TrailBLAZER

A road-towable trailer that unfolds into a small solar power station. No grid connection. No planning permission for short deployments. No noise. No emissions. Just clean electricity, deployable anywhere a vehicle can reach, on the same day the need arises. That was the TrailBLAZER concept — and by May 2018, it existed as a working, certified prototype, handed over to Cardiff Council as the culmination of a two-year SBRI innovation competition.

Working via BRE to conceive the original idea, and as project management subcontractor to lead company I2O, the project took a novel idea from tender submission through to physical prototype, navigating along the way everything from trailer fabrication in Newhaven to lithium-ion battery certification under the Dangerous Goods Act.

The problem it solved

Construction and temporary sites — festivals, markets, emergency response locations, outdoor events, construction compounds — typically either run noisy diesel generators or require costly, disruptive grid connections. Neither option is clean, quiet, or straightforward. TrailBLAZER proposed a third way: a self-contained renewable energy unit, purpose-built around flexible photovoltaic technology, that any organisation could tow to a site, deploy without specialist knowledge, and leave running.

Zero Carbon site operations or temporary events - mobile power at scale

The system required no grid connection, generated power from diffuse as well as direct sunlight, and — for deployments under 28 days — required no planning permission. It could be daisy-chained with other trailers to scale capacity. South Wales Fire & Rescue were invited to observe a trial deployment, recognising its potential for emergency and resilience use.

What was built

The prototype was a purpose-designed double-axle trailer carrying 42 flexible TensilePV modules — large-format photovoltaic panels bonded to tensile membrane fabric substrates. Unlike conventional rigid panels, these generated usable power from diffuse light, making them effective in the variable British climate. Each panel was colour-coded with 3D-printed connectors designed so that the wrong connection was physically impossible, allowing non-specialist operatives to deploy the full array safely.

Onboard power outputs covered 240v mains, 110v site power, and twin EV charging connections — making it immediately compatible with the full range of temporary site power requirements. A National Grid direct-sell connection was also included, enabling future participation in flexibility and grid balancing markets. A Siemens S7 communications system unified the battery management, inverters, and solar generation data into a single monitoring connection, readable remotely via ethernet or cloud link.

Technical specifications

Length

4.05m (5.55m with tow hook)

Width

2.5m

Height

2.3m

Laden weight

3,200 kg

Battery cells

64 × Winston Lithium Ion (GWL Power)

Battery capacity

82 kWh (64 × 1.3 kWh)

PV modules

42 TensilePV (modified MiaSole FLEX-02W)

PV module size

2.8m × 2.2m each

PV efficiency

~15% conversion

Outputs

240v mains, 110v site, 2× EV charge, grid sell

Engineering challenges overcome

The project encountered and resolved a series of genuine engineering and regulatory challenges that no off-the-shelf solution existed for. The most significant was working-at-height safety: the original design required operatives to lift PV panels onto a roof-mounted stack at a height that fell foul of health and safety legislation. The solution — a rail-and-winch slide system with a curved, self-draining PV bed — preserved the target dimensions and weight while entirely eliminating the unsafe loading operation.

Battery procurement required multiple supplier changes before the final specification of 64 Winston Lithium Ion cells was settled, each requiring a redesigned enclosure built from treated plywood with fire-retardant intumescent lining and aluminium end plates. Each cell weighed 13kg — the full battery pack came to 832kg — housed within a bespoke rear container that also met Dangerous Goods requirements.

Trial deployments

Three demonstrator sites were agreed with Cardiff Council for the prototype's operational trials, all within the city:

Trials were scheduled for March–April 2018 to ensure sufficient daylight hours. A dedicated Deployment Tool — a spreadsheet-based guide for non-technical operatives — was developed alongside the hardware, estimating power supply, charging times, and providing step-by-step deployment guidance and risk information.

The consortium