You are here

Waste Heat Recovery Project

In FY 2015, the City installed three Electratherm Green Machine Organic Rankin Cycle (ORC) heat recovery generators at the Dutch Harbor Power Plant.  The new units began routine operations the first week of October 2014.  Each ORC generator can produce up to 50 KW. 

The BTU output of the Powerhouse engines is capable of producing more than 105 KW, which is equivalent to about 2% of total power produced.  Powerhouse staff are persistently seeking ways to optimize waste heat recovery, but capturing all of the available heat has been challenging.  The Powerhouse has routinely produced between 45 and 70 KW depending upon demand and the loads on each engine.  Staff hopes to continue to push this closer to full capacity.

Future waste heat recovery projects are expected to include a fourth ORC unit and eventually stack robbers.  The ORC system was designed and installed with a fourth ORC unit in mind.  With the necessary funding, the fourth ORC unit could be installed with minimal effort.  

Currently, the largest potential for waste heat recovery at the City Powerhouse lies in stack robber technology.  However, this is not considered feasible until the customer base has grown to an average demand of at least 8000 KW.  The average demand in FY 2015 was about 5300 KW, but a few of the local seafood processors with their own generation systems have expressed interest in purchasing more efficient power from the City.  Within a few years, it’s anticipated that the average demand should increase to about 9300 KW and stack robbers may become a viable option for waste heat recovery.

There is another green energy project for which the City is now seeking funding.  The City plans to install microturbines in the new Water Treatment Plant to convert water pressure and flow to produce electricity.  Completion of this project should provide virtually all electrical needs by the Water Treatment Plant and should provide an excess that may be sent to the City’s main power distribution grid.