CORE Electric Cooperative serves more than 173,000 member homes, serving approximately 300,000 total members along Colorado’s Front Range. Their nearly 5,000-square-mile service area includes portions of 11 counties to the east, west and south of Denver.

They are the largest electric distribution cooperative in Colorado, and one of the largest in the U.S. As a member-owned cooperative, CORE operates on a not-for-profit basis. Earnings beyond expenses are invested in the infrastructure used to provide reliable electric service or booked as member equity. Some of this equity is typically returned to members each year as capital credit refunds.

CORE is governed by an elected board of directors. Their service area is divided into seven geographic districts based on population. Members within each district elect a fellow member to serve on the board and represent their interests regarding CORE business and policies, including service rates and regulations.

CORE purchases wholesale power under long-term agreements with several providers. They also purchase the output of several utility-scale solar facilities.

CORE’s headquarters is in Sedalia, about 20 miles south of Denver, and their district offices are in Bennett, Conifer and Woodland Park.

A transmission line is a high voltage electric line that delivers power from a generation station to a substation or between substations. Once the transmission line enters the substation, the voltage is reduced, and power is transmitted over sub-transmission lines to distribution substations. The power is transformed again to a lower voltage for delivery to members. Final transformation usually occurs near the user’s location.

Electric substations are a key component of any electric delivery system. Substations receive electric power from high voltage lines. Electrical equipment within the substations reduces, or “transforms”, higher voltage levels to lower voltage levels. Once the voltage is reduced, it is distributed to other substations or members by way of electric distribution lines, or “feeders.”

An easement is defined as a permanent land right acquired by a person or party to use the land or property of another for a special or particular purpose. Landowners are paid a fair market value for the easement and can continue to use the land for most uses, such as agriculture.

Design and construction of transmission lines must be in compliance with the National Electrical Safety Code. The voltage of the line and conductor (wire) positions determines the easement width. Also, there must be enough width for the sway of the conductors (wire) to be contained within the width of the easement under certain code requirements and to meet state regulations.

Every effort is made to ensure safety in construction, operation, and maintenance of transmission lines. Lines and line infrastructure are designed to withstand extreme weather conditions. Protective devices at line terminals stop the electricity flow under any abnormal operating circumstances. Utility practices meet or exceed standards set by the National Electrical Safety Code as well as those adopted by local governments.

Structures are only as tall as they need to be to support the wires and to comply with all safety and operational requirements. Shorter structures result in a higher number of structures per mile.

All construction project’s have a certain degree of construction noise; however, the proposed project will have adequate setbacks to reduce noise impact to residential and commercial neighbors. Some noise will be generated during the construction period from construction machinery and employee vehicular traffic. Construction vehicles and equipment will be required to be maintained in proper operating condition and equipped with manufacturer’s standard noise devices or between (e.g., mufflers, engine enclosures). High voltage transmission lines do have a tendency to emit noise when they are wet. However, the proposed transmission line will be designed to operate within the noise parameters deemed reasonable by the Colorado Public Utilities Commission, which is the legal authority in the state to make such a determination.

Several factors produce audible noise on high voltage transmission lines. Corona is a small electrical discharge, not unlike the static electrical charge that a person may experience when touching a metal object while walking on carpet. Corona is what creates the hissing, crackling or random popping sound. It increases substantially in wet weather when water droplets form on a transmission line. All high voltage transmission lines experience corona during wet weather. In fair weather conditions, corona and its corresponding audible noise are usually at low levels. The higher the voltage on the transmission line, the greater the corona activity on the line. This line is a 115kV line and is considered a lower voltage transmission line.

Corona on transmission line conductors can generate noise at the frequencies at which radio and television signals are transmitted. This noise can interfere with receiving of these signals and is called “radio interference” and “television interference” depending on the frequency.

Radio reception in the AM broadcast band (535 to 1605 KHz) is most often affected with what is commonly referred to as static. This problem typically occurs when we have loose hardware which can be corrected. There also may be AM radio interference when one is directly under the lines. FM radio reception is rarely affected. In the past, radio noise was a concern for the video portion of analog television signals; however, this is no longer the case in the United States because broadcast stations have switched to digital broadcasting and no longer transmit older analog AM video signals.

Corona effects from this project are expected to be low enough so that no objectionable audible noise or radio or television interference would result outside the right-of-way. If any problems do occur, transmission line maintenance activities are intended to locate and correct these problems as they occur.

Electric and magnetic fields (EMF) are created by anything that conducts electricity, including transmission lines, household appliances and business equipment. These fields are strongest closest to their source, so the farther away you are from the source, the less EMF reaches your body. The EMF associated with a high voltage transmission line occurs mainly on the transmission line right-of-way since the electric and magnetic fields surround the conductor and decrease rapidly with increasing distance from the conductor. Magnetic fields travel through most materials including iron, steel, lead, and the soil. Magnetic and electric field strengths drop rapidly as distance increases from the conductors such that at a few hundred feet from the line the fields are non-detectable. Depending on the flow of electrons, when there are two lines side by side, there can be cancellation of EMF. Magnetic fields are caused by current, not voltage. With a higher voltage more power is delivered with less current.

Considerable research and study has been done to investigate potential health effects of electric and magnetic fields (EMF) from high-voltage transmission lines on living organisms. Based on the National Institute of Environmental Health Sciences (NIEHS) and National Institute of Health (NIH) 2002 booklet "Electric and Magnetic Fields Associated with the Use of Electric Power”, minimal biological hazards have been identified from EMF produced by electric transmission lines. Nevertheless, the proposed transmission line will be designed to operate within the EMF parameters deemed reasonable by the Colorado Public Utilities Commission. The proposed transmission line will also be designed and constructed to meet or exceed all applicable requirements of the National Electrical Safety Code.

Transmission line and substation construction is scheduled to begin summer 2024 with the transmission line being energized early 2025.

The transmission structures will be between 80 and 110 feet in height.

Currently, CORE does not have any plans identified for new transmission lines in this area, other than the proposed project.

There are no planned or projected utility scale generation facilities to be interconnected with this line segment, therefore, reliable electric service may not be available to the area for existing and proposed developments under varying scenarios of growth and outages.

Since this project is an addition to the high-voltage transmission system, it will improve overall system operations, performance, and reliability.

The transmission line and substation are System Improvement project’s; thus, the project is funded by CORE’s rate structure.

Line construction involves a series of distinct activities that are performed in sequence, including: vegetation management, installation of access roads and gates, staging the structures, foundation construction, framing and erecting the structures, stringing the wires, and clean-up and reclamation. Line construction work is not continuous; rather, it is conducted in phases so delays may be expected between portions of work.

CORE will be conducting two open house meetings in the project area to answer questions and ask for comments about the project. The public assists by providing local knowledge regarding characteristics and resources of the study area. The preferences of the public are considered along with other criteria including engineering needs, maintenance requirements, environmental resources, and legal and economic considerations.

CORE knows it is important to be a good neighbor and they hope to be well received by area residents who understand there is a strong need for the project. They will make every effort to work through siting and other issues with the public, agencies, and other interested parties.

It is important that our siting process, public involvement efforts, environmental practices and engineering practices are transparent and acceptable to the public and agencies. We will continue to work with federal, state, and local agencies as well as environmental organizations, individuals, and private and public groups in order to address their concerns.

Any required federal, state, county and local permits will be obtained before the transmission line can be built.

All utilities must approach their project’s from a prudent business position and as such are proposing overhead lines because of reliability and cost. The equivalent underground transmission line will cost 10-20 times more than the overhead line to install. CORE does not have the equipment nor crews with the appropriate experience to operate and maintain underground transmission for long distances. Additionally, land purchases may be required.

CORE will competitively bid the proposed project’s construction to a list of pre-qualified contractors who are familiar with transmission line and substation construction, minimizing impacts and respecting property rights. At the contractor’s discretion, local labor may be used for less technical portions of the proposed project.

The proposed project is expected to provide significant socioeconomic benefits to local residents as a result of a more reliable supply of power for businesses and agricultural operations. The project will accommodate the anticipated growth and development as well as the existing development in the area. Affordable, reliable electricity is the engine for economic growth.

The proposed project will generate a broad array of public revenues from sales and property taxes and franchise, license and permit fees, and other charges. The ongoing revenues from the taxes and fees generated by the proposed project will benefit the County and its residents.

The proposed transmission line and substations will not present hazards to the local community or the environment. The project will be constructed and operated to eliminate the potential for contamination. Environmental damage will be limited to site disturbances required for construction and operation of the project. When possible, aspects of project construction, operation and maintenance will preserve natural resources. Construction plans, methods and practices are extremely important for the project and shall be designed to minimize damage to privately owned lands involved in the project. All work will, therefore, be performed in a manner that will minimize impacts to the landscape or sedimentation of surface waters. Disturbed areas will be returned to preconstruction conditions as much as possible or better.

The structures for this project, regardless of route alternative, consist of self-weathering steel monopoles similar in color to wood poles. The table below lists the transmission line characteristics.