Thermal Battery System by Antora Energy: status and timeline

Thermal Battery System

Thermal battery stores electricity as heat in insulated carbon blocks for long-duration storage. Discharges over hours or days.

DeployStage 4 of 5

5 GWh system operational at POET; manufacturing scaled; second facility planned.

Updated 10d agoChecked 10 Oct0 updates this week

Milestones

Next · Second U.S. manufacturing facility planning

San Jose factory capacity doubledQ2 2026Complete.
5 GWh POET system commissioned at Big Stone City, South Dakota19 May 2026Complete.
Series C closes at $2.47B valuation30 Jul 2026Complete.
Second U.S. manufacturing facility planningTarget Q3 2026Current milestone.
Pratt Energy 5.8 GWh Kansas project announcedTarget 1 Oct 2026Not yet reached.

Most important updates

Upcoming

Q3 2026Second U.S. manufacturing facility planning (next)
1 Oct 2026Pratt Energy 5.8 GWh Kansas project announced
2027Second manufacturing facility opens

Current obstacles

Round-trip efficiencyThermal losses reduce round-trip efficiency to 40-50%, lower than lithium-ion; trade-off for cheaper storage.
Customer adoption and integrationIndustrial customers must redesign heating processes to accept stored heat on a dispatch schedule.

Physics limits

Thermal insulation lossHeat flows toward cooler surroundings; perfect insulation is impossible. Losses increase over days.
Temperature gradient and Carnot efficiencyCarnot efficiency limits heat-to-electricity conversion, requiring high temperature storage for useful work.

How it works

3 parts

Charging

Convert electricity to heat

Electric heaters convert off-peak electricity into heat in carbon blocks at 500-700°C.

Storage

Insulated carbon blocks hold heat

Thick insulation keeps heat stable for hours or days with minimal loss, unlike batteries.

Dispatch

Heat powers process or generates electricity

Heat flows through industrial equipment or through a turbine to generate electricity on demand.

Spec sheet

Spec	Thermal Battery System
POET system storage capacity	5 GWh^R (reported)
POET system power output	50 MW^R (reported)
Standard thermal battery unit	50 MWh^R (reported)
Multi-day discharge capability	Up to 24+ hours^R (reported)

^R reported by the company

Update log

2 updates

Thu 1 Oct

Minor: Antora and Pratt Energy announce 5.8 GWh thermal battery project in KansasPressCommercial

Tue 19 May

Major: Antora and POET commission 5 GWh thermal battery in South DakotaPressCommercial

About Antora Energy

The team behind Thermal Battery System

Antora Energy

Thermal battery, carbon heat storage, grid storage

Antora Energy builds thermal batteries that store electricity as heat in solid-carbon blocks. In July 2026, Antora closed a $550M Series C and commissioned a 5 GWh system at POET's South Dakota facility.

Antora's thermal batteries store cheap electricity as heat in carbon blocks, usable for industrial heat or power generation.
The company commissioned a 5 GWh system at POET's bioethanol facility in May 2026, the largest thermal storage project worldwide.
Series C funding of $550M (July 2026, $2.47B valuation) will expand production and establish a second U.S. facility.

antora.com (opens antora.com)Company profile →

Founded: 20188 yrs
Headquarters: United States
Status: Private
Valuation: $2.5BprivateJul 2026
Raised: $700M2 rounds
Last round: Series C · $550M30 Jul 2026
Works in: EnergyGrid storage
Coverage: 1 program · 3 updateslatest 10d agochecked 10 Oct
Lead investors: G2 Venture PartnersEclipse
Customers: POET (opens antora.com)
Partners: Pratt Energy (opens ess-news.com)
People: Andrew PonecCEO & Co-founder

Spec

Thermal Battery System

POET system storage capacity

5 GWh^R (reported)

POET system power output

50 MW^R (reported)

Standard thermal battery unit

50 MWh^R (reported)

Multi-day discharge capability

Up to 24+ hours^R (reported)