Benefits of Tilt and Shading Analysis Learned at PV EXPO: Supporting Investment Decisions and Maximizing Power Generation Efficiency

In recent years, exhibitions like the PV EXPO have spotlighted “tilt analysis” and “shading analysis” as new technologies in the solar power industry. While solar power is expected to become a main power source in a decarbonized society, the environment surrounding the industry is changing significantly. Against a backdrop of the reduction of the Feed-in Tariff (FIT), declining purchase prices, and an increasing need to install panels on rooftops and small spaces, there is a greater demand than before for precise estimates of power generation and maximizing efficiency. For this reason, technologies that analyze tilt and shading in detail have come to play an important role in both supporting investment decisions and optimizing actual power generation.

This article explains the significance of tilt and shading analysis—topics that drew attention at the PV EXPO—with contractors and small-to-medium installers of rooftop solar in mind. We will carefully unpack why these analyses are useful for investment decisions and how they can maximize power generation efficiency, along with the latest industry trends and background. Using the recently introduced smart construction support system LRTK as an example, we will also introduce how to utilize the latest technologies such as tilt and shading measurement, point cloud scanning, and AR navigation for panel placement guidance, and touch on the advantages of using these technologies in construction proposals.

Industry background: FIT reduction and growing demand for rooftop installations

First, let’s organize the industry background. In Japan, the FIT (Feed-in Tariff) started in 2012, and because it initially guaranteed a high purchase price—around the 40 yen per kWh level—with a 20-year purchase guarantee, investment in solar power exploded. However, subsequent annual revisions to purchase prices gradually lowered unit prices, and by the mid-2020s residential rates have fallen to around 15 yen per kWh and commercial rates to about 10 yen per kWh【EV DAYS explanation】(https://evdays.tepco.co.jp/entry/2022/01/06/000027). FIT durations have also been shortened, with small-scale systems sometimes limited to a 10-year guarantee, so stable revenues based on selling electricity can no longer be expected to the same extent as before. Therefore, to ensure the profitability of solar power projects, it has become important to reduce generation costs, utilize self-consumption, and operate to maximize actual generated energy.

Furthermore, while large-scale mega-solar development has stalled due to local opposition and lack of suitable sites, the use of idle rooftop space on buildings has been strongly promoted in recent years. The government has also signaled urgency and announced a policy to require certain large-scale factories and stores to set rooftop solar installation targets from fiscal 2026【SOLAR JOURNAL column】(https://solarjournal.jp/information/61844/). This policy aims to expand renewable energy by placing solar panels on rooftop spaces that have not been fully utilized. In fact, in Germany around 70% of installed solar capacity is rooftop-mounted on houses and industrial facilities, whereas in Japan it remains at about 40%, suggesting there is still significant potential for rooftop installations【SOLAR JOURNAL column】(https://solarjournal.jp/information/61844/). From these trends, demand for installing solar panels on residential and small building roofs, as well as narrow idle plots and over parking lots, among other limited spaces, is expected to grow.

However, securing maximum generation from limited roof area requires more precise design and simulation than ever. Unlike large ground-mounted systems, rooftop installations are relatively more affected by differences in slope angle and shading from surrounding obstacles. This is where tilt analysis and shading analysis become important. From the next section we will look at exactly what these analyses mean and how they help.

What is tilt analysis: How roof angle and orientation determine generation potential

Tilt analysis examines the slope (pitch) and orientation (azimuth) of the surface where panels will be installed, evaluating whether conditions are suitable for power generation. Solar panels generate most efficiently when they receive sunlight at angles close to perpendicular to the incoming rays. Therefore, the tilt angle of the mounting surface and its north–south orientation are key factors that determine generation potential.

Generally, around Honshu in Japan, a tilt angle of about 30 degrees tends to maximize annual generation, and panels ideally face due south. However, actual rooftop installations are constrained by roof shape, so tilt angle and orientation are not always ideal. For example, a low-slope flat roof may have panels close to 0 degrees (horizontal), resulting in somewhat reduced annual generation due to insufficient elevation angle. Conversely, a steep mono-pitched roof may exceed 30 degrees and be advantageous in winter but could reduce generation in summer. If a roof faces east–west, panels are installed on two faces (east and west), generating in the morning and evening respectively, but peak output will be lower than a due-south installation. North-facing roofs receive significantly less solar irradiation in Japan and are generally judged unsuitable for solar installations.

Tilt analysis measures and computes the roof’s pitch angle and azimuth accurately to evaluate how suitable the roof is for power generation. Specifically, the roof angle can be measured with a protractor or inclinometer on-site, or calculated from building drawings. Orientation is checked with a compass or positioning tools to determine the deviation from true south. Using solar curve theory and historical weather data, the expected annual generation estimate under those conditions is calculated.

Whether the tilt angle is appropriate affects not only generation efficiency but also installation methods and construction costs. For example, on a flat roof, using mounts to angle panels can increase generation, but that raises costs and structural load. Conversely, on very steep roofs panels are more exposed to wind and require careful consideration of the strength of mounting hardware and construction methods. By conducting tilt analysis beforehand and considering the optimal installation plan for that roof (e.g., distribution between east/west faces, adjusting mount angles, mounting methods), a design that balances efficiency and safety becomes possible.

In short, tilt analysis is the process of assessing how much power that roof can generate and identifying design challenges and possible measures. With appropriate analysis, you can prevent post-installation dissatisfaction or problems such as “it generates less than expected” or “maintenance is difficult because of the angle.”

What is shading analysis: Reading shadow impacts to minimize generation loss

By contrast, shading analysis identifies the sources of shadows that fall on panels and analyzes their impact. Solar panels experience significant output drops even when partially shaded. In extreme cases, a small shadow blocking part of a panel cell can limit the current of the entire series circuit, causing generation loss or hot spots. On rooftops, surrounding buildings, chimneys, trees, utility poles, and other objects may cast shadows, and shadow positions change with time of day and season. Shading analysis is essential to identify these shadow sources and the extent and timing of shadow coverage, and to evaluate their effect on annual generation.

Typical shading analysis methods rest on two pillars: on-site surveys and simulation. On-site surveys observe the surroundings visible from the planned panel location and estimate shadows by referencing the sun’s path. A traditional method is to map surrounding obstructions on a sun path chart (all-sky diagram) to calculate annual sunlight hours. Dedicated shadow measuring instruments or fisheye-lens all-sky photos analyzed with tools are also used. Based on such surveys, you can obtain information like “at noon on the winter solstice the neighbor’s shadow partially covers the roof” or “from 3 p.m. onward the building to the west casts a shadow.”

Recently, 3D simulation on computers has become popular. By modeling the building and surroundings in 3D and reproducing the sun’s movement in software, you can simulate time-specific shadows. Originally used in architectural design, these methods are now applied to solar power planning. This enables quantitative calculation of the annual shading loss rate. For example, a roof with an expected annual generation of 5,000 kWh might suffer a 5% loss due to shading, reducing actual generation to 4,750 kWh.

The significance of shading analysis lies in understanding shadow impacts in advance and taking countermeasures. If analysis shows large shading impacts, several options are possible, for example:

• Layout optimization: Avoid roof areas prone to shading and place panels in well-sunlit areas. If some areas will inevitably be shaded, reduce the number of panels there and concentrate on areas that reliably receive sunlight.

• Equipment selection: Use systems resistant to partial shading such as microinverters or power optimizers. With traditional string-connected systems plus a centralized inverter, a small shaded area can drag down the whole string; per-panel control localizes losses to the shaded modules.

• Environmental measures: Reduce shading sources. For trees on the site, consider pruning or removal; for adjacent structures, negotiate to implement shading mitigation where realistic. If rooftop antennas or chimneys can be relocated, moving the source of shadows is also effective.

• Time-specific generation planning: If shading is inevitable during morning and evening, accept reduced generation at those times and design for peak generation around midday (for example, use batteries to store midday surplus to supply evenings), thereby indirectly mitigating shadow impacts.

By optimizing installation plans and equipment selection based on shading analysis results, shading losses can be minimized as much as possible. Even in small or difficult sites, understanding shadow movement in advance prevents critical failures such as “after installation, it barely generated in the afternoon.”

The role of analysis in investment decisions

Tilt and shading analyses can each quantify potential generation and risk factors, making them extremely useful tools for solar investment decisions.

When introducing rooftop solar, contractors and installers present expected generation and financial plans to owners (clients). How many years it will take to recoup the investment, how much electricity cost will be saved, and how much income from sold electricity will be earned—these are major decision factors for clients. You cannot provide estimates without addressing uncertainties, and if clients later feel “this is not what we were told,” it becomes a credibility issue. This is where detailed simulations based on tilt and shading analyses are powerful.

For example, consider installing a 10 kW system on a store roof. A simple estimate might say “about 10,000 kWh per year,” but due to roof orientation, angle, and surrounding shadows actual generation might be 20% lower—about 8,000 kWh. With tilt and shading analyses you can present evidence-based figures such as “under these conditions, we expect about 8,000 kWh per year, totaling X kWh over 10 years.” If you provide a simulation report with monthly generation graphs and shading impact breakdowns (e.g., what percentage loss occurs in which months), customers will gain strong confidence. Clarifying risks and returns supports decision-making on whether to proceed.

Detailed analysis data also increases credibility when obtaining financing from banks or leasing companies. Especially for commercial (high-voltage) projects, evidence for generation estimates is often required; predictions that consider tilt and shading make project reviews easier to pass. Conversely, failing to analyze and giving optimistic estimates can lead to underperformance and cash-flow problems. High-accuracy pre-analysis stabilizes business plans and enhances the contractor’s credibility.

In short, tilt and shading analyses allow you to logically present scenarios of “if we install solar here, this much generation and this much revenue (or electricity cost savings) will result.” For customers, this provides reassurance and persuasive power that helps them decide to invest. For installers, data-driven proposals reduce the risk of taking on unsuitable projects based on gut feeling.

Using analysis to maximize generation efficiency

The benefits of tilt and shading analyses extend beyond investment decisions into construction and operation: their results directly contribute to maximizing generation efficiency. By feeding analytical insights back into design and construction, you can literally implement measures that maximize output.

If tilt analysis shows a roof angle deviates from the ideal, construction methods can compensate. For example, on a flat roof, consider using specialized mounts to give panels the appropriate tilt. Of course, increasing mount angle too much can cause interference between panels or increase wind loads, so you should reconcile the analysis-derived “optimal angle” with actual construction constraints to choose a safe and efficient compromise angle. On very steep roofs, panels are typically mounted parallel to the roof surface; however, if analysis shows a significant azimuth deviation, you might prioritize generation and choose to install only on south-facing roofs. For houses with roofs in multiple directions, analysis allows strategic choices such as whether to include east and west faces to increase total yield or avoid a west face with heavy shading.

Shading analysis yields highly practical guidance. Knowing the time and extent of shading lets you adjust the layout plan: “let’s omit this row,” or “leave a small gap here.” For example, if a lightning rod or vent casts a shadow in the afternoon, omit panels in that immediate area and densely pack panels elsewhere. Even if annual losses are only a few percent, concentrating those losses on specific panels localizes damage. Optimizing layout according to observed shading patterns helps ensure maximum total generation while minimizing the negative effects of shade.

Analysis also informs equipment choices. If shading analysis shows “the west half is shaded after 4 p.m. in winter,” you can separate that portion into its own circuit by splitting strings. That way, only the shaded string loses output while other strings operate normally. Incorporating microinverters or power optimizers as mentioned earlier is another way to preempt shading issues. In short, design the system to be resilient to shading based on analysis outcomes.

By applying tilt and shading analysis in construction planning, you achieve detailed, waste-minimizing designs that maximize generation. To squeeze out every extra kWh from limited roof area, it’s crucial to fully incorporate insights from these analyses.

Advanced technologies supporting tilt and shading analysis (point cloud scanning and AR)

Conducting advanced tilt and shading analyses requires detailed on-site measurement data. Traditionally, collecting this data was time-consuming and labor-intensive. For example, measuring roof tilt used ladders and protractors or laser levels, and assessing surrounding shadows meant visiting the site multiple times at different dates and times. For small and medium installers, hiring survey specialists or acquiring expensive equipment posed high barriers, and accurate data could be hard to obtain depending on site conditions.

However, in recent years advanced technological tools have transformed this situation. A representative example is the smartphone-linked simple surveying system “LRTK.” LRTK combines a high-precision GNSS (RTK) receiver with the smartphone’s built-in LiDAR (light detection and ranging sensor) to enable anyone to perform centimeter-accuracy 3D surveys easily. By walking around a roof or building with a smartphone in hand, you can capture high-precision point cloud data—a collection of countless 3D coordinate points—almost like recording video.

Point cloud data is a digital as-built model obtained by 3D scanning terrain and structures【Related blog: 3D with point cloud scanning】(https://www.lrtk.lefixea.com/blog-js/taiyoukou-sekou3). For example, scanning a house roof with a point cloud provides measurements of roof dimensions, tilt, and height, and reproduces the positions of rooftop obstacles and surrounding buildings and trees to scale in 3D. Because LRTK’s RTK-GNSS tags every point with absolute coordinates (latitude, longitude, elevation), aligning measured point clouds with each other or with design drawings is straightforward. What previously required specialized surveying instruments or drone photogrammetry can be completed with LRTK by one person in a matter of minutes.

This point cloud data is extremely useful for tilt and shading analysis. First, automatic calculation of tilt angles becomes possible. By fitting planes to roof point clouds, software can immediately compute tilt and azimuth angles. This is more accurate than manual measurement and works for complex mono-pitched or curved roofs. Also, roof area and dimensions can be measured automatically from point clouds, enabling data-driven determinations of “how many panels fit” and “how to lay them out.”

Point clouds are particularly powerful for shading analysis. Instead of inferring the surrounding environment from drawings or photos, the point cloud retains the environment as a 3D model. For example, you can measure the neighbor’s height and distance or the extent of tree branches directly on the point cloud. Importing these into solar simulation software allows solar radiation simulation (calculating shadows from the point cloud), so you can perform shading analysis while reproducing the actual site in a computer. Even without full simulation, viewing the point cloud makes it intuitive to see “the winter solstice morning sun is blocked by that building” or “this antenna’s shadow equals X panels.” In short, digitizing the site enables detailed office-based analysis.

LRTK also includes many convenient features for using acquired point clouds and design data. For instance, you can view and share point clouds in the cloud, measure distances and areas, and overlay CAD drawings for comparison. Notably, it offers AR (augmented reality) features: when you view the site through the smartphone screen, a 3D model can be overlaid precisely and without drift【From LRTK feature introduction】. Because RTK provides high-precision position and orientation, you can prepare a 3D model of panel layout and see it appear on the roof as if drawn there. AR-based panel placement simulation and marking make customer explanations and installation verification easy.

Competitive advantages for contractors adopting LRTK

By adopting advanced tools like LRTK, contractors can gain significant advantages across survey, design, and construction. Below are the main benefits.

• Streamlined site surveys: Roof measurements and angle surveys that previously took hours can be completed quickly with LRTK. Because one person can scan the roof shape and surroundings, labor costs and scaffolding arrangements are minimized, allowing rapid collection of detailed data even on busy sites.

• Improved proposal accuracy: Tilt and shading analysis results derived from point cloud data can be reflected directly into proposals. Presenting precise generation simulations and visualized shading materials enables persuasive proposals to customers. Showing evidence-based figures differentiates you from competitors and builds trust.

• Optimized construction plans: Because you can simulate panel layout and mount placement on the acquired 3D model, design mistakes and rework after installation are minimized. Confirming the completed image on-site in AR allows you to detect and correct issues before construction, such as “it will interfere with piping and cannot be installed.”

• Improved construction quality and safety: LRTK’s coordinate navigation/AR navigation functions guide precise panel and hardware placement on site. Even non-surveying professionals can follow smartphone guidance to mark positions with sub-centimeter accuracy, preventing crooked panel rows or incorrect spacing. This standardizes construction quality and reduces the risk of additional work or repairs.

• Enhanced customer service: Point clouds and AR are effective customer briefing tools. Showing an AR view of the expected completion lets customers intuitively grasp the post-installation image and feel reassured. Storing point cloud data also enables comparisons with the original state during after-sales maintenance. Providing such digital data improves customer satisfaction.

As shown above, adopting LRTK creates a virtuous cycle: shorter surveys → stronger proposals → higher construction efficiency & quality → better customer satisfaction. While others still rely mainly on manual methods, adopting digital technologies early provides a competitive edge.

Conclusion: Make tilt and shading analysis your ally with the latest technologies

The solar industry has entered a phase where, amid FIT reductions and changing market conditions, meticulous planning and technical capability are required more than ever. Particularly as rooftop and small-space installations increase, tilt and shading analysis have become indispensable steps to support investment decisions and maximize actual generation. As seen at exhibitions like PV EXPO, the industry is beginning to recognize the importance of digital analysis and simulation.

What matters most is putting analysis into practice. Using the latest tools like LRTK makes precise on-site analysis accessible to any field team. By visualizing tilt angles and shading impacts with data and feeding those insights back into design and construction, you can maximize the generation obtainable from limited roofs. Leveraging advanced analysis also dramatically improves a contractor’s proposal capability and credibility.

Shifting to solar generation that produces sufficient benefits without relying solely on FIT—the key lies in meticulous planning through tilt and shading analysis and adoption of advanced technologies. We encourage you to actively utilize the latest analysis technologies and digital tools like LRTK to differentiate your services and propose optimal solar plans for your customers. By staying ahead of industry trends and achieving both high generation efficiency and customer satisfaction, you can build solid competitiveness in the future solar business.