If you talk with your family and friends, you might hear that they purchased a 5kW solar system for themselves. Sometimes a salesperson from a solar installer is convincing you to buy a 10kW system. While it’s great to invest in solar because it’s environmentally friendly, blindly investing in solar can cost a lot of money.
You should find out what your average daily energy consumption is to see how much energy you consume on average. If the 5kW solar system is too big, you can invest in solar batteries and use feed-in tariffs to utilise the excess energy. Your rooftop should also be able to support 25-26 solar panels and sources of shade should be minimized.
Look at your energy consumption habits and whether they match with peak solar generation during the day. If your peak energy usage happens at night with no solar energy, you should either invest in battery storage or draw power from the grid during the night.
Does your power consumption match your planned power generation?
It’s important to make a distinction between kW and kilowatts per hour (kWh). When a system says it can produce 5kW, it means the system will produce 5kWat its maximum output. It’s not referring to the total amount of energy generated, which is represented by kWh.
A 5kW solar system will produce approximately 20 kWh in a single day during summer. During winter, solar panels generate 52% of their total energy in South Australia since weather can block the sunlight your panels receive. That means your 5kW solar system will produce 10-11 kWh and you must keep that in mind when determining your energy requirements.
If your energy consumption goes above what your solar system can generate, you won’t have enough power to operate your devices. Look at the devices and the energy they consume over an hour. The average power consumption for these devices are:
Some devices, like an EV requiring 35-60 kWh to charge, will consume more than the average 5kW system can generate. In those cases, you either draw power from the grid during certain times or build energy storage solutions.
Your energy provider’s app, such as Origin’s, can provide you with this information over a set period of time. Consider their usage (TVs consume less power on standby) and the duration of their use (fridges run 24/7). Once you have a better idea of how much power your devices consume, you can adjust your usage accordingly.
Look at previous energy bills and your energy meter, which give you an idea of your total consumption habits. This helps you decide if you can be energy independent or whether you will need to draw power from the grid.
What is your load profile during the day?
Your load profile, also known as your energy consumption profile, looks at the energy your property needs every day. It considers devices that are used throughout the day such as refrigerators or occasional device usage such as a microwave. Peak usage is also considered, such as the time when everyone is at home or one device is used more often.
For example, a working professional would not have a high load profile in the morning and afternoon, as they would be working during the day. A few devices would be used for an hour at most, like making breakfast or using a hair dryer. After they come home during the evening, they would be using several devices such as the TV, induction stove top, and air conditioning. Since they require the most energy during that time, the evening would be peak usage for a working professional.
A retired couple would likely have their energy usage spread throughout the day. Since they stay at home for most of the day, their energy usage would remain somewhat stable as they use their devices throughout the day. While evening will see increased usage with more lights being used, the peak won’t be as large as a working professional.
The following table reflects 24 hour power consumption habits in January in South Australia for the average household.
Most families or working households will use most of their power in the evening. It doesn’t match the time when solar energy is being generated, which is the greatest during the middle of the day (12-1 PM). That energy is going back into the grid or is stored in a solar battery. When it is at night, there is no solar power and you must draw energy from the grid or an alternative power source.
Knowing your load profile helps you devise a strategy to utilise the energy that would normally go into the grid. You can either revise your daily schedule around peak solar energy generation or invest in batteries to capture that energy. Using your solar system for your daytime needs while using the grid at night is also a solution.
What if you use more energy than a 5kW system can provide?
There will always be some days where you use more energy than others. If you frequently use more than 40 kWh in a day, you will need a larger system to support your energy consumption. But if your usage occasionally goes above 40 kWh, you will draw non-solar power from the grid, which will cost money. This also happens if the weather causes less sunlight to come through and provide unexpected shading.
You can avoid that by investing in a solar battery that can store excess energy. If your usage goes above 40 kWh and you have energy in the battery, that energy is used instead of the grid. Batteries such as the sonnenBatterie hybrid 9.53 have the capacity to store large amounts of energy on days when energy usage is low. With a proper batter set-up, excess energy will be stored and ready to use when consumption goes above the average requirements.
Is it bad if your solar system is too big for your needs?
While setting up a solar power system is always beneficial, it is a large investment. If you install a solar system that produces more energy than you need, the excess energy is clipped off. It is sent back into the grid where feed-in tariffs apply. This is called an oversized system. It’s not harmful, but you won’t be able to take advantage of that energy for your own use.
If you expect your home to consume more energy in the near future (new family member, installing a pool), then an oversized system could be beneficial. You anticipate your increased energy consumption and make preparations to avoid having to pay more later on.
Solar batteries can also be used to store that energy, especially on days where you might not get as much sunlight. You can also check the feed-in tariffs in your area, which pay you money to send energy back into the grid. It helps pay off your system faster while using energy that would otherwise be wasted.
How many solar panels can your roof support?
Before you start installing a system, you should make sure that your rooftop can support 25-26 solar panels. A 5kW system requires 10-14 400 W solar panels to generate that energy. For example, the Q.MAXX BLK-G5+ solar panel from Q Cells can generate 410 W per panel. One panel is 1.7m by 1.1m, and they are usually placed in rows along your rooftop. Each panel weighs 21.1 kg, which would put 527.5 kg of weight on your rooftop.
Solar panels do not have to be in one straight line, and you can have several panels in rows aligned on your roof. If your roof cannot support that much weight or there isn’t enough room for 14 panels, you can utilise alternate locations. A shed or your garage can also work for panel placement.
How much shading will your roof experience?
While solar panel technology is improving, shading will reduce the amount of sunlight a panel receives, lowering their energy conversion. If there is a lot of shade on your property, your system’s output could be much lower than expected.
Look around your property and see any potential sources of shade such as other buildings or tree branches. If it’s feasible to remove the shade, consider how often you need to remove them. For example, tree branches can be cut off but smaller trees can grow and provide their own shade. If objects can fall from trees, such as leaves or other debris, think about how often you must remove them.
Some sources of shade, like a chimney, will be difficult to remove. Look at areas on the roof where you can avoid the shadow of those sources for good placement. Since shade can change as the sun moves, you should be looking at the full range of potential shade movement.
Do you have feed-in tariffs for extra energy?
If your solar panel system is producing more energy than you require, you can send the extra energy back to the electricity grid. This gives you a feed-in tariff, which provides some cents per kWh (c/kWh) you feed back into the grid. Every provider has their own feed-in tariffs and conditions, and you should shop around to see which ones are right for you.
All solar power systems are compatible with the energy grid in Australia, which means you always have access to a feed-in tariff. Check any special conditions for tariffs to ensure you get the highest tariff you can afford.
Conclusion
Getting a 5kW solar system is a great decision if you can justify the energy consumption. Looking at your current load profile tells you when you use the most energy and how much you should plan for. If it’s more than you need, having a plan for excess energy generation avoids wastage. Your rooftop should also be able to support 25 solar panels without issue, preferably in areas without much shading.
If you are interested in obtaining a 5kW solar system but aren’t sure about the cost, check out Go Sunny’s ANYTIME solar plan. There is a $0 upfront cost and you pay that back through installments. You get the benefits and savings of solar while monitoring how your system operates. We will advise you on proper panel positioning and set you up with the best solar products within your budget. Contact us to find out more.
