Pipelines and Environmental Stewardship

Woodway Energy Infrastructure is committed to staying abreast of technological advances in the pipeline industry, and is on the forefront of assuring best practices in pipeline safety systems.  This blog sets the context on how we think about it at Woodway Energy Infrastructure.

Pipelines and Environmental Stewardship

Pipelines are the veins and arteries that help transport America’s energy supply in support of many industries including power generation.  Natural gas pipelines support almost 40% of the nation’s electrical power generation requirements alone, and that number continues to grow.  Ultimately, over 2.6 million miles of natural gas and petroleum pipelines in the United States move trillions of cubic feet of gas and billions of ton/miles of liquid products each year, something no other form of transportation of these products can efficiently achieve, especially with respect to the environmental impact of that mode of transport.

With that in mind, it is critical that the more than 3000 pipeline operating companies in the United States continually address how their projects and assets impact the environment.  Among other things, pipeline operators use engineering, technology, environmental experts, and old-fashion “boots on the ground” combined with high-tech eyes in the sky to provide best-in-class environmental stewardship with this most efficient energy-transportation asset.

Environmental stewardship starts at pipeline conception and continues throughout the life of the asset.  Prudent operators implement Integrity Management Programs (IMP) that outline specific actions and processes to protect the assets and ultimately the environment.  Within most Integrity Management Plans, three specific programs which help mitigate environmental impacts include project-related Right of Way (ROW) restoration plans, Cathodic Protection (CP) plans to reduce or eliminate metal corrosion, and proactive operational monitoring, surveys, and inspections of both the pipeline and the ROW during the life of the asset.

Right of Way Restoration

Pipeline routing is a vital aspect to any project and there is a lot of thought and work put into minimizing the impacts to landowners and the environment.  Often, pipelines are collocated with other rights of way including existing power lines or other pipelines and the width of the ROW is minimized to just what is required for proper maintenance.  This reduces the amount of vegetation clearing and tree removal thus helping maintain the environment.

During construction, native topsoil and its seedbank are segregated and retained by processes including “double ditching” and the use of silt fencing to prevent soil from eroding off the ROW.  Regardless of where a new pipeline is installed and how much native soil is reused, the ROW must be revegetated quickly to prevent erosion and to allow the local species to return, if they were affected at all.

Given that pipelines often cross many vegetatively unique habitats within relatively short passes across the landscape, the planning and work to determine the best revegetation program begins during the engineering and design phase and should be ready by the time a construction contractor is selected.  Environmentally conscious operators will work with local experts to determine, and develop, if necessary, the appropriate seed mix for an area.  For that portion of a ROW that requires revegetation, local and native seed mixes are not only the obvious solution, but also the most expedient which improves how quickly a ROW can be restored.  Silt fences are removed at the 70% revegetation milestone as estimated by an environmental consultant to be consistent with state and federal permits.

A pipeline revegetation plan also considers soil characteristics, the construction schedule with respect to the next growing season, application processes, imported soil requirements, invasive weed control, monitoring, and soil erosion mitigation techniques (pre and post-erosion events including significant precipitation).  These plans impact the successful revegetation cycle and ultimately minimize the environmental impact of a pipeline project by quickly returning the ROW to a stable vegetative state.

Cathodic Protection

Unprotected metal (pipe) corrodes when faced with an electrical current in an electro-chemical reaction.  In short, electrical ions “leave” the metal pipe to neutralize the electrical imbalance.  The ions that are lost by the pipe in this manner is also known as corrosion.  Corrosion reduces the thickness of the pipe walls ultimately reducing the strength leading to possible failures and product releases.  In order to ensure this does not occur, pipeline operators use engineering and technology to protect the pipe, within the areas of pipeline coating, as well as Cathodic Protection (CP).

There are two main types of CP, galvanic anode and impressed current.  The galvanic anode system uses more active metals such as aluminum, magnesium, and zinc to act as the protection (cathodic protection) of the base carbon steel pipe and corrodes in lieu of the carbon steel.  Alternatively, the Impressed Current method uses DC current to counteract the electro-chemical process.  DC power is applied to the pipe via transformer rectifiers or a battery (sometimes via solar-powered batteries).  The DC acts as the balancing agent to counteract the naturally occurring electro-magnetic process and thus protects (cathodic protection) the underlying carbon steel.

These are simple explanations of a complicated but routine process pipeline companies use.  The planning for it begins with initial routing, especially along any shared powerline ROW, and continues during the engineering and design phase when rectifier locations and power sources are determined.  CP continues during the construction phase by installing the prescribed CP materials and then during the life of the asset, CP is maintained as part of the IMP through annual CP testing, monitoring, repairs, and surveys.

Operational Monitoring, Surveys and Inspections

Pipeline operators must inspect their assets.  There are numerous codes, regulations, manufacturer requirements, and best practices, too many to mention here, that dictate what to inspect and how often to inspect.  All of these inspections are ultimately focused on one thing – the integrity of the pipeline asset and the product(s) the pipeline helps transport.

Some of the inspections include the testing and monitoring of the previously mentioned CP systems, leak monitoring with specialized gas detection monitors, aerial surveys with aircraft-mounted leak detection devices, population density class surveys, valve inspections, and exposed pipe inspections.  There are also many other tests and reports that are maintained anytime an operator visits an area of the pipeline, all of which build a documented history of the pipeline.