Solar Ready CCR Site Closures Help Energy Companies Move Toward a Sustainable Future
Electricity is the one big energy source that can be free of carbon emissions. You can make it from the sun. You can make it from the wind. Tap the heat of the Earth, hydropower. While all utilities are moving in a sustainable, environmentally friendly direction, Aliant Energy stands out for making progress and keeping rates reasonable for consumers.
At the recent USWAG Workshop on Decommissioning, Repurposing & Expansion of Utility Assets held October 2019, Eric Nelson presented on the opportunities for solar generation at closed CCR sites and provided an overview of civil and geotechnical considerations when redeveloping closed sites as solar generating assets. His presentation demonstrated these considerations through the use of a case study.
SCS Engineers has assisted Alliant Energy with the design and/or construction of multiple coal combustion residual (CCR) surface impoundment closures. Two of the completed closures are the former Rock River Generating Station in Beloit, Wisconsin, and the M.L. Kapp Generating Station in Clinton, Iowa.
Both sites were closed by incorporating Alliant Energy’s vision to create “solar ready” sites. The Rock River site is now home to just over 2 megawatts (MW) of solar photovoltaic (PV) generating capacity, which was developed on the footprint of the now-closed on-site landfill and ash ponds. Although no solar assets have been developed at the site, the M.L. Kapp ash pond closure represents another opportunity for Alliant Energy to repurpose a closed ash pond for clean power.
Two additional closure designs are in process that incorporates similar elements, making them available for future solar generating asset development.
Eric J. Nelson, PE, is a Vice President of SCS Engineers and one of our National Experts for Electric Utilities. He is an experienced engineer and hydrogeologist.
When the Federal Coal Combustion Residual (CCR) rule went into effect in 2015, it was a new regulatory layer on top of a widely varying landscape of state regulations affecting CCR management in impoundments and landfills. Some states already had significant regulations on the books for CCR impoundments and/or landfills, while others did not.
Where state regulations existed, they varied widely from state to state. While a few states have moved toward closing the gap between state and Federal CCR requirements, many utilities continue to face confusing and conflicting requirements coming from different regulatory programs as they move ahead with managing their CCR facilities.
In her paper entitled State vs Federal CCR Rule Regulations: Comparisons and Impacts, Nicole Kron shares state-versus-federal regulatory challenges utilities have encountered during landfill design and management, impoundment closure, and groundwater monitoring and reporting since the implementation of the Federal CCR rule. For example, some sites have completely distinct groundwater monitoring programs under state-versus-federal rules, with different well locations, well depths, and monitoring parameters for the same facility. She highlights unique approaches to bridging regulatory gaps and resolving regulatory conflicts between state and Federal CCR requirements. Ms. Kron also provides insights gained on the long-term potential for regulatory resolution of these issues based on discussions with state regulators in multiple states.
About the Author: Nicole Kron has nearly a decade of experience in the environmental consulting field. Her experiences focus on groundwater quality analysis of sites contaminated with coal gasification byproducts, coal combustion byproducts, chlorinated solvents, petroleum products, metals, and PCBs. Her experience includes managing team task coordination, groundwater modeling, and statistical analysis of CCP/CCR sites. She is experienced in planning and performing soil and groundwater contamination investigations, air monitoring, well design and installation, and soil and groundwater sampling.
The World of Coal Ash (WOCA) conference is an international conference organized by the American Coal Ash Association (ACAA) and the University of Kentucky Center for Applied Energy Research (CAER). The 2019 conference will be held May 13-16, 2019, in St. Louis Missouri. This 8th joint biennial meeting will focus on the science, applications and sustainability of worldwide coal combustion products (CCPs) as well as gasification products.
SCS Engineers is a Platinum sponsor of this year’s conference, and numerous SCS professionals plan to present or attend, including our Senior Vice President of Environmental Services, Mike McLaughlin. Our presenters will be:
Check back for more details, which will be posted as the agenda is finalized.
Even the simplest impoundment closures come with design challenges. It is a challenge to navigate project constraints, whether technical, regulatory, or financial, to design and implement an effective closure strategy. Cost often helps to determine the “balance” between project constraints when the future end use of a closed CCR surface impoundment or the property it occupies is undefined. When a post-closure end use is defined, finding balance among project constraints to best serve that future use provides rewarding challenges.
SCS Engineers has navigated this balancing act on impoundment closure projects during facility decommissioning. Through a presentation of case studies, you will learn how this team has approached ash pond closure planning and execution where the future use of the impoundment site ranged from undefined to the home of a new solar photovoltaic installation. Examples also include potential future industrial use or property sale.
Case studies will highlight how geotechnical, hydrological, regulatory, or simple physical constraints have influenced the design and implementation of CCR surface impoundment closures.
A Midwest power plant that was constructed as a zero discharge facility in 2012 was experiencing water management issues due to excessive absorber recycle water with concentrated chlorides and leachate generation from the CCR landfill at the facility. The facility started exploring wastewater management options in 2013 that consisted of evaluating the feasibility of a deep injection well as a fluid disposal option and the results indicated that this option was a technically feasible alternative.
From 2014-2015 the plant continued to experience water balance and chlorides management challenges and conducted a plant review and water balance study to see if the chloride concentration and leachate generation issue could be resolved through process changes within the plant. The resulting water balance study concluded that while minor changes and optimizations could occur, it would not resolve the underlying water quality or water balance challenges at the facility. Other water disposal and management options were also explored by the plant in that included RO, evaporators and the deep well as retained alternatives.
In 2016, the deep injection well was selected as the preferred water management alternative and permitting was initiated. The goal was to get the deep well permitting started while the plant refined plant process modifications and additional water quality data on the feed water(s) is collected.
Water quality data from the site has indicated that iron, carbonate and sulfate are the dominant water quality parameters that drive scaling within the current system and will need to be addressed prior to injection so the well does no scale and clog.
The deep well was completed in 2018 and the final surface treatment system is currently under design. The facility anticipates full-scale operation of the system in early 2020.
When the Federal CCR rule went into effect in 2015, it was a new regulatory layer on top of a widely varying landscape of state regulations affecting CCR management in impoundments and landfills. Some states already had significant regulations on the books for CCR impoundments and/or landfills, while others did not. Where state regulations existed, they varied widely from state to state. While a few states have moved toward closing the gap between state and federal CCR requirements, many utilities continue to face confusing and conflicting requirements coming from different regulatory programs as they move ahead with managing their CCR facilities.
Through case studies, SCS Engineers will share state-versus-federal regulatory challenges utilities have encountered in different regions of the country during landfill design and management, impoundment closure, and groundwater monitoring and reporting since the implementation of the Federal CCR Rule. For example, some sites have completely distinct groundwater monitoring programs under state versus federal rules, with different well locations, well depths, and monitoring parameters for the same facility. We will highlight unique approaches to bridging regulatory gaps and resolving regulatory conflicts between state and Federal CCR requirements.
SCS will also share insights gained on the long-term potential for regulatory resolution of these issues based on discussions with state regulators in multiple states.
Learn how to minimize leachate and contact water management at coal combustion residual (CCR) landfills using good design, physical controls, and operational practices. Through our presentation of case studies, you will learn how to assess leachate and contact water management issues and implement techniques to minimize leachate and contact water management at your landfill.
Leachate management and contact water management at CCR landfills can be expensive, cause operational headaches, and divert valuable resources from other critical plant needs. Our presentation will provide you with useful tools to ensure your landfill is designed and operated to effectively reduce leachate and contact water and alleviate operator stress. We will present case studies that highlight how design features, physical controls, and operational practices have effectively decreased leachate and contact water management at CCR landfills.
The Utility Solid Waste Activities Group (USWAG) will host a CCR Workshop, March 20-21, 2019 at the Hilton Crystal City at National Airport in Crystal City, Virginia, near Washington, DC. Meet SCS professionals Nicole Kron, Eric Nelson, and Monte Markley, all of whom will be presenting at this prestigious event. SCS Senior Vice President of our Environmental Services Division, Mike McLaughlin, will also participate in the workshop.
Visit SCS Engineers at Booth 483 and meet our professionals, including Mike McLaughlin, Phil Gearing, Eric Nelson, Jeff Pierce, and Sarah Hoke at the 22nd Annual EUEC 2019: Energy, Utility & Environment Conference, February 25 – 27, 2019, at the San Diego Convention Center. SCS presentations will include:
Phil Gearing will speak about
“How to Minimize CCR Landfill Leachate and Contact Water Management”
Eric Nelson will present on
“Finding Balance: How Future Use Guides Ash Pond Closure Strategies”
Jeff Pierce will speak about
“Conversion of Biogas Renewable to Power to RNG – a Value Proposition”
The EUEC will feature exhibits, networking, and 10 speaking tracks:
This is the largest professional educational training & networking event of its kind in the United States. Mark your calendars!
Join Stephanie Hill, on Tuesday, Feb. 26 from 10:30 a.m. – 12:00 p.m. for her Class I UIC session titled Geochemical Evaluation for Scale Reduction of Coal Combustion Residuals Leachate in Class I UIC.
Downhole scaling of organic compounds presents challenges in Class I disposal wells. Once chemical and physical conditions drive biological growth and mineral precipitation, the resulting downhole scale must be confronted with expensive workovers, stimulations, or even plugging and abandonment.
In one Midwest case study, an electric utility is battling ferric, carbonate, and sulfate precipitate driven by fluctuating pH in its coal combustion residuals (CCR) leachate. Using a variety of geochemical models, Stephanie’s team is taking a proactive approach to eliminate expensive fixes by simulating the saturation indices of key mineral species under defined parameters that drive the formation of downhole precipitate under temperature and pressure.
Using a variety of chemical equilibrium models such as PHREEQC, MINTEQ, WATEQ4F, and Geochemist’s Workbench, conceptual scenarios are run at the surface and in the mixing zone of the downhole reservoir using site-specific water-quality data, pressures, and temperatures. Each scenario provides anticipated mineral saturation states, used to estimate mass removal or chemical neutralization to prevent downhole precipitation. To mirror the dynamic nature of the CCR leachate water chemistry, modeling will continue as an iterative process whereby we will continue to collect data and run simulations to stay ahead of changes that could affect the downhole well chemistry.
SCS Engineers’ proactive approach will reduce the potential for downhole scaling to increase operational efficiency, reduce maintenance costs, and extend the life of this Class I well.