Abandoned Wells Can Provide Use for Pulverized Wind-Turbine Blades

Abstract

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 213000, “Improving Economics for Abandoning Orphaned and Idle Oil and Gas Wells by Providing Storage for Pulverized Blades From Wind Turbines,” by Elena Ikeocha, SPE, and Iraj Ershaghi, SPE, University of Southern California. The paper has not been peer reviewed. _ The complete paper outlines a potential solution for handling leftovers from wind-turbine blades. Bisphenol A (BPA) is a chemical used in such blades. The risk of BPA leaching into groundwater resources and the soil from wind-turbine-blade landfills can damage the food chain and can harm future generations through exposure to contaminated resources. The solution discussed by the authors is the potential use of the casing of idle wells considered for plugging and abandonment (P&A) for housing pulverized blades mixed with Portland cement. ​​​ Introduction The first large wind farms in the US were installed in the 1980s. Since then, the US has experienced two generations of wind-turbine installations, meaning that many of the early-generation turbines have already reached their end of life (EOL). Approximately 85% of turbine components are recyclable. Because of the complexity of the recycling process, however, these parts typically end up in landfills. Using landfills is, unfortunately, the most-common method for blade disposal in the US because of its convenience and cost efficiency. Wind turbines are manufactured using composite materials formed by the combination of polymer resins and high-tensile-strength fibers to develop glass-fiber-reinforced (GFRP) or carbon-fiber-reinforced polymers. These composite materials provide strength, weight, and durability. The strength and durability of the turbines, in conjunction with their size, create a disposal problem during their EOL. A singular wind turbine blade can be up to 100 yards long. The average weight of a wind turbine blade 128 ft long is 5,200 lbm. Blades that measure 155 ft can weigh up to 27,000 lbm. The annual rate of blade decommissions is projected to reach 2.2 million tons per year by 2050. Breaking down the statistical outlook further, 400,000 tons of blades will be decommissioned annually by 2030. This number is projected to reach 800,000 tons annually by 2050. EOL Options for Wind Turbines Between 80 and 90% of a wind-turbine blade’s mass consists of composite materials. Of that percentage, 60–70% is made up of reinforced fibers, while the remainder is resin. BPA is a chemical produced mainly for use in polycarbonate plastics. The epoxy used to form the blade consists of approximately 30–40% BPA. BPA can leak out because of blade erosion after landfill placement. Wind-turbine-blade landfills have the potential not only to leach hazardous chemicals into the environment but also to affect subsurface aquifers. Because of their durable nature, they will remain in landfills forever and leach volatile organic compounds and other toxins for decades.