COGENCanada CHP Association
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Cogeneration Project Challenges

Among the main challenges to complete a cogeneration or combined heat and power project is having all the players work together: For example:
  • The Utility may not want to buy the power or may put large restrictions or costs to connecting to the grid such as a standby charge when the cogenerator is shut down.
  • The steam host may have fluctuating heat or steam requirements which may be hard to follow.
A good way to have the cogeneration system follow the steam host's steam load is to duct burn1 The amount of duct burning can be varied. This is efficient because, with 15% oxygen in the gas turbine exhaust, no additional air needs to be added(unless the duct burning is extremely high). The additional air would have exited the stack at a temperature higher than outdoor temperture- a waste.

With electricity more valuable, the tendancy is to generate a lot of electricity, leaving only a small proportion of the potential heat for the steam host and the rest lost at condenser cooling tower or heat exchanger to the river.

1 (burning more natural gas between the gas turbine and HRSG (or boiler)