Advantage of Cogeneration

Efficiency is a key element in Mercer's strategy. Pulp mills are the most efficient facilities for extracting materials and energy from wood. We seek to leave no forest resource wasted by extracting not only the high value cellulose portions of the wood to make pulp, but also the other biomass materials that are left over. The majority of the pulping process left-overs are utilized to make sustainable chemicals and green energy, or they are recycled and reused in the pulping process. The green energy that we produce provides the operations with the necessary electricity, heat and process steam to run the mills, as well as additional revenue from the sales of excess production.

The energy process utilized in our mills is called Combined Heat and Power (CHP) generation, also known as cogeneration. The biomass in our energy system is processed in a boiler to produce high pressure steam which drives electricity turbines and generates green energy. After passing through the turbine, the steam's pressure lowers (some of the energy has been used to make electricity) and this low pressure steam is used to dry our pulp and heat our mills. The process is more fully illustrated in the overview of our products.

An industrial facility that does not cogenerate typically relies on a power plant (for the electricity) and a boiler plant (for the steam). These conventional facilities are far less efficient than CHP facilities. As compared to conventional generation, cogeneration provides the most efficient use of the biomass resource by:

  • Increasing thermal efficiency from 45% to 85%, thereby eliminating waste of our resources
  • Reducing dependency on non-renewable fossil fuels by optimizing a sustainable source of green energy
  • Reducing greenhouse gas emissions by up to 50% by requiring less fuel inputs
  • Reducing transmission and distribution losses due to the co-location of the energy system and the industrial operations

The following graphic highlights the superior efficiency of a cogeneration operation compared to a conventional separate generation system. To generate the same energy output, a conventional system requires 89% more fuel input.