Installing Solar PV panels on a flat roof

The intention was to install a 1.8Kw solar photovoltaic system on the flat roof of a house in Yorkshire, England. The roof is aligned south and there are no trees to shade it, so in theory it is an ideal location. The main issues with the install were bureaucratic and logistical.

The Bureaucracy

For some time now the Department for Energy and Climate have been giving out grants worth up to £2500 for the installation of green technologies. You have to have applied for and been granted the grant before installation of the system can commence. Kirklees Council were also running a scheme whereby they would lend you up to £10000 interest free for the installation of green technologies. You only pay back the loan when you sell the house. The DECC grant is only valid for six months. If you have not installed and commissioned the system in that time you will lose the grant. You have to get the grant in place before you start with the paperwork for Kirklees and being a council, their timescale for processing the paperwork works in months not days.

After about four months of waiting on Kirklees and with the clock ticking on the DECC grant, final approval was given to start the install. However, there was another issue to now overcome…

The Logistics

Solar PV systems use an inverter to convert the low voltage DC current to 240v AC current used by standard mains appliances. Just before Christmas 2009, the governments of Germany and France announced ‘Feed in’ tariffs which suddenly made solar PV very popular in those countries. The problem was, that Germany was also the major supplier of the inverters that all the UK installers use and it was keeping them all to itself. With only eight days left on the DECC grant a one month extension was granted, but it was made clear that it would not be extended any more as it would then pass into a new financial year. The inverters were not due for at least two months so it looked as though the grant would be lost. This situation didn’t just effect this installation, it effected installations all over the country so pressure was applied by MPs and other interested parties. DECC finally gave in and said that if ninety percent of the installation was complete by the deadline, they would pay ninety percent of the grant. The other ten percent could be claimed when the installation was finally commissioned.

The race was therefore on to get the panels up and the wiring in before the grant expired…

Day 1: Eleven days until the grant expires.

The installers arrived bright and early at 08:00. In their van were ten PV panels. These were lifted off the van and carried onto the roof.

Panels laying on roof

Unfortunately the chosen mounting system, manufactured by Solion, had not turned up so the work that was available to do on the roof was limited. They spent the day concentrating on the electrical side, this consisted of drilling through the roof, mounting a waterproof junction box

Waterproof box

and running the cables to the inverter. Also finished was the installation of a sub board (as there were no free slots on my consumer unit) and running cables between the sub board and the inverter (when it turns up).

Sub board with no generation meter

Day 2

Still no Solion mounts. There were due to have been delivered to the installer’s offices the day before but they were now coming directly here to the site. They turned up around 10:00 and are just large plastic trays that are angled to allow optimum alignment of the PV panels.

Solion panels as delivered

Even though they have been tested with 100mph winds, they are only held down by five standard size house bricks.

Solion panel with bricks

The panels do however interlock with the capping strips but there is no need to physically anchor them to the roof.

Apparently, the center capping strip has been delivered to the installers office so they will have to come back tomorrow. All ten mounts now contain panels and have all been plugged together. Testing of the wiring commences.

Solar array with no cappings installed

Day 3

Another early start. The cappings were fitted, as was the generation meter. All the panels and mounts were washed with soapy water and the wiring tested. The panels are running at 135v per string of five. All that is needed now is the inverter.