Loviisan Lämpö Invests in Polar Night Energy's Sand Battery in Pornainen – Towards Non-Combustion Heat Production

Polar Night Energy and Loviisan Lämpö have agreed on the construction of an industrial-scale thermal energy storage. The new 1 MW Sand Battery will be built in Pornainen, integrating with Loviisan Lämpö's district heating network. The thermal energy storage medium will be crushed soapstone, a byproduct of Tulikivi's production of heat retaining fireplaces.

Loviisan Lämpö's CEO Mikko Paajanen and CapMan Infra's Investment Director Sauli Antila with Polar Night Energy's Product Sales Manager Matti Ulvinen and CEO Tommi Eronen (from left to right) at Pornainen district heating plant. The new Sand Battery will be built next to the old district heating plant. PHOTO: Marjaana Malkamäki

See below for Finnish.

Polar Night Energy and the Finnish district heating company, Loviisan Lämpö, have entered into an agreement to build an industrial-scale Sand Battery in Pornainen for Loviisan Lämpö’s district heating network. The heating power of the new Sand Battery is 1 MW and it can store up to 100 MWh of thermal energy, making it about ten times larger than the Sand Battery in operation in Kankaanpää since 2022.

The purpose of the Sand Battery is to reduce carbon dioxide emissions of the district heating production in the Pornainen municipality and introduce a new flexible heat production technology.

"Loviisan Lämpö is moving towards more environmentally friendly energy production. With the Sand Battery, we can significantly reduce energy produced by combustion and completely eliminate the use of oil," says Mikko Paajanen, CEO of Loviisan Lämpö.

The impact of the investment on total emissions is approximately 160 tons of carbon dioxide equivalent per year, translating to nearly a 70% reduction in emissions from the district heating network of Pornainen. In addition to eliminating the usage of oil, the combustion of woodchips is expected to decrease by around 60%.

The municipality of Pornainen is enthusiastic about the new heating method, aligning with its goal of "Towards a Carbon-Neutral Pornainen." Many of the municipality's own buildings, including the Comprehensive School, town hall, and library, rely on district heating.

"Our municipality welcomes all innovative development projects that reduce emissions in district heating operations and contribute to network expansion," says Antti Kuusela, Mayor of Pornainen.

The Sand Battery is flexible in both its electricity usage and district heating production. It is charged from the electric grid using charging algorithms developed by Polar Night Energy, minimizing the cost of electricity used for charging while meeting the heat demand of the district heating network. The thermal energy storage capacity corresponds to almost one-month heat demand in summer and a one-week demand in winter in Pornainen.

"We want to enable the growth of renewable energy. The Sand Battery is designed to participate in all Fingrid's reserve and balancing power markets. It helps to keep the electricity grid balanced as the share of wind and solar energy in the grid increases," says Mikko Paajanen.

Loviisan Lämpö is owned by CapMan Infra fund, a part of the investment company CapMan. CapMan's vision is to be the most responsible private assets investor in the Nordics, committed to creating a sustainable future by addressing climate challenges and utilizing resources efficiently.

"Loviisan Lämpö’s investment in the Sand Battery is a concrete step towards CapMan's climate goals. We are committed to reducing our carbon dioxide emissions and seeking solutions that lead us towards net-zero emissions, of which this innovative solution is an excellent example," says Sauli Antila, Investment Director at CapMan Infra.

Polar Night Energy will deliver the Sand Battery to Loviisan Lämpö as a turnkey project. The Sand Battery will be approximately 13 meters high and 15 meters wide. The estimated duration for construction and testing is around 13 months. The project has received support from Business Finland's new technology energy aid.

"It's exciting to build a large-scale thermal energy storage, which will also act as a primary production plant in Pornainen's district heating network. This is a significant step in scaling up the Sand Battery technology," says Liisa Naskali, COO at Polar Night Energy.

Polar Night Energy's CEO Tommi Eronen and Loviisan Lämpö's CEO Mikko Paajanen planning the new Sand Battery for Pornainen district heating network. PHOTO: Marjaana Malkamäki

The Sand Battery in Pornainen Will Have Tulikivi’s Crushed Soapstone as the Storage Medium – a Choice That Promotes Circular Economy

Loviisan Lämpö's new thermal energy storage will use crushed soapstone produced as a byproduct of Tulikivi's manufacturing process. Tulikivi is the market leader in heat retaining fireplaces in the world.

"Collaborating with Polar Night Energy is an interesting venture into new business, leveraging the traditional strengths of soapstone, such as excellent heat conduction and retention properties. This collaboration supports Tulikivi's goals of maximizing the utilization of raw materials," says Heikki Vauhkonen, CEO of Tulikivi.

Sand Batteries can use sand or sand-like materials as the storage material. Soapstone conducts heat better than conventional sand. According to research conducted by Polar Night Energy and Tulikivi, soapstone is an excellent choice for Loviisan Lämpö’s Sand Battery due to its unique properties.

"We always choose the thermal energy storage medium based on the customer's needs. Examining and testing different materials is crucial for us to use materials that are suitable in terms of properties, cost-effectiveness, and promotion of circular economy," says Liisa Naskali of Polar Night Energy and adds, "Tulikivi is a well-known and traditional company. The soapstone they use is a very Finnish thing. It's great to collaborate with Tulikivi."

"This collaboration supports Tulikivi's goals of maximizing the utilization of raw materials," says Heikki Vauhkonen, CEO of Tulikivi.

About the companies

Loviisan Lämpö is a Finnish district heating company that supplies district heating to its customers in Loviisa, Pukkila, Pornainen, Pyhtää Siltakylä, Pyhtää village center, and Lappohja. Loviisan Lämpö is owned by CapMan Infra.

CapMan is a leading Nordic private asset expert with an active approach to value creation. We have developed hundreds of companies and real estate assets and created substantial value in these businesses and assets over the past 30 years. We have over €5 billion in assets under management and our investment strategies cover real estate and infrastructure assets, natural capital and minority and majority investments in portfolio companies.

Tulikivi is the market leader in heat retaining fireplaces in the world. Tulikivi was born by combining Finnish knowledge of arctic conditions, wood heating know-how and a unique soapstone reserve.

Polar Night Energy is a Finnish startup that designs and manufactures high temperature thermal energy storages for wind and solar energy. The Sand Battery developed by the company enables a significant increase in wind and solar energy production while reducing the use of fossil fuels. The company was founded in 2018.

Press photos and interview requests:

Miika Peltola
Communications Manager
miika.peltola@pne.fi

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Loviisan Lämpö investoi Pornaisissa Polar Night Energyn hiekka-akkuun – Matkalla kohti polttamatonta lämmöntuotantoa

Polar Night Energy ja Loviisan Lämpö ovat sopineet lämpöenergiavaraston rakentamisesta. Uusi 1 MW hiekka-akku rakennetaan Pornaisiin Loviisan Lämmön kaukolämpöverkolle. Lämpöenergiavaraston väliaineena käytetään Tulikiven varaavien tulisijojen tuotannon sivuvirtana syntyvää vuolukivimursketta.

Polar Night Energyn tuotemyyntipäällikkö Matti Ulvinen ja toimitusjohtaja Tommi Eronen yhdessä Loviisan Lämmön toimitusjohtajan Mikko Paajasen ja CapMan Infran sijoitusjohtajan Sauli Antilan kanssa Pornaisissa. Uusi hiekka-akku rakennetaan vanhan kaukolämpölaitoksen viereen. KUVA: Marjaana Malkamäki

Polar Night Energy ja kotimainen kaukolämpöyhtiö Loviisan Lämpö ovat sopineet teollisen mittakaavan hiekka-akun rakentamisesta Pornaisiin Loviisan Lämmön kaukolämpöverkolle. Uuden hiekka-akun teho on 1 MW ja varastointikapasiteetti 100 MWh. Se on noin kymmenkertainen vuodesta 2022 Kankaanpäässä toimineeseen hiekka-akkuun verrattuna.

Hiekka-akun tavoitteena on Pornaisten kunnan alueella toimivan kaukolämpöverkon lämmöntuotannon hiilidioksidipäästöjen vähentäminen ja uudentyyppisen joustavan lämmöntuotantoteknologian käyttöönotto.

”Loviisan Lämpö etenee kohti ilmastoystävällisempää energiantuotantoa. Hiekka-akun avulla voimme merkittävästi vähentää polttamalla tuotettua energiaa ja luopua kokonaan öljyn käyttämisestä”, sanoo Loviisan Lämmön toimitusjohtaja Mikko Paajanen.

Investoinnin vaikutus kokonaispäästöihin on noin 160 hiilidioksidiekvivalenttitonnia (t CO2e) vuodessa, mikä tarkoittaa lähes 70 prosentin päästövähennystä Pornaisten kaukolämpöverkossa. Öljystä luopumisen lisäksi hakepolttoaineen käyttö vähenee noin 60 prosenttia.

Myös Pornaisten kunta on innoissaan uudesta lämmitysmuodosta. Yksi Pornaisten kuntastrategian päämääristä on ”Kohti hiilineutraalia Pornaista”. Suuri osa kunnan omista rakennuksista on kaukolämmössä, kuten Yhtenäiskoulu, kunnantalo ja kirjasto.

”Kuntamme toivottaa tervetulleiksi kaikki kaukolämpötoiminnan päästöjä vähentävät, innovatiiviset kehityshankkeet ja verkon laajentamisen”, sanoo Pornaisten kunnanjohtaja Antti Kuusela.

Hiekka-akku on joustava sekä sähkö- että kaukolämpöverkon suuntaan. Hiekka-akkua ladataan sähköverkosta Polar Night Energyn kehittämän latausalgoritmin mukaan siten, että lataukseen käytettävän sähkön hinta minimoidaan ja samalla kaukolämmön tulevat lämmöntarpeet pystytään täyttämään. Lämpövaraston kapasiteetti vastaa kesäaikaan vajaan kuukauden ja talvella vajaan viikon lämmön tarvetta Pornaisissa.

”Haluamme olla mahdollistamassa uusiutuvan energian kasvua. Hiekka-akusta tehdään sen kokoinen, että sillä voi osallistua myös kaikille Fingridin reservi- ja säätösähkömarkkinoille. Hiekka-akku auttaa pitämään sähköverkkoa tasapainossa, kun tuuli- ja aurinkoenergian osuus verkossa kasvaa”, sanoo Mikko Paajanen.

Loviisan Lämmön omistaa pääomasijoitusyhtiö CapManiin kuuluva CapMan Infran rahasto. CapManin visiona on olla vastuullisin pääomasijoittaja Pohjoismaissa. Yritys on sitoutunut luomaan kestävää tulevaisuutta vastaamalla ilmastohaasteisiin sekä hyödyntämällä resursseja tehokkaasti.

”Loviisan Lämmön tekemä investointi hiekka-akkuun on konkreettinen askel kohti CapManin ilmastotavoitteita. Olemme sitoutuneet vähentämään hiilidioksidipäästöjämme ja etsimään ratkaisuja, jotka vievät meitä kohti nettonollapäästöjä, ja joista tämä innovatiivinen ratkaisu on erinomainen esimerkki”, sanoo CapMan Infran sijoitusjohtaja Sauli Antila.

Polar Night Energy toimittaa hiekka-akun Loviisan Lämmölle avaimet käteen -toimituksena. Hiekka-akusta tulee noin 13 metriä korkea ja 15 metriä leveä. Hiekka-akun rakentamisen ja testaamisen arvioitu kesto on noin 13 kuukautta. Projekti on saanut Business Finlandin uuden teknologian energiatukea.

”On hienoa päästä rakentamaan suurta teollisen mittakaavan lämpövarastoa, joka tulee vieläpä toimimaan primäärituotantolaitoksena Pornaisten kaukolämpöverkossa. Tämä on iso askel hiekka-akkuteknologian skaalaamisessa”, sanoo Polar Night Energyn operatiivinen johtaja Liisa Naskali.

Pornaisten hiekka-akun väliaineena käytetään Tulikiven sivuvirtakiveä – Valinta edistää kiertotaloutta

Loviisan Lämmön uuden lämpöenergiavaraston väliaineena tullaan käyttämään Tulikiven tuotannon sivuvirtana syntyvää vuolukivimursketta. Tulikivi on varaavien tulisijojen markkinajohtaja maailmassa.

”Yhteistyö Polar Night Energyn kanssa on mielenkiintoinen avaus uuteen liiketoimintaan, jossa hyödynnetään vuolukiven perinteisiä vahvuuksia, kuten hyviä lämmönjohto- ja varausominaisuuksia. Yhteistyö tukee Tulikiven tavoitteita raaka-aineen mahdollisimman korkeasta hyödyntämisestä”, sanoo Tulikiven toimitusjohtaja Heikki Vauhkonen.

Hiekka-akuissa voi käyttää lämmönvarastointimateriaalina joustavasti erilaisia hiekan kaltaisia materiaaleja. Vuolukivimurske johtaa tavanomaista hiekkaa paremmin lämpöä. Polar Night Energyn ja Tulikiven tekemien tutkimusten perusteella vuolukivimurske sopii ominaisuuksiensa takia erinomaisesti käytettäväksi Loviisan Lämmön hiekka-akussa.

”Valitsemme väliaineen aina asiakkaan tarpeiden mukaan. Erilaisten materiaalien tutkiminen ja testaaminen on meille tärkeää, jotta pystymme käyttämään materiaaleja, jotka ovat ominaisuuksiltaan sopivia, kustannustehokkaita ja kiertotaloutta edistäviä”, sanoo Polar Night Energy Liisa Naskali ja lisää:

”Tulikivi on tunnettu ja perinteinen yritys. Heidän käyttämänsä vuolukivi on hyvin suomalainen juttu. On hienoa tehdä yhteistyötä Tulikiven kanssa.”

Lisätietoa yrityksistä

Loviisan Lämpö on kotimainen kaukolämpöyhtiö, joka toimittaa kaukolämpöä asiakkaalleen Loviisan, Pukkilan, Pornaisten, Pyhtään Siltakylän, Pyhtään kirkonkylän sekä Lappohjan alueilla. Loviisan Lämpö Oy:n omistaa CapMan Infra.

CapMan on johtava pohjoismainen aktiivista arvonluontityötä tekevä pääomasijoittaja. Olemme kehittäneet satoja yhtiöitä ja kiinteistöjä ja luoneet merkittävää arvoa yli kolme vuosikymmentä. Hallinnoimme yhteensä yli 5 miljardin euron pääomia ja sijoitusalueemme kattavat kiinteistö-, infrastruktuuri- ja luonnonvarasijoittamisen, sekä vähemmistö- ja enemmistösijoitukset kohdeyhtiöihin.

Tulikivi on varaavien tulisijojen markkinajohtaja maailmassa. Tulikivi on syntynyt yhdistämällä suomalainen arktisten olosuhteiden tuntemus, puulämmitysosaaminen ja ainutlaatuinen vuolukivivaranto.

Polar Night Energy on tamperelainen startup-yritys, joka suunnittelee ja valmistaa korkean lämpötilan energiavarastoja tuuli- ja aurinkoenergialle. Yrityksen kehittämä hiekka-akku mahdollistaa tuuli- ja aurinkoenergian voimakkaan lisäämisen ja fossiilisten polttoaineiden käytön vähentämisen. Yritys on perustettu 2018.

Kuva- ja haastattelupyynnöt

Miika Peltola
Viestintäpäällikkö
miika.peltola@pne.fi

The Sand Battery as Balancing Service Provider – Gain Profit for Stabilizing The Electric Grid

Few of us realize that maintaining the stability of the electric grid requires careful planning and real-time adjustment. This post explains how Polar Night Energy’s Sand Battery can help with grid balancing and make profit by accessing the grid balancing markets. In our simple case study the final heat price is -94 e/MWh after the profits from balancing markets – yes, you make money by producing heat!

Graph 1. Profits from aFRR markets during the assessed period from August 16 to September 15. The profit is the historical hourly market price (EUR/MW) times the capacity 2 MW.

The production and consumption of electricity must meet at all times to maintain the 50 Hz frequency of the electricity grid. This is mainly achieved by careful planning. In case of a deviation of production and consumption of electricity due to, for instance, un unplanned powerplant outage or inaccurate weather forecast, grid balancing services are needed.

In many countries, especially in EU, grid balancing services are procured from open markets that are managed by the local transmission system operator, for example Fingrid in Finland. Any entity with flexible electricity production or consumption fulfilling certain technical requirements, like our Sand Battery, can participate in these markets and serve as a reserve.

Reserve Products

Fingrid maintains several reserve products for different purposes. Frequency Containment Reserves (FCR), are constantly controlling the grid frequency. Frequency Restoration Reserves (FRR) are used to return the grid frequency to the nominal value 50 Hz and free the activated Frequency Containment Reserves in case of frequency deviation. Table 1 summarizes all the automatic reserve products maintained by Fingrid.

In Table 1, the direction of regulation is understood from the electric grid point of view. Upregulation aims to increase the grid frequency, which a reserve does by increasing production or reducing consumption. Downregulation respectively decreases the grid frequency by decreasing production or increasing consumption. For FCR-N, which is a symmetric product, the reserve must be capable to regulate in both directions.

Table 1. Summary of the automatic reserve products maintained by Fingrid.

Reserve Product	Explanation	Direction of regulation	Frequency bandwidth (Hz)
FCR-N	Frequency Containment Reserve for Normal Operation	Symmetric	49.9–50.1
FCR-D up	Frequency Containment Reserve for Disturbances	Up	< 49.9
FCR-D down	Frequency Containment Reserve for Disturbances	Down	> 50.1
FFR	Fast Frequency Reserve, addresses lack of inertia in the electricity system	Up	< 49.5
aFRR up	Automatic Frequency Restoration Reserve	Up	Activation controlled by Fingrid
aFRR down	Automatic Frequency Restoration Reserve	Down	Activation controlled by Fingrid

Sand Battery as Reserve

The Polar Night Energy’s Sand Battery is charged via electric resistors, and the energy is stored as heat. Hence, the Sand Battery is a flexible electricity consumer. Table 2 explains how the Sand Battery can operate in different markets.

Table 2. Sand Battery's operation as reserve.

Direction of regulation	Sand Battery operation
Up	The Sand Battery charges. If the reserve is activated, charging is stopped (decrease consumption).
Down	The Sand Battery does not charge. If the reserve is activated, charging is initiated (increase consumption).
Symmetric	The Sand Battery charging is set to half power. The charging is reduced or increased according to the grid's frequency (adjust consumption).

Attending to different grid balancing markets allows the Sand Battery to gain extra profits while optimizing the behaviour based on spot prices and the user’s heating demand.

Potential Income from Reserve Markets

All the reserve products described above are balancing capacity markets. That is, a market attendant gets compensation for readiness to balancing, irrespective of whether the reserve is activated. Let’s assume we have a Sand Battery with 2 MW charging power, and we want to attend the FCR-D down market. This is how it works:

1. The Sand Battery operator sends reserving capacity bids for the following day. A single bid could look like this:

• Market: FCR-D down

• Time period: 15:00 – 16:00

• Capacity: 2 MW

• Price: 30 EUR/MW

2. Fingrid sorts all the received bids from cheapest to the most expensive. Fingrid accepts bids starting from the cheapest until the required capacity is procured. Every reserve whose bid gets accepted is paid according to the most expensive accepted bid (this is called Marginal pricing).

3. Assume the most expensive accepted bid is 50 EUR/MW. That means that the Sand Battery operator’s bid was accepted, and they get 50 EUR/MW * 2 MW = 100 EUR compensation.

4. At 15:00 the following day, the Sand Battery sets charging power to zero and starts to follow the grid frequency. If the frequency rises above 50.1 Hz, the Sand Battery starts charging and helps to restore the frequency below 50.1 Hz.

Simple Case Study

In our previous blog post we presented a simple case study for a spa with 2 MW Sand Battery and constant 500 kW heat demand. We argued that the Sand Battery should be charging 25% of hours to produce the needed 360 MWh of heat. By allocating the charging to cheapest hours, we ended up with 4 200 e charging costs and 11 e/MWh final heat price.

What if the Sand Battery would have in addition accessed the grid balancing markets?

Let’s assume that the Sand Battery operator would have bidden to aFRR up and down markets during the assessed period 16/8/2023 – 15/9/2023. Following the logic explained in Table 2, for the charging hours they would bid the 2 MW resistor capacity to aFRR up market. The rest of the time they bid 2 MW capacity to aFRR down. In this way, acting as reserve would not disturb the optimal charging pattern.

Assume for simplicity that all the bids were accepted. This would be the case with constant bid size 0 EUR/MWh, assuming the relatively small bid capacity would not change the market dynamics. Due to marginal pricing, the income from each hour would have been the historical market price for the hour (X EUR/MW) times the bidden capacity 2 MW. The hourly profits are illustrated in Graph 1.

The outcome?

Profits from aFRR up:	9,000 EUR
Profits from aFRR down:	29,000 EUR
Total aFRR profits:	38,000 EUR
Charging costs:	4,200 EUR
Final costs:	-33,800 EUR
Price for produced heat:	-94 EUR/MWh

The profits from aFRR markets were enough to cover the charging costs, with a nice margin! Yes, that would mean that you make money by producing heat.

Text: Terhi Moisala, Data Scientist

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The Next Step: A Feasibility Study

Interested in a thorough and transparent analysis of your energy system, complete with realistic simulations and intelligent charging algorithms? Our feasibility study evaluates your system's needs, including local energy production and storage, for optimal performance.

Visit our Solutions page for details!

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This article was conducted under the project NewSETS – New energy storages promoting sustainable energy transition in societies.

This project has received funding in the framework of the joint programming initiative ERA-Net Smart Energy Systems’ focus initiatives Smart Grids Plus and Integrated, Regional Energy Systems, with support from the European Union’s Horizon 2020 research and innovation programme under grant agreements No 646039 and 775970.

The content and views expressed in this material are those of the authors and do not necessarily reflect the views or opinion of the ERA-Net SES initiative. Any reference given does not necessarily imply the endorsement by ERA-Net SES.

Empowering the Energy Transition: The Sand Battery's Impact on Heating Costs

Ever wondered how thermal energy storages, like Polar Night Energy’s sand battery, can help save on heating expenses? We'll walk you through a simple real-world example that demonstrates their cost-saving power.

Energy storage is vital for the energy transition, but did you know that thermal energy storages can also significantly reduce heating costs compared to traditional sources such as natural gas, oil, coal, biomass or even heat pumps?

Case: Spa and its heating system, Finland

Energy storage: Polar Night Energy’s 2 MW thermal energy storage with a capacity of 200 MWh

Heat demand: Constant 500 kW

Time period: 16/8/2023 – 15/9/2023

Total heat needed during the period: 372 MWh

Electricity contract: electricity with spot pricing, per hourly market price

Costs: The sand battery is charged with electricity when spot prices are low, avoiding peak hours. This approach results in significantly lower costs compared to both direct electricity (average of spot price) and traditional combustion methods.

The following table shows the heating costs using different energy sources (without tax). The 'PNE spot' refers to the final price for purchased electricity used to charge the sand battery.

Source	Heat price EUR/MWh	Total cost EUR
PNE spot	11	4,170
Direct electricity	86	30,980
Heat pump (COP 2.5)	34	12,390
District heating	90	32,450
Natural Gas	70	25,240
Oil	125	45,060

If you want to see how PNE spot is formed, keep reading!

Method: There are two important parameters for the sand battery:

• Charging power versus heat demand (share of charging hours)

• Capacity (time scale for charging)

In this case, the storage has 2 MW charging power, and the heat demand is constantly 0.5 MW. That is, we need to charge 25% of all hours.

With this heat demand, the natural time range for the storage is 15 days.

Hence, from every 15-day slot, the storage must charge 25% of the time to fulfil the heat demand. In this simple computation, we get the price 11 EUR/MWh with the following procedure:

1. Divide the time to 15-day slots,

2. from each slot, choose 25% * 15 days = 181 cheapest hours and

3. compute the average spot price for the chosen hours. This is the final ‘PNE spot’.

The figure 1 illustrates the charging cost of the sand battery over time. During 75% of the time, the sand battery is not charged, with PNE spot at 0 EUR/MWh. In the remaining 25% of hours, PNE spot mirrors the spot price, resulting in peaks in the PNE spot curve. The highest spot prices are effectively avoided.

Figure 1. The charging cost of the sand battery over time.

The greater the charging power is compared to the heat demand and the greater the capacity is, the lower the PNE spot price will be. Fewer charging hours allow us to focus on cheaper times, while greater capacity provides more flexibility in selecting charging hours.

Keep in mind that when calculating the cost of produced heat, it's necessary to adjust the prices using the efficiency coefficient, which can reach up to 95% for our heat storage. You can find more details in our Lead Scientist's blog article.

Furthermore, the sand battery's flexible electricity usage enables participation in grid balancing markets, potentially reducing your heating costs significantly. Curious to learn more? Stay tuned for our upcoming post on FCR and FRR markets!

The Next Step: A Feasibility Study

The calculation above is a simplified representation of a basic use case. Interested in a thorough and transparent analysis of your energy system, complete with realistic simulations and intelligent charging algorithms? Our feasibility study evaluates your system's needs, including local energy production and storage, for optimal performance.

Visit our Solutions page for details!

Text: Terhi Moisala, Data Scientist

Sources for energy prices: Finnish day-ahead electricity prices, ENTSO-E Transparency Platform, Statistics Finland

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This article was conducted under the project NewSETS – New energy storages promoting sustainable energy transition in societies.

This project has received funding in the framework of the joint programming initiative ERA-Net Smart Energy Systems’ focus initiatives Smart Grids Plus and Integrated, Regional Energy Systems, with support from the European Union’s Horizon 2020 research and innovation programme under grant agreements No 646039 and 775970.

The content and views expressed in this material are those of the authors and do not necessarily reflect the views or opinion of the ERA-Net SES initiative. Any reference given does not necessarily imply the endorsement by ERA-Net SES.

Polar Night Energy’s Sand Battery Doesn’t Cause Sand Shortage – Thermal Energy Storage Medium Explained

Yes, the world might face shortage of sand. No, the sand battery won’t make the problem worse. Polar Night Energy’s Data Scientist explains how the sand battery is a perfect match for circular economy.

Polar Night Energy’s sand battery is a high temperature thermal energy storage that uses sand or sand-like materials as its storage medium. It stores energy in sand as heat.

We use sand because it allows a wide temperature range with storage time from hours to months. It is also affordable, non-toxic and can be locally sourced.

Meanwhile, we are about to face a crisis of sand shortage. Extraction of sand is an enormous unregulated business and rarely sustainable. (1)

We have been asked whether our technology is only making the problem worse. The short answer is no, and the next four points explain why.

1. The sand battery can use all sorts of sand

Sand is a key element in concrete, and hence vital for modern construction. A good quality concrete requires sand which has certain grain size distribution and shape, which is why sand is extracted even from coastal ecosystems rather than deserts.

However, our technology is flexible: the sand battery can use sand with varied mineral composition, very wide range of grain size distributions, and no restrictions to microscopic characters of the sand grains. This enables the usage of materials that are locally and commonly available, or even considered as waste.

We like high density, low-cost materials that are not from scarce sources. Someone else’s dirt could be our heat storage medium.

2. Mine waste volumes are overwhelming

Most of the substance extracted in mines needs to be disposed of. Only a small fraction of the material is utilized, and the rest is left to lie in heaps. Since mines can operate for decades, they are often accompanied with mountains of waste rock in their backyards.

In many cases this waste could be used to store energy in our sand batteries. And believe me, there are enough of heaps to build all the sand batteries we need.

Based on the estimate of Mission Innovation, 737 TWh of energy will need storage in 2030. (2) Let’s imagine that we would store all that energy in our sand batteries (a silly thought, since even if a sand battery is great for many applications, it can never fulfill all the storing needs. Imagine a few tons of sand battery in the trunk of your Tesla!).

Nevertheless, building all these sand batteries would require 200 million tons of sand or sand-like material, and the sand batteries would serve for decades. For comparison, 500 million tons of mining waste was produced only in EU during the year 2020. (3)

3. Mining industry seeks ways to direct mine waste streams into usage – we are happy to help

Mine waste is not only poorly utilized but causes many problems from land usage to soil contamination. The mining industry is now looking for solutions to this environmental hazard: ever larger portion of the wall rock streams is directed to circular economy, and we are actively searching opportunities to collaborate.

Mine waste volumes are too large for our sand batteries to completely tackle this problem, but we can do our part. At very least, no new mines are needed to fill sand batteries.

4. Our system is robust and safe

The design life of the storage is tens of years. All the materials used in construction of the system are recyclable and non-toxic. Even the storage medium will be reusable.

As our sand battery can be connected to existing infrastructure, building a combustion-free solution is straightforward and cost-effective.

To mitigate climate change, we desperately need solutions to store energy from weather dependent renewable sources, such as solar and wind. If we want these solutions to thrive, they need to be environmentally and socially sustainable as well as economically viable – like our sand battery.

Or as Donald Sadoway puts it: “If you want to make something dirt-cheap, make it out of dirt. Preferably dirt that’s locally sourced.” (4)

Text: Terhi Moisala, Data Scientist

Sources:

1 UNEP: Our use of sand brings us “up against the wall”, says UNEP report

2 Mission Innovation: Sand-Based High Temperature Seasonal Heat Storage by Polar Night Energy Oy, Avoided Emissions Framework – Level 2 version 0.8 assessment, 2020

3 Eurostat: Waste statistics

4 TED: Reinventing the battery: Donald Sadoway at TED2012

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This article was conducted under the project NewSETS – New energy storages promoting sustainable energy transition in societies.

This project has received funding in the framework of the joint programming initiative ERA-Net Smart Energy Systems’ focus initiatives Smart Grids Plus and Integrated, Regional Energy Systems, with support from the European Union’s Horizon 2020 research and innovation programme under grant agreements No 646039 and 775970.

The content and views expressed in this material are those of the authors and do not necessarily reflect the views or opinion of the ERA-Net SES initiative. Any reference given does not necessarily imply the endorsement by ERA-Net SES.

The First Commercial Sand-based Thermal Energy Storage in the World Is in Operation – BBC News Visited Polar Night Energy

Polar Night Energy’s first commercial sand-based high temperature heat storage is now in operation at Vatajankoski power plant area. The heat storage, which has a hundred tons of sand inside, is producing low emission district heating to the city of Kankaanpää in Western Finland. BBC made a story about Polar Night Energy’s heat storage solution.

See below for Finnish and French.

Polar Night Energy and Vatajankoski, an energy utility based in Western Finland, have together constructed a sand-based thermal energy storage. It is the world's first commercial solution to store electricity in the sand as heat to be used in a district heating network.

The storage, with Polar Night Energy’s patented heat storage system inside, is placed on Vatajankoski’s power plant area, and it provides heat for Vatajankoski’s district heating network in Kankaanpää.

– The construction of the storage went well, especially considering that the solution is completely new. We managed to get everything in order despite some challenges and a short delay. Now the sand is already hot, says Polar Night Energy’s Co-Founder and CTO Markku Ylönen and continues:

– We have already learnt that our system has even more potential than we initially calculated. It’s been a positive surprise.

The actual heat storage is about 4 meters wide and 7 meters high steel container that has an automated heat storage system and a hundred tons of sand inside. As a material, sand is durable and inexpensive and can store a lot of heat in a small volume at a temperature of about 500–600 degrees Celsius.

A small pile of sand that was left over from the heat storage.

The heat storage has 100 kW of heating power and 8 MWh of energy capacity.

– This innovation is a part of the smart and green energy transition. Heat storages can significantly help to increase intermittent renewables in the electrical grid. At the same time we can prime the waste heat to usable level to heat a city. This is a logical step towards combustion-free heat production, says Ylönen.

Vatajankoski uses the heat provided by the storage to prime the waste heat recovered from their data servers which are intended for high-performance computing. Depending on the season, the temperature of the 60-degree waste heat from the servers must be raised to 75–100 degrees before it is fed into the district heating network.

BBC News Made a Story About Polar Night Energy’s “Sand Battery”

BBC, the national broadcast company of the UK, visited us in Finland. During two days of filming, BBC’s Environmental Correspondent Matt McGrath and cameraman Tony Jolliffe examined Polar Night Energy’s pilot in Hiedanranta, Tampere and the heat storage in Vatajankoski, Kankaanpää.

BBC’s Environmental Correspondent Matt McGrath (in the middle) and cameraman Tony Jolliffe (right) interviewing Polar Night Energy’s Co-Founder and CEO Tommi Eronen (left).

They interviewed an energy and climate specialist Elina Seppänen from the City of Tampere and the managing director Pekka Passi from Vatajankoski in addition to the company founders Markku Ylönen and Tommi Eronen.

At the end of the second day, we made a trip to a place where they use the heat: the pool of Kankaanpää’s swimming hall is heated by district heating from Vatajankoski. Therefore, it was only natural (and funny) that part of the story was filmed in a pool of warm water.

Inside the article Vatajankoski’s Pekka Passi tells BBC that the storage is working fine and gives an apt comment: "It's a bit crazy, if you wish, but I think it's going to be a success."

Read the story: BBC: Climate change: 'Sand battery' could solve green energy's big problem

Check out the news item from BBC News, BBC World or BBC YouTube Channels.

Contact information

Polar Night Energy
Markku Ylönen
Co-Founder & CTO
markku.ylonen@pne.fi
+358 45 7832 8399

Vatajankoski
Pekka Passi
Managing Director
pekka.passi@vatajankoski.fi
+358 40 508 6367

Vatajankoski provides district heating and cooling services as well as electricity distribution services to its clients in Kankaanpää region in Western Finland and aims to produce its energy as sustainably as possible. / www.vatajankoski.fi

Polar Night Energy designs and builds high temperature & zero emission heat storages. / www.polarnightenergy.fi

BBC’s Matt McGrath (left) getting ready to interview Polar Night Energy’s Co-Founder and CTO Markku Ylönen (right).

BBC’s Matt McGrath (right) interviewing Vatajankoski’s Managing Director Pekka Passi next to our heat storage.

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Maailman ensimmäinen kaupallinen hiekkaan perustuva lämpövarasto käynnistyi – BBC News vieraili Polar Night Energyn luona

Polar Night Energyn ensimmäinen kaupallinen hiekkapohjainen korkean lämpötilan lämpövarasto käynnistyi Vatajankosken voimalaitosalueella. Sata tonnia hiekkaa sisältävä lämpövarasto tuottaa vähäpäästöistä kaukolämpöä Kankaanpäähän. BBC teki jutun Polar Night Energyn ratkaisusta.

Uusiutuvan energian lämpövarastoja toteuttava Polar Night Energy ja uuden energian yhtiö Vatajankoski rakensivat lämpövaraston, jossa sähköenergiaa varastoidaan lämpönä hiekkaan.

Kyseessä on maailman ensimmäinen kaupallinen ratkaisu, jossa sähköä varastoidaan hiekkaan lämpönä kaukolämpöverkossa hyödynnettäväksi. Polar Night Energyn patentoituun teknologiaan pohjautuva lämpövarasto sijaitsee Vatajankosken voimalaitosalueella, jossa se tuottaa lämpöä Kankaanpään kaukolämpöverkkoon.

– Lämpövaraston asennus meni hienosti, varsinkin siihen nähden, että ratkaisu on täysin uusi. Selvisimme kaikista vastaan tulleista haasteista ja pienestä viivästyksestä hyvin. Siellä se hiekka jo varastoi lämpöä, sanoo Polar Night Energyn tekninen johtaja Markku Ylönen ja jatkaa:

– Opimme, että järjestelmässä on vielä enemmän potentiaalia kuin alun perin arvioimme. Se on ollut positiivinen yllätys.

Lämpövarasto on noin neljä metriä leveä ja seitsemän metriä korkea terässäiliö, jonka sisällä on automaattinen lämmönsiirtojärjestelmä ja sata tonnia hiekkaa. Hiekka on materiaalina kestävää ja edullista. Siihen saadaan varastoitua paljon lämpöä pieneen tilavuuteen noin 500–600 asteen lämpötilassa.

Varaston lämmitysteho on 100 kW ja varastoimiskyky 8 MWh.

– Ratkaisu on osa energiamurrosta. Lämpövaraston avulla uusiutuvan energian määrää voidaan merkittävästi lisätä sähköverkossa. Samalla saamme matala-arvoisen hukkalämmön tasolle, jossa sitä voi käyttää kaupungin lämmitykseen. Tämä on looginen askel kohti polttamatonta kaukolämpötuotantoa, sanoo Ylönen.

Vatajankoski käyttää varastoitua lämpöä omistamiensa suurteholaskentakapasiteetin vuokraamiseen tarkoitettujen dataservereiden tuottaman hukkalämmön lämpötilan nostamiseen. Servereistä saadun 60-asteisen hukkalämmön lämpötilaa täytyy nostaa vuodenajasta riippuen 75–100 asteeseen ennen sen syöttämistä kaukolämpöverkkoon.

BBC News tutustui Polar Night Energyn ”hiekka-akkuun”

Britannian yleisradioyhtiö BBC vieraili Polar Night Energyn luona Suomessa. Kahden kuvauspäivän aikana BBC:n ympäristötoimittaja Matt McGrath ja kuvaaja Tony Jolliffe tutustuivat Tampereella Hiedanrannan pilottiin ja Kankaanpäässä Vatajankosken lämpövarastoon.

Polar Night Energyn perustajien Markku Ylösen ja Tommi Erosen lisäksi haastatteluun pääsivät Tampereen kaupungin energia- ja ilmastoasiantuntija Elina Seppänen ja Vatajankosken toimitusjohtaja Pekka Passi.

Toisen kuvauspäivän lopuksi teimme vielä kuvausreissun kohteeseen, jossa lämpöä oikeasti käytetään: Kankaanpään hienon uimahallin vesi lämmitetään Vatajankosken kaukolämmöllä. Siksi olikin luontevaa (ja hauskaa), että osa jutusta kuvattiin uima-altaan lämpimässä vedessä uiden ja sukellellen.

Itse artikkeli päättyy Vatajankosken toimitusjohtaja Pekka Passin haastatteluun, jossa hän kertoo, että varasto toimii hyvin ja kiteyttää asian: ”Onhan se vähän hullu idea, mutta uskon, että siitä tulee menestys.”

Lue juttu: BBC: Climate change: 'Sand battery' could solve green energy's big problem

TV-uutisen voit katsoa BBC News ja BBC World -kanavalta.

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Le premier stockage commercial d'énergie thermique à base de sable au monde est en service - BBC News a visité Polar Night Energy

Le premier système commercial de stockage de chaleur à haute température à base de sable de Polar Night Energy est maintenant en service dans la centrale électrique de Vatajankoski. Le stockage de chaleur, qui contient 100 tonnes de sable, produit du chauffage urbain à faibles émissions pour la ville de Kankaanpää, dans l'ouest de la Finlande. BBC a réalisé un reportage sur la solution de stockage de chaleur de Polar Night Energy.

Polar Night Energy et Vatajankoski, une compagnie d'électricité basée dans l'ouest de la Finlande, ont construit ensemble un système de stockage d'énergie thermique à base de sable. Il s'agit de la première solution commerciale au monde permettant de stocker l'électricité dans le sable sous forme de chaleur à utiliser dans un réseau de chauffage urbain.

Le stockage contient le système de stockage de chaleur breveté de Polar Night Energy; il est placé sur la zone de la centrale électrique de Vatajankoski, et il fournit de la chaleur au réseau de chauffage urbain de Vatajankoski à Kankaanpää.

« La construction de l'entrepôt s'est bien déroulée, surtout considérant le fait que la solution est totalement innovante. Nous avons réussi à tout mettre en place malgré quelques difficultés et un léger retard. Maintenant, le sable est déjà chaud. » déclare Markku Ylönen, cofondateur et directeur technique de Polar Night Energy, et poursuit :

« Nous avons d’ores et déjà appris que notre système a encore plus de potentiel que ce que nous avions initialement calculé. Cela a été une fantastique surprise. »

Le stockage de chaleur actuel se présente sous la forme d'un conteneur en acier d'environ 4 mètres de large et 7 mètres de haut, équipé d'un système de stockage de chaleur automatisé et contenant une centaine de tonnes de sable. Le sable est un matériau durable et peu coûteux qui peut stocker beaucoup de chaleur dans un petit volume à une température d'environ 500-600 degrés Celsius.

Le stockage de chaleur a une puissance de chauffage de 100 kW et une capacité énergétique de 8 MWh.

« Cette innovation fait partie de la transition énergétique intelligente et verte. Les réservoirs de chaleur peuvent contribuer de manière significative à l'augmentation des énergies renouvelables intermittentes dans le réseau électrique. En même temps, nous pouvons amorcer la chaleur résiduelle à un niveau utilisable pour chauffer une ville. C'est une étape logique vers la production de chaleur sans combustion. » déclare M. Ylönen.

Vatajankoski utilise la chaleur fournie par le stockage et récupère la chaleur résiduelle sur leurs serveurs de données destinés au calcul haute performance. Selon la saison, la température de la chaleur résiduelle de 60 degrés des serveurs doit être portée à 75-100 degrés avant d'être injectée dans le réseau de chauffage urbain.

BBC News a fait un reportage sur la "Batterie de Sable" de Polar Night Energy

La BBC, la société nationale de radiodiffusion du Royaume-Uni, nous a rendu visite en Finlande. Pendant deux jours de tournage, le correspondant environnemental de la BBC, Matt McGrath, et le caméraman Tony Jolliffe ont examiné le projet pilote de Polar Night Energy à Hiedanranta, Tampere, et le stockage de chaleur à Vatajankoski, Kankaanpää.

Ils ont interrogé une spécialiste de l'énergie et du climat, Elina Seppänen, de la ville de Tampere, et le directeur général Pekka Passi, de Vatajankoski, ainsi que les fondateurs de l'entreprise, Markku Ylönen et Tommi Eronen.

À la fin du deuxième jour, nous nous sommes rendus dans un endroit où ils utilisent la chaleur : la piscine de la salle de natation de Kankaanpää est chauffée par le chauffage urbain de Vatajankoski. Il était donc tout à fait naturel (et amusant) qu'une partie de l'histoire soit filmée dans une piscine d'eau chaude.

Dans l'article, Pekka Passi, de Vatajankoski, explique à la BBC que le stockage fonctionne bien et fait un commentaire pertinent :

« C'est un peu fou, si vous voulez, mais je pense que ce sera un succès. »

Lire l’article : BBC: Climate change: 'Sand battery' could solve green energy's big problem

Consultez les actualités de BBC News, BBC World ou des chaînes YouTube de BBC.

French translation by Sienna Berreby.