Title: An analytical method for identifying synergies between behind-the-meter battery and thermal energy storage

Abstract

Electric utilities build generation capacity to meet the highest demand period, and they often pass on the costs associated with these peaking generators to building owners through demand charges. Building owners can minimize these demand charges by shifting energy use away from peak periods with behind-the-meter storage. This storage can include batteries, which can directly shift the metered load, or thermal energy storage, which can shift thermal-driven electric loads like air conditioning. However, there is a lack of research on how best to combine battery and thermal energy storage. In this study, we develop an analytical sizing method to calculate the potential demand reduction and annualized cost savings for different combinations of thermal and battery energy storage sizes. We show that adding batteries to a thermal energy storage system can increase the total system's load shaving potential. This is particularly true when the building has onsite photovoltaic generation or electric vehicle charging, which add significant variability to the load shape. We also show that for a given total storage size, selecting a higher fraction of thermal energy storage can significantly lower the cycling of the battery, and therefore extend the battery life. This, combined with the expected lower first costmore » of thermal energy storage materials compared to batteries, shows that hybrid energy storage systems can outperform a standalone battery or standalone thermal storage system. Assuming the thermal storage has a capital cost 6x lower than the battery, our analysis shows that the optimal system is 71% thermal energy storage and 29% battery energy storage for a scenario with electric vehicle charging. The annualized cost savings for this system are $48.6 k/yr, whereas an equivalently sized standalone thermal energy storage system would provide annualized cost savings of $28.5 k/yr and a standalone battery would lead to savings of $8.72 k/yr. The hybrid system also reduces battery cycling by 52% compared to a standalone battery, extending battery lifetime.« less

Authors:

Brandt, Matthew  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-2056-1334"

Woods, Jason  ^[2];

• Search DOE PAGES for author "Woods, Jason"
• Search DOE PAGES for ORCID "0000-0002-7661-2658"

Tabares-Velasco, Paulo Cesar ^[1]

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+ Show Author Affiliations

1. National Renewable Energy Lab. (NREL), Golden, CO (United States); Colorado School of Mines, Golden, CO (United States)
2. National Renewable Energy Lab. (NREL), Golden, CO (United States)

Publication Date:

Fri Feb 25 00:00:00 EST 2022

Research Org.:

National Renewable Energy Laboratory (NREL), Golden, CO (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Building Technologies Office; USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V)

OSTI Identifier:

1855380

Report Number(s):

NREL/JA-5500-79251
Journal ID: ISSN 2352-152X; MainId:33477;UUID:6b52f14a-d538-47dc-bf47-abec8968c5a3;MainAdminID:64037

Grant/Contract Number:  

AC36-08GO28308

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Energy Storage

Additional Journal Information:

Journal Volume: 50; Journal ID: ISSN 2352-152X

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

25 ENERGY STORAGE; battery; energy storage; thermal energy storage