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.’

Unfortunately the solar industry is not a level playing field at present.  The Chinese government has provided some enormous loans to their top PV manufacturers (e.g. http://uk.reuters.com/article/idUKHKH00202420100414).  These manufacturers are using the money for incredibly rapid expansion so that they are fast outgrowing all of their European competitors.  Being bigger means they have greater efficiency, which means the large Chinese players now have even lower costs than their foreign competitors.  There are obviously cries from US and German manufacturers about violations of international trade laws etc and indeed the situation is particularly unfair seeing as it was the German FiT that created the Chinese manufacturers in the first place, but there is little chance of any legal recourse in the near term.  The situation has led German policy makers to think about protectionist policies for solar though (‘buy German’) and provided fuel for the anti-solar lobby.

All that aside, the top-tier Chinese solar manufacturers are now producing high quality modules with lower costs than anyone else.  They have had a lot of experience with due diligence from European banks and are now pro-active in respect to quality control and bankability.  They are also beginning to invest heavily in R&D which will close the already small technology gap with Japanese and European competition.  Chinese solar manufacturers are integrating vertically in the value chain in a big way.  This means that for example cell manufacturers are starting to make wafers, silicon and modules etc. This gives them greater ability to control quality and improves margin retention.  They are also expanding downstream and bulking up sales teams in Europe with Europeans. This reduces the ‘fear factor’ of working with Chinese companies and taking revenue away from European wholesalers.  The strength of the big Chinese players is evidently putting a strain on its competition. If one had to choose between German or Chinese manufacturers as the most likely to be around in 25 years it would almost certainly be the Chinese.

It should be noted that there a number of Chinese manufacturers that do not have such high standards and should be avoided.  Many people in the solar industry are not convinced that the UK’s Microgeneration Certification Scheme is effective at weeding out these poor manufactures judging from the companies which have gotten through.  There are also lots of counterfeit modules  on the market now (for example fake Trina Solar and ET Solar modules are widespread) so its important to find installers with good checking procedures.

So does the rise of the big Chinese solar manufacturers damage the UK and make the Feed-in tariffs pointless, seeing as it will support the continued growth of unbeatable foreign competition?  I would argue that the only way to create growth in our manufacturing industry is to develop a domestic end-user market.  For a long time the UK has precious little in terms of PV manufacturing capability, which means that the strength of Chinese companies has little impact on us.  If we were not buying from China, we would be buying from elsewhere.   As the UK market grows, more people become engaged in the industry and start to look at product innovation.  Already there are a number of UK companies developing solar products specific to the UK market as a direct result of the introduction of the Feed-in tariff.

Furthermore, module manufacturing makes up only a small portion of the solar value chain.  Installing roof-top PV is highly labour intensive, and the feed-in tariffs will create a huge number of jobs in the badly suffering building services industry.  The fact that there are good quality, cheap Chinese panels available allows solar PV to be more competitive as a renewable energy source.  Costs are expected to fall rapidly over the coming years (as they have already) meaning that in around 5-6 years time the cost of solar electricity will be at par with retail electricity prices, which means the FiTs won’t be needed anymore.

Another point is that the big Chinese PV manufacturers will start doing the last manufacturing step, module integration, close to their markets.  This is because you can air freight solar cells, but you have to ship finished solar panels because of the glass (regular glass factories normally only serve a radius of 100km).  By doing module integration close to their key markets, manufacturers won’t have working capital tied up for 4 weeks and will reduce the risk of damage in transport.  Sharp already do this with a module integration plant in Wrexham, and we may well start seeing the Chinese companies open manufacturing plants in Europe, even in the UK, over the next couple of years which would provide an interesting boost to UK industry.

Eventually the playing field will level out again – China will get more expensive and there will be space for newcomers with new technologies, but for now the Chinese players clearly have the upper hand.

After a large number of companies developing thin film PV panels got huge amounts of venture capital funding between 2005 and 2008, a handful are now emerging with viable products.

Thin film PV panels are manufactured in a radically different way to traditional crystalline silicon PV panels.  This means they have the potential to be dramatically cheaper than regular panels because the manufacturing process is faster, uses less energy and requires fewer raw materials.  Despite this promise, thin film PV has a number of drawbacks.  The mains ones are efficiency (thin film PV tends to 11% efficient at best compared with 16% for crystalline silicon) and reliability (early thin film panels showed signs of degradation).

Since the thin film companies got their money a few ago, many have fallen by the wayside.  Setting up a thin film solar factory requires huge amounts of capital so a lot of companies just ran out of money and couldn’t convince investors to top them up with cash.  On the other hand, there are a few who managed to actually complete their manufacturing lines and start producing solar panels.  Unfortunately there is still a long way to go before the solar panels can be sold once that stage has been reached however.  In all markets, solar panels are now seen as a long term investment.  This means that investors need to have absolute confidence that the panels will last through their warranty period (usually 20 or 25 years).  Proving reliability is no easy task.  The panels have to go through months of intense testing, and many banks require at least 2 years of real field data before agreeing to lend money to projects involving those panels.  This means there is a long, long wait before these manufacturers can actually sell panels in any large quantities.

Up until recently there were only one, or possibly two, thin film PV companies that had reached that point, the most notable being First Solar who are one of the two largest solar manufacturers of any kind worldwide.  It seems that after all this time there is now a small selection of companies who may be about to join this list.

For me the front runners for this are the Californian company Miasole, the Japanese manufacturer Solar Frontier, and possibly the German company Q Cells with their Q.Smart thin film panels.  Miasole have just announced a large sales contract with the well respected German distributor Phoenix Solar on the back of two years of testing at their Bavarian headquarters.  Solar Frontier have announced a range of lucrative sales contracts around the world which should mean their panels should start to be seen much more widely in the near future.

There is still a long way to go before we know if people will start choosing silicon over thin film panels.  They still have a lower efficiency, which means they have to be sold significantly cheaper than higher efficiency panels, but it could be that the manufacturing costs are so much lower (once they get to large scale production) that the thin film PV companies are still able to make a good profit when selling at much below current prices.  Whether thin film PV enjoys rapid success or not, from now on there will be significantly more thin film PV companies to choose from.