Invertersrepresent about 8 per cent of the total cost of a solar installationbut result in a disproportionate instance of reliability issues. Andthe traditional method of stringing photovoltaic panels in series hasinherent inefficiencies that Greentech Media Research has explored indeep detail. (See The Coming Disruption in the Inverter Market).
Entrepreneursand VC investors have turned out in full force to confront theseinverter reliability and performance issues with a number of differentapproaches. In the microinverter camp are start-ups like Enphase andPetraSolar, pairing discrete, self-contained inverters with each solarpanel. In another take, companies like National Semiconductor, Tigo,and SolarEdge have designed distributed MPPT DC-DC solutions whichlocate some of the inverter electronics at the module.
In bothof these cases – energy harvest is improved and certain designconstraints like panel mismatch, varying roof pitch, and shading areminimized.
Entering this fray is another player, Sustainable Energy Technologies,S.E.T., and their "Paralex" inverter. Designed with low-voltage thinfilm modules in mind, the S.E.T. inverter is a parallel solution butwithout locating any electronics at the PV module itself. Instead, apre-assembled wiring harness connects the thin-film panel to a"Sunergy" (not be be confused with Sunrgi)inverter specifically designed to work with the low-voltages of thinfilm panels built from Cadmium Telluride, amorphous silicon, or CIGS. Efficiencies are optimized for these low voltage panels. In S.E.T.’scase "Module voltage equals system voltage equals inverter voltage."
Unlikemost of the long list of players in the distributed inverter field,S.E.T. is publicly traded on the TSX Venture Exchange, a small capbourse analogous to the London Stock Exchange’s AIM listing. Forcompanies in Western Canada like S.E.T., the TSX Venture Exchange is away of raising capital, absent a thriving VC community. As testamentto the value of their idea S.E.T. did raise $7.6 million from UKventure firm Doughty Hanson earlier this year.
S.E.T. istargeting Southern Europe and Greece and already has 6MW of standardinverter product in the field. Brent Harris, cofounder and Director ofTechnology at S.E.T. claims they are working with First Solar’sdistributors in Spain and are on First Solar’s approved inverter list. He also says that one of the advantages is cost – the S.E.T. parallelinverter topology is competitive with traditional central inverters.
According to the company, their Sunergy inverter "sells for $0.40/W at a healthy margin."
S.E.T adds yet another inverter technology to the list.
And here’s the list:
- Accurate Solar
- EnPhase Energy
- GreenRay Solar
- Petra Solar
DC-DC Inverter Architectures
- Accurate Solar
- National Semiconductor
- Tigo Energy
Other Inverter Start-Ups
- Apollo Solar
- Act Solar (acquired)
- Array Converter
- Princeton Power
- Sustainable Energy Technologies
- TerraWatt Power
From the S.E.T. website: