The configuration of the co-generation system is important to ensure high efficiency and better return on investment.

With a growing demand for power security, co-generation presents as an attractive yet challenging opportunity. Cogeneration yields heat and power from a single fuel source but the monetary advantage gained can get easily eroded if the process heat and electrical requirements are not matched effectively.

To make co generation viable, a match between process steam demand and power requirement is integral. A shortcoming here leads to:

• Operations at off design conditions lowering operational efficiencies – due to mismatch between steam generator and turbine.
• Steam venting – if the process steam demand is less that electricity demand.
• Poor steam quality or pressure drops in process plant – Incorrect design of the utility system.
• Low cogeneration efficiency.

These issues result in under-utilization of the system, wastage of energy and projected returns remain unachieved. Thus in case of co-generation systems it is important to ensure the right system configuration to ensure satisfactory performance.

Illustration:

At one of the co-gen sites we visited, the process steam demand was over estimated during design stage. This lead to lower turbine efficiencies. The facts are presented below:

Over 6% drop in generation efficiency because of operation at off design conditions!