Decatur, Illinois, United States, located in the Northern Temperate Zone, offers variable potential for solar energy generation throughout the year. This location experiences significant seasonal fluctuations in solar electricity production that prospective solar panel owners should consider.

Seasonal Solar Production

Solar panels in Decatur demonstrate strong performance during summer months, generating approximately 6.45kWh per day for each kilowatt of installed capacity. Spring follows as the second most productive season with 5.38kWh/day per installed kilowatt. Production decreases considerably during autumn to 3.67kWh/day, while winter shows the lowest output at just 2.17kWh/day per kilowatt of installed capacity.

This seasonal pattern reveals that Decatur's solar potential is heavily concentrated in the warmer months, with summer and spring together providing substantially more energy than autumn and winter combined. The nearly three-fold difference between summer and winter production highlights the seasonal variability at this location.

Optimal Panel Installation

For maximum year-round electricity generation in Decatur, fixed solar panels should be installed at a 34-degree tilt angle facing south. This specific angle has been calculated to optimize annual solar production by accounting for Decatur's latitude, seasonal sun paths, and the Earth's elliptical orbit.

Environmental Considerations

Several environmental factors in Decatur may impact solar production. The region experiences seasonal snowfall that can temporarily cover panels during winter months, further reducing output during an already low-production season. Installing panels at the recommended 34-degree tilt helps facilitate snow shedding compared to flatter installations.

Decatur also experiences occasional severe weather including thunderstorms and hail, which could potentially damage solar equipment. Using impact-resistant solar panels and proper mounting systems designed to withstand local wind conditions is advisable.

The area's four distinct seasons bring varying amounts of cloud cover, with winter months typically experiencing more overcast days. This natural variability is already reflected in the seasonal production figures and reinforces the importance of designing systems with annual production patterns in mind rather than focusing solely on peak summer performance.

Dust and pollen accumulation can also marginally reduce panel efficiency, particularly during spring and in dry summer periods. Implementing a regular cleaning schedule or installing self-cleaning panels can help maintain optimal performance throughout the year.

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 Decatur, Illinois

Seasonal solar PV output for Latitude: 39.8367, Longitude: -88.9428 (Decatur, 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 Decatur, Illinois, United States

To maximize your solar PV system's energy output in Decatur, Illinois, United States (Lat/Long 39.8367, -88.9428) 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 Decatur, 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 Decatur, 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
24° South in Summer	44° South in Autumn	54° South in Winter	33° 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 Decatur, 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 Decatur, 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 Decatur, Illinois, United States

The terrain surrounding Decatur, Illinois is characterized by a gently rolling landscape typical of the Central Plains region of the United States. Located in Macon County in central Illinois, Decatur sits within what geographers call the Till Plains section of the Central Lowland Province. This area was shaped primarily by glacial activity during the Pleistocene epoch, resulting in a relatively flat to moderately undulating topography with subtle elevation changes. The average elevation around Decatur is approximately 675 feet (205 meters) above sea level, with minimal variation across the immediate area. The landscape features a mix of agricultural plains, shallow valleys, and low moraines - ridges of glacial debris deposited as ice sheets retreated northward thousands of years ago. The Sangamon River cuts through this terrain, creating a shallow valley system that introduces some topographical variety to an otherwise predominantly level landscape.

Agricultural Plains and Solar Potential

The extensive agricultural plains surrounding Decatur present promising opportunities for large-scale solar photovoltaic (PV) development. These flat, open farmlands offer several advantages for solar installations: minimal grading requirements, good drainage characteristics, and limited shadowing concerns. The rural areas to the east and south of Decatur, characterized by particularly level terrain with minimal tree cover, would be especially suitable for solar PV arrays. The agricultural nature of much of the land means there are large, contiguous parcels potentially available for development, which is advantageous for achieving economies of scale in solar installations. These areas also typically have existing access to roads and may be near transmission infrastructure, further enhancing their suitability.

Riverine Areas and Considerations

The Sangamon River valley introduces some topographical variation to the region. While the gentle slopes found in these areas might seem appealing for solar orientation, these locations generally present more challenges than opportunities for large-scale solar development. The valley areas may be subject to periodic flooding, have more tree cover creating shadowing issues, and often contain more environmentally sensitive habitats that might face development restrictions.

Optimal Locations for Solar Development

The most favorable areas for large-scale solar PV development near Decatur would be the flat agricultural lands, particularly those: 1. Located on higher ground away from the Sangamon River floodplain 2. Situated in the eastern and southern quadrants of the Decatur area 3. With existing access to transportation and transmission infrastructure 4. On land with minimal environmental sensitivity designations The level terrain in these areas would minimize construction costs related to land preparation, while the predominantly agricultural use patterns suggest fewer competing land use priorities compared to more developed or environmentally sensitive zones. The glacial till soils common to the region generally provide good drainage and stable foundation conditions for solar array mounting systems. These soil characteristics, combined with the minimal slope of the landscape, create favorable conditions for the installation and long-term stability of ground-mounted solar panels.

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!

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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.