Seward’s City Council has approved a plan aimed at using tidal energy to heat city buildings. If successful, the project could turn out to be the first ocean -sourced district heating system in the state. A resolution passed by the Seward City Council the evening before President Obama’s arrival is on-point with the president’s climate warming message. But assistant city manager Ron Long says it was not planned to go with the president’s visit.
“Purely coincidental. It sure worked out well that is was picked up by news media in town, so we have a chance to tell our story to a little broader audience than we might have.”]
Long says the city is planning to move away from the use of heating oil, while it attempts to create a renewable energy heating district in the city that would include four public buildings. The resolution approved Monday gave the go-ahead for seeking grant funding, and spending city funds, on the innovative project. Long says the plan is unique to Seward, because of the city’s location and because of the position of the buildings involved. The plan to use tidal forces to produce energy requires heat loops to be buried in gravel below the city’s waterfront.
“While it is warmed by sea water, we don’t pump sea water, so we don’t have to deal with any of the corrosives, extra pumps, all those other pieces of a system that we might otherwise have to have.”
The fluid in the loops absorbs heat from sea water according to Andy Baker, a consultant with Your Clean Energy, and energy auditing and consulting company.
“Vertical loops that will be drilled into the deep gravel along their bike path, where the ocean tides are washing in and out twice a day.
So the idea is that the loops would intercept the tidal water, the heat from the ocean water will go into the loops. The loops are part of one big closed loop that goes around and around in four different buildings. In each of those buildings are heat pumps. the heat pumps extract the heat from the loop.”
Interestingly, Resurrection Bay water is warmest in the month of November, according to Baker, a fact that Baker says is fundamental to understanding why ocean heat is such a great resource for much of southeast and south central coastal Alaska. The North Pacific Ocean gyre starting at the Equator eventually brings warm water to the Alaska current which flows through Prince William Sound to the front of Resurrection Bay
“And in October when they get the big rain storms here, fresh water flows out of Resurrection Bay and then draws in the deep sea water from the Alaska current. So it is sort of like a bathtub that fills up with hot water just before winter. ”
Seward will apply for a Alaska Energy Authority Renewable Energy Fund grant of 850 thousand dollars and use 85 thousand dollars in city funds for the project. City officials estimate heating the library, city hall, a city annex and fire department with renewable energy will save the city up to $76,000 annually.
Seward mayor Jean Bardarson says the city will apply for the grant this month.
“And they are awarded in January. So we are looking forward to hopefully winning those fiances to funding that project in January.”
The city’s proposed tidal energy project is different from the ocean water heating system used by the Alaska Sea Life Center in Seward. The Sea Life Center uses sea water pumped directly from the ocean then filtered and then pumped into a heat exchanger. Baker says the proposed city project requires no water pumping.