Currently, Tunisia’s energy mix is largely dominated by fossil fuels - mainly depending on gas imports to meet its primary energy demands. However, the country’s vast exposure to wind and sunlight are opening up an enormous potential for the integration of renewable energies and increased energy independence. To foster this goal, Tunisia’s Renewable Energy Law for Electricity Production (No.74/2013) aims to increase the share of renewable energy to 30% of Tunisia’s total electricity production by 2030. At the same time, the country is facing a steep, continuous rise in electricity costs while trying to keep up with its growing power consumption.
This also affects the operation of wastewater treatment plants (WWTPs) of the National Sanitation Utility (ONAS). Anchored within the cooperation framework of the German Federal Ministry for Economic Cooperation and Development with the Republic of Tunisia, the German government (via KfW Development Bank) supports a project to increase the energy efficiency of WWTPs in Tunisia. Dorsch International Consultants GmbH has been entrusted with implementing energy efficiency measures for 12 WWTPs across multiple locations in the entire country.
Together with the Tunisian partner I2E, Dorsch International Consultants GmbH is responsible for the preliminary and detailed design of energy efficiency measures at the WWTPs and of 3 photovoltaic (PV) plants, the preparation of tender documents, assessment of the reduction of energy consumption and greenhouse gas (GHG) emissions, environmental and social impact assessments, public consultations with key stakeholders, support in procurement, contract negotiations, as well as regular monitoring, control and surveillance of construction works and the 1st year of operation. Further, concepts for sludge treatment and disposal are prepared.
“We are proud to be part of a major initiative towards increasing the share of renewable energy in Tunisia, which is only about 5% now” – Laure Nicolet-Misslbeck, Project Manager
The investments for the energy efficiency measures at the WWTPs include the installation of energy saving equipment such as diffused air instead of surface aeration systems, or the replacement of pumps and motors, combined with the necessary rehabilitation and extension works of some WWTPs. Additional investments are made to produce electricity from PV panels installed on the sites of the WWTPs. This includes close cooperation with the public electricity Provider Société Tunisienne de l’Electricité et du Gaz.
The project leads to a reduction of 21% to 37% in electricity consumption and GHG emissions of the various WWTP. Ultimately, these dedicated energy efficiency measures - paired with the integration of low carbon power sources - contribute to the decarbonization strategy of Tunisia that aims to meet the standards set by the 2015 Paris Agreement. The project kicked-off in September 2019 and will continue until August 2024.