peakers have to be able to come up to speed on 10 to 15 minutes notice. They are very inefficient and expensive to run, but are great sources of electricity when utilities are on the verge of rolling blackouts. At that point, operating expenses are down the list of priorities.
Shown at the left is a photo of APS’s Sundance peaker plant near Coolidge, AZ. The site consists of ten generators, and all ten can be on the grid within 10 minutes generating 450 MW of power. Each generator consists of a converted GE Boeing 747 jet engine powered with natural gas which can be turned on with a click of a mouse and will generate 45 MW of power.
How Long Does It Take For A 5kw System To Pay Itself
When you purchase a solar system, you invest in the system. As a result, you want to see a return on your investment. The return on investment is the time it takes for you to recover your investment in the solar system.
For a 5kW solar system, it takes about 3.5 to 5 years for a 5kW system to pay itself.
How long it takes for a system to pay itself depends on several factors.
- First, solar power consumption. When you consume most of the power produced by your solar panels, you make more savings on your electricity bill.
- Second, electricity consumption. The more electricity you consume when you have solar, the longer it will take to return your investment.
- Third, feed-in tariffs. They help offset your electricity bill against the amount of solar you export to the grid. Maximum use of solar in the home coupled with payment for the solar power exported and reduced use of electricity help to shorten your payback period.
Don’t Miss: Does Tesla Install Solar Panels
Kw Vs Kwh: How To Determine The Difference
Green Coast is supported by its readers. We may earn an affiliate commission at no extra cost to you if you buy through a link on this page. Learn more.
Do you know the difference between kW and kWh? In this kW vs. kWh article, we will help you determine the difference.
How Many Solar Panels Do I Need
Your energy needs determine how many panels you need, which affects the overall price of your solar system installation. To eliminate your electric bill entirely, you must generate 100% of the electricity your home needs. Most homeowners need between 25 and 35 panels to achieve complete energy independence.
Average households need867 kWh/monthin electrical power
A solar panel typically produces about one kilowatt-hour per day, so if your daily kWh usage is 30, you would need 30 solar panels to generate all of your energy needs. If you need to generate extra energy to heat a pool or run the air conditioning for most of the year, this adds to your energy costs.
To estimate the amount of energy youll need, you need to know your average kilowatt-hours . This number should be on your utility bill as kWh used. To get your monthly average, look at bills for the past year, add up the stated kWh used and divide by 12.
Next, divide your monthly kWh average by 30 to calculate your daily average. For instance, if your average monthly kWh is 900, then your average daily kWh is 30.
For a more accurate calculation, try to factor in times when there is not as much solar power available, like when its cloudy or in the evening. There are two main ways to account for this:
These additional calculations can be difficult, but they are necessary if you want the optimum solar power system for your home.
Don’t Miss: What Different Types Of Solar Panels Are There
What Happens When You Dont Have A Battery System
Without a battery system, you can export your excess power to the grid.
To do this, you need to get into an agreement with an electricity retailer. Your solar system will then be connected to the grid.
You will be paid for the amount of power you send to the grid at an agreed-upon rate known as a feed-in tariff. For most households, this helps to offset any electricity bills incurred.
How Do Solar Panels Work
Before we look at how many kWh a solar panel produces a day, lets first take a look at how they work. Solar panels are attached usually to the roof of a house and work to generate energy that can be used in your home. This is done by the panels absorbing sunlight using photovoltaic cells.
Its worth thinking of these PV cells like a sandwich that features two slices of semiconducting material like silicon. When the light interacts with a silicon cell, it prompts electrons to be set in motion. These initiate a flow of electric current known as the photovoltaic effect.
You can also think of it in these three simple steps:
The panels will then convert this sunlight into direct current, or DC energy, which is fed to your house through an inverter.
The inverter will then convert your DC energy into alternating current energy. It is this AC energy that will flow into your homes electrical panel and power your appliances with electricity.
If there is any leftover electricity that you havent used, it will be sent to the electric grid. From there, it can be distributed to other appliances and homes across your town or city. Likewise, if you need more electricity than your solar panel can provide you with, this will be fed to your house from the electric grid.
Recommended Reading: How Much Do Solar Cells Cost
China Made Solar Panels Cheap
Seeing a great chance in solar power, China started opening their own solar panel factories. The cost of solar kept decreasing and the total cost of solar was at the historic minimum year after year. Utility-scale solar plants started appearing in Germany and the USA which brought solar system cost and installation costs down manyfold.
What Solar Panels Produce The Most Electricity
Solar panels usually range in wattage output from around 250 watts to 400 watts, but some panels exceed the 400 watt mark. The solar panel with the highest watt is the SunPower E-Series, a commercial solar panel line. The top panel in the E-Series comes out at a whopping 435 watts. When just looking at residential solar panel wattage, the top panel available is the SunPower A-Series AC Module the top panel in the A-Series line boasts a wattage of 425 watts.
Read Also: How Much Does The Solar System Cost
Solar Panel Output Per Square Metre
The most popular domestic solar panel system is 4 kW. This has 16 panels, with each one:
- around 1.6 square metres in size
- rated to produce roughly 265 watts of power
To work out the output per square metre, use this formula:
Number of panels x Capacity of solar panel system
Capacity ÷ Total size of system
Example
- 16 panels of 265 W each:
- 16 x 265 = a capacity of 4,240 kW
- Total size of the system
- 4,240 ÷ 6 = 165 W per m2
How Many Kwh Per Day Does A 5kw System Produce
A 5kW solar power system with an average irradiance of 4 peak-sun-hours per day will theoretically generate 20kWh per day. This assumes clear skies with no shading and will vary according to location. In practice, a 5kW system may produce less than this, as solar losses reduce the power output.
5000 watts of solar power is just about the average size of a US domestic solar system and represents 17 solar panels @ 300 watts each.
The energy output of any solar power systems depends on the suns energy, or irradiance, and this varies from state to state.
For example, the irradiance in peak-sun-hours in Arizona is 3 times more than in Alaska, so the difference van be very big. For most purposes, and estimate using an average irradiance value of 4 peak-sun-hours gives a good idea of solar output.
Read Also: How Can I Make A Solar Panel
Power Rating Of Solar Panel
The last part of the formula all depends on what sort of solar panels you plan on buying for your home solar installation, it could be a 100W, 400W, 500W?
Most residential solar installations use 400 watt solar panels. The reason for this is you get more power output per square footage.
So, to continue our example on figuring out how many solar panels you need for 1000kWh, now you need to divide 6203 by the solar panel power output .
6203 ÷ 400W = 15,50 .
Implication Onto Electricity Bill Management And Energy Investment
There is no silver bullet in electricity or energy demand and bill management, because customers have different specific situations, e.g. different comfort/convenience needs, different electricity tariffs, or different usage patterns. Electricity tariff may have a few elements, such as daily access and metering charge, energy charge or peak demand charge . PV is a promising option for reducing energy charge when electricity price is reasonably high and continuously increasing, such as in Australia and Germany. However, for sites with peak demand charge in place, PV may be less attractive if peak demands mostly occur in the late afternoon to early evening, for example residential communities. Overall, energy investment is largely an economical decision and it is better to make investment decisions based on systematical evaluation of options in operational improvement, energy efficiency, onsite generation and energy storage.
Also Check: Which Solar Battery Is Best
Is 1 Kw Enough To Run A House
Considering the average household in the United States uses roughly 29kWh per day, and 1kW of solar will give you 4-5kW of power with 5 hours of sunlight, this will not be enough for most homes.
That being said, it can certainly help lower your dependence on mains power and save you money on electricity bills.
It also helps to look at your energy requirements and usage, and see where you can save on power. For example, using a solar geyser to heat water, a gas fridge, and a stove, and heating your home with a fireplace or gas heater will save a ton of power overall.
In my home, a have a 1kW solar system that provides me with more power than I need, since I save on energy usage by using gas appliances and a solar geyser. This is more than enough to run lights, computers, a TV, and other small appliances.
How Many Solar Panels Do I Need Then
Related:How many solar panels do I need?
Typically, a modern solar panel produces between 250 to 270 watts of peak power in controlled conditions. This is called the nameplate rating, and solar panel wattage varies based on the size and efficiency of your panel. There are plenty of solar calculators, and the brand of solar system you choose probably offers one. That said, there is a simple equation to calculate the amount of kilowatt-hours your solar panel system will produce.
So now that we know you need to produce about 6kW of AC output, we can work backwards to figure out how many solar panels you need. Solar panels produce direct current , and your home runs on alternating current .
Yep, like the band, AC/DC.
Because of physics, there are losses in converting the energy from the sun into DC power, and turning the DC power into AC power. This ratio of AC to DC is called the derate factor, and is typically about .8. This means you convert about 80% of the DC power into AC power.
This continues to improve ever so slightly, but the losses are unavoidable because of physics! So you take the AC amount you need: 6kW and divide by .8 . This means that youll need 30 250Wp solar panels or 27-28 270Wp panels.
Also Check: How Many Kwh Does A 5kw Solar System Produce
What About A Battery
A storage battery will capture the unused solar power generated during the day, for use at night and on low-sunlight days. Installations that include batteries are increasingly popular. See our case study of the first Australian home to install a Tesla PowerWall battery.
But for most homes, we think a battery doesn’t make economic sense yet. Batteries are still relatively expensive and the payback time will often be longer than the warranty period of the battery. However, it’s likely that battery technology and prices, together with future changes in how the electricity market works, will make batteries a good option for most homes within the next few years.
And remember: for most grid-connected systems, having a battery doesn’t necessarily protect you in the event of a blackout. You may still lose all power to your home, despite having solar panels producing power and a charged battery ready and waiting. This is because grid-connected systems have what’s known as “anti-islanding protection”. During a blackout, the grid and any engineers working on the lines must be protected from “islands” of electricity generation pumping power unexpectedly into the lines.
For most solar PV systems, the simplest way to provide anti-islanding protection is to shut down entirely. So, when it senses a grid blackout, your solar PV system shuts down and you have no household power at all.
Forget Single Solar Panelshow Much Energy Will Your Whole System Produce
Knowing how much energy a single solar panel produces is all well and good, but more importantly, how much solar power can your roof generate? Lets do the math below:
Take our example above, where youre getting an average of five hours of direct sunlight per day and using solar panels rated at 290 W. Lets say you install 30 of those premium solar panels on your roofthat nets you a 8,700 watt, or 8.7 kW solar panel system, near the average system size purchased on the EnergySage Marketplace. Multiply the five direct sunlight hours we estimated above by 8.7 kW, and we get approximately 43.5 kWh of electricity produced per day. And for one final conversion, if we multiply 43.5 by 365 days in a year, we get approximately 15,800 kWh of electricity produced in a full calendar year from a rooftop array of 30 premium, 290 W solar panels. Considering the average electricity use per year in the U.S. is around 10,600 kWh, thats probably more than enough to power your home on solar.
This estimate is likely on the high end for most solar shoppers, and likely because of our estimate for the amount of sunlight the system will get . To learn more about average sun hours, check out our blog here, where we take a look at average sunlight per year by location.
Read Also: How To Change From Sole Proprietorship To Corporation
Kwp: And It Will Have A Maximum Power Rating In Peak Kilowatts
This has been likened to the horsepower rating in cars.
The peak power rating on a solar panel represents the most power that it would produce under ideal conditions for solar production in other words, between 11 and 1PM on a sunny day, when the temperature is not too hot solar panels would really to be no more than 110 degrees F and ideally between 65 and 85 degrees, and of course, when there is no snow cover.
How Much Is A 30 Kwh Solar System
- The quality of the components you purchase
- Your location
- Installation
You can save quite a bit of money if you install the system yourself, but this is certainly tricky. Installation costs will vary widely depending on who does the installation for you, but for a system this large you can expect to pay around $10,000 for installation.
In general, solar panels cost around two or three dollars per watt. Taking into consideration the quality of components you choose, installation, and your location, you can expect to pay anywhere from $60,000 to $80,000 for a 30 kWh solar setup.
Recommended Reading: How Many Solar Panels To Make A Megawatt
