Hans Flat Ranger Station

The 7.2 kilowatt solar array is mounted on 12 trackers which follow the sun from east to west as the sun crosses the sky.

The Hans Flat Ranger Station is located in the Maze District of Canyonlands National Park. This remote ranger station is accessible by a 46 mile dirt road from Utah Highway 24. The facilities consist of a visitor center, maintenance shop, and two four-plexs.

Electricity was provided by diesel generators which operated 24 hours a day consuming over 7,000 gallons of fuel annually.

The National Park Service spent over $18,000 each year to generate electricity at Hans Flat at a cost of $0.80/kilowatt-hour (kWh). A partnership between the National Park Service and the Utah Department of Natural Resources (DNR) was created to provide financial resources, technical engineering assistance and project management expertise necessary to install a photovoltaic/diesel hybrid power system.

Project Description

This building houses the batteries and power electronics.

Installation of a 7 kilowatt (kW) photovoltaic system with a 180 kWh battery bank and two 12 kW inverters was completed in October 1995.

Project cost was $80,000 and funded through a cost-share between the state of Utah's Department of Natural Resources and Department of Community and Economic Development ($40,000) and the National Park Service ($40,000).

A 1995 energy audit conducted by engineers from DNR identified additional cost-effective energy efficiency measures to reduce electricity, propane and water use. The measures include a lighting retrofit, energy efficient appliances, and building envelope upgrades to the maintenance shop.

Results

The battery room is spacious and well lit. South-facing windows provide light and winter time heating.

The inverter and other power electronics shown here were replaced in 2001 with equipment that is significantly more efficient.

The photovoltaic/diesel hybrid power system reduced diesel run-time to 1,400 hours annually. The savings in diesel fuel and maintenance costs associated with operating the diesel generators is estimated to be $13,500 per year.

The 7.2 kilowatt solar array is mounted on 12 trackers which follow the sun from east to west as the sun crosses the sky. The trackers increase the output of the solar array, which generates approximately 46 kilowatt-hours per day, enough for two average homes in Utah or nine highly energy-efficient homes.

In 2001, the two inverters were replaced with a more efficient unit which is estimated to reduce generator run time to 400 hours per year.

Estimated annual electric savings if energy efficiency measures are installed is 2,100 kWh. The energy and water efficiency measures are being installed as funds become available.

Environmental benefits include a significant reduction of air and noise pollution from the diesel generators. Emissions reductions are estimated to be 48 tons of CO², 620 lbs. of NOX, 120 lbs. of SOX and 70 lbs. of CO annually.