With a virtual power plant (VPP) aggregated from household solar-plus-storage installations operating in Germany’s primary balancing energy market since November 2018, German energy storage specialist Sonnen has developed software it says can operate the system up to 90% more cost-effectively.
The SonnenVPP package connects residential batteries and appliances to the VPP via an internet connection for only a fractional additional cost, according to the company.
Recent changes to IT requirements for Germany’s four electricity transmission system operators mean even small, 25 kW systems – such as household batteries, heat pumps and electric vehicle charging stations – can be connected to the Sonnen VPP via a VPN internet connection and without any additional devices. The system, said Sonnen, means the energy provided by the VPP “can be provided in a permanently stable and significantly more economical way.”
Big break
Previously, it was necessary for every home storage system connected to the VPP to have its own communication channel and ‘media break’, which separated it from other internet data. Now that requirement has been removed, Sonnen can bundle systems into 2 MW units at data centers, each with a media break.
In the event of extensive internet failure, individual home storage systems can continue to function as part of the VPP independently, according to Sonnen.
“In the new energy world there is an almost infinite number of small systems such as electricity storage, heat pumps, electric cars or air conditioning systems,” said Jean-Baptiste Cornefert, MD of Sonnen E-Services. “Only if they can be easily networked can they be used sensibly in the energy system and take over the tasks of conventional power plants.”
Wider use
The change in IT regulation means home energy storage systems “no longer have to pretend to be a nuclear power plant in a matchbox,” added Cornefert.
Sonnen has registered a patent for the software and wants to enable third-party providers to use it under license. A joint project has already been set up with British utility Centrica.
To date, Sonnen has pooled 2 MW of solar-linked home storage for use in the balancing energy market in Germany. “We are of course continuously expanding this and are aiming for at least a medium two-digit-megawatt range in the medium term,” a company spokesman told pv magazine. The new software and smart meter rollout could significantly accelerate that development.
