Engensa, a UK based solar company recently installed the UK’s first micro-converter system – a radical new technology that enables millions of otherwise unsuitable roofs to be used for solar PV by eliminating many of the problems associated with shading.
As thousands of families each month install solar PV systems, the crucial role of the inverter – the nerve centre of any system – is coming under increasing scrutiny.
A standard inverter has two distinct roles: the first is to convert the DC current produced by the panels into AC current that can be used in the home. The second, crucially important, role is to manage the output of each of the panels and this is where traditional inverters can struggle. The problems come about when even a small part of the installation is shaded by a tree or a nearby building. Solar cells are essentially large semi-conductor diodes (similar to computer chips) which convert sunlight into electricity and are connected together to make a panel. When even a single cell within a panel is shaded it limits the current that can flow in the whole system, because with a normal inverter the solar panels are connected in series. This means that with a regular inverter the entire system performs to the standard of the weakest panel.
As the snows fell before Christmas, Engensa installed the UK’s first ever micro-converter – a radically different kind of solution manufactured by SolarEdge, an Israeli based leader in PV power optimization.
Instead of having a single inverter, the SolarEdge system is made up of multiple PowerBoxes, which sit under each solar panel and maximise the power of each individual panel and communicating this to a central inverter across the existing power lines. In addition, PowerBoxes maintain a fixed DC string voltage, allowing optimal efficiency of the SolarEdge PV inverter at all times and enabling a significant increase in the amount of electricity generated over the lifetime of the system.
According to Dr. Toby Ferenczi, Engensa CTO, it is ‘the UK’s first of a kind installation with distributed power harvesting. In plain English that means you get more energy output and greater PV monitoring capability compared with a conventional solar PV system because each panel is controlled separately.’ According to experts at Engensa, this new technology means that the impact of shadows falling on the panels is greatly reduced because only the output of the shaded panels are affected, rather than the whole system. It also means you can install panels in different orientations giving much greater flexibility when designing the system. A third benefit is that system owners have much greater insight into how their system is performing since it allows the output of each individual panel to be monitored in real-time, even from an iPhone.
‘SolarEdge’s product is a breakthrough that we have been waiting for,’ says Dr Ferenczi. ‘Our focus, in the increasingly competitive solar market, is to provide our customers with the best technological innovations from around the world and as part of this commitment we are delighted to have installed the first SolarEdge system in the UK.’