Editorial: Biomass, dehydrated sludge and Colterm's energy independence: green solutions that Timișoara ignores

by Ilie Vasile Sirbu, Local Counsellor and member of Climate Council

Timișoara is, paradoxically, one of the greenest cities in Romania and, at the same time, one of the most dependent on methane gas for heating homes. We have the most parks in the country, entire neighborhoods built as "garden streets", a unique plant heritage, the Green Forest – a huge forest reservoir – and we are surrounded by hundreds of thousands of hectares of agricultural land. Every year, tons of biomass are produced here: leaves, branches, thin wood, forest residues, straw, stems, pellets, vegetable shreds. A renewable, local and cheap resource.

At the same time, another energy resource is produced at the city's sewage treatment plants: dehydrated sludge, a carbon-rich material with real calorific value, which in Europe is burned in cogeneration plants in Vienna, Helsinki, Amsterdam, Munich or even in Romanian cities such as Oradea and Iași. Instead of being treated as an expensive waste, sludge can be transformed into fuel, reducing Colterm's costs and eliminating an environmental problem.

We therefore have two green, renewable, local energy sources capable of reducing gas dependence: biomass and dry sludge. And yet, Colterm still burns almost exclusively gas, enduring market fluctuations, price increases and huge losses in the network.

It is time for Timisoara to move from vulnerability to energy independence.

Biomass from parks, the Green Forest and agricultural holdings can be transformed into fuel for hybrid power plants. Leaves, branches, thin wood, sawdust from logging, horticultural waste – all can feed modern boilers, just as it happens in dozens of European cities. It is a local resource that renews annually, is not imported and does not depend on geopolitical crises.

In parallel, the dehydrated sludge produced by Aquatim can enter the same energy cycle. After drying to 85–90% and stabilization, it becomes a fuel with properties similar to pellets. It can be burned directly or mixed with biomass, significantly reducing gas consumption. This means money saved, reduced emissions and a real circular economy, in which the city transforms waste into thermal energy.

This transition does not mean the complete abandonment of gas, but an intelligent strategy: hybrid power plants, which burn gas + biomass + dry sludge, in proportions adapted to the season and needs. Exactly the model used in cities in Western Europe, where climate resilience and energy independence are real priorities.

The benefits of such a strategy for Timișoara are obvious:

– substantial reduction of Colterm costs;

– reduction of financial losses and waste;

– transition to local, cheap and renewable energy;

– reduction of pollution and CO₂ emissions;

– eliminating part of the sludge treatment problem;

– resilience to climate change;

– greater independence from the gas market and external shocks;

– developing a local circular economy, where waste becomes a resource.

Timișoara has everything it needs to become a model of energy efficiency: greenery, agricultural resources, forestry resources, dehydrated sludge, technical universities, strong local companies and access to European funds.

What it does not have yet is the decision to put all these resources to work.

Colterm cannot survive in the 21st century on gas alone. But it can become a modern and competitive system if it starts using biomass, dried sludge and all the local renewable resources that the city has at its disposal.

It is time for Timișoara to stop ignoring what other cities have already been using for years: green energy produced right here, in our gardens, parks and wastewater treatment plants.