Louisville, Illinois, located in the Northern Temperate Zone, presents a moderately favorable location for year-round solar energy generation, though with significant seasonal variations that potential solar installers should carefully consider.

Seasonal Solar Performance

The solar energy output at this location shows dramatic seasonal swings. Summer delivers the strongest performance at 6.53 kWh per day per installed kilowatt, making it an excellent time for solar generation. Spring also provides robust output at 5.46 kWh per day per kilowatt, representing the second-best season for solar production. However, the colder months present challenges. Autumn drops to 3.89 kWh per day per kilowatt, while winter plummets to just 2.40 kWh per day per kilowatt. This winter figure represents less than 37% of summer production, highlighting the location's seasonal dependency.

Optimal Installation Configuration

For fixed panel installations at Louisville, Illinois, the ideal tilt angle is 34 degrees facing south to maximize total year-round production. This angle is calculated by analyzing daily solar elevation angles throughout the year and weighting them by solar irradiance data to find the optimal compromise for annual energy generation.

Local Factors Affecting Solar Production

Several environmental and weather factors in this Illinois location can significantly impact solar energy production:

• Snow accumulation: Winter weather can deposit snow on panels, blocking sunlight and reducing output during already low-production months
• Ice formation: Freezing conditions may create ice buildup that persists longer than snow
• Midwest storm systems: The region experiences thunderstorms, hail, and severe weather that can damage panels or reduce production
• High humidity and fog: Moisture in the air can scatter sunlight and reduce panel efficiency
• Agricultural dust and pollen: Rural Illinois locations may experience dust from farming operations and seasonal pollen that accumulates on panels

Preventative Installation Measures

Several strategies can help maximize solar production despite these local challenges:

• Steeper tilt angles: While 34 degrees is optimal for year-round production, slightly steeper angles can help snow slide off more easily
• Quality mounting systems: Robust mounting designed for wind and hail resistance protects against severe weather damage
• Regular cleaning schedules: Planned maintenance to remove dust, pollen, and debris, especially during high-pollen seasons
• Accessible panel placement: Installing panels where snow can be safely removed when necessary
• Bypass diodes and optimizers: These technologies minimize production losses when portions of panels are shaded or blocked

The location offers reasonable solar potential, particularly during spring and summer months, but requires thoughtful installation planning to address seasonal weather challenges and maintain optimal year-round performance.

Note: The Northern Temperate Zone extends from 35° latitude North up to 66.5° latitude.

So far, we have conducted calculations to evaluate the solar photovoltaic (PV) potential in 4253 locations across the United States. This analysis provides insights into each city/location's potential for harnessing solar energy through PV installations.

Link: Solar PV potential in the United States by location

Solar output per kW of installed solar PV by season in Louisville, Illinois

Seasonal solar PV output for Latitude: 38.7718, Longitude: -88.5141 (Louisville, Illinois, United States), based on our analysis of 8760 hourly intervals of solar and meteorological data (one whole year) retrieved for that set of coordinates/location from NASA POWER (The Prediction of Worldwide Energy Resources) API:

 

Ideally tilt fixed solar panels 34° South in Louisville, Illinois, United States

To maximize your solar PV system's energy output in Louisville, Illinois, United States (Lat/Long 38.7718, -88.5141) throughout the year, you should tilt your panels at an angle of 34° South for fixed panel installations.

As the Earth revolves around the Sun each year, the maximum angle of elevation of the Sun varies by +/- 23.45 degrees from its equinox elevation angle for a particular latitude. Finding the exact optimal angle to maximise solar PV production throughout the year can be challenging, but with careful consideration of historical solar energy and meteorological data for a certain location, it can be done precisely.

We use our own calculation, which incorporates NASA solar and meteorological data for the exact Lat/Long coordinates, to determine the ideal tilt angle of a solar panel that will yield maximum annual solar output. We calculate the optimal angle for each day of the year, taking into account its contribution to the yearly total PV potential at that specific location.

Seasonally adjusted solar panel tilt angles for Louisville, Illinois, United States

If you can adjust the tilt angle of your solar PV panels, please refer to the seasonal tilt angles below for optimal solar energy production in Louisville, Illinois, United States. As mentioned earlier, for fixed-panel solar PV installations, it is optimal to maintain a 34° South tilt angle throughout the year.

Overall Best Summer Angle	Overall Best Autumn Angle	Overall Best Winter Angle	Overall Best Spring Angle
23° South in Summer	43° South in Autumn	53° South in Winter	32° South in Spring

Our recommendations take into account more than just latitude and Earth's position in its elliptical orbit around the Sun. We also incorporate historical solar and meteorological data from NASA's Prediction of Worldwide Energy Resources (POWER) API to assign a weight to each ideal angle for each day based on its historical contribution to overall solar PV potential during a specific season.

This approach allows us to provide much more accurate recommendations than relying solely on latitude, as it considers unique weather conditions in different locations sharing the same latitude worldwide.

Calculate solar panel row spacing in Louisville, Illinois, United States

We've added a feature to calculate minimum solar panel row spacing by location. Enter your panel size and orientation below to get the minimum spacing in Louisville, Illinois, United States.

Our calculation method

1. Solar Position:
   We determine the Sun's position on the Winter solstice using the location's latitude and solar declination.
2. Shadow Projection:
   We calculate the shadow length cast by panels using trigonometry, considering panel tilt and the Sun's elevation angle.
3. Minimum Spacing:
   We add the shadow length to the horizontal space occupied by tilted panels.

This approach ensures maximum space efficiency while avoiding shading during critical times, as the Winter solstice represents the worst-case scenario for shadow length.

Topography for solar PV around Louisville, Illinois, United States

Topographical Features of the Louisville Region

The area surrounding Louisville in southern Illinois sits within the relatively flat agricultural landscape of the Ohio River valley. This region is characterized by gently rolling terrain with minimal elevation changes, making it part of the broader Mississippi River drainage basin. The topography consists primarily of prairie and farmland that has been shaped by centuries of river activity and glacial processes.

The terrain around Louisville features subtle undulations rather than dramatic hills or valleys. Most of the surrounding countryside maintains elevations that vary gradually across the landscape, with occasional low ridges and shallow depressions that were formed by ancient waterways and ice age activity. The area lacks significant topographical barriers such as mountains, steep hills, or deep valleys that might create shadows or complicate large-scale development projects.

Drainage and Water Features

The region's drainage patterns are dominated by small creeks and tributaries that eventually flow toward the Ohio River system. These waterways have carved gentle channels through the landscape over time, creating a network of shallow valleys and modest ridgelines. The overall drainage creates a slightly varied terrain that still remains highly suitable for development while providing natural water management.

Seasonal water features and wetland areas are scattered throughout the region, though they tend to be relatively small and well-defined. These areas represent natural low points in the landscape where water collects during wet periods, and they are typically surrounded by slightly elevated ground that offers excellent development potential.

Optimal Areas for Large-Scale Solar Development

The most suitable locations for extensive solar installations would be the broad, gently sloping agricultural fields that dominate the landscape south and west of Louisville. These areas offer large contiguous parcels of relatively flat land with minimal obstructions from trees or buildings. The agricultural nature of much of this land means it is already cleared and maintained, reducing preparation costs for solar development.

Areas with slight southern-facing slopes would be particularly advantageous for solar panel positioning, as they naturally orient installations toward optimal sun exposure throughout the day. The gentle ridgelines that run through the region often provide these preferred orientations while maintaining easy access for construction and maintenance equipment.

The eastern portions of the surrounding area also present excellent opportunities, particularly where the terrain opens up into broad agricultural valleys. These locations combine favorable topography with proximity to existing electrical infrastructure, as many power lines follow the natural corridors created by the region's gentle topographical features.

Land immediately adjacent to the small creek systems might be less ideal due to occasional flooding potential and environmental considerations, but the elevated areas between these waterways offer premium locations for solar development. The consistent, moderate topography throughout most of the region means that multiple large-scale installations could be developed without competing for the limited number of truly optimal sites that might exist in more varied terrain.

United States solar PV Stats as a country

United States ranks 2nd in the world for cumulative solar PV capacity, with 95,209 total MW's of solar PV installed. This means that 3.40% of United States's total energy as a country comes from solar PV (that's 26th in the world). Each year United States is generating 289 Watts from solar PV per capita (United States ranks 15th in the world for solar PV Watts generated per capita). [source]

Are there incentives for businesses to install solar in United States?

Yes, there are several incentives for businesses wanting to install solar energy in the United States. These include federal tax credits, state and local rebates, net metering policies, and renewable energy certificates (RECs). Additionally, many states have enacted legislation that requires utilities to purchase a certain amount of electricity from renewable sources such as solar.

Do you have more up to date information than this on incentives towards solar PV projects in United States? Please reach out to us and help us keep this information current. Thanks!

Citation Guide

Article Details for Citation

Tell Us About Your Work

We love seeing how our research helps others! If you've cited this article in your work, we'd be delighted to hear about it. Drop us a line via our Contact Us page or on X, to share where you've used our information - we may feature a link to your work on our site. This helps create a network of valuable resources for others in the solar energy community and helps us understand how our research is contributing to the field. Plus, we occasionally highlight exceptional works that reference our research on our social media channels.

Feeling generous?

Share this with your friends!

Compare this location to others worldwide for solar PV potential

The solar PV analyses available on our website, including this one, are offered as a free service to the global community. Our aim is to provide education and aid informed decision-making regarding solar PV installations.

However, please note that these analyses are general guidance and may not meet specific project requirements. For in-depth, tailored forecasts and analysis crucial for feasibility studies or when pursuing maximum ROI from your solar projects, feel free to contact us; we offer comprehensive consulting services expressly for this purpose.

Helping you assess viability of solar PV for your site

Calculate Your Optimal Solar Panel Tilt Angle: A Comprehensive Guide

Enhance your solar panel's performance with our in-depth guide. Determine the best tilt angle using hard data, debunk common misunderstandings, and gain insight into how your specific location affects solar energy production.