Duke Energy Coal Ash Beneficial Reuse Technologies Study Presentation to the GWWMC Raleigh, NC November 9, 2016

Coal Ash Beneficial Use Program Duke Energy is committed to exploring safe and economic ways to recycle coal ash. So far in 2016, the company has recycled more than 58% of the total production ash (total CCPs >80% reuse) that is produced at our coal plants. The CCPs are currently used in concrete, cement, structural fills, wallboard, agricultural, misc. products. We’re committed to recycle as much material as we can, but this is driven by many factors including market demand and transportation costs. Ultimately, we seek to make investment and recycling decisions that benefit our customers. Status of coal ash beneficiation technology study per the CAMA and HB-630

Overview of CAMA Section 4.(e) - Requirements Coal Ash Management Act of 2014 / HB-630 Required study of CCP uses and markets Submittal to EMC and the CAMC August 1, 2016 Duke selected EPRI through RFP to conduct the “CAMA Study” Project Scope Overview Phase 1: Market Study Phase 2: Beneficiation Technologies Phase 3: Alternative and Innovative Technologies Present findings of RFP per HB-630 Section 4.(e) to the EMC before 08/01/16. Note: The reports were issued to Mr. Rowland, Chairman of EMC, on 7/18/16.

Duke Energy Coal Ash Beneficial Reuse Technologies Study Phase 1: Market Study

Market Drivers Supply – Produced + stored; Must be reliable and consistent supply Demand – Current and new uses Transportation – Bulk material of low to moderate value; transportation costs have a large impact on value and marketability Quality – Ash Characteristics (e.g. LOI, fineness, Ammonia / FGD/ other constituents, etc.) and Consistency of Supply. Price – “Hurdle Rate” equals cost of disposal. New laws (CAMA, HB-630) & regulatory environment for disposal should incentivize more product options for beneficial reuse. Regulatory/Public Perception Risk – Regulatory uncertainty and public perception influence market viability Competition – Coal fired generation has significantly decreased, but impetus among utilities to use both produced and stored CCPs.

Operating Coal Fired Duke Plant Sites

Retired Duke Coal Fired Plant Sites Buck 5.3 MT Weatherspoon 1.5 MT Dan River 2.8 MT HF Lee 6.0 MT Riverbend 4.9 MT Sutton 7.2 MT 7 Inactive CCP Sites 64 CCP impoundments 34 MT Stored CCPs Station Stored Tons Cape Fear 5.7 MT

Duke NC Coal Ash Market Map

Fly Ash Projections into Concrete Products Markets in NC Estimated Maximum Annual Fly Ash Demand into Concrete Products Estimated by 2015 to 2019 2020 to 2030 Duke 0.600 0.800 Leming (2015) 0.997 1.531

Duke NC - Coal Ash Quality CCPs at most sites do not meet NCDOT or ASTM specs for use in concrete, primarily LOI Belews Creek – Best quality and good sales in concrete markets Roxboro Beneficiation – Electrostatic Separation Limited Sales from other plants due to quality, consistency, or qty Data on quality and consistency limited

Other Current Ash Use Markets in NC

Phase 2: Beneficiation Technologies Duke Energy Coal Ash Beneficial Reuse Technologies Study Phase 2: Beneficiation Technologies

Options to feed Ready Mix Concrete Market Dry Beneficiation Selective Collection Air Classification Tribo-Electrostatic Separation Thermal Technology (FBC) Chemical Passivation Wet Beneficiation Thermal Beneficiation (SEFA STAR) Ash Recovery Froth Flotation Screening Hydraulic Separation

Tribo-electrostatic Separation Tampa Electric Big Bend Power Plant Longannet Power Plant Examples: Duke Roxboro Power Plant Tampa Electric-Big Bend Station South Mississippi EP -R.D. Morrow Plant RWE npower-Aberthaw Station

Thermal Beneficiation PMI Dense Phase FBC High Thermal Mass Long Retention Time Fluidizing gas = Combustion gas LOI Limitations Proven Track Record SEFA Dilute Phase FBC Short Retention Time Fluidizing gas ≠ Combustion gas Can go to Zero LOI Stand alone system Operated on ponded ash Proven Track Record LOI +++ Fineness + Uniformity Complexity ++++ Examples: PMI Carbon Burn Out® SEFA STAR®

Phase 3: Innovative Technologies Duke Energy Coal Ash Beneficial Reuse Technologies Study Phase 3: Innovative Technologies

Alternative and Innovative Technologies Objective Identify, categorize, and describe alternative and innovative technologies and products for the use of coal ash. Technologies that currently have limited or no commercial markets Assess technology maturity and potential market Approach Literature and internet searches Industry and vendor contacts Papers and conferences and Academia An Open Innovation Search process Technologies grouped into broad categories to facilitate comparison.

Technology Grouping Market Ready Technologies Mature Technologies Emerging Technologies Technologies with current limited market potential

Limited current market Market ready Emerging Mature Limited current market Flowable Fill Cenospheres Superpozzolans Aggregates Geopolymer Masonry units Alternative cement Wastewater stabilization Metal Composites Proppants Polymer composites Autoclaved concrete Zeolites Metal Recovery Rare earth recovery Nanotechnology Plasma vitrification

Limited current market Market ready Emerging Mature Limited current market Flowable Fill Cenospheres Superpozzolans Aggregates Geopolymer Masonry units Alternative cement Wastewater stabilization Metal Composites Proppants Polymer composites Autoclaved concrete Zeolites Metal Recovery Rare earth recovery Nanotechnology Plasma vitrification Colored ones have very limited acceptance in the US – or not cost competitive High Value Potential for large market

Recommendations for Beneficial Reuse Know your ash By unit and time: Due to changing coal supply, coal quality changes frequently, so testing by unit occurs on an as needed basis Core ponds: Underway at Allen, Buck, Cape Fear, Cliffside, HF Lee, Mayo, Weatherspoon, others Work with vendors to explore technologies / new products Evaluate the viability of the ash technologies. Testing is cheap HB-630: Mandate to install three (3) ash beneficiation units Evaluating new product options: brick, block, pavers, aggregates, etc. Submit RFP to better understand the markets No panacea exist Stay involved with our ash marketers to continually enhance market options

Thank You Any Questions???