How Many Solar Panels Needed to Generate 1 Megawatt of Power?

Installing a 1 megawatt (MW) solar system is a significant undertaking, typically suited for commercial buildings, large residential developments, or dedicated energy projects. 

One of the most important planning steps is determining how many solar panels are needed for 1 megawatt of capacity.

This in-depth guide explores everything UK property owners need to know, from how many panels you’ll need and how much space is required, to system costs, energy output, and key considerations that affect performance.

How Many Solar Panels Are Required to Generate 1 Megawatt?

You’ll need approximately 2,500 solar panels to generate 1 megawatt of power.

The exact number of solar panels needed depends on the wattage of each panel. In the UK, high-efficiency panels typically range from 370W to 450W. For example:

To calculate the number of panels, divide 1,000,000 watts (1 megawatt) by the wattage of the panel you plan to use. Fewer panels are needed when opting for higher-wattage models, which can help reduce installation space and labour costs.

Tip: Understanding how much electricity a solar panel produces can help determine the ideal panel choice.

What Factors Can Affect the Number of Panels Needed for 1MW?

Several variables can impact the actual number of solar panels required to generate 1 megawatt of power. Understanding these factors is essential when planning a large-scale solar installation, especially in the context of the UK’s climate, regulations, and site constraints.

1. Panel Efficiency

The most influential factor is the efficiency of the solar panels. High-efficiency panels (typically 20–22%) generate more electricity per square metre than lower-efficiency models (15–18%). This means:

• Higher efficiency = fewer panels needed to reach 1MW.
• Higher-efficiency panels are ideal when space is limited or where installation costs per panel are high (e.g., complex rooftops).

For example, using 450W panels reduces your panel count and installation area compared to 370W models.

According to the Energy Saving Trust, panel efficiency plays a crucial role in determining how much space and how many panels are needed for a system.

2. Installation Angle and Orientation

Solar panels perform best when they face true south and are installed at an angle that optimises exposure to sunlight. In the UK, the ideal tilt is typically between 30° and 40°, depending on geographic location.

Flat or shallow-angled roofs may require additional mounting structures to achieve optimal tilt. Poor orientation (e.g., east-west facing panels) can reduce daily output, meaning you may need more panels to meet 1MW capacity.

The Microgeneration Certification Scheme (MCS) provides guidance on optimising tilt and orientation to maximise energy generation from solar PV systems.

3. Shading and Roof Obstructions

Shading is a major performance inhibitor. Trees, chimneys, neighbouring buildings, and rooftop equipment like air conditioning units can cast shadows on panels, reducing their output significantly.

Shaded panels produce less energy, requiring additional panels to compensate for reduced system efficiency. Microinverters or optimisers can help mitigate shading losses, but at an added cost.

Professional site assessments typically include shade analysis using tools like Solar Pathfinder or drone imagery to model seasonal shading.

The Energy Saving Trust recommends professional shading assessments as part of a full feasibility survey before installing solar PV.

4. Geographic Location and Solar Irradiance

The UK's solar irradiance varies by region. Southern England receives more solar energy than northern regions or Scotland, affecting how much electricity each panel can generate annually.

In areas with lower irradiance, more panels may be required to achieve consistent energy yields equivalent to 1MW of peak output.

Site-specific yield assessments are based on the Microgeneration Certification Scheme guidelines and tools like PV*SOL or PVGIS.

The UK Government's National Renewable Energy Planning Database (REPD) provides irradiance maps showing regional solar potential.

5. Inverter and System Losses

Solar systems experience inevitable performance losses due to:

• Inverter inefficiencies (typically 2–5%)
• DC to AC conversion losses
• Cable resistance
• Soiling (dust, debris, bird droppings)
• Temperature derating (panels produce less energy when hot)

These losses can reduce system performance by 5–10%, meaning you'll need to slightly oversize the array to ensure your system consistently meets a 1MW rating under real-world conditions.

According to Solar Energy UK, performance losses from inverters, wiring, and soiling are standard in large solar installations and should be factored into design calculations.

6. Roof or Ground Constraints

Space limitations, structural load capacity, and layout inefficiencies may prevent ideal panel placement. Irregular roof shapes, limited southern exposure, or tight planning constraints may all require adjustments in:

• Panel quantity
• Panel type (size, weight, format)
• Layout optimisation using software tools

For systems over 50kW, the UK Planning Portal advises that formal planning permission is often required, particularly for ground-mounted systems.

How Much Space Is Required for a 1 Megawatt Solar System?

To install a 1 megawatt (MW) solar PV system, you’ll typically need between 3,800 and 4,600 square metres equivalent to roughly 0.93 to 1.13 acres. The exact footprint depends on the wattage of the panels and the layout of the array (e.g., tilt angle, row spacing, and mounting system).

Each solar panel in the UK generally occupies about 1.7 m², including clearance for maintenance and to prevent shading between rows. However, panel layout efficiency differs based on whether the system is ground-mounted or roof-mounted:

Ground-mounted systems

Ground-mounted arrays are commonly used for 1MW systems due to the significant space required. These installations often feature tilted racks facing south at 30–40° angles to maximise sun exposure. 

To avoid self-shading and allow for maintenance access, additional space must be allocated between panel rows. This typically increases the overall land requirement by 30–40% compared to the total panel area alone.

• Total space required: ~1.1–1.3 acres (4,400–5,200 m²)
• Ideal for: Agricultural land, brownfield sites, industrial estates
• Considerations: Requires planning permission for systems over 50kW

Rooftop-mounted systems

Large, flat commercial roofs such as those found on warehouses or retail centres can support 1MW solar arrays if the structure can bear the load. Because rooftop arrays don’t require as much spacing between rows, they are generally more space-efficient.

• Total space required: ~3,800–4,200 m²
• Ideal for: Commercial buildings, factories, distribution centres
• Considerations: Structural surveys are essential to confirm load-bearing capacity. Roof access and orientation also impact efficiency.

Important Note: Shading from trees, buildings, or other rooftop infrastructure (like HVAC units) can reduce available space and system output. A professional site assessment is essential to accurately design the layout and maximise generation potential.

For tailored system design and accurate space assessments, it’s best to request multiple proposals from vetted installers using Eco Answers’ Quote-Comparison Tool.

What Are the Costs Involved in Installing a 1 Megawatt Solar System in the UK?

As of 2025, the typical cost to install a 1 megawatt (MW) solar PV system in the UK ranges from £750,000 to £1.1 million. 

The final figure depends on various factors, including whether the system is ground- or rooftop-mounted, the type and efficiency of panels used, the complexity of the installation, and the cost of grid connection and permitting.

While prices have steadily fallen over the past decade due to advances in solar technology and economies of scale, large-scale systems like 1MW arrays still require significant capital investment. 

However, they also offer considerable long-term savings and potential income through the Smart Export Guarantee (SEG) and carbon savings.

Typical Cost Breakdown for a 1MW Solar System in the UK

These figures are estimates based on commercial and industrial-scale solar PV projects. Actual costs of solar panels may vary depending on regional labour rates, property access, grid constraints, and component availability.

Key Cost Drivers to Consider

• System Type: often involve higher infrastructure and land preparation costs, while rooftop systems may require structural reinforcements and access solutions.
• Location: Areas with restricted grid capacity may incur higher grid connection charges from the .
• Installation Complexity: Custom layouts, elevation changes, or shaded environments may increase labour and engineering costs.
• Panel Efficiency: Higher-efficiency panels reduce the number of panels needed, potentially saving on racking and labour, but often come at a premium.
• Regulatory Requirements: Projects over 50kW typically require , environmental assessments, and grid impact studies.

While the upfront cost is substantial, many commercial clients offset these expenses through capital allowances, corporate sustainability goals, and long-term electricity savings. Some may also qualify for green finance or low-interest sustainability loans.

Want to understand your project’s costs more accurately? Use Eco Answers’ free Quote-Comparison Tool to get matched with trusted UK solar installers and receive detailed, tailored quotes for your property.

Is It Worth Investing in a 1 Megawatt Solar System in the UK?

Absolutely, investing in a 1 megawatt (MW) solar system can deliver substantial benefits, particularly for commercial properties, large residential developments, and organisations aiming to reduce operational costs and environmental impact. 

The financial and environmental returns make such an investment increasingly attractive in the UK’s evolving energy landscape.

Key Benefits

Here are all the reasons why commercial solar panels are a worthwhile investment.

Significant Savings on Energy Bills

A 1MW solar installation can drastically reduce your electricity consumption from the National Grid by generating your own clean power onsite. This shields your business or property from volatile energy prices and future hikes. 

Solar PV systems typically provide a strong return on investment through bill savings over their 25+ year lifespan, according to the Energy Saving Trust.

Income Through the Smart Export Guarantee (SEG)

Under the UK Government’s Smart Export Guarantee (SEG) scheme, you can sell any surplus electricity generated back to your energy supplier. 

The SEG replaced the older Feed-in Tariff scheme and incentivises renewable energy generation at commercial scale. This can add a steady income stream, improving project economics.

Enhanced Energy Performance Certificate (EPC) Rating

Installing solar PV helps improve a building’s EPC rating, a key factor in property valuation and compliance with evolving regulations, especially for landlords. 

Higher EPC ratings can make properties more attractive to tenants and buyers while aligning with government net-zero targets.

Substantial Reduction in Carbon Emissions

A 1MW solar system can offset approximately 300 to 500 tonnes of CO₂ annually, depending on regional solar irradiance and system efficiency. 

This is equivalent to removing dozens of cars off the road each year, making a measurable contribution to corporate social responsibility and environmental goals. Read our article on why solar panels are good for the environment.

According to Carbon Trust, deploying solar PV is one of the most effective ways to reduce onsite emissions in commercial properties.

Additional Considerations

• Regulatory Compliance: The UK Government is increasingly encouraging or mandating renewable energy integration for commercial and residential properties, especially with upcoming regulations like .
• Corporate Social Responsibility (CSR): Demonstrating commitment to renewable energy can improve brand reputation and attract eco-conscious tenants or customers.

For tailored guidance and competitive supplier quotes based on your property type and energy goals, use Eco Answers’ Quote-Comparison Tool to connect with vetted UK solar installers and find the best deals.

FAQs

1. Can I install a 1MW system on a commercial building roof in the UK?

Yes, many large commercial buildings like warehouses and factories have the roof space to support a 1MW array. Structural assessments are required to confirm load capacity before installation.

2. Do I need planning permission for a 1 megawatt solar system?

For rooftop systems, planning permission is usually not required unless the property is listed or in a conservation area. Ground-mounted systems over 50kW generally do need planning consent. Always consult your local planning authority.

3. What is the payback period for a 1MW solar system?

The average payback period is between 7 to 11 years, depending on energy consumption, system costs, and SEG payments. After that, you can enjoy 15+ years of free energy generation.

4. Can I export electricity from a 1MW system to the National Grid?

Yes. You’ll need to register under the Smart Export Guarantee (SEG) and work with your DNO (Distribution Network Operator) for grid connection approval.

5. Are there government grants or incentives for 1MW systems?

Large-scale systems don’t typically qualify for homeowner-level grants, but capital allowance schemes and tax reliefs may apply for businesses. 

Final Thoughts

A 1-megawatt solar installation is a serious investment but one that pays long-term dividends in energy savings, environmental impact, and property value. 

The number of panels required depends on panel efficiency and available space, but you can expect to need around 2,200 to 2,700 panels.

Whether you're a UK homeowner, landlord, or commercial property manager, planning the right system size starts with accurate quotes and trusted suppliers. 

Use Eco Answers’ Quote-Comparison Tool to get multiple offers from vetted UK solar installers and take the next step toward powering your property with clean, renewable energy.