“Sand batteries” can solve the main problem of clean energy

  • Matt McGrath
  • environment reporter

Subscribe to the “Context” newsletter: it will help you make sense of the events.

Illustrative image,

So it looks like a “sand battery” from the outside

The world’s first sand battery has been launched in Finland, allowing it to store energy from the sun, wind and other renewable sources for months.

Technology developers hope that their invention will solve the main problem standing in the way of the rapid development of green energy – its seasonal nature.

The principle of battery operation is simple: cheap solar and wind energy is used to heat a pond filled with cheap dirty sand.

Sand can be heated to temperatures of about 500 degrees Celsius, and its high heat capacity allows it to store the lion’s share of energy, which can later be used to heat apartment buildings in the winter, when demand for heat increases dramatically – and prices rise with he – she.

Finland buys most of its gas from Moscow, so the massive invasion of the territory of Ukraine by Russian forces made the problem of energy transportation “on a green railway” particularly relevant.

Of all the EU countries, Finland has the longest border with Russia – and after Helsinki announced its desire to join NATO, Moscow completely stopped the delivery of gas and electricity to its “unfriendly” western neighbor.

Winters in Finland are long and cold, so the lack of certainty about how homes will be lit and heated with the onset of cold weather worries not only politicians, but also ordinary citizens of the country.

A new technology launched on Tuesday at a small power plant in the western part of the country may help solve this pressing problem.

The novelty does not look impressive, in fact, it is a giant dugout of a dull gray shade, filled with 100 tons of construction sand. However, the potential of this repository is huge.

It is possible that this widespread and affordable building material has the properties necessary to create an inexpensive and efficient battery that allows the accumulation and storage of environmentally friendly energy.

The global climate crisis and, more recently, rising fossil fuel prices have led to increased investment in renewable energy.

Finding suitable sites for this, equipping solar or wind farms there, and operating the power grid from them is a relatively simple task. It is difficult to solve another problem – the inevitable dependence of production volumes on the time of year and time of day.

What do you do when the sun doesn’t shine and the wind doesn’t blow? How do we ensure the continuity of power supply?

In addition, the sharp increase in the number of green power plants requires that energy production be increased in other ways in order to balance the grid if necessary.

The most obvious solution to the problem is to build large accumulators that allow the generated energy to accumulate, and then put it back in again, balancing the grid as production drops seasonally.

Photographer, Tony Golf

Illustrative image,

Huge battery tank filled with this sand.

Most batteries today are made of lithium. It’s relatively expensive, takes up a lot of space, and doesn’t handle overcharging very well.

However, a group of young engineers has just completed the installation of the world’s first sand collector in Kankanpa, Finland, which offers a cost-effective and safe solution to this problem.

“Every time production of affordable green electricity jumps, there is a need to quickly redirect it to some buffering,” Markku Ülönen, technology co-developer and co-founder of Polar Night Energy explains.

The first sandblasting complex was installed at the Vatajankowski Power Plant, which provides district heating for neighboring communities.

Cheap electricity heats sand to a temperature of 500 ° C due to the so-called resistive heating (exactly according to the same principle, the operation of electric stoves is arranged).

From the sand, air is heated, which circulates inside the battery compartment using a heat exchanger.

Sand is great for saving energy because the material has a high heat capacity – which means it heats up very slowly but cools slowly. According to the developers, storage can keep sand at around 500 degrees for several months.

When electricity prices begin to rise seasonally, hot air from the collector is used to heat water for the central heating system. Already from there, heating is provided for apartments, offices, and even heating of the local pool.

Illustrative image,

Sand Technology Developers – Markku Ylönen and Tommi Eronen

cheap and cheerful

The prototype of the sand battery was developed at a former pulp mill in Tampere, for which the city council intentionally provided the site and financed.

“If the power plants could only run for a few hours a day in the coldest of winters, heating would be too expensive,” explains Elena Sipanin, who oversees energy and climate issues in the city government.

“But if we get the ability to store that energy and, if necessary, quickly redirect it back to the grid, the savings from that storage can be huge.”

Photographer, Tony Golf

Illustrative image,

The water in the local pool is also heated by central heating.

The main unanswered question is the viability of the experimental technology. How profitable is the sand battery? Is its energy sufficient to ensure that the supply of hundreds of homes with heat and electricity will not be interrupted?

Sand perfectly stores heat, but its reverse conversion into electrical energy necessary to supply the grid is a less efficient and more expensive process.

However, in the long run, the technology can be very useful for large industrial enterprises, whose main energy costs are now covered mainly by burning fossil fuels.

In the same direction – the use of sand as a thermal collector for green energy needs – several other research groups around the world are working, including the team of the US National Renewable Energy Laboratory.

However, the Finns were the first to create an efficient trading system – and so far, according to one of the project’s investors, “everything is going well.”

“The route is really simple, but we loved the idea of ​​trying something new – being the first in the world to make something like this,” admits power plant managing director Bekka Bassi. “To some extent, this is probably a crazy project, but I think it will come to a successful conclusion.”

To keep getting BBC news, subscribe to our channels:

Download our app:

Leave a Comment