Emberlith Concept site by heyim.london Case study

Thermal batteries for industrial heat

Store the sun in brick. Burn nothing.

Emberlith heats refractory brick to 1,100°C on cheap wind and solar power, then turns that heat into steam for your plant, day and night. We build the core on your site and run it. You pay for the heat, and it costs less than gas.

Book a site assessment See how it works

Brekkeby Paper, a tissue mill in Värmland, has run on brick heat since May 2026.

A simulated day inside Core E1: it charges while power is cheap and sends steam to the plant around the clock.

Most factory steam still comes from burning gas. The wind and sun that could replace it turn up at the wrong hours of the day.

It's a kiln with a steam pipe on the side.

Heating rods warm the brick when power is cheap. Fans blow air through the hot brick and into a steam generator, all day and all night. The hard part is keeping 1,100°C brick in one piece for thirty years, next to a plant that can't stop.

  1. Charge on cheap power

    When wind and sun flood the grid, power gets cheap, and some hours the grid pays you to take it. Emberlith buys those hours. Heating rods hang down through slots in the brick and run white-hot while it charges.

    30 MW charge power3.5 h empty to full

  2. Store it as heat

    Brick is cheap and doesn't wear out, however often you cycle it. It's the same stuff that lines steel furnaces. Inside 80 cm of insulation, a full core loses less than 1% of its heat a day.

    100 MWh per core<1% lost a day

  3. Deliver steam around the clock

    Fans pull air through the hot brick and down a duct into a steam generator. Your plant gets steam at the pressure it already runs on, and the gas boiler goes on standby.

    120–250°C steam5 min to full output

At one in the afternoon, the grid pays you to take its power.

The core fills up in the cheap hours and sends out the same 12 t/h of steam all day. Drag through the day to see it.

Power price−€6 to €169 per MWhCharges under €45

€150 €100 €50 €0 Charging Charging Below zero

Heat in store22% to 94% full

Steam to your plant12 t/h, every hour

Charging: power under €45/MWh Illustrative prices for a windy night and a sunny day. Real schedules follow day-ahead and intraday markets.

We own the core. You get a heat bill.

There's nothing to buy and nobody new to hire. We pay for the core and its grid connection and run it from our control room in Gothenburg. Once a month you get a bill for the heat you used.

Emberlith Heat AB

Sample

Heat statement, March

A made-up plant with 2 × Core E1 · 1 to 31 March

Sample heat statement for March
Heat delivered 9,840 MWh at €38.20€375,888.00
Grid connection, maintenance, insurance€0.00
Due by 30 April€375,888.00
The same heat from gas 10,933 MWh of gas at €45.00, burnt at 90%
€492,000.00
Saved against gas
€116,112.00
The price per MWh is fixed for the whole contract, 12 to 15 years. Your gas boiler stays connected as backup, on your own gas. In March it ran for three hours, for its annual inspection.

Price your own switch off gas.

A rough estimate from your steam, your hours and your gas price. A site assessment replaces every assumption below with your meter data.

Your plant

10 t/h

Tonnes of steam an hour, averaged over your running hours.

6,000 h

8,760 means every hour of the year.

€40/MWh

Your contract price per MWh, before carbon costs.

Illustrative estimate not a quote

What you could save, per year

€168kto€420k

Gas you stop burning
42,000 MWh a year
CO2 you stop emitting
8,400 t a year
Suggested system
1 × Core E1 100 MWh of storage
Book an assessment with these numbers

How we got there

  • A tonne of steam takes about 0.7 MWh of heat.
  • Your gas boiler turns 90% of its fuel into steam.
  • Emberlith covers 90% of your steam. Your boiler covers the rest.
  • Burning gas emits about 0.2 t of CO2 per MWh.
  • Heat is priced 10% to 25% below your current cost of gas heat.
  • Each core stores 100 MWh, and we size for 14 hours of your load.

Illustrative only, for a made-up product. Not financial advice.

Core E1 Datasheet, rev. C

It's brick, a steel box and rock wool. There's no lithium in it, and nothing in it can catch fire.

Cutaway drawing of an Emberlith Core E1, drawn to scale: a 7.4 by 7.4 metre, 9.6 metre tall steel vessel with 80 centimetres of insulation, packed with glowing refractory brick. Heating rods hang from the roof through slots in the brick, a grid connection sits on the roof, a hot-air duct runs to a steam generator beside the vessel, and a steam line leads out to the plant. A 1.8 metre person stands by the steam generator for scale. 11 AA 22 BB 33 CC 44 DD 9.6 m 7.4 m 1 2 3 4 5 6 7 CORE E1 · GENERAL ARRANGEMENT REV C 05 m
  1. Grid connection, 10 to 33 kV
  2. Heating rods, hung through slots in the brick
  3. Refractory brick, up to 1,100°C
  4. Firebrick and mineral wool, 80 cm
  5. Steel shell, warm to the touch
  6. Steam generator
  7. Steam line to your plant

Drawn to scale: a 7.4 × 7.4 × 9.6 m vessel, with a 1.8 m person by the steam generator.

Heat out
OutputSteam, 120 to 250°C, up to 40 bar. Or hot air up to 950°C.
Discharge power10 MW thermal
RampStandby to full output in 5 minutes
Storage
Capacity100 MWh thermal
Core temperatureUp to 1,100°C
Round-trip efficiencyUp to 95%, power to delivered heat
Standing lossUnder 1% a day
Charging
Charge powerUp to 30 MW electric
Empty to full3.5 hours
Grid connection10 to 33 kV
Site
Footprint12 × 10 m, steam generator included
Height9.6 m
Design life30 years, no cycle fade

Brekkeby has been on brick heat since May.

One plant is on steam, one is commissioning and one is still a hole in the ground. All of them kept their old boilers.

Steam since 12 May 2026

Brekkeby Paper

Tissue mill · Värmland, Sweden

Heat
24 t/h of steam at 190°C
System
3 × Core E1
Replaced
Two gas boilers, from 1998 and 2004. Both still connected.

“The old boilers are still there. We've fired one twice since June, both times because the inspector asked.”

Ingrid Solberg, energy manager
Hours a week on the gas boilers, April to mid-September

168 hours, every hour of the week, through April. Falling after first steam on 12 May, to 9 hours in the last week of May. Zero since, apart from 6 hours in mid-June and 4 hours at the end of August, both for inspections.

Next on site
PlantHeatSystemStatus
Vossberg ChemieSpecialty chemicals · Lower Saxony, Germany Hot air at 450°C for a rotary dryer 2 × Core E1 Commissioning. First heat in November.
Halloran CreameryMilk powder · County Cork, Ireland 14 t/h of steam at 175°C 2 × Core E1 Groundworks. First steam spring 2027.

Who's building it.

Maren Holt, our CEO, ran energy for a paper mill for eleven years and got tired of buying gas. Idris Kallas, the CTO, spent fifteen years designing the brick linings of glass furnaces.

  • Priya Venkat VP, Projects Has taken 600 MW of solar from permit to power, on three continents.
  • Jonas Berg Head of Controls Writes the software that decides when to buy power. Usually around 1 p.m.

We're hiring field technicians in Lower Saxony and a second power trader in Gothenburg. If you've spent a career around furnaces, we'd like to meet you.

What plant managers ask us first

What if the wind and sun disappear for a week?

A full core runs your plant for 10 hours at full output and loses under 1% of its heat a day. Through a long grey spell it charges on the cheapest grid hours instead, and your gas boiler stays connected as backup.

Is 1,100°C brick safe to have on site?

The brick sits inside 80 cm of insulation and a steel shell that stays warm to the touch, not hot. The core isn't a pressure vessel and there's no fuel on site, so there's nothing in it to explode or leak.

Who owns and maintains it?

We do, and our own crews service it. You sign a heat contract, usually for 12 to 15 years, and pay for each MWh of heat you use.

How much space does it need?

One Core E1 and its steam generator fit on 12 × 10 m, less than half a tennis court, and stand 9.6 m tall. Most sites use a corner of the car park or a yard next to the boiler house.

Do we need a bigger grid connection?

Usually, yes, and we handle it. A core charges at up to 30 MW, so the connection application with your grid operator is part of our project, not yours.

How long from first call to first steam?

Typically 12 to 18 months, most of it spent on the grid connection and permits. The core itself goes up in about 16 weeks.

What does a site assessment involve?

An engineer spends a day on site. They read your steam meters, look at the boiler house, check what your grid connection can take and walk the yard for a spot about 12 by 10 metres.

Give your gas boiler its last shift.

Tell us where the plant is. An engineer calls within two working days, visits once, and two weeks later sends you a layout and a fixed heat price. You don't owe us anything for it.

  • Your heat load, worked out from your own meter data
  • A fixed price per MWh of heat, for the length of the contract

Book a site assessment

Tonnes per hour. A rough number is fine.

Concept site: this form checks your details, then sends nothing.