Proposer: City of Seward
Benefit/Cost Ratio: Applicant 4.56 AEA 2.52 ISER NS 3.50
The City of Seward proposes a second 90-ton seawater heat-pump funded by AEA to be installed alongside the first, which has been funded by a Federal Emerging Technology Grant. Together, the two pumps are targeting displacement of about 58,000 gallons of heating oil. This comes with an increase in net electrical load of 613,000 kWh.
Heat pump technology utilizing seawater has been proven technically sound for producing building/hot water heat. There are numerous large-scale operations with proven track records worldwide. The largest is in Stockholm, Sweden, serving 6,000 customers and producing 5,700 Gwh of heat annually. However, this application does have its own engineering challenges.
This kind of technology is most promising where electricity to drive the pumps is cheap and plentiful such as hydro. Cheap electricity is enough to offset the high capital costs. In this case there are economies derived from Alaska SeaLife’s existing infrastructure – there are already ocean water handling facilities, an existing exchanger, space for electrical components along with the pumps, etc. So for a relatively small capital expense the system can do well despite electricity being more expensive than in other places where heat pumps are in use.
Contribution to Lower the Cost of Energy:
Replaces heating oil with a much smaller amount of electrical energy used to drive the heat pumps. It should be noted their feasibility study demonstrated the highest first use is replacement of electric-boiler generated heat.
Useful life was per AEA assumptions at 20 years compared with applicant 30. Also assumed 90% efficiency of the model used by applicant. See concern below
The cost of electricity was calculated based on the cost of power from the Railbelt South of Alaska Range region instead of a simple annual cost as reported in the application.
The performance of the system was for a production model that will need additional engineering as described by the project feasibility report: “The requirement of using heat transfer fluid with high concentrations of propylene glycol that increases flow viscosity and reduces heat capacity.” The performance of these units will not be the same simply by changing fluids. There may be some additional capital expense to engineer around it, or reduced performance.
It appears to be about the limit of physical room in the facility.
Resurrection Bay is a deep resource relative to this use and sustainability should not be a question.
Potential Public Benefits:
The major beneficiaries are those associated with Alaska Sealife – those bearing the expense of operations. About 20% of that is user fees, but the remainder is Federal, Private, and Foundation funding. All will benefit to the extent their contribution to costs is lowered.
This is a technology that will pay where there is an abundant source of hydro at tidewater. There are other locations in Alaska that could benefit from the anticipated engineering advances.