Molecular Solar have achieved and demonstrated a record voltage for organic photovoltaic cells that means these highly flexible, low cost solar cells can be put to commercial use in a wide range of consumer electronics. The research team believe 4V is a record for an organic PV device.

“This is an important advance. We are now very close to having highly flexible organic photovoltaiccells that will be capable of delivering electrical energy at a voltage suitable for recharging lithium ion batteries that are widely used in portable consumer electronics," comments (right) Dr Ross Hatton, research director. "Remarkably, this high voltage is achieved using a cell with only 4 junctions (sub-cells).’’  

University of Warwick researcher Professor Tim Jones, CTO Molecular Solar, (left) added:“The first generation of organic photovoltaics will be exceptionally well matched to consumer electronics applications. The advantage of Molecular Solar’s high voltage cells is that a single cell can be used with no requirement to connect multiple cells in series for these applications, saving manufacturing cost. ’’

Andrew Oldfield, head of Cleantech at Mercia Fund Management said, “We were attracted to Molecular Solar’s unique approach to realizing truly flexible, environmentally sustainable photovoltaics that are well matched to the burgeoning portable consumer electronics market.”

Molecular Solar are currently finalising a £5m investment round to complete the up-scaling of their OPV and MS-Flexifilm electrode technology.


ROOFTOP PV APPROACH


Gothenburg envisions rooftop gardens and solar power arrays with water and energy harvesting and accordingly  Swedish scientists from Gothenburgh develop a European tool that uses the actual conditions on roof solar panels to determine maximum magnitude of solar incidence in a whole town, a neighbourhood or particular roof to assess viability.

It is becoming more and more common to install solar panels on roofs in order to obtain green electricity, but not all roofs are equally suitable. Scientists surveying Gothenburg in a pilot project have taken a modular approach that means that systems are designed to be clustered into over 1MW blocks, with each block using a pair of centralised inverters. 

"The roofs structures of a town may be more or less suitable for the installation of solar panels, depending on such factors as how much a particular roof is shadowed by surrounding buildings and vegetation, the gradient of the roof, and the angle of incidence of sunlight. It is now possible for the first time to determine how much solar energy a particular roof will receive during the year", says (right) Fredrik Lindberg of the Department of Earth Sciences at Gothenburg University.

The scientists at the University of Gothenburg have worked together with consultants WSP to develop a GIS system that can calculate the potential of actual roofs to produce energy from solar panels. The system is called "SEES" – Solar Energy from Existing Structures – and  freely available to both companies and municipalities.

The new tool is based on computer-based geographical information systems (GIS) that collect, store, analyse and present geographical data. This means that the tool describes real roofs in the correct surroundings. The sun in the model illuminates the three-dimensional built environment and simulates how surrounding buildings, terrain and vegetation throw shadows.

The shadow effect can be calculated for each month or for a complete year, and this means that certain parts of a roof may turn out to be unsuitable for collecting solar energy, even though the roof has both optimal direction and gradient. In this way, it is possible to calculate the total solar radiation on each part of a roof structure within a given area, calculated as kilowatt hours per square metre.

SEES can provide a map over the suitability, based on the user's requirements for good, less good and poor annual solar incidence. Climate data (either measured or calculated values) with a resolution as high as 1 hour is used for the location at which SEES is being used, in order to obtain as accurate an estimate of solar incidence as possible.

"We have used Gothenburg as pilot town in the project, but the method can be used in all municipalities where the necessary data is made available. The users can judge the suitability of a roof for solar voltaic panels or solar thermal panels across a wide range, based on this", says Lindberg.

SCALING UP CPV POWER 

The system consists of 12 CPV modules, each generating more than 2 kW of peak power and Soitec reconfigured its Concentrix modules to reduce the number of parts per CPV system, making installation in the field simpler and faster. The concentrator uses a silicone-on-glass Fresnel lens construction.



“We are ready now to provide very cost-effective deployment of CPV solar power plants capable of generating hundreds of megawatts of electricity,” said (left) Hansjörg Lerchenmüller, Soitec’s senior vice president, customer group for the solar energy business unit.

Soitec’s two-axis-tracking CPV systems are intended for installation sites with high direct solar radiation. The systems produce a high, constant power output curve throughout the day, able to match peak-load demands.

Already shipping demonstration units to project sites, plans call for volume production to ramp in 1Q,  2012 at the company’s manufacturing facility in Freiburg, Germany, and later at Soitec’s planned new factory in San Diego, California.