Hull Rust Mine Panorama, Hibbing Minnesota
Donald R. Fosnacht, Ph.D.
Meeting State Mandates for Renewable Power Generation y Minnesota renewable energy standard (MN Statute
216B.1691: 25% renewable by 2025 for non‐nuclear power utilities and 30% by utilities with nuclear capability). y Minnesota’s climate change goal (MN Statute 216H.02: 30% reduction by 2025 and 80% reduction in green house gases by 2050)
How can increasing amounts of renewable energy be integrated into the power grid system without causing significant disturbance?
y Solar and wind energy are intermittent energy
resources y As more and more wind and solar energy is brought “on‐line” they will have increasing effects on system stability y Energy managers believe that penetration beyond 12% of overall power generation will require fossil fuel based peaking plants and various types of energy storage systems
Why? Balance Intermittent Power Source Generation with Need
Load versus Wind Power Generation for MN on 1/3/2010 (Source: MISO)
Pumped Hydro Energy Storage y y y y y y
Known technology over 40 sites exist in US today Very high capacity Predictable capital and operating costs Easily integrated into the grid management system Requires significant water resource Requires power source to move water from lower to upper reservoir y Modern variable speed systems now achieve 86% overall efficiency It should be viewed as a facilitation technology for renewable energy implementation
Existing PHES Facilities in USA Courtesy of Rick Miller, HDR Inc.
Various Energy Strategies are under development
Ibrahim, H., Ilinca, A., and Perron, J., 2008, Energy storage systems – characteristics and comparisons: Renewable and Sustainable Energy Reviews.
Cost and Storage Capability are key to large scale renewable implementation Annual Costs for 8-hr Bulk Energy Storage Technologies ($/kW-year) $1,600.00 $1,400.00 $1,200.00 $1,000.00 $800.00 $600.00 $400.00 $200.00 $0.00 CAES
PHES
PHES (variable Na - S Battery LA Battery (FC) speed)
LA Battery (VRLA)
Zn-Br Battery
Ni/Cd Battery
Source: Schoenung, S. M., and Hassenzahl, W. V., 2003, Long- vs. short-term energy storage technologies analysis: A life cycle cost study: A study for the DOE Energy Storage Systems Program: Sandia National Laboratories Report SAND2003-2783, 60 p.
Basic Concept Diagram
http://upload.wikimedia.org/wikipedia/commons/9/9a/Pumpstor_racoon_mtn.jpg]
Basic Operating Concept During off‐peak periods, wind energy is plentiful and low priced
Upper, lower reservoirs are existing, out of service, Iron Range open pit mines ?
PHES facility stores low price energy, releasing it during peak periods when demand and price is high
Comparison of Technologies
Bogenrieder, W.: 2.6. Pumped storage power plants. Heinloth, K. (ed.). SpringerMaterials ‐ The Landolt‐Börnstein Database DOI: 10.1007/10858992_7
Storage Benefits need to be reflected in revenue and cost equations ‐‐ PHES can: y Allow firming of overall
y y y y y
capacity from renewable sources Significant capacity per unit capital cost Long term facility life Can follow load requirement Provide a fast acting spin reserve Help regulate system voltage requirements
y Provide transmission
y y y y
systems support and buffer possible congestion Employ time of use energy cost management Demand charge management Add soaking capabilities Provide reliable power quality
Overall Energy Efficiency for PHES Systems ‐‐ Example
Modern variable speed systems can approach 86% efficiency
Bogenrieder, W.: 2.6. Pumped storage power plants. Heinloth, K. (ed.). SpringerMaterials ‐ The Landolt‐Börnstein Database DOI: 10.1007/10858992_7
Minnesota Opportunity y Take advantage of water resources on MN’s Iron Range
(MIR) from abandoned mine pits y Close proximity to Minnesota Power’s DC transmission line from North Dakota wind resources y Great River Energy and Minnesota Power have ample transmission line capability near the various mining sites y Allow potential large scale energy storage using a proven technology to aid in adoption of renewable energy from wind
Why this project? y Key questions that need study: y What potential sites exist on the MIR? y y
What makes a good pumped storage site? Are there potential sites for closed loop pumped storage in Northeastern Minnesota with sufficient scale to support a project from previous mining activities?
y Can a closed loop pumped storage project co‐exist with
present and/or future mining activities? y How can PHES be implemented in an environmentally benign way? y Are any changes needed to state policy to remove roadblocks that would impede implementation of the technology that balances the value of the environment, minerals and renewable generation?
UM – diverse input to project y UM Participants y Natural Resources Research Institute y UMD Civil engineering y Saint Anthony Falls Laboratory y Humphrey Institute y Commercial Participants y Great River Energy y Minnesota Power y Barr Engineering
Four focus areas y Environmental Issues y Facilities requirements y Geotechnical parameters y Policy and economic factors
Geotechnical Team y Assess the integrity and properties of the rock at any y
y y y y
selected location Determine the geologic conditions that exist at any site and the likelihood for coherent rock structures for the upper and lower reservoir basin Generate maps and datasets illustrating site characteristics Lead assessment of alternative land use Assess integration of pumped hydro storage design with the long‐range mining plans of existing mining operations Characterize select waste materials for economic and environmental purposes
Geotechnical Team y Geotechnical Assessment y ‐ Rock Mechanics – Sampling & Testing/GIS; y ‐ Mineral Assessment/Permitting/GIS; y ‐ Rock Stratification/Geological Mapping/GIS; y ‐ Geological Integrity/Geological Mapping/GIS; y ‐ Minerals Usage and Value/GIS; y ‐ Waste Rock Characterization & Analysis/GIS;
and y ‐ Archeology/Historic Sites/GIS.
Facilities Team y Survey of existing pumped hydro facilities, overview of
overall systems/components and overview of design variations y Component characterizations including cost and potential size limitations (civil and mechanical works) y Review of current economic analysis of pumped hydro plant construction (i.e., cost/MW(h)) including currently reported estimates and models
Critical Component areas Reservoirs
Mechanical and Electrical
y Sealing mechanisms and
y y y y y y y y y
y y y y y y
construction techniques Overflow controls Leakage monitoring Intake and associated gates Penstock to pumphouse Embankment/dam construction Rock walls/manifolds/surge tanks
Pump/turbine Motor/generator Draft tube Start‐up systems Pumps Compressors Gate Actuators Controls/meters/actuators Transmission lines and transmission equipment
Environmental Team y Consider environmental impacts of both mining and PHES
implementation y Study areas: 1. 2.
Geology and soil Water resources • groundwater & surface water • water quality & quantity • greenhouse gases 3. Terrestrial resources • wetlands and vegetation
4. 5. 6. 7.
Wildlife Threatened & endangered species Cultural Resources Air quality & Noise
8.
Hazardous Materials
Permit assessment State permits 1. 2. 3.
4. 5. 6.
Minnesota Public Utility Commission (PUC) permits DNR Water Appropriation Permit MPCA National Pollutant Discharge Elimination System (NPDES) Permit Dam Safety Permit Wetland Conservation Act (WCA) compliance MPCA Industrial Stormwater Permit
Federal permits 1.
2.
Federal Energy Regulatory Commission (FERC) Licensing Section 404 Permit (if wetlands are impacted)
FERC “Initial Consultation List”: http://www.ferc.gov/industries/hydropower/enviro/consultlist.aspx?State=Minnesota
Surface and Ground Water Exchange 1. Within what area surrounding the pit will groundwater flow (direction and magnitude) be changed? 2. How might these changes affect the oxidation/reduction of iron and sulfur within the affected area and therefore, the water quality in pit lakes? 3. How might PHES development affect ongoing and future mine land reclamation efforts? 4. What is the potential for PHES to exacerbate existing water resource issues in the region? (e.g. sulfate, fish‐ mercury, heavy metals, sedimentation, et al.)
Modeling of System
y Conceptual model for PHES effects on water resources under
development Surficial geology, unconsolidated, high K •Pumping drawdown may influence surficial hydrogeology that influences surficial hydrologic budget
HWL
−K
Mean WL LWL
Bedrock geology, consolidated, low K
Short‐term exchange of GW with SW in reservoir
dh dL
Long‐term average flux of GW to reservoir
•Characterizing hydraulic properties of fracture dominated rock
•Two mechanisms foreseen for altering mass transfer from rocks to SW
Pump discharge into complex limnology of deep pit reservoirs
QP (t )
1.
Wetting/drying cycles speed oxidation processes
2.
Hydrostatic pumping increase exchange with groundwater
Policy Team y Assess land use and mineral rights issues that would be impacted by y y y y
locating PHES facilities on the MIR. Identify socio‐political factors that affect PHES deployment on the MIR, including key stakeholders and their perception of PHES. Determine policy implications of closed loop PHES on the MIR and identify legal or regulatory barriers to implementation. Identify life cycle parameters that will need to be quantified in more detail in future studies Outline potential benefit stream from PHES deployment
PHES implications – some initial considerations (1) Improve System Reliability Pumped storage is alternative to natural gas power plants for providing back‐ up generation for variable generation • Pumped storage also serves as a load during pumping. Therefore, it could reduce episodes when wind producers are asked to shut down because there is not enough demand, termed curtailments. • Under most power purchase agreements, utilities bear the risk of curtailment (2) Reduce transmission congestion • A high location marginal price (LMP) is a signal of weakness in the power system. High LMPs can be alleviated with either new generation or new transmission. • PHES is an alternative to building additional transmission • Generators (e.g. PHES) capable of closely matching LMP patterns on the local region are of higher value to the system as they are more effective at reducing need for, and stress on, the transmission network
PHES implications – continued (3) Arbitrage electricity prices and provide ancillary services •
•
The profit of the pumped‐storage plant is maximized by operating the facility as a generator when the LMP is high and as a pump when the LMP is low The revenue of a pumped‐storage unit includes the revenue received by selling energy when it is in the generating mode and by being accepted in the non‐synchronous reserve market when not in the generating or pumping mode
(4) Offer system balancing services •
Bid the services of pumped storage into the ancillary markets when it is not pumping or generating
Relationship of PHES to Minnesota’s Renewable Energy Standard • Unclear whether PHES would be treated as renewable power. • Pro ‐ PHES operates similar to a hydroelectric facility in that it releases water through turbines to generate electricity. • Con ‐ the fuel for pumped storage is off‐peak power, not water. The pumped storage facility is a net consumer of energy. • Current MN policy states that hydroelectric with a capacity of less than 100 MW qualifies as an eligible energy technology for purposes of satisfying the renewable energy standard • PHES facilities will most likely need to be larger than 100 MW to be viable economically – this is a potential policy barrier.
Potential MIR Schemes •Pit‐to‐pit •Most difficult to find in topography •Reduced cost due to completed reservoirs •May require patches to slow leakage •Natural Pit to Constructed Upper reservoir •Reservoir Construction •Easier to find in topography •Isolated Pit to Constructed Upper Reservoir
Project Status Milestone • Tour of Ludington, MI PHES Facility • PHES Policy Group Focus Meeting @ GRE • Tour of Selected Potential PHES Sites • Research, Literature Review • Compile, Analyze GIS Data • Geological Mapping of Potential Sites
Completion Date 30‐Jul‐10 28‐Sep‐10 14‐Oct‐10 Underway Underway Underway
Future Activities Milestone • Develop Site Assessment Guidelines • Develop Site Survey Plan (locations) • Review Site Survey Plan w/DNR • Conduct Site Survey • Geological Sampling • Site Ranking • Policy Factors Review • Draft Project Report • Final Project Report • PHES Project Completion Date
Completion Date Underway Underway Underway Jan‐2011 Feb‐2011 Feb‐2011 Mar‐2011 Mar‐2011 Apr‐2011 30‐Jun‐2011
Participants in Study Overall Coordination
Policy Team
y y y
y
Dr. Donald Fosnacht, NRRI, Principle Investigator Mr. Dwight Anderson, Minnesota Power Mr. Vince Herda, Great River Energy
Facilities Team y y y y
Mr. Jeffrey Marr, St. Anthony Falls Laboratory, UMTC* Dr. John Gulliver, Civil Engineering, UMTC Mr. Matthew Lueker, St. Anthony Falls Laboratory, UMTC Mr. David Aspie, Minnesota Power
Geotechnical Team y y y y y y y y y
Mr. Steven Hauck, NRRI* Dr. Carlos Carranza‐Torres, Civil Engineering, UMD Dr. George Hudak, NRRI Mr. Mark Severson, NRRI Mr. John Heine, NRRI Mr. David Aspie, Minnesota Power Ms. Rochon Kinney, Minnesota Power Mr. Carl Sulzer, Great River Energy Ms. Julie Oreskovich, NRRI
y y y y y y y y y y
Dr. Elizabeth Wilson, Humphrey Institute of Public Affairs* Melisa Pollak, Humphrey Institute of Public Affairs Nathan Paine, Humphrey Institute of Public Affairs Mr. Dwight Anderson, Minnesota Power Mr. Steve Garvey, Minnesota Power Ms. Cindy Hammerlund, Minnesota Power Mr. Mike Klopp, Minnesota Power Mr. Bob Ambrose, Great River Energy Mr. Mark Fagan, Great River Energy Mr. Jay Porter, Great River Energy Mr. Bob Sandberg, Great River Energy
Environmental Team y y y y y y
Dr. Nathan Johnson, Civil Engineering UMD* Xianben Zhu, Civil Engineering UMD Dr. Rich Axler, NRRI Mr. Kurt Johnson, NRRI Mr. Blake Francis, Minnesota Power Mr. Mark Strohfus, Great River Energy
*Team Leaders
