Seven Basic Measures to Increase Solar Power Generation

When you want to increase the power output of a solar power system, the first things that may come to mind are adding panels or replacing equipment. However, in reality there is rarely a single cause of poor output: shadows, dirt, orientation, tilt, temperature, wiring, equipment condition, and lack of maintenance often interact. Before blindly increasing equipment, it is important to identify where current generation is being lost and implement measures in order of their expected effectiveness. This article explains the seven basic measures to increase solar power generation for practitioners searching for "how to increase power output."

Table of Contents

• Accurately assess the current situation before increasing power generation

• Measure 1: Check shadow effects to reduce generation loss

• Measure 2: Inspect panel surface for dirt to maintain generation efficiency

• Measure 3: Review orientation and tilt angle to increase solar exposure

• Measure 4: Reduce output drop caused by temperature rise

• Measure 5: Check wiring and equipment condition to reduce losses

• Measure 6: Analyze generation data by month and by time of day

• Measure 7: Establish an operational structure that facilitates maintenance

• Decisions to avoid when increasing power generation

• Summary

Accurately assess the current situation before increasing power generation

The first thing to do to increase solar power generation is not to start countermeasures but to accurately understand the current situation. Even if you feel the output is low, you cannot choose the appropriate improvement measures unless you distinguish whether it is truly an abnormality, a natural fluctuation due to season or weather, or the result of equipment degradation or soiling.

Solar power generation is not a system that produces the same amount of electricity year-round. In spring and autumn, the balance of temperature and solar irradiance is favorable, so it can be relatively easy to generate power. In summer, although solar irradiance is high, rising panel temperatures can reduce output. In winter, with shorter daylight hours and lower sun angles, shadows tend to lengthen and generation tends to decline. In snowy regions, snow accumulating on panels can also cause periods when they cannot generate power.

Therefore, when evaluating power generation, it is important not to judge solely by a single month's output. Comparing with the same month of the previous year, with months under similar conditions, with weather and solar irradiance conditions, and checking generation per unit of installed capacity makes it easier to identify the causes of decreased generation. Rather than simply seeing it as "less than last month," confirm whether it is "lower than the expected value for the same season," "low even after accounting for weather," or "only falling during specific time periods."

Also, to increase power generation, you need to look not only at generation data but also at on-site conditions. Check whether the panels are shaded, whether dirt has accumulated, whether trees have grown, whether rooftop equipment has been added, and whether there are any abnormalities in equipment or wiring. Roof and land conditions change over time, so the conditions at installation may no longer apply.

When considering how to increase power generation, it is important to first identify the factors causing the decline in generation before proceeding with equipment replacement or expansion. With a clear understanding of the current situation, priority measures such as shading mitigation, cleaning, inspections, layout revisions, and enhanced maintenance will become apparent. Improvements in power generation should be pursued by combining data and on-site verification, rather than by intuition.

Measure 1: Check the impact of shadows and reduce generation losses

The first thing to check when trying to increase the output of a solar power system is the effect of shadows. If a panel is shaded, it cannot receive enough sunlight, and its power output drops. Although shadows are an obvious cause of reduced output, they change with the seasons and time of day, so they are also a factor that is easily overlooked.

Causes of shading include surrounding buildings, rooftop equipment, railings, penthouses, piping, air-conditioning equipment, utility poles, signage, trees, slopes, and differences in terrain elevation. Even in locations that had little shading at the time of installation, shading can increase after several years due to tree growth or changes in the surrounding environment. On roofs, equipment or piping added later can also become causes of shading.

Pay particular attention to shadows in winter. Because the sun’s elevation is lower in winter, the same obstacles cast much longer shadows. A site that appears fine when visited in summer may have shadows falling on the panels in winter. If energy production drops significantly only in winter, you should suspect not only shorter daylight hours but also the effects of shading.

As a shading countermeasure, first check the power generation data by time of day. If the output fails to rise only in the morning, consider shading from the east; if the output drops early in the evening, consider shading from the west; if there is an unnatural dip around noon, consider shadows from rooftop equipment or surrounding structures. If the decrease in generation is concentrated in specific time periods, it becomes easier to estimate the direction from which the shadows are coming.

During on-site inspections, we pay attention to the times of day and seasons when panels are shaded. If trees are the cause, consider pruning or management; if rooftop equipment is the cause, review the layout and installation area; and for land projects, if surrounding structures are the cause, consider adjusting the position and tilt of the rows of panels. However, reducing the number of panels to avoid shading can lower system capacity. In that case, decisions are made not only based on total generation but also on generation per unit of capacity and on self-consumption.

Reducing the impact of shading is very effective for increasing power generation. Before adding more equipment, it is important to first check whether any generation is being lost due to shading.

Measure 2: Inspect the panel surface for dirt to maintain power generation efficiency

As a basic measure to increase power output, checking the panel surface for dirt is also indispensable. Because solar panels generate electricity by receiving sunlight, when dirt adheres to the surface, light has difficulty reaching it and power output decreases. Dirt often accumulates gradually, so it can be hard to notice as the cause of reduced power output.

Sources of dirt include sand and dust, pollen, yellow sand, fallen leaves, bird droppings, exhaust-related grime, particulate matter, and residues left after snowfall. Areas with many trees nearby are more susceptible to soiling from fallen leaves and birds. Unpaved land, farmland, construction sites, and locations near busy roads tend to accumulate soil dust and particulates more easily. On rooftops, panels installed near exhaust outlets or ventilation equipment may be more prone to soiling.

The impact of soiling also depends on roof pitch and panel angle. With a sufficient slope, light dirt may be washed away by rain, but installations with a shallow angle can more easily retain dirt. Bird droppings, debris from fallen leaves, and dust that has adhered may not be sufficiently removed by rain alone. If power generation is gradually decreasing, or if only a particular surface is producing less power, check for an accumulation of dirt.

When considering cleaning, prioritize safety and the condition of the equipment. Work on roofs is hazardous, so avoid attempting tasks that are unsafe. Also, cleaning methods that could damage panel surfaces can be counterproductive. In practice, first inspect to determine the extent of soiling and, after assessing its relationship to any decrease in power generation, decide on the necessary cleaning and maintenance measures.

Dirt control measures are not a one-time task. Because the likelihood of dirt accumulation changes with the seasons, it is important to consider inspection timing according to local conditions—such as spring pollen and dust, autumn fallen leaves, and dirt after snowfall. Maintaining stable power generation requires operational practices that keep panel surfaces in good condition.

Measure 3: Review orientation and tilt angle to make it easier to receive solar radiation

To increase the power output of solar power generation, it is necessary to check how efficiently the panels can receive solar radiation. Orientation and tilt angle are important for that. For already installed equipment, large changes may not be possible, but when expanding, rearranging, or redesigning flat-roof or land projects, considering orientation and tilt angle can lead to improved power generation.

Orientation has a major impact on the times of day when power is generated. Surfaces facing closer to south tend to achieve higher annual generation, but east- or west-facing surfaces are not necessarily at a disadvantage. East-facing surfaces tend to generate more in the morning, while west-facing surfaces tend to generate more in the afternoon. If a facility’s power demand is biased toward the morning or afternoon, generation from east- and west-facing surfaces can help with self-consumption.

The tilt angle affects how solar radiation is received in each season. Changing the angle alters configurations that favor strong summer performance, those that make generation easier in winter, and those that provide a better annual balance. However, increasing the tilt angle does not necessarily increase energy output. A larger angle lengthens inter-row shading, which may require widening the installation spacing. As a result, the number of panels that can be installed may decrease, and the overall generation of the system may not increase.

For rooftop projects, installations are often made to match the existing roof pitch, so the tilt angle cannot always be freely changed. In such cases, it is important to organize the orientation and tilt of each roof surface and prioritize the surfaces with better conditions. When there are multiple roof surfaces, rather than forcing the use of surfaces with lower power output, strengthening maintenance and soiling countermeasures on the better surfaces can lead to improved power generation.

For flat-roof and ground-mounted projects, you can compare racking tilt angles and row spacing. Use simulations to compare multiple angles and evaluate them together based on annual energy production, monthly generation, installed capacity, inter-row shading, and maintainability. Reviewing orientation and tilt is effective not only for improving generation but also for aligning generation timing with facility demand.

When reviewing orientation and tilt angle, it is important to choose conditions that can be constructed on-site and managed over the long term, rather than those that maximize theoretical power output.

Measure 4: Reduce output loss due to temperature rise

Solar power generation generally increases with solar irradiance, but panel output can decrease when panel temperature rises. This temperature-related loss is a factor that is easily overlooked when trying to boost generation. In particular, during summer or with roof-mounted installations, generation may not increase as much as expected despite high solar irradiance.

When considering temperature losses, check the heat-dissipation conditions around the panels. If the roof surface tends to become hot or the rear side of the panels has poor ventilation, panel temperatures are more likely to rise. Heat can also become trapped when low racking is used on a flat roof or when surrounding equipment restricts airflow.

Ground-mounted installations can sometimes dissipate heat more readily than rooftop installations, but care is needed when conditions such as overgrown grass that impedes airflow, surrounding structures that cause air to stagnate, or strong reflection from the ground are present. Because temperature losses vary with the installation environment, it is important not to judge based solely on general loss rates.

For temperature management, consider arranging panels so as not to obstruct airflow behind them, using mounting conditions that prevent heat buildup, ensuring heat dissipation around equipment, and managing vegetation. However, changing rack height or tilt angle to improve ventilation can affect wind loads, constructability, and installed capacity. Therefore, rather than addressing temperature losses in isolation, decisions should be made by comprehensively considering power generation, constructability, maintainability, and safety.

In power generation data, when summer solar irradiance is high but output doesn’t increase, suspect the influence of temperature-related losses. Looking at monthly generation, spring and autumn may appear to produce more stable output. To raise generation, it is important not to be overly optimistic about summer output but to consider improvements based on a realistic estimate of temperature losses.

The reduction in output caused by rising temperatures is a generation loss that is not easily visible, but it affects annual power generation. In facilities that especially prioritize summer generation for self-consumption, measures to address temperature-related losses lead to improved generation.

Measure 5: Check the condition of wiring and equipment to reduce losses

To increase power generation, you need to check not only the panels themselves but also the condition of the wiring and equipment. The electricity generated by the solar panels is used within the facility through wiring and power conversion equipment. If there are losses or malfunctions in this process, the amount of electricity actually available for use may be reduced even if the panels are generating power.

Wiring losses depend on the wiring distance, wiring route, and condition of the connections. If equipment locations or wiring routes have been changed from the initial design, the actual losses may differ from those that were assumed. If the wiring is too long, follows a complex path, or runs through locations that are difficult to inspect, it will be harder to identify the cause when power output decreases.

The condition of the power conversion equipment is also important. If the equipment is not operating properly, even if the panels are generating power, the facility cannot make full use of it. If generation suddenly drops or if only a particular system has low output, it is necessary to check the equipment and connection points for abnormalities. Being able to check generation data by installation surface and by system makes it easier to narrow down the cause.

The balance between equipment capacity and panel capacity also affects power generation. Even if you increase panel capacity, output may be capped by the equipment-side capacity or connection conditions. A capped output is not necessarily bad in itself, but it is important to check during which time periods and to what extent generation losses are occurring.

Also check the environment of the equipment installation site. Locations that tend to become hot, that are easily affected by rain or snow, that have poor ventilation, or that are difficult to inspect carry higher risks for long-term operation. Ensuring easy access to the equipment and space for inspection and replacement is important for maintaining power generation.

When it comes to measures to increase power output, attention tends to focus on improvements on the panel side, but the route that delivers electricity to the facility is just as important. Regularly inspecting wiring, connection points, and equipment condition, and detecting abnormalities early, makes it easier to prevent drops in power generation.

Measure 6: Analyze power generation data by month and time of day

To increase power generation, it is important not only to inspect the site but also to correctly analyze the generation data. Looking only at the total annual generation does not tell you where generation is being lost. By checking generation by month, by time of day, and by installation surface, you can identify points that need improvement.

When you look at monthly power generation, you can see seasonal changes in output. If generation drops sharply only in winter, check not only the shorter daylight hours but also the effects of shading and snowfall. If generation does not increase as much as expected in summer, check for temperature-related losses, soiling, and the condition of the equipment. If a decline is observed in spring or autumn, consider pollen, dust, fallen leaves, and the effects of birds.

Viewing power generation by time of day makes it easier to detect shadows and equipment anomalies. If generation in the morning is weak, it may be shading on the east side; if it drops early in the evening, it may be shading on the west side; if there is an unnatural dip around midday, shadows from rooftop equipment or equipment problems may be the cause. Time-of-day variations are important clues that cannot be seen from annual generation alone.

If you can check power output by mounting surface or by circuit, you can further narrow down the cause. If only a specific roof surface has low output, check that surface for shading, dirt, orientation, tilt, and wiring. If only a specific circuit has low output, check the condition of the equipment, connection points, and wiring. If overall output is low, check the weather, solar irradiance, temperature, common equipment, and output conditions.

In analysis of power generation data, comparing it with simulated values is effective. If you keep baseline monthly generation figures and hourly generation curves from before installation, it becomes easier to spot deviations from actual performance. When differences are found, you can check in order whether they are due to weather effects, changes in site conditions, or equipment issues.

To increase power generation, it is important to identify causes from data rather than relying on intuition. By analyzing results by month and by time of day, it becomes easier to judge which measures—cleaning, shading countermeasures, equipment inspection, or layout revision—should be prioritized.

Measure 7: Establish an operational system that is easy to maintain

The final basic measure is to establish an operational system that is easy to maintain. Solar power generation systems are equipment intended for long-term use, and simply installing them does not mean they will consistently maintain the same power output. It is important not only to increase power generation, but also to create a system that can detect declines early and respond to their causes.

A maintenance-friendly operational system includes securing inspection routes, layouts that are easy to clean, designs that allow access to equipment, verification of power generation data, and rules for responding to abnormalities. For rooftop projects, it is important to ensure access to drains, inspection hatches, and rooftop equipment. For land projects, management pathways, weed control, drainage, and working space around equipment are required.

If you cram too many panels together to maximize power generation, inspections and cleaning can become difficult after installation. Even if output appears high in the short term, if you cannot address soiling or malfunctions, generation may decline over the long term. To maintain generation over time, it is important to leave sufficient clearance for maintenance.

Also, after installation, regularly check the actual power generation. Record monthly generation, generation by time of day, self-consumption, and surplus electricity, and compare them with the expected values. If generation falls, being able to check, in order, the weather, shading, dirt/soiling, snow accumulation, equipment shutdowns, wiring faults, and changes in demand will speed up the response.

Maintenance planning is not something to consider after power output has declined. It is important to decide during the pre-installation design stage what to inspect, which access routes to use, and which data to verify. Even for existing installations, reviewing current inspection routes and data verification methods can lead to improvements in power generation.

As a way to increase power generation, establishing a maintenance system may seem unremarkable. However, in the long term, quickly identifying the factors that reduce power generation and responding appropriately is one of the most reliable improvement measures. To increase power generation, it is essential not only to add more equipment but also to put systems in place that protect power generation.

Decisions to Avoid When Trying to Increase Power Output

What you should avoid when trying to increase power output is considering adding equipment or making major changes without checking the cause. If low output is due to shading, dirt, or equipment stoppage, on-site inspection and maintenance may be more effective than adding panels. First, it is important to confirm where the power is being lost.

Also, you should avoid judging the effectiveness of improvements based solely on annual power generation. Even if annual generation increases, if the increase simply becomes surplus, the benefit to self-consumption is limited. Improvements in generation and improvements in the effectiveness of the installation are not the same. It is necessary to check self-consumption, surplus electricity, and the time periods of generation together.

Be careful about adding panels into shaded areas. Increasing installed capacity may increase total generation, but in locations with significant shading the generation per unit of capacity can be lower. Even if avoiding shade reduces capacity, it can improve generation efficiency and the stability of actual output.

Changes to the layout that sacrifice maintainability should also be avoided. Even if you increase power generation by cutting inspection walkways and cleaning space, if it becomes harder to deal with soiling or malfunctions after installation, long-term power generation may decline. Measures to increase power generation should be premised on being maintainable over the long term.

Furthermore, it is important not to be satisfied with improvements only in simulations. Even if calculations indicate increased power generation, it is meaningless unless you confirm that those conditions can be realized on site. Verify orientation, tilt, shading, constructability, wiring, maintenance access, and connection conditions in the field, and assess whether the proposed improvements can actually be implemented in operation.

To increase power generation, it's important not to focus on producing good-looking numbers, but to eliminate the causes of reduced generation one by one. Improvement measures should be chosen based on data and on-site verification.

Summary

To increase solar power generation output, it is necessary not only to increase the number of panels but also to comprehensively review shading, soiling, orientation, tilt, temperature-related losses, wiring, equipment condition, and maintenance practices. The causes of low generation output are not necessarily singular and multiple factors may overlap. Therefore, it is important to first check the current generation data and on-site conditions, then prioritize and implement countermeasures.

Measure 1 checks the impact of shading. Shadows from surrounding buildings, rooftop equipment, trees, utility poles, and variations in terrain elevation can significantly reduce power generation. Measure 2 inspects the cleanliness of the panel surfaces. Sand and dust, pollen, fallen leaves, bird droppings, and particulate matter can reduce generation efficiency. Measure 3 reviews the orientation and tilt angle. Confirm not only the power output but also the compatibility with the facility’s demand time periods.

Measure 4 reduces output decline caused by temperature increases. In summer and for rooftop installations, heat dissipation and airflow affect power generation. Measure 5 checks the condition of wiring and equipment. If there are losses or faults in the process from generated power to its use in the facility, the amount of usable electricity decreases. Measure 6 analyzes generation data by month and by time of day. By checking which season, which time of day, and which installation surface show reduced generation, the areas that need improvement become clear. Measure 7 establishes an operational system that facilitates maintenance. With layouts and management standards that allow inspection and cleaning, it becomes easier to detect declines in power generation at an early stage.

When trying to increase power generation, things to avoid are considering adding equipment without confirming the causes, judging improvement effectiveness solely by annual generation, and cramming layouts at the expense of maintainability. Improving power generation is not about inflating simulation numbers but about recovering the generation actually lost on site.

Accurate on-site information is the foundation for increasing power generation. If the candidate installation area, rooftop equipment, obstacles, trees, site boundaries, orientation, tilt, inspection routes, and candidate connection points can be accurately identified, it becomes easier to address issues related to shading, soiling, wiring, and maintainability.

If you want to accurately record on-site installation extents, obstacles, trees, rooftop equipment, site boundaries, orientation, tilt, and inspection routes, and clarify improvement points to increase power generation, leveraging LRTK — an iPhone-mounted GNSS high-precision positioning device — is effective. With highly accurate on-site positional data, it's easier to sort out causes of shading, areas prone to soiling, feasible installation areas, wiring routes, and maintenance routes, enabling a smooth, integrated workflow from on-site verification and simulation comparison to post-installation performance management aimed at improving power generation. To truly increase solar power output, it's important not only to rely on desk-based measures but also to accurately grasp the site and appropriately address the causes that are reducing generation.