Optimizing Heat Recovery Systems for Power Generation in Rural - PowerPoint PPT Presentation

Optimizing Heat Recovery Systems for Power Generation in Rural Alaska Tanana Chiefs Conference and Alaska Center for Energy and Power Dr. Chuen-sen Lin • Ross Coen • September 28, 2009

Chena Hot Springs

Project Summary  Power generation through use of an Organic Rankine Cycle (ORC) unit with heat recovery from diesel generator.  Laboratory and field tests.  Preferred vendor: ElectraTherm.

ORC Technology

Project Objectives  To achieve ORC efficiency of 10% and corresponding fuel efficiency by ~3%.  Reduced fuel consumption.  Lower costs.  Reduced greenhouse gas emissions.

Project Objectives  To achieve ORC efficiency of 10% and corresponding fuel efficiency by ~3%.  Reduced fuel consumption.  Lower costs.  Reduced greenhouse gas emissions.  To evaluate feasibility, operation / maintenance requirements, and economic impact.

Project Objectives  To achieve ORC efficiency of 10% and corresponding fuel efficiency by ~3%.  Reduced fuel consumption.  Lower costs.  Reduced greenhouse gas emissions.  To evaluate feasibility, operation / maintenance requirements, and economic impact.  To develop guidelines for ORC application, particularly in rural Alaska.

Tanana Chiefs Conference

Galena, Alaska  ~ 650 people  270 air miles west of Fairbanks  Transportation, economic, and government hub of Yukon- Koyukuk sub-region  Supply access by barge (river ice-free from mid-May to mid- October); regular air access year-round

Galena, Alaska  City Power Plant  Fuel consumption (2007) = 574,000 gallons diesel  Total fuel cost (574,000gal x $6.50) = $3.73 million  Total electric costs (fuel + non- fuel) = $4.69 million  Average load = 501 kW  Peak load = 1000 kW

Effect of ORC on overall efficiency Starting engine fuel 14.5 14.5 14.5 efficiency (kw-hr/gal) Gal fuel per 1000 kW-hr 68.9655 68.9655 68.9655 Cost per 1000 kW-hr (at $448.28 $448.28 $448.28 $6.50/gal) ORC efficiency 10 9 5 improvement (%) ORC fuel efficiency 1.6675 1.50075 0.83375 improvement (kW-hr/gal) Net fuel efficiency (kW- 16.1675 16.00075 15.33375 hr/gal) Gal fuel per 1000 kW-hr 61.8525 62.4971 65.2156 Cost per 1000 kW-hr (at $402.04 $406.23 $423.90 $6.50/gal) Cost savings $46.24 $42.05 $24.38

Potential total cost savings ORC efficiency 10 9 5 improvement (%) Cost savings per $46.24 $42.05 $24.38 1000 kW-hr/gal In 2007, the approximate electric production in Galena was 4,387,284 kW-hr. Potential annual savings $202,868 $184,485 $106,961 with ORC

Economic analysis (payback time) Cost of ORC unit = $128,000 Fuel efficiency = 14 kW-hr/gal, Operation = 24 hr/day

Potential Economic Impact… ACROSS RURAL ALASKA: Electric power generation in rural Alaska in 2007 = 375,000 MW-hr Fuel consumption = 26 million gallons With ORC operating at 10% efficiency, total potential savings in 2007 = $17,340,000 With ORC in every village over 20 years = $346,800,000

Current Status of ORC for Mid-sized engines  Power capacity: Less than 100 kW  Development status: R&D and prototype (pre- commercial)  Efficiency of prototypes:  7% from jacket coolant / exhaust gas recirculation  12.5% from jacket coolant / exhaust of long-haul truck  9% from hot coolant Now is the right time for a small-scale field test in Alaska!

Relevance to Alaska  ORC technology is currently being used in large- scale and industrial applications around the world…however…  Few data exist on small-scale applications, especially in Alaska’s unique environmental and climatic conditions.  There is a need for laboratory / field performance data for optimal application and design improvement.

A successful ORC project has the potential… • To provide data and insight on small- to mid- scale ORC applications.

A successful ORC project has the potential… • To provide data and insight on small- to mid- scale ORC applications. • To reduce fuel consumption and greenhouse gas emissions.

A successful ORC project has the potential… • To provide data and insight on small- to mid- scale ORC applications. • To reduce fuel consumption and greenhouse gas emissions. • To be replicated in other villages in rural Alaska.

Tanana Chiefs Conference Alaska Center for Energy and Power