UK's Smallest Power Station

The Newport Eco House in West Wales was established in 1995 after years of campaigning by the Newport and Nevern Energy Group to act as an energy advice centre for energy use and conservation and houses the Dyfed Energy Advice Centre.

Wind & Sun were approached to supply a demonstration battery charging PV system to power computer equipment and lighting.

The previous year Wind & Sun had installed the country’s first domestic PV system for The Autonomous House in Nottinghamshire using a 1.8KW SMA inverter. Since then SMA had introduced a new concept for string inverters known as ‘Sunny Boys’ enabling smaller more affordable PV systems to be implemented.

Consequently, it was suggested to the Eco Centre that by grid connecting the PV system it would enable more solar energy to be supplied for the budget available and would be a better demonstration, as the majority of visitors to the Eco Centre would be grid connected.

It would also, allow them to become the UK’s smallest registered power station!

The photovoltaic array, consisted of six 75Wp monocrystalline PV modules connected in series giving a peak output of 450W fed into an SMA SWR-700 700W ‘Sunny Boy’ inverter sited in the loft. The inverter AC output was connected to the building consumer unit. Generated power is supplied to Eco-house loads reducing the demand from the grid with any surplus power exported to the grid. A graphical display was provided in the Visitor Centre to show performance.

The PV system was designed by Steve Wade of Wind & Sun and installed in one day in February 1996 with the assistance of Martin Cotterell of Sundog. Commissioning, however, took another eight months.

In 1996 there were no UK standards for PV grid connected inverters which meant SWALEC (The local electricity utility) had nothing to refer to satisfy safety concerns regarding the equipment. They proposed the inclusion of dedicated G59/1 protection equipment which conformed to UK standards but this would have added approx. 20% to the cost of the system.

Wind & Sun argued that the SMA inverter contained all the necessary protection equipment needed and that treating this type of system in the same way as a connecting a rotating generator to the grid was inappropriate and added unnecessary cost.

After a long period of negotiation, it was agreed to conduct in-situ tests on the inverter to demonstrate that the inverter would shut down within the limits of the G59/1 standard and there was no risk of islanded operation. These tests were carried out by Wind & Sun and Jonathan Hill from Econnect to the satisfaction of SWALEC and the system was finally commissioned on the 11th October 1996 as a “demonstration project”.

At the time SWALEC were keen to point out that this was only a demonstration project and any further connections would have to undergo the same scrutiny as this one, with the terms of connection still very much up to the local engineer.

At the time, there were concerns within the electricity industry in the UK, who argued that PV systems were dangerous, and could not be relied upon to maintain safety standards. Our reasoning was that new equipment available off-the-shelf from Germany met all the necessary criteria and would ensure safe and trouble-free operation. At first, SWALEC insisted on calling the installation "a demonstration project" but after many more months of negotiations the rewriting of UK-wide installation and operational guidelines was completed, opening the way for the installation of the many thousands of PV installations which we see across the country today.

This led in to the development of a new connection guidelines document (G77) aimed specifically at < 5kW grid connected PV, the type testing and certification of inverters. In later years this further developed into G83 and then to G98 - guidelines that have enabled the easy connection of residential solar PV systems, lower costs for end users and a much easier time for installers ever since!

This pioneering solar photovoltaic (PV) systems celebrated its 20th anniversary on 11th October 2016.

Notable for being:

• The first grid linked PV system in Wales
• The UK's first sub-kW power station
• The first use of string inverters in the UK (using an SMA Sunny Boy)
• Directly responsible for the development of the G77 and then G83 standards that are used today to enable the uptake of solar PV

We revisited the Eco Centre and met up again with some of the people involved in the project and were pleased to see that the system was still operating, with a total generation over the period of at least 5463 kWh making this Sunny Boy inverter the oldest operating domestic PV inverter in the country!

With reports these days of some inverters failing after only a few years it shows that it’s worth choosing the right equipment from the start.

Local installer Bob Robarts of Sustainergy said “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”.

Steve Wade from Wind & Sun added: “It certainly was a battle to get this system commissioned and we’re pleased that things have moved on. 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”.

Although the Eco Centre (in a building owned by Pembs CC) is now empty, the PV power station is still feeding power into the grid.

Speaking as the ex-Chair of the Eco Centre (which closed its doors in 2013) Dr Brian John said: "We are still immensely proud of the fact that the PV revolution started in Newport. The negotiations with SWALEC and the local authorities were extremely difficult, but we persisted -- and now, twenty years down the line, we can see what a massive contribution PV systems are making to the UK energy supply. All from very small beginnings!"

Steve from Wind and Sun, said: "“It certainly was a battle to get this system commissioned and we’re pleased that things have moved on. But it was a privilege to have obtained the contract for the commissioning of the UK’s smallest power station, and to have been involved in the 1996 underpinnings for what is now a very large industry.