How To Develop Photovoltaic System Design To Achieve High Energy Yield
A solar energy system is a significant investment for any household or business, with an average price of a 6 kW system being around $18,000. Therefore, it’s natural to research the long-term cost-efficiency solar panels that can maximize your ROI.
For this, though, you have to understand the factors that influence solar energy yield and overall system performance. So let’s walk through the key photovoltaic system design factors that affect energy yield.
This guide to photovoltaic system design and installation explains how to keep your renewable energy solution at peak efficiency so it provides the highest ROI.
What Is Solar Energy Yield?
Solar energy yield is the amount of electricity or thermal energy generated by a solar power system over a specific period, measured in kilowatt-hours (kWh) for photovoltaic (PV) systems or thermal units for solar thermal systems.
7 Key Factors Affecting Solar Panel Yield
1. Solar Irradiance
Solar irradiance is the amount of sunlight per unit area, measured in watts per square meter (W/m²). Generally speaking, the higher the solar irradiance during the day, the more light reaches the panels, resulting in a higher production rate.
For example, iIf a location receives 1,000 W/m² of sunlight, a panel with standard solar cells of 1 kW produces 1 kWh/hour under ideal conditions.
Keep in mind that clouds, shading, smog, dust, and snow on panels lower the system’s irradiance. You’ll receive the maximum results only during lunch hours. During morning and evening, the Sun is lower, reducing possible generation.
2. Installation Angle & Orientation
The ideal tilt angle should be close to the location’s latitude to maximize energy production throughout the year. Since Chicago is located at 42° N, your panels should face south with a tilt angle of 42°.
It would be perfect if your solar energy system design allows you to install adjustable mounts. In that case, you can modify the tilt throughout the seasons, increasing it to 43-45° during winter and lowering it to 37-40° during summer.
3. Panel Efficiency
Panel efficiency shows how much sunlight a panel can convert into usable electricity. Even the most efficient monocrystalline solar system can generate electricity only with 18-22% efficiency. Polycrystalline panels usually have a 12-17% conversion rate, and thin-firm panels may have even lower parameters, down to 8-14%.
If you have limited space, the solar photovoltaic system design should allow you to fit the panel where you want it to operate. Meanwhile, if you have a large backyard, you can mix different panel types.
4. Shading & Obstructions
If one panel doesn’t get sunlight, it also reduces the energy yield of the other non-shaded panels that are connected in series. So locate the system so your chimney, other buildings, or trees won’t cast a shadow on solar cells.
Temporary shading from clouds, snow, dirt, and debris also affects net energy yield. You can’t change the weather, but you can remove temporary obstacles and ensure proper maintenance of your panels.
You can improve energy yield by adding microinverters and power optimizers:
Microinverters are small inverters installed on each panel, so they work independently. If one panel is shaded or underperforms, it does not affect the rest of the system. Meanwhile, in traditional systems, one damaged panel compromises the whole system output.
Power optimizers are DC-DC converters installed on each panel. Instead of converting DC to AC like microinverters, they modify & optimize the voltage before sending it to a central inverter, improving overall system efficiency.
5. Temperature & Heat Losses
Another factor to consider is how your photovoltaic system reacts to temperature. Unlike most electronics, panels perform better in colder conditions, from 10°F to 70°F. As temperature increases above 80°F, panels may lose some efficiency. This loss is measured using the temperature coefficient—typically -0.3% to -0.5% per °C.
Thus, chill Chicago weather perfectly suits efficient photovoltaic systems’ design. Even during hot summer days, the temperature here rarely exceeds 70-75°F, so your panels work at their full potential.
6. System Components & Losses
Even with high-efficiency solar panels, system losses can occur due to inefficiencies in the inverter, wiring, and battery storage. Even the best inverters have a 95%-99% conversion rate, while string inverters (used for multiple panels) are usually less efficient than microinverters or power optimizers.
To achieve energy yield, remember that electricity traveling through long or thin wires leads to voltage drops and power loss of 1% to 3%, depending on wiring quality. To ensure maximum efficiency, use thicker, high-quality copper cables that minimize resistance.
If you design an off-grid photovoltaic system, remember that batteries don’t store 100% of generated electricity. In the best-case scenario with premium lithium-ion accumulators, you’ll see 90%-95% battery efficiency.
If you use old-style acid batteries, you may note that their average performance varies from 80% to 90%. So you may need to mount more panels to get the desired amount of energy.
7. Degradation Over Time
When developing your solar energy system, keep in mind that solar panels lose from 0.5% up to 1% of their efficiency yearly. In most cases, only 75-80% of the original capacity remains by the end of the guarantee.
If you find out that your system degrades faster during the annual energy yield assessment, book a meeting with your local solar installer. They’ll inspect the system, find what causes energy leakage, and fix it.
Looking for a cost-efficient solar system that can endure any weather conditions in Illinois? Get your free solar quote in minutes.
FAQ
What is a PV system?
It’s a solar system that uses the photovoltaic effect to convert the energy from the sun rays to electricity. It can be grid-tied (connected to the city grid), off-grid (independent of batteries), or hybrid (connected both to grid and batteries).
What is PV design?
A solar design is the process of planning and configuring a solar system, including selecting the right panels, inverters, wiring, and battery storage based on factors like available sunlight, location, panel efficiency, roof space, and energy needs.
What does energy-yielding mean?
Energy yielding refers to the amount of energy a system generates, such as a solar panel, wind turbine, or any energy-producing source. It indicates how much electricity a solar panel or other system generates.
Why does solar energy have a higher net energy yield than petroleum?
Solar platforms have a higher net energy yield than petroleum because they use renewable resources with no extraction costs. In contrast, petroleum requires energy-intensive extraction, transportation, and refining processes.
Why is minimizing voltage drop in a photovoltaic system design important?
Minimizing voltage drop in a photovoltaic (PV) system design is crucial because it ensures efficient energy transfer from panels to the appliances. A significant voltage drop can lead to energy losses, reduce system performance, and increase the risk of overheating or system damage.
