With more than 11.5GW installed and swathes of developers currently rushing to complete as many 1.2 ROC sites as possible prior to next March’s final deadline, it’s perhaps easy for the industry to forget the significant strides it has made in the last three or four years, let alone 20. 

But, earlier this month, that’s precisely what installation firm Wind & Sun did when it revisited one of its first installs in Newport, Pembrokeshire; one that blazed a trail for hundreds of thousands of residential systems that followed it.

The system’s history began in 1995, when Wind & Sun was first approached by The West Wales Eco Centre interested in adopting solar PV – very much a nascent technology at the time – in order to educate the public as to its benefits. The system was hoped to supply a demonstration battery which would then be used to power computer equipment and lighting. 

Only after visiting the site did Wind & Sun suggest that the PV system be connected to the grid, enabling it to both supply more energy and pose as a better demonstration project for the general public to understand considering the majority of visitors would be connected to the national grid.

In February the following year the system was designed by Wind & Sun’s Steve Wade and Solar Power Portal Awards outstanding achievement award alumni Martin Cotterell. Six Siemens SM-75 75Wp monocyrstalline PV modules were connected in series and connected to an SMA 700W Sunny Boy inverter, shown below being installed into the Eco Centre’s loft space.

The entire system cost around £4,000, funded by Preseli Pembs District Council and the Welsh Office.

But it wasn’t for another eight months until it would be embraced by the local utility and commissioned.

Same old story: Grid problems

When approached by Wind & Sun, the local utility SWALEC had no proper documentation to refer to regarding the safety of the system and its connection to the grid. There were no national standards for PV grid connected inverters and SWALEC’s initial proposal – that G59/1 protection equipment be included within the system architecture – would’ve added around 20% to the overall cost of the system.

Wind & Sun argued that the SMA inverter contained all the necessary protection and controls required, and that anything else would be overkill that would merely add to the cost unnecessarily. SWALEC eventually relented after months of protracted negotiations and agreed to conduct tests on the inverter to demonstrate its safety and capability to shut down within G59/1 standard limits.

It might have been originally conceived as an interesting demonstration project designed to educate the general public as to the potential of renewables, but the system can be argued to have had a far greater impact and one which helped shape the UK’s renewables framework. 

SWALEC originally considered that all grid-connected solar PV systems would face similar in-situ testing and scrutiny, a practice which would obviously add great time and expense to any install. In completing and commissioning the Eco Centre system, pressure mounted for the creation of specific guidelines to be drawn up and lessons learned from it were drawn upon for the creation of the G77 connection guidelines document, resulting in significantly lower costs for installers.

A lasting legacy

Wade recently revisited the project, discovering that not only is the system still operating but that the original Sunny Boy inverter is still in full working order, making it the oldest operating PV inverter in the UK. Wade looks back on the six month battle to have the install commissioned and is pleased with how things have progressed since then.

“With the current interest in adding storage to PV systems many of the same questions are being raised by DNOs regarding their connection. We look forward to seeing type testing and certification for both energy storage and export limitation systems so that PV can really become the energy generation choice for the future,” he adds.

Bob Robarts, from local installer Sustainenergy, paints a grander picture of the Eco Centre system’s legacy in UK solar. “Installers don’t appreciate how times have changed and how things we take for granted like G83 certification for inverters and permitted development rights for PV installations, have enabled PV to become mainstream and commonplace,” he says.

Since its connection, the 450Wp system has generated more than 5.4MWh of clean electricity of significant benefit to the Eco Centre. But of far greater impact to its generation is the legacy the system leaves, and its undoubted help in marking the way for the many installs that have followed it.