REPOWER – INSIGHTS FROM INDUSTRY REQ


Is meeting EMC standards one step too far for the industry?


R


ecent figures from the Department of Energy & Climate Change (DECC) show that over 80,000 solar PV systems were installed


across the country between January and August of this year - a 23% increase on the same period last year.


Self-consumption technologies – delivering consumer benefits There is now a proliferation of microgeneration power diverters that are sold throughout the UK and Europe. These devices are rapidly becoming highly desirable for eco-conscious homeowners looking for new ways to save money and embrace ever-greater levels of sustainability. Power diverters help end-users self- consume the green energy that is produced by their microgeneration system. These devices monitor power being exported to the grid and divert this surplus power to a designated load, normally an immersion heater.


Whether in a domestic or small scale commercial scenario, up to 100% of self- generated power can be consumed. This helps to reduce reliance on the grid, reduce


Eco businesses nationwide have dedicated significant


resource into developing innovative cleantech products, says Jodi Huggett, Innovation Director at 4eco Ltd


energy costs and reduce individual carbon footprints. These devices require minimal initial investment and are easily installed, either as a retrofit project or as part of a new microgeneration set-up. The latest insight from UK installers has identified that over 50% of new solar PV installations include such devices, demonstrating the technology’s influence


in the purchase decision of consumers nationwide. This means that, this year alone, around 50,000 devices have been installed as part of new microgen set-ups. In addition to this, there are the many thousands of devices that have been retrofitted.


Innovative technology – but is it fit for purpose? To say that all microgen power diversion technologies are comparable is simply not true. These devices vary significantly in performance, efficiency and durability. The market currently plays host to over


a dozen different devices – all claiming to deliver the same results. This, unfortunately, is not the case. In fact, as the development of many of these devices has been rushed to meet market demand, a high percentage fail to meet the EMC standard for harmonic emissions. Many of the 50,000 devices installed so far this year, do not comply. The immerSUN®


’s truSINE® power


control technology diverts self-generated renewable energy to its destination. This technology employs pulse width modulation (PWM) that ensures the power is delivered to the load as a true sine wave. This highly effective control method means the immerSUN®


complies with all applicable


parts of the EMC directive 2004/108/EC, including EN 61000-3-2 - the harmonised standard for regulating levels of harmonic emissions.


The same cannot be said for all devices,


however. Of the fifteen known systems currently on the market, only three use PWM. The others use an alternative energy management technology called ‘phase angle control’.


The immerSUN® has


been tested for EMC compliance by York EMC who are a UKAS accredited test lab


Phase angle control devices do not produce a true sine wave. Instead, the waveform is severely distorted, creating vast amounts of harmonic emissions. This practice can cause problems with the inverter and other electrical equipment, including premature degradation of the heater element. Such harmonic interference is also conducted through the cabling, resulting in possible overheating, and can affect neighbouring properties as well as being transmitted back to the grid.


Devices which use phase angle as their 16 REQ RENEWABLE ENERGY QUARTERLY | | WINTER 2014 www.r-e-a.net


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