Today our CREATE team visited Reterra, the biodigester
company responsible for collecting the organic waste from Freiburg’s
residences. The resulting methane is mixed with landfill gas and burned to
provide both heat and electricity. The liquid and solid remains are provided to
farmers and home gardeners as fertilizer. Remarkably, with such a wide
collection of organic waste, the operators say that the supply to the
biodigester is stable for the nourishment of the methane producing bacteria. To
deal with the problem of contamination of the organic waste, Reterra has
developed an innovative system of manipulating the material prior to its
insertion in the digester in order to remove items like plastic bags: Reterra
operators use a joystick to maneuver a claw to manipulate the organic material.
https://www.remondis-aktuell.com/en/012016/latest-news/clean-energy-and-quality-compost-in-freiburg/
We crossed the street to the headquarters of Badenova, a
local utility. Badenova explained two of their pilot projects with battery
storage. Project INVADE is funded by the European Union and has sites located
in five different countries. Freiburg’s portion consists of a vanadium redox
flow battery (VRFB) installed at the end of a long feeder line that has a
several large photovoltaic systems connected. The combination of these items
makes maintaining the voltage and avoiding energy supply congestion difficult.
The VRFB has the capacity for 20,000 + cycles and fits the characteristics of
the location. Initial tests seem positive for both voltage regulation and peak
shaving, potentially enabling the distribution grid to continue to operate
without upgrades and enabling the prosumer owners of PV systems to supply
electricity to the grid without interruption. A representative of Storion
Energy, the company responsible for creating this battery, provided a brief
description of the operation of this type of battery and its advantages.
The second pilot involves connecting 10 residential
customers with various energy storage systems together and controlling the
operation of their energy storage systems based on the needs of the
distribution grid. While the project shows the implementation of such a
“network” is technically feasible, the regulations in Germany do not currently
allow for this kind of operation. Badenova has proposed to the Federal grid
agency to change the regulations, allowing for this type of innovative
connection and control.