Highway Right of Way (ROW) represents an unused resource to most DOTs. Instead of using ROW areas for traffic safety zones and utilities placements, DOTs could be using their ROWs more effectively to generate alternative energy. This action would help reduce the consumption of fossil fuel-generated electrical energy and greenhouse gas emissions, which is consistent with many state’s climate control action plans (such as Colorado). Why are ROWs not being used for alternative energy generation? Is it not technically feasible? Is it “red tape”? Is it a lack of management innovation and imagination? Is it capital? It is all the above?

The National Highway System (NHS) is approximately 163,000 miles of roadway consisting of the Interstate Highway System and approximately 69 percent located within rural areas. It is estimated that there are approximately five million acres of NHS ROW nationwide and approximately 68 percent of those acres (3.4 million) are estimated to be unpaved. The amount of NHS ROW within Colorado is estimated to be 110,156 acres (Department of Transportation, 2010,). CDOT maintains approximately 9,144 total linear miles of ROW (CSU-Pueblo, 2011).

It is impressive that the Oregon Department of Transportation has established a ROW solar array system in the Portland Area consisting of 594 solar panels that produce nearly 112,000 kWh per year to light the I-5/I-205 Interchange. The project uses the utility grid as a battery, gathering energy during the day to light the interchange at night. Oregon DOT is working through a public private partnership to expand this solar highway concept with a goal of lighting the entire transportation system with renewable energy (TR News 267, 2010). This aggressive strategy is being taken by Oregon even though it does not have high average amounts of sunshine days; Portland, Oregon has an annual percent average possible sunshine percentage of 48%. In comparison, Denver, Colorado has an annual percent average possible sunshine percentage of 69% (NOAA, 2004). In a state that promotes the “green economy” and its high quality alternative energy resources, there are no ROW solar array systems managed by the Colorado Department of Transportation (CDOT).

The CDOT DTD Applied Research and Innovation Branch funded a research project entitled Assessment of Colorado Department of Transportation Rest Areas for Sustainability Improvements and Highway Corridors and Facilities for Alternative Energy Source Use to assess the alternative energy generation potential within their ROW. The alternative energy research was conducted by Colorado State University at Pueblo and by David Evans & Associates (Denver, Colorado). The year-long research study evaluated CDOT ROW power generation from potential alternative sources such as solar, wind, geothermal, biomass and hydroelectric generation (see the report at www.coloradodot.info/programs/research/pdfs/2011/restareas/view). This alternative energy information was recently presented at the National Association of Environmental Professionals in Denver, Colorado. The following summarizes the key points of the presentation and report:

Solar – Based on the rates of solar insolation in various areas within Colorado and the existing
ROW acreage in each insolation level, Colorado ROW receives almost 554,700 giga-watt hours of solar energy per year (GWh/year). If 100 percent of this energy was converted to electricity it would meet ten percent of Colorado’s total electricity demand based on year 2007 consumption rates. However, based on an estimated net efficiency rate of ten percent, approximately 55,500 GWh/year could be produced from CDOT ROW.

Wind – Although Colorado does have windy areas, relatively little usable CDOT ROW is located in those locations. Wind energy is still limited by technology, and large turbines require wide spacing and safety set-backs from the highway for safe and efficient operation. Total potential wind for all usable ROW would generate approximately 380 GWh/year statewide.

Biomass – Most of the state is capable of producing some amount of biomass from wood (beetle killed forests), certain grasses, landfill methane, manure and crops including corn. One ton of dry biomass can produce approximately 1 MWh of electricity, and for the entire state an estimated 4,974 tons could be roduced annually on CDOT ROW, generating approximately 5.0 GWh/year.

Geothermal – Research indicates that geothermal resources within Colorado are concentrated in the south central portion of the state. Statewide, approximately 8,530 acres of ROW are located in geothermal areas. Opportunities for CDOT to use geothermal resources may include heating and cooling with heat pumps and the production of steam power.

Hydropower -It is unlikely that CDOT ROW contains any existing hydropower facilities and the study did not attempt to quantify usable acres of ROW. Rather, about a dozen potential sites that may be located within 1/2 mile of a CDOT roadway were identified. Such sites could provide electricity through a short transmission line to CDOT facilities such as rest areas, maintenance buildings and for roadway lighting or signals.

Transmission – Although Colorado has thousands of miles of transmission lines, there are large portions of the state with sparse coverage. Yet, these mostly rural areas can have significant potential for renewable energy production such as wind, solar and biomass. Without access to transmission lines, production of such energy may be cost prohibitive.

FHWA -Prior to 1988, the FHWA prohibited the installation of most new utilities within interstate ROW, and many states including Colorado adopted the same policy for state highways. In 1988, that policy was changed to allow each state to decide whether to permit new utilities within interstate ROW and to specify the conditions for approval. Each state is required to prepare a Utility Accommodation Policy (UAP) that describes the state’s plan for allowing public and/or private utilities within ROW. The state’s Utility Accommodation Policy must be approved by FHWA.

CDOT- CDOT’s most recent UAP was adopted in 2009. However, the definition of ‘utility or utility facility’ does not specifically describe alternative energy sources such as wind, solar, geothermal or biomass, nor does it provide guidelines or standards for permitting alternative energy in ROW such as setbacks or other safety buffers. A recommendation of the study is that CDOT revise the UAP to include design standards for alternative energy within ROW.

My final thoughts- perhaps better leadership with technical and regulatory guidance can be developed by FHWA to DOTs that will promote the use of ROWs for alternative energy generation. The energy generated within the ROWs could be used to power near-by maintenance facilities, rest areas and lighting systems in addition to putting the energy onto the grid. This localized approach may make the ROW concept cost effective at some locations. It is recommended that CDOT continue further research on ROW/alternative energy generations in the form of feasibility studies to evaluate existing technologies, to reduce greenhouse gas emissions, and fossil fuel based energy consumption, and assess full life cycle costs and return on investment. All these elements are consistent with former Governor Ritter’s Executive Order for State of Colorado agency sustainability.