Commercial Solar PV Guide

Why Commercial Solar Makes Sense

Commercial solar PV is one of the most effective ways for UK businesses to reduce energy costs and carbon emissions. With electricity prices at historic highs and solar panel costs at historic lows, the financial case has never been stronger.

40-70%

Typical electricity cost reduction

3-6 Years

Typical payback period

25+ Years

Expected system lifespan

Key Benefits for Businesses

Reduced electricity costs - Generate free electricity during peak business hours
Protection against price rises - Lock in energy costs for 25+ years
Carbon reduction - Meet sustainability targets and customer expectations
Enhanced property value - Improve EPC ratings and asset value
Tax benefits - Enhanced Capital Allowances for plant and machinery
Brand enhancement - Demonstrate environmental commitment

System Sizing for Your Business

The optimal system size depends on your electricity consumption, available roof space, and budget. Here's how to approach sizing:

Matching Generation to Consumption

The goal is to maximise "self-consumption" - using the electricity you generate rather than exporting it. This is where commercial solar excels over residential:

Commercial buildings typically operate during daylight hours when solar generates
Higher base loads (lighting, IT, HVAC) provide consistent consumption
Self-consumption rates of 70-90% are common for commercial installations

System Size Guidelines

Building Type	Typical Size	Annual Generation
Small office (500m²)	20-30kW	18,000-27,000 kWh
Medium office (1,500m²)	50-75kW	45,000-68,000 kWh
Warehouse (5,000m²)	150-250kW	135,000-225,000 kWh
Large warehouse (10,000m²+)	300-500kW+	270,000-450,000 kWh

Roof Space Requirements

As a rule of thumb, you need approximately 5-7m² of roof space per kWp of solar capacity. A 100kW system requires approximately 500-700m² of suitable roof area.

Financial Returns and ROI

Commercial solar typically delivers returns of 15-25% per year, far outperforming most business investments.

How Returns Are Calculated

Self-consumed electricity - Saves you the full retail electricity rate (typically 25-35p/kWh)
Exported electricity - Earns Smart Export Guarantee payments (typically 5-15p/kWh)
Total return = (Self-consumed kWh x retail rate) + (Exported kWh x export rate)

Example ROI Calculation

100kW System - Manufacturing Facility

System cost: £70,000
Annual generation: 90,000 kWh
Self-consumption: 80% (72,000 kWh at 30p = £21,600)
Export: 20% (18,000 kWh at 10p = £1,800)
Total annual benefit: £23,400
Payback period: 3.0 years
25-year return: £515,000

Finance Options

You don't need capital upfront to benefit from commercial solar. Several finance options are available:

Outright Purchase

Best returns. You own the system and all benefits immediately. Enhanced Capital Allowances may allow 100% tax relief in year one.

Best for: Businesses with available capital seeking maximum returns.

Asset Finance / Lease

Spread the cost over 5-10 years. Monthly payments often lower than energy savings, making it cash-positive from day one.

Best for: Businesses wanting to preserve capital while still capturing benefits.

Power Purchase Agreement (PPA)

A third party owns and maintains the system; you buy the electricity at a fixed rate below grid prices. Zero upfront cost.

Best for: Businesses wanting guaranteed savings with no investment or maintenance responsibility.

Public Sector (Salix)

Interest-free loans for public sector organisations. Repaid through energy savings over the loan term.

Best for: Schools, NHS, councils, and other public bodies.

The Installation Process

A typical commercial solar installation follows these steps:

1. Site Survey

We assess your roof structure, electrical infrastructure, shading, and energy consumption patterns to design the optimal system.

2. Design & Proposal

Detailed system design with 3D modelling, energy yield predictions, and comprehensive financial analysis.

3. Planning & Approvals

Most commercial installations are permitted development. We handle any planning applications and DNO connections required.

4. Installation

Professional installation by MCS-certified engineers. Typically 1-4 weeks depending on system size, with minimal business disruption.

5. Commissioning

System testing, grid connection, and handover. Full training on monitoring and operation provided.

6. Ongoing Support

Remote monitoring, maintenance packages, and ongoing support to ensure optimal performance throughout the system's life.

Is Your Building Suitable?

Most commercial buildings are suitable for solar. Key factors include:

Roof Considerations

Roof type - Flat roofs (ballasted systems), pitched metal roofs (clamp-mounted), and tiled roofs are all suitable
Roof condition - Should have 15+ years of remaining life; replacements can be coordinated with installation
Structural capacity - Modern systems are lightweight (12-15 kg/m²); most roofs can accommodate solar
Shading - Minimal shading from adjacent buildings, trees, or equipment
Orientation - South is optimal, but east-west arrays work well for commercial buildings

Electrical Considerations

Supply capacity - Your incoming supply must be able to accept the solar generation
Three-phase supply - Required for systems above approximately 17kW
DNO approval - Required for larger systems; we handle this process

Commercial Solar Case Studies

Warehouse

250kW Warehouse Solar

Bedford distribution centre. £42,000 annual savings, 4.2 year payback.

Agriculture

150kW Farm Solar

Bedfordshire arable farm. £25,000 annual benefit, 4.5 year payback.

Hospitality

85kW Hotel Solar + Battery

Hertfordshire country hotel. 80% self-consumption, backup power.