It is bizarre. Germany has an enormous capacity of 27 GW photovoltaic power installed right now. On May 25th, a record of 22 GW peak output was achieved which equals the production of about 20 nuclear power plants around noon time. 189.24 GWh were produced by PV during the day (which would correspond to the energy produced by seven nuclear power plants (each 1.1 GW) in 24 hours). This is the amount of electrical energy generated from more than a million PV solar systems spread all over the country on that record day. That was almost 14% of Friday’s total electricity consumption in Germany1.

Fig.1 Solar energy production during the “record day” (Source: Green Technica)

Good news, it seems. High PV production at peak times (noon) leads to a drop of electricity prices at the stock exchange (European Energy Exchange EEX) for traders. However, a lot of fed-in solar energy results in an electricity price increase due to the high Feed-in Tariff (FIT). The difference between the FIT and the low electricity prices (as shown in Fig. 2 for that very day) will be allocated mainly among the private consumers.

Fig. 2 Price development for electricity in relation to the solar production during the “record day” (Source: EPEXSPOT, 25th May, 2012)


With a drastic decrease in FIT the German government wants to regulate the development of renewable energy on an economically and ecologically balanced basis. That includes, e.g., a decrease of FIT from 24.43 to 19.50 ct/kWh for PV-plants producing up to 10 kW. Also, only 80% of the produced energy can be sold for this price to enforce self-comsumption2. Since the FIT will be decreased even more, or might be abolished altogether, self-consumption becomes more and more cost-efficient. Therefore, photovoltaics need adequate electricity storage solutions and intelligent energy management to be an attractive investment option for house owners. Among the 1909 exhibitors at the Intersolar Munich (www.intersolar.de), held from 11-15th June 2012, more than 140 international exhibitors presented the latest products and solutions for energy management and storage3. E.g., Solarwatt presented a system where the production of the solar module and the household consumption is recorded by a monitoring device. The system then activates and deactivates household appliances via a wireless interface according to the production of the power plant4. But smart energy managers require also smart batteries. Saft and Schüco presented a combined system: The Schüco Energy Manager determines if energy should be stored, used or sold back to the grid. The newly developed, extremely efficient Li-ion batteries from Saft support the highly dynamic charging and discharging characteristic for PV applications5.

Hopefully, we will see more development in this field to achieve a convenient, flexible and affordable supply by renewable energy.

Dr. Sandra Schicho, Post-Doc, 2nd year at Université de Sherbrooke

1Source: Clean Technica

2Bundesamt fuer Umwelt, Naturschutz und Reaktorsicherheit www.bmu.de

3http://www.intersolar.de

4http://www.solarwatt.de

5press release Saft

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