23.8% Annual Return on Investment – 110kW Commercial Solar with a Payback of Just 4.2 Years

Hatchers Department Store | Taunton, Somerset

Over 60% reduction in grid electricity consumption, an estimated annual return on investment of 23.8%, and a payback period of only 4.2 years.

For a business that has been serving Taunton since 1775, investing in the future is nothing new.

Hatchers Department Store is one of Britain's oldest independent, family-run department stores, having celebrated its 250th anniversary in 2025. Located in the heart of Taunton, the business has grown from a traditional drapery shop into a major independent retailer offering fashion, home furnishings, electrical appliances and much more.

With over 250 years of trading history and a strong commitment to remaining independent, Hatchers recognised that investing in renewable energy offered an opportunity to substantially reduce operating costs while protecting the business against rising electricity prices.

The Solution – Maximising Every Square Metre of Roof Space

Callidus delivered a 110kWp commercial solar PV installation, designed specifically for the building's flat roof.

The system uses an east-west solar panel configuration, allowing more panels to be accommodated within the available roof space while generating electricity across a broader period of the working day.

This approach was particularly beneficial for a busy department store, where electricity is consumed continuously throughout trading hours for lighting, tills, escalators or other building services where installed, and general retail operations.

The installation incorporates:

• 110kWp of JA Solar bifacial solar panels, backed by a 30-year performance warranty.
• SolarEdge inverter technology providing advanced system management and monitoring.
• Module-level power optimisers helping reduce the impact of shading and differences in panel performance.
• Integrated fire alarm shutdown, allowing the solar system to be automatically shut down when the building's fire alarm is activated.
• Flat roof mounting with perimeter edge protection, providing safer access for inspections and ongoing maintenance.

Advanced SolarEdge Technology and Fire Safety

For a public-facing retail building, safety and reliability were essential considerations.

The SolarEdge system uses power optimisers to manage panel performance individually, helping maximise electricity generation where shading or differing operating conditions could otherwise reduce output.

The system also incorporates SolarEdge's SafeDC technology, designed to reduce DC voltage to safer levels when the inverter is shut down.

By integrating the solar shutdown controls with the building's fire alarm system, the installation provides an additional layer of protection for emergency situations.

This allows the solar installation to respond automatically to a fire alarm activation, supporting safer emergency procedures and maintenance operations.

Designed for Long-Term Maintenance

The flat roof installation, combined with suitable edge protection, provides excellent access for routine inspections, servicing and future maintenance.

This makes the installation particularly well suited to an ongoing operations, maintenance and monitoring (O&M) package, helping maintain long-term system performance and reliability.

Exceptional Financial Performance

With a projected reduction of over 60% in grid electricity consumption, Hatchers benefits from substantially lower electricity purchases and reduced exposure to future energy price increases.

The project's estimated payback period of just 4.2 years represents an annual simple return on investment of approximately 23.8%.

Financial highlights

• 23.8% estimated annual simple ROI
• 4.2-year estimated payback period
• Over 60% reduction in grid electricity consumption
• 238% gross cumulative return over 10 years
• 138% net cumulative ROI over 10 years
• 476% gross cumulative return over 20 years
• 376% net cumulative ROI over 20 years

These projections assume consistent annual savings and exclude future maintenance expenses, system degradation, financing and other costs.

System Specifications

• Client: Hatcher & Sons Ltd
• Location: Taunton, Somerset
• Solar PV capacity: 110kWp
• Solar panels: JA Solar bifacial modules
• Panel performance warranty: 30 years
• Inverter and optimisation: SolarEdge
• Roof type: Flat roof
• Panel layout: East-west configuration
• Fire safety: Integrated fire alarm shutdown and SolarEdge SafeDC functionality
• Maintenance: Roof access and edge protection supporting an O&M package
• Estimated grid electricity reduction: Over 60%
• Estimated annual simple ROI: 23.8%
• Estimated payback: 4.2 years

Protecting a 250-Year-Old Business for the Future

Hatchers demonstrates that even one of Britain's longest-established department stores can benefit from adopting modern renewable energy technology.

By transforming previously unused rooftop space into an electricity- generating asset, the business can substantially reduce its operating costs

while retaining the character and heritage that have made it an important part of Taunton's High Street for generations.

With a 23.8% estimated annual return on investment, a 4.2-year payback and over 60% less grid electricity required, this installation demonstrates the commercial value of investing in solar energy.

Callidus Trade – Commercial Solar Solutions Engineered to Perform.