Benefits of Thermal Energy Storage

Jul 16, 2018

Today’s thermal energy storage (TES) technologies and systems provide a major opportunity for better economic benefits and enhanced energy management of existing and planned energy assets and infrastructure [1]. This covers any expected mismatches in both supply and demand for heating or cooling requirements thereby offsetting differences in time and magnitude of heat or cooling production. With increased attention from the energy industry on a smooth transition to sustainable forms of energy, TES can also assist in harnessing and integrating “stranded” renewable power supply through distributed energy resources and micro-grids such as solar photovoltaics, wind, and hydropower.

There is potential for TES to provide tangible economic benefits by reducing the overall capital costs and operations and maintenance costs of heating or cooling by designing systems to meet average demand, rather than just peak and cycling demand. TES can support the increase in demand side management and boosting capacities, reducing life cycle costs and levelized cost of energy along with potentially advancing time of use rates and billing. In addition, TES can enhance energy efficiency and enable potential reductions in carbon footprint and greenhouse gas emissions.

Energy management is another key focus area wherein TES can help improve overall system stability, performance and demand response by smoothing out any potential imbalances in supply and demand and system temperature fluctuations. In addition, it can improve the reliability, availability, operability and maintainability of the heating or cooling source(s) while enabling synergies by serving as an alternative or adjunct to battery storage and other energy storage strategies (e.g., pumped hydro and related storage options).

There are currently three main categories of TES heat storage technologies and systems as follows:

  1. Sensible – tank (TTES), pit (PTES), borehole (BTES), and aquifer (ATES), and electric storage heaters
  2. Latent – uses different types of phase change materials (PCM)
  3. Thermochemical heat storage (THS) – using reversible chemical reactions to store large quantities of heat in a compact volume

The three primary applications for TES are intraday heating or cooling along with concentrated solar power generation. For intraday heat applications for private and multifamily residences, district heating and commercial and institutional buildings, the two technologies which are important consist of hot water tank (TTES) units and electric storage heaters. For cooling applications for residences, offices, commercial and institutional buildings, and for many industrial systems, PCM (ice and/or special eutectic salts, waxes, etc.) can be used as well as THS. For concentrating solar power applications, molten salt systems are utilized, as an example, in multiple concentrated solar arrays of ground-mounted mirrors directly focused on a central receptor-heat collector on a tower that supplies steam to a thermal power generation system.

In order to increase the role and market share of TES, it is important for owners and sponsors of process and commercial industries and other stakeholders to develop an effective roadmap and viable pathways for TES via conventional and renewable energy sources. It is also essential to determine the potential impact of TES in the current and future sustainable energy mix. Further, it is paramount to ascertain the key drivers and enabling federal and state regulatory framework and policies to effectively propagate TES deployment while increasing process and industrial applications.

Nexant is preparing a multi-client report on Thermal Energy Storage as part of the TECH Program (Technoeconomics - Energy & Chemicals, formerly PERP). The report is expected to be published in Q3 2018. For more information please visit our Nexant Subscriptions portal.

 

[1] Includes load management, optimization, balancing, levelling, and potential time-shift.