I grew up near Freiburg and as a youth I fought against the planned atomic power plant in Whyl.
All my life I've tried to use energy as sparingly as possible - and today it's possible to generate and consume your own energy. That's just fantastic!"
As could be expected Andreas Klatt generates his own electricity for his electric car,
and he joined others to form the grass-roots energy collective Genossenschaft Bürger-Energie Bodensee and helped build a solar farm.
The farm's collective photovoltaic modules supply enough electricity for approximately 700 people.
"The problem is always ground space. At over 40 acres our system is already relatively large.
Being able to produce more energy using the same amount of space would be a great advantage."
Solar cells absorb sunlight and use it to make electricity. In conventional cells a large portion of the light is lost out the backside and is useless for generating electricity.
These losses can be reduced by inserting an innovative intermediate layer into the backside of the solar cell.
Scientists at the Freiburg Fraunhofer Institute for Solar Energy Systems ISE developed a way
to produce these high-efficiency cells in industrial series quantities, revolutionizing the photovoltaics market.
"By inserting a mirror into the back of the solar cell which is highly reflective of long-wave photons, exactly those photons that previously were not absorbed
when passing through the silicon wafer are reflected back into the cell, passing through the semiconductor several times and increasing electricity production."
Since this mirror is not conductive and separates the semiconductor from the electrodes,
thousands of minute connections have to be made through this layer so that electricity can flow from the wafer to the electrodes.
Fraunhofer researchers achieved this with Laser Fired Contact technology.
Each of the appr. 100,000 contacts is created with a single laser pulse.
"I have to find a laser process that's strong enough to melt the metal […],
but I still have to be able to work extremely precisely in order to minimize damage to the semiconductor."
"And now the difficulty is that I have one second to get all fifty to one hundred thousand laser pulses exactly where I want to have the contacts."
Several million solar cells have already been produced worldwide using the new Fraunhofer technology.
This means the next evolutionary step in the silicon solar cell has already been made.
"The Laser-Fired Contact process is a very simple, low-cost process.
This means that a highly efficient solar cell structure can be realized without substantial additional costs."
"The first to apply this technology could significantly increase the efficiency of their solar cells and offer their modules as a premium product in the market."
Higher performance of the solar modules at comparable costs benefits power producers and power customers alike.
"This means less space, more revenue, and reduced capital commitment… Then it all pays off."
