Great Falls, Virginia offers reasonably good conditions for solar energy generation throughout most of the year, though like many locations in the Northern Temperate Zone, it experiences significant seasonal variation in solar output.

Seasonal Solar Performance

The location shows strong solar production during the warmer months, with summer delivering the highest output at 6.44 kWh per day per kW of installed solar capacity. Spring follows as the second-best season at 5.71 kWh per day per kW, making these two seasons ideal for solar energy generation at this location. Autumn production drops to 3.94 kWh per day per kW, while winter shows the lowest output at just 2.43 kWh per day per kW. This winter decline is typical for northern temperate locations and represents the main limitation for year-round solar generation in Great Falls. For homeowners considering a fixed solar panel installation, the optimal tilt angle is 34 degrees facing south. This angle maximizes total annual energy production by accounting for the sun's changing position throughout the year and the varying solar irradiance levels at this latitude.

Local Factors That Could Impact Solar Production

Several environmental and weather factors in the Great Falls area can significantly affect solar panel performance:

• Snow accumulation: Winter snowfall can completely block solar panels, eliminating energy production until the snow melts or is removed
• Deciduous tree coverage: The heavily wooded nature of Northern Virginia means seasonal shading from trees can reduce output, particularly in summer when leaves are full
• High humidity and frequent storms: The region's humid subtropical climate brings regular thunderstorms and overcast conditions that reduce solar irradiance
• Atmospheric haze: Summer heat and humidity often create hazy conditions that can scatter sunlight before it reaches solar panels

Preventative Measures for Better Solar Performance

Several installation strategies can help maximize solar energy production despite these local challenges: Installing panels at the recommended 34-degree tilt helps snow slide off more easily and reduces accumulation. Additionally, choosing a mounting system that allows safe snow removal access can help restore production quickly after winter storms. Careful site selection is crucial for avoiding tree shading. Conducting a thorough shade analysis throughout different seasons helps identify the best placement. In some cases, selective tree trimming may be necessary to maintain optimal solar access. Using high-quality panels with good low-light performance can help maintain production during overcast conditions common in this humid climate. Anti-reflective coatings on panels can also help capture more diffuse light during hazy conditions. Regular cleaning and maintenance become more important in this environment due to increased pollen, humidity, and storm debris that can accumulate on panel surfaces and reduce efficiency.

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 Great Falls, Virginia

Seasonal solar PV output for Latitude: 38.9982, Longitude: -77.2883 (Great Falls, Virginia, 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 Great Falls, Virginia, United States

To maximize your solar PV system's energy output in Great Falls, Virginia, United States (Lat/Long 38.9982, -77.2883) 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 Great Falls, Virginia, 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 Great Falls, Virginia, 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	44° South in Autumn	54° 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 Great Falls, Virginia, 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 Great Falls, Virginia, 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 Great Falls, Virginia, United States

Topographical Features of Great Falls

Great Falls sits in the rolling hills of northern Virginia, approximately twenty miles northwest of Washington, D.C. The area is characterized by gently undulating terrain with elevations ranging from around 200 to 500 feet above sea level. The landscape features a mix of wooded hills, open meadows, and residential developments scattered throughout the countryside. The region lies within the Piedmont physiographic province, where ancient geological formations have been weathered and eroded over millions of years to create the current moderate topography. The Potomac River forms a significant geographical feature to the north and east of Great Falls, carving through the landscape and creating the dramatic waterfalls that give the area its name. South and west of the community, the terrain gradually rises into higher elevations as it approaches the foothills of the Blue Ridge Mountains. The area experiences typical mid-Atlantic climate patterns with four distinct seasons, including warm summers that provide favorable conditions for solar energy generation.

Optimal Areas for Large-Scale Solar Development

The most promising locations for large-scale solar photovoltaic installations around Great Falls would be the open agricultural fields and cleared areas found primarily to the west and southwest of the community. These areas offer several advantages including relatively flat to gently sloping terrain that requires minimal grading, existing cleared land that reduces environmental impact, and good accessibility to existing electrical infrastructure along major transportation corridors. The farmland areas along and near Route 7 (Leesburg Pike) extending westward toward Leesburg present particularly attractive opportunities. These locations feature large contiguous parcels of land with southern-facing slopes that would optimize solar panel orientation. The agricultural nature of much of this land also means fewer environmental restrictions compared to the heavily forested areas closer to the Potomac River. Areas south of Great Falls toward Reston and Herndon also contain suitable terrain, though much of this region has already been developed for residential and commercial use. The remaining undeveloped parcels tend to be smaller and more fragmented, making them less ideal for utility-scale solar projects but potentially suitable for smaller commercial installations. The terrain immediately around Great Falls village itself is less suitable for large solar installations due to heavy tree cover, steep slopes near the river, and the predominantly residential character of the area. The wooded areas extending north toward the Potomac and east toward McLean are also challenging for solar development due to environmental sensitivities and the need for extensive tree clearing. Transportation access represents another important consideration, with areas near major roads like Route 7, Route 193 (Georgetown Pike), and the Dulles Toll Road offering better logistics for construction and maintenance activities. The proximity to existing electrical transmission infrastructure along these corridors also reduces the cost and complexity of connecting solar installations to the power grid.

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.