Industrial heat.
Powered by the sun.

Capture solar energy, store it as high-temperature heat, and use it whenever your process needs it.

See how it works

Industry still runs on fossil heat

Solstice heat

1000°C

Hot enough for industrial processes. Stored in sand and available day and night.

Industrial heat

75%

of industrial heat is still produced by burning fossil fuels.

Electrification is not a solution

Electrifying high-temperature processes directly loses a lot of energy in conversion and is expensive to run.

Limited alternatives

Renewable alternatives such as wood chips and bio-oil are expensive and hard to scale.

Thermal sand storage + concentrating solar power

Solstice turns renewable energy into high-temperature heat and stores it, so it can run your industrial processes around the clock. The system is robust and cost-efficient.

It is built from sand, steel and sunlight. These simple, low-cost materials are easy to maintain and keep downtime to a minimum.

How it works

Capture. Store. Deliver.

CaptureSunlight to heat
StoreHeat in sand
DeliverHeat to your process

Rows of Solstice solar collectors in a field

Collect solar heat

Our solar collectors concentrate sunlight into high-temperature heat, right where it is needed.

Solstice thermal energy storage container, a sand battery, on site

Keep the heat for when you need it

The heat is stored in sand. Sand is simple, abundant and durable, and it can hold large amounts of thermal energy for hours or days.

Industrial facility supplied with heat from Solstice storage

Heat, ready for your process

The stored heat goes to your existing industrial process at high temperature. Your factory runs on renewable heat, even when the sun isn't shining.

Renewable industrial heat.
Whenever you need it.

Our mission

To accelerate the world's transition to renewable, fossil-free industrial heat.

We store solar energy as heat for industry.

We develop high-temperature solar-thermal systems that replace fossil fuels in industrial processes. Our heat is reliable and available on demand, so industry can stop burning fuel to make it.

Frequently asked questions

Common questions about how our storage works.

Not directly. The main charging system runs on direct sunlight. The system can also be fitted with a second charger that uses grid electricity, and that electricity can come from wind.

Yes. Sand is non-toxic, non-flammable and chemically inert. There is no risk of thermal runaway or chemical fires, so the system can be installed next to industrial sites or homes.

Yes, especially in summer, when the days are long. In winter it works mainly as a thermal store charged with electricity.

As long as needed. In most cases the system runs a daily cycle to follow energy prices. Longer storage, even seasonal, is possible with extra insulation and a business case built for it.

Unlike chemical batteries, the sand does not degrade over time. The mechanical parts are designed to last more than 40 years.

Lithium-ion batteries suit fast response and short storage, around 1 to 4 hours. Our thermal storage is built for long durations, from 8 to over 100 hours, at a much lower cost per stored MWh. It also lasts longer and does not degrade. Batteries balance the grid over seconds and minutes, while we supply affordable energy over hours and days, so the two work well together.