U.S. Department of Energy - Energy Efficiency and Renewable Energy
Federal Energy Management Program
FEMP Helps Denali's Wonder Lake Ranger Station "Get Back to Nature"
February 28, 2003
Wonder Lake, Denali National Park
Denali National Park and Preserve's Wonder Lake inspires images of tranquil, peaceful beauty. This isolated mountain lake in Alaska is cradled in a valley deep in the heart of the Park. For those who want to "get back to nature," Denali is an ideal place. But not too long ago, for Park employees and visitors at Wonder Lake Ranger Station, nature was less than peaceful, even 90 miles into the Park. A noisy 30-kilowatt diesel generator that powered the station and its buildings ran 24 hours a day, and a good night's sleep wasn't always possible. Guided by a sustainable design feasibility study funded with a technical assistance grant from FEMP, the National Park Service has achieved its goals to reduce electricity demand and emissions, eliminate fuel spills, and minimize noise levels at Wonder Lake Ranger Station.
Built in 1939 by the Civilian Conservation Corps, the historic ranger station serves visitors, and additional structures provide summer housing for Park staff. The site includes individual bunkhouses for the rangers, a headquarters building, a shop, a pump shed, and miscellaneous small structures. A staff of eight Park rangers occupies the station from mid-May to mid-September when the weather is less harsh. During these months, the employees depend solely on site-generated power to provide all of their electricity. At Wonder Lake Ranger Station, as in most remote areas of the Park, diesel is the primary fuel for electricity generation and space heating, as well as for Park vehicles. Noise pollution from generators using diesel fuel resulted in a number of problems, including emissions of air pollutants, risks of ground contamination from spills, and high maintenance and repair costs.
Wonder Lake Ranger Station and outbuildings.
Because duty at the Wonder Lake Ranger Station can be demanding and lonely, the Park Service is improving the "quality of life" for the rangers by making accommodations as comfortable as possible. Elwood Lynn, Chief of Maintenance at Denali National Park, wanted to improve the facility and save energy and costs, but he also wanted to incorporate sustainable design, construction, and renovation principles into the standard operating procedures for the ranger station. Lynn turned to FEMP for technical assistance concentrated on two fronts' reducing electric demand and replacing the power generation equipment with a more environmentally friendly system.
Using a 1999 DOE energy survey as a starting point, Mike Gregg, a member of DOE's Oak Ridge National Laboratory FEMP team, analyzed every point use of electric energy and the potential for fuel switching and load reduction. Gregg enlisted Hal Post of DOE's Sandia National Laboratories to visit the ranger station and report any additional details.
To provide site power, the FEMP team proposed a hybrid system consisting of a 12-kilowatt, propane-fueled generator augmented by a battery storage system. The Park Service opted to use a battery bank that limited the generator run-time to only 6 to 8 hours every fourth or fifth day to recharge the batteries, significantly reducing noise. The FEMP team also recommended that a small, four-module photovoltaic system be installed to trickle-charge the battery bank during the dormant period from mid-September until mid-May. "FEMP helped us quantify our loads and identify where we could reduce them, and helped us understand potential environmental savings using the hybrid system," Lynn reported. "For instance, some refrigerators, although purchased only 8 years ago, were considerably less efficient than new ones. FEMP helped us justify all of our appliance upgrades and the conversion from diesel to propane."
Hybrid power system consisting of propane-fueled generator, battery bank, and inverters inside generation/distribution building.
The project's installation cost was approximately $45,000, and energy savings are estimated at 16.8 million Btu per year. The project reduced annual fuel consumption by 50 percent, or 2,500 gallons; exhaust emissions; carbon dioxide, sulfur dioxide, and nitrous oxide; were reduced by 34 tons, 119 pounds, and 52 pounds, respectively. Electricity usage was reduced by about 50 percent with a peak demand of approximately 11 kilowatts, down from 27 kilowatts. According to Lynn, while the station ". . . realized significant fuel savings through reducing loads and installing the hybrid power system, for the Park Service, the greater payback comes from the reduced maintenance requirements." Servicing the generator had required 4 hours of mechanic time every week. Due to the reduced run time on the generator, now it only needs to be serviced once during the 100-day season.
Additionally, FEMP's recommendation to switch fuels and install a hybrid propane fuel/battery system provided an elegant solution to the problems of exhaust emissions and soil contamination risks. The reduction in fuel consumption has reduced the amount of fuel that must be transported through the Park. The conversion to propane has eliminated the threat of soil contamination from spills and has significantly reduced exhaust emissions.
"We have a bunch of believers now," said Lynn. "At the start, they were sure that the system would significantly compromise their comfort. In fact, quite the opposite has occurred." He remarked that folks enjoyed the quiet so much that they asked if we could pursue funding to purchase additional solar panels so as not to run the generators at all.
The Park Service was able to become more energy-efficient, apply renewable energy technologies, strengthen its commitment to the environment, and embark on life cycle cost-effective operations, and is pleased to use this project as a model for future energy efficiency projects. "The entire Denali planning, design, construction, and operations and maintenance team were committed to making sustainability an integral part of this project and the credit goes to each member of the Denali National Park staff," added Arun Jhaveri of DOE's Seattle Regional Office FEMP Team.
For more information, please contact Elwood Lynn of Denali National Park and Preserve at 907-683-9561, Mike Gregg of DOE's Oak Ridge National Laboratory at 865-574-5420, Arun Jhaveri of DOE's Seattle Regional Office FEMP Team at 206-553-2152.