Thermal Energy Storage
A Quiet Revolution in the Energy Transition
We set out to explore Thermal Energy Storage (TES), aiming to grasp its types, applications, key players and the investment landscape. Thanks to recent innovations, new materials now store heat better. Smarter design means thermal storage units are smaller, expanding the range of installation sites. TES is cost-effective, efficient, extends equipment life, and benefits the environment.
21% of Total Global Energy goes to industrial heat. This is big.
High energy prices and new tech means thermal storage is becoming smart to do for purely financial reasons.
There is no clear winner yet. A few companies are developing exciting tech suggesting the market might evolve with distinct solutions for various applications.
Europe dominates this space accounting for 38% of the global heat recovery equipment market.
The need
Energy demand is very volatile intra-day, between seasons and during various industrial processes.
In the absence of an established storage technology, we are forced to install peak load power generation or waste a lot of energy for cooling and heating.
It’s worth noting that industries such as cement, steel or aluminium production, require fuel or electricity-powered heating (up to 1,500°C) and cooling. Storing and recycling this heat could lead to substantial savings.
Current market and growth prospects
Industrial heat represents >21% of global energy demand (circa 23,300 TWh.)
TES is key for decarbonising industrial heat.
TES mitigates risk from volatile gas prices.
TES global capacity lags behind lithium-ion: 4.7 GWh (USA) vs 120 GWh for lithium-ion and 18.3 GWh (worldwide) vs 400 GWh for lithium-ion.
Tesla’s Master Plan 3 predicts TES capacity to surpass lithium-ion in the US within the next decade.
Types of Thermal Storage and applications
There are three TES types: sensible, latent, thermochemical.
Sensible TES: heats material without going through phase change. Examples: domestic hot water tanks. Water is stored and heated to be used later. Another example is molten salt. Sensible is best for temperatures > 500°C
Latent TES: Stores heat via phase change, e.g. from solid to liquid. Such as using ice for air-conditioning to cool a building
Thermochemical TES: Heat is released using reversible chemical reactions (e.g. heat charge/discharge during hydration/dehydration).
General Observations
Sensible TES is currently the most viable and mature tech; cost effective and suitable for sectors harder to decarbonise such as cement and steel.
Sensible solid-state TES is using cost-effective durable materials (lifetime 40-50 years), which can handle temperatures up to 1,500°C benefiting industries like iron and steel. Recent innovation is expanding the energy storage density and storage duration.
TES meets intra-day or intra-week demand of heat derived by air, specialty liquids such as oil and water, and by steam production with round-trip efficiency over 90%.
Companies involved
We reviewed notable TES developers such as Brenmiller (BNRG US Equity), Kyoto (KYOTO NO Equity) and private companies such as Kraftblock, Rondo, and Energynest.
Our key selection criteria was pilot plant presence, collaborations with large industries, working temperature above 500°C, round-trip efficiency over 90%, and expected system lifetime over 20 years.
Significant investments include: Microsoft and Aramco’s $60m in Rondo Energy and $50m in Antora, and also Shell's investments in MGA Thermal and Antora
We are excited about the thermal energy storage sector and the innovation in this space. We welcome you to share your comments and thoughts. Please do touch base with us should you wish to review our resources and discuss our findings in more detail.
SUSTEN - Research and Investment team
August ‘23
Please see also a patented Finnish TES-innovation made by Elstor Oy ( www.elstor.fi/en ). Elstor Oy has had its pilot plant operated 22 months now. And more sold deliveries after the pilot, where Elstor's TES-solution replaces fossil fuel use in steam generation, and where Elstor-investment has competitive payback time as well. Summary: TES providing emission-free steam and saving costs simultaneously, and provides demand response as a bonus.