Powering you into the future: Our Thermal Battery™ technology for thermal energy storage

At the core of all of our energy storage solutions is our modular, scalable ThermalBattery™ technology, a solid-state, high temperature thermal energy storage.

Integrating with customer application and individual processes on site, the ThermalBattery™ plugs into stand-alone systems using thermal oil or steam as heat-transfer fluid to charge and discharge green energy on demand.

Standardized modular thermal energy storage technology


Standardized modular thermal energy storage technology


Our standardized ThermalBatteryTM modules are designed to be handled and shipped as standard 20ft ISO shipping containers. A 20ft module can store up to 1.5 MWh, a 40ft module up to 3 MWh. Depending on customer demand, storage from 5 to >1000MWh can be inputted.


Thermal energy stored in innovative HEATCRETE®


Thermal energy is stored in our high-performance thermal concrete, HEATCRETE®, at temperatures up to around 400°C. Compared to standard concrete this material has a far higher thermal storage capacity and conductivity, and remains robust under thermal stress.


Integrated heat exchanger pipes adapted to customer need


The ThermalBatteryTM’s integrated heat exchanger pipes are designed according to process-specific requirements including type of heat transfer fluid (HTF), pressure and temperature. Every battery is customized to meet client need.

Liftetime: up to 30+a

Designed to last


Our ThermalBatteryTM technology is designed to be robust and maintenance-free. It’s constructed entirely of solid-state materials (steel and HEATCRETE®) and has no moving parts – making it an enduring investment for energy transition.


Cost effective

Due to the design and material choice, our ThermalBatteryTM represents a cost-effective solution to waste heat recovery. Modules are manufactured by our partners offsite and delivered to our customers for easy assembly onsite – all cutting costs and increasing value.

Safe to use

ENERGYNEST modules are designed in adherence to relevant codes and standards and are inherently safe due to their all-welded piping design. They also undergo rigorous testing and certification before delivery to customer sites, and are CE marked.

Take a look at how our ThermalBatteryTM is assembled for our project with YARA.

Easy to install

When arriving onsite, the modules are ready for immediate assembly, significantly reducing construction time and giving customers quicker access to the operational benefits.

Rapid carbon payback

The payback from cutting your carbon footprint with ENERGYNEST solutions is remarkably fast – with an estimated time of 2 months based on current calculations.
That means your decarbonization strategy could soon start paying for itself – or generate even more value

Peer-reviewed design

The design of our system and the results of our ThermalBatteryTM pilot have been published in the Journal of Energy Storage as peer reviewed article “Long-term performance results of concrete-based modular thermal energy storage system”

Frequently Asked Questions

How does a ThermalBatteryTM work?
Energy in form of heat is transferred to the ThermalBatteryTM using a heat transfer fluid (HTF). The HTF can in principle be any fluid with adequate heat transfer properties. In most cases this is either thermal oil or water/steam. Heat from the HTF is transferred to the solid-state storage material HEATCRETE® via cast in “U-shaped” carbon steel heat exchanger tubes. There is no direct contact between the heat transfer fluid and HEATCRETE®; the heat transfer occurs through the heat exchanger steel tubes only. The thermal storage element design using U-tubes ensures that thermal stresses in the axial direction are minimized. The thermal elements also include a steel casing which has three functions; being a permanent casting form, an external reinforcement reducing the risk of spalling or cracking, and HTF containment (in the very unlikely case of HTF leakage inside the element).
What makes ENERGYNEST different to electrochemical batteries?
Electrochemical batteries, such as lithium-ion and lead acid, need electricity to charge, whereas the ENERGYNEST ThermalBatteryTM charges with heat. This means that the ThermalBatteryTM can be used for applications (such as combined heat and power) which are not physically possible with electrochemical batteries. Moreover, the ThermalBatteryTM has a significantly longer lifetime, near-zero performance degradation, in addition to being made of fully recyclable materials. These materials primarily consist of steel and concrete, which are cheap and globally available commodity materials. This is why the system comes at a significantly lower cost than batteries.
Who is responsible for building the ThermalBatteryTM ?
We offer our customers the most convenient option for their situation, which is typically one of these two:   The Customer brings its own EPC contractor to site, and ENERGYNEST offers site advisory services, to guide them during the construction of the ThermalBatteryTM.   We are in charge of a turnkey solution, together with one of our international EPC partners.
How do you assure the quality of your system?
We only work with ISO 9001:2015 certified suppliers and partners, who provide top-confidence on our products and services. Additionally, we perform 2nd Party Audits, together with certified bodies, and on-site supervision during the critical phases of the construction process.
What is the lead time for installing a ThermalBatteryTM?
(assume: delivery of materials + construction)
Three months after the closure of the ThermalBatteryTM design, key components are ready to be shipped to site. Transport to site duration will very much depend on project´s location: from one week in an European project, to one month, if it is overseas. The construction process duration depends on the size of the storage, but a good reference is three months for a small project, from civil works to cold commissioning, to six months for a bigger project.
What are the carbon emissions associated with building a ThermalBatteryTM?
Emissions are highly dependent on context and likely to vary from one project to another. What is certain is that their effect will generally not be substantially more significant than that of cement. A conservative total estimate would put overall emissions at 15 kg per kWh of storage capacity. Comparing this number with about 300g CO2 per kWh from burning fossil fuel, one can see that a reasonable number for payback of the CO2 debt for a ThermalBatteryTM is less than two months. Therefore, no matter what type of project, the ENERGYNEST ThermalBatteryTM will recover its carbon debt very quickly. The ENERGYNEST ThermalBatteryTM thus constitutes an elegant and cost-effective solution for reducing carbon emissions in heat-intensive industries and electric power generation.
How do you generate savings and reduce carbon emissions for industrial facilities?
ENERGYNEST project developers will start by evaluating process data from the facility. This includes analyzing different heat sources and heat sinks, in terms of temperature, pressure, and flow rates. Many industrial facilities have processes that are either intermittent or highly variable in their energy production and consumption. By recovering thermal energy from high-temperature waste heat sources, storing it, and discharging this energy into downstream processes at a later point in time, ENERGYNEST opens up entirely new possibilities for waste heat recovery: Instead of consuming fossil fuels to generate the heat that they need, industries can simply rely on stored thermal energy. The reduction in fossil fuel consumption allows an equivalent reduction in carbon emissions. The ThermalBatteryTM effectively grants industrial plant owners optimal management of their energy use.
What kind of revenue opportunities do you create for independent power producers?
The ThermalBatteryTM is the ultimate flexibility solution for thermal power plants. It can be directly integrated into existing steam cycles, effectively providing a steam storage buffer between the boiler and the turbine. This allows plant operators to run their boiler continuously while boosting or reducing the electric output on demand. Depending on the case, the system reaction time can be less than 7 seconds. This makes the ThermalBatteryTM a perfect solution for providing thermal power plants with the flexibility required to respond to primary frequency response. The ThermalBatteryTM can thus be designed to provide a short or long response time, depending on what provides most value in electricity markets.
How much does the ThermalBatteryTM cost?
The material cost for our basic storage modules can be as low as 25 USD/kWhth of storage capacity in favorable project conditions. This includes the storage medium, the containment of the medium and the means to input and extract heat from the medium. However, this indicative cost figure excludes local EPC costs which tend to vary significantly from one project to another. The total system cost will therefore vary depending on its size, functionality, subcomponents, and geographic location.
What kind of temperatures can your ThermalBatteryTM handle?
Our storage material HEATCRETE® has been tested up to 550°C, and is guaranteed to perform as intended up to 450°C.
How does the ThermalBatteryTM withstand the stress from thermal expansion?
The storage material is designed to have a similar coefficient of thermal expansion to that of the cast-in carbon steel pipes.
How many charging/discharging cycles can your ThermalBatteryTM handle?
With daily cycling, a ThermalBatteryTM would experience less than 20,000 cycles during 50 years operation. Since the stress values are far away from the failure values for concretes, the stress and fatigue pose no operation issues to our ThermalBatteryTM system over 10,000 – 20,000 cycles.
Does the performance of the ThermalBatteryTM degrade over time?
The ThermalBatteryTM itself does not have any performance degradation during operation, because the system is entirely made of durable concrete and steel, which can tolerate tens of thousands of stress cycles. All materials are operated within bounds that preserve their integrity for up to 50 years.
How do you minimize technical risk?
ENERGYNEST has designed the Thermal BatteryTM to have the lowest possible technical risks. Our technology has undergone a significant number of tests, both in laboratory settings and with real operational pilot facilities, which have been certified by third-party auditors. Data on exact material performance can be shared upon request. The modular system design allows material malfunctions and contingencies to be dealt with swiftly, by shutting down the part of the storage that is affected.
What are the heat losses over time?
Thermal losses will be less than 2% over 24hrs for large-scale projects. Smaller projects will have somewhat higher losses as the surface-to-volume ratio increases.
What maintenance does the ThermalBatteryTM require?
The ThermalBatteryTM requires very low maintenance as there are no moving parts other than a few control valves on the piping interface with the plant.
How fast can the battery respond?
The ENERGYNEST ThermalBatteryTM can respond very quickly, and can provide anything from short term frequency response (30 min charge/discharge) up to longer cycles over several days.
How do you measure the performance of the ThermalBatteryTM?
The performance of the ThermalBatteryTM is based on measurements of the inlet and outlet HTF temperature and mass flow through the system. These parameters allow for accurate performance monitoring. In case of water/steam, the performance is measured based on mass flow of fluid in either liquid form (water) or vapor (steam), combined with temperature and pressure.