Northwest Energy Association

NWEA Speaker Program for 2019-2020


Thursday February 20 , 2020


Please note: We can only accept cash and checks at this meeting. We encourage you to pay in advance by requesting a Square Invoice.
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An Integrated Feasibility Study of Reservoir Thermal Energy Storage in Portland, OR, USA

Authors: 
John Bershaw1, Erick R. Burns2, Trenton T. Cladouhos3, Alison E. Horst4, Boz Van Houten5, Peter Hulseman1, Alisa Kane6, Jenny H. Liu1, Robert B. Perkins1, Darby P. Scanlon7, Ashley R. Streig1, Ellen E. Svadlenak8, Matt W. Uddenberg9, Ray E. Wells10, Colin F. Williams10

1Portland State University, Portland, OR  97201, USA
2United States Geological Survey, Portland, OR  97201, USA
3Cyrq Energy, Salt Lake City, UT  84101, USA
4Washington State Department of Natural Resources, Olympia, WA  98504, USA
5University of Oregon, Eugene, OR  97403, USA
6City of Portland, Portland, OR  97204, USA
7Chevron Corporation, Bakersfield, CA  93311, USA
8GSI Water Solutions, Inc., Portland, OR  97204, USA
9AltaRock Energy Inc., Seattle, WA  98103, USA
10United States Geological Survey, Moffett Field, CA  94043, USA
Email: bershaw@pdx.edu

Abstract

In regions with long cold overcast winters and sunny summers, Deep Direct-Use (DDU) can be coupled with Reservoir Thermal Energy Storage (RTES) technology to take advantage of pre-existing subsurface permeability and storage capacity to save summer heat for later use during cold seasons. Many aquifers worldwide are underlain by permeable regions (reservoirs) containing brackish or saline groundwater that has limited beneficial use due to poor water quality. We investigate the utility of these relatively deep, slow flowing reservoirs for RTES by conducting an integrated feasibility study in the Portland Basin, Oregon, USA, developing methods and obtaining results that can be widely applied to groundwater systems elsewhere. As a case study, we have conducted an economic and social cost-benefit analysis for the Oregon Health and Science University (OHSU), a teaching hospital that is recognized as critical infrastructure in the Portland Metropolitan Area. Our investigation covers key factors that influence feasibility including 1) the geologic framework, 2) hydrogeologic and thermal conditions, 3) capital and maintenance costs, 4) the regulatory framework, and 5) operational risks. By pairing a model of building seasonal heat demand with an integrated model of RTES resource supply, we determine that the most important factors that influence RTES efficacy in the study area are operational schedule, well spacing, the amount of summer heat stored (in our model, a function of solar array size), and longevity of the system. Generally, heat recovery efficiency increases as the reservoir and surrounding rocks warm, making RTES more economical with time. Selecting a base-case scenario, we estimate a levelized cost of heat (LCOH) to compare with other sources of heating available to OHSU and find that it is comparable to unsubsidized solar and nuclear, but more expensive than natural gas. Additional benefits of RTES include energy resiliency in the event that conventional energy supplies are disrupted (e.g., natural disaster) and a reduction in fossil fuel consumption, resulting in a smaller carbon footprint. Key risks include reservoir heterogeneity and a possible reduction in permeability through time due to scaling (mineral precipitation). Lastly, a map of thermal energy storage capacity for the Portland Basin yields a total of 87,000 GWh, suggesting tremendous potential for RTES in the Portland Metropolitan Area.


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Location:   Multnomah Athletic Club
                   1849 SW Salmon Street 
                   Portland, Oregon 97205

Parking: Free Parking in the MAC structure, across the street from the main entrance

Date and Time: Thursday, February 20, 2020, 11:30 AM to 1:00 PM

Luncheon:              Menu – Beef Short Ribs
                                 Price: $30 for members, $35 for non-members. 
                                 Please let us know if you require a special-order meal.

Payment: Pay at the door by check or cash, or in advance over the internet via a Square invoice; we will issue the invoice upon  your request.

Cancellation Policy:  We are billed for the number of reservations turned in by noon on the Monday before the luncheon: Therefore, we must have all reservations or cancellations before noon on the Monday before the meeting. Any late cancellations or no-shows will be billed for the full cost of the luncheon.


Future NWEA Meetings 2019-2020



Thursday March 19, 2020

Thursday April 16, 2020

Thursday May 21, 2020