HomeMy WebLinkAboutNorth Pole GVEA Heat Recovery Case Study - REF Grant 2195391 est 2015North Pole, Alaska
North Pole Heat Recovery Project
Quick Facts
Total Project Costs: $1,021,615
Capital Costs
Design: $26,836
Construction: $994,779
Equipment
Glycol Heater Make/Model: Coimac AFH-
45x54-816L-G-36-EG-DT-L-O
Diesel Fuel Offset
Estimated Annual: 92,000 gallons
Actual Annual: 50,000 gallons
2009-2014: 250,000
Fuel Savings
Estimated Annual: $233,333
Actual Annual: Approx. $193,000
2009-2014: $690,000
Estimated Payback: 5 years
Actual Payback: 7.9 years
CASE STUDY
Project Overview
In conjunction with the Alaska Energy Authority,
Golden Valley Electric Association’s (GVEA) North
Pole Expansion Plant (NPEP) began a heat recovery
project. Th e project harnesses waste heat from their
Rankine cycle electric generators and uses it to heat
NPEP facilities. To accomplish this, they installed 520
feet of underground supply/return piping, a glycol
distribution system inside NPEP, and 12 new glycol
unit heaters. Steam condensed from turbine exhaust is
recovered through the glycol piping system. It is then
distributed through 12 heaters, emitting heat to NPEP
facilities that used to require 15 electric heaters.
Objectives
Th e main objective of this project was to create a
system that uses waste power plant heat to heat several
other NPEP facilities. Prior to this project, the heat
produced by the turbine exhaust was released to the
atmosphere via fi n fan coolers. By making use of this
heat, NPEP was able to replace 15 electric unit heaters
in their facility. Th e replacement of these alone totaled
500,000 watts of saved energy. Any electricity conser-
vation and fuel savings benefi t GVEA’s 33,000 mem-
bers from Cantwell to Delta Junction by reducing both
energy costs and atmospheric emissions.
Heat Recovery-How it Works
NPEP is somewhat of a unique heat recovery project-it
does not require a heat exchanger. Instead, it pulls the
heat directly from their facility using glycol piping.
Th ey incorporate a Rankine steam cycle to recover gas
turbine exhaust heat and generate additional electric
power. As the turbine exhaust steam is condensed
back to water, heat is rejected from the steam cycle and
emitted to the atmosphere. Th is project captures that
wasted heat and routes it through the glycol piping
system to the 12 glycol heaters where it is used to heat North Pole expansion plant, photo courtesy of AEA.
their facility. Th e energy conserved increases available
power to GVEA members by 410 kW without install-
ing new generating capacity. Th at amount may be the
diff erence between being able to provide the required
load with one turbine or having to start a second when
the load exceeds NPEP’s capacity. Member fuel savings
in this case are exponential due to the poor effi ciency
of a second gas turbine at low loads.
Economic Feasibility
Th e waste heat recovery system became operational
in November of 2009. Since then it has provided the
North Pole community with 13,622 MMBtu of ther-
mal energy and displaced 250,000 gallons of diesel
fuel. Th is displacement has saved North Pole $690,000.
Over its 20 year projected lifespan, the project has a
benefi t/cost ratio of 3.44, meaning that benefi ts out-
weigh the costs by 3.44.
Allocation of Funding
Th e Renewable Energy Fund contributed $817,292 and
GVEA funds contributed $204,323. Renewable Energy
Fund money went to the purchase and installation of
the 520 feet of underground supply/return piping in
addition to the glycol distribution piping system inside
NPEP. GVEA matches went to equipment, labor, and
the installation of the 12 new Coimac glycol heating
systems.
Learning Experiences/Challenges
1. Despite being engineered, the piping is slightly
oversized. As a consequence,GVEA is considering
the addition of several buildings onto the heat recov-
ery system. Heating the plant barely puts a dent in
the energy available with the system. Th e additional
buildings would add another 10 to 20 percent of the
currently serviced square footage without impacting
system performance. Any use of waste heat improves
the effi ciency of the plant providing it; by adding
buildings to the system GVEA would be able to use
more of NPEP’s wasted heat, further improving the
facility’s effi ciency.
Community Benefi ts
1. An important benefi t to this project is less diesel fuel
combustion, resulting in less associated emissions to
the atmosphere. Th is provides a healthier environment
for everyone.
2. Another equally important community benefi t
is that there are increasingly lower energy costs for
GVEA members, especially those that reside in North
Pole. Th e City of North Pole purchases its electricity
from GVEA at an average rate of $0.16/kWh. As NPEP
continues to increase its effi ciency, a signifi cantly less
amount of fuel is wasted and they have to purchase
that much less fuel for the performance of their plant.
Project Contact Information
Parties Involved:
Rose-Mary Wiebold, GVEA project accountant
Email: RWiebold@gvea.com
Phone: 907-451-5659
Paul C. Morgan, GVEA project manager
Email: PCMorgan@gvea.com
Phone: 907-458-5780
Case Study Author:
Zoe Tressel, AEA
Website: Akenergyauthority.org
Phone: 907-771-3000
North Pole, AK
Photo courtesy of explorenorth.com
North Pole, Alaska