Langan Addresses Environmental Liability at Legacy and Renewable Energy Sites
Utilities play a fundamental part of everyday life, supplying gas and electricity to residential, commercial, and industrial properties around the world. Unfortunately, the production, storage, and delivery of gas and electricity has resulted in a legacy of soil and groundwater contamination. While utility companies are moving toward clean and renewable energy sources, they remain obligated to investigate and remediate legacy contamination. Langan has supported the utility industry for over 25 years, providing various environmental services at both legacy and renewable energy sites.
Gas generation began in the 1800s, primarily through coal carbonization at manufactured gas plants (MGPs) situated along water bodies in urban areas. Typical MGP contaminants include volatile organics, polynuclear aromatic hydrocarbons, heavy metals, and cyanide. Additionally, oil (light non-aqueous phase liquid) is sometimes observed on the groundwater table with denser coal tar product (dense non-aqueous phase liquid) migrating downward into bedrock aquifers. The migration path of MGP-related contamination is often complex, influenced by the underlying and heterogeneous substrate typically consisting of both man-made fill and natural geological substrate.
While electricity production does not have the same stigma as MGP sites, many power plants utilize coal, oil, and gas to generate electricity. The generated electricity is then routed through substations and switchyards, where electric voltage levels are changed prior to being distributed. Historically, the substations have consisted of transformers with dielectric fluids containing polychlorinated biphenyls, or PCBs, regulated by the U.S. Environmental Protection Agency’s Toxic Substances Control Act.
However, the shift to alternative energy sources, primarily solar and wind, comes with its own set of environmental challenges, including the development of contaminated properties and natural resources concerns. Due to siting requirements, solar projects are often located on brownfield sites or closed landfills, which often triggers the need for remediation or modifications to the engineering controls. Additionally, the linear routes from wind turbines to a substation frequently pass through properties that can include contamination or sensitive environmental concerns such as wetlands or tidal lands. Unlike remediation associated with most legacy utility projects, these linear projects focus on managing contaminated material. Langan’s GIS capabilities are a valuable asset in site selection, helping clients evaluate environmental and natural resources concerns at properties available for these alternative renewable sources and along project routes.
Each utility site, whether legacy or renewable energy, has its own challenges and remedial objectives. Investigation strategies may require hydrogeologic assessment of fate and transport of MGP site product through overburden (e.g., unconsolidated media) as well as in bedrock, ecological risk assessments of adjacent water bodies, vapor intrusion evaluations, investigation to support brownfield redevelopment, and assessment of closed landfills. Remedial actions, including excavations and in-situ technologies, depend on a variety of factors, and should consider the surrounding area and sustainability goals. Linear construction utility projects may only require management of contaminated soils. From former MGP sites to renewable solar and wind, Langan has the knowledge and expertise to address environmental liabilities on a wide variety of utility projects.