But how exactly does the battery stand up in terms of performance compared with other batteries, in particular its electrochemical counterpart: lithium-ion batteries?

Eronen says that "starting a company is a bit like competing in sport: you want to win". Together with Ylönen, he chose to cycle 170km (106 miles) from their home town of Tampere to attend an energy conference in Helsinki in 2018. "All the other participants arrived by car or plane. That made us think: 'we really have to make an impact'."

The floor access covers, wall access panels, ceiling access panels, linear drainage and architectural metalwork we manufacture at our facility in Hertfordshire, are used in some of the most prestigious buildings in the world. Credentials include ISO 9001 accreditation; the CE Mark for structural steel and numerous testimonials from our customers explaining why they use Howe Green. Suitable for all types of floor finishes, including ceramic tiles and resin with a load bearing capacity of up to 3 tonnes. HG100 CHANNEL DRAIN Some industries need very hot air, 300C (572F), for drying something, for example. We are now looking at cooperating with industrial companies in the Kankaanpää area that use electricity to produce heat. Having a sand battery that they can charge overnight would give them flexibility and shield them from price fluctuations," he says. It's a low-maintenance system, says Kivioja. The company uses cheap, low-quality sand that's been rejected by builders instead of high quality river-sand which is used in vast quantities for construction, leading to a global shortage. The Vatajankoski power plant is home to the world's first commercial-scale sand battery. Fully enclosed in a 7m (23ft)-high steel container, the battery consists of 100 tonnes of low-grade builders' sand, two district heating pipes and a fan. The sand becomes a battery after it is heated up to 600C using electricity generated by wind turbines and solar panels in Finland, brought by Vatajankoski, the owners of the power plant.

This is for a significantly bigger system: 2MW in heating power and 500MWh in storage capacity. That's 10 times bigger than what we have in Kankaanpää," says Eronen. The 7500 Series is a popular choice for commercial and retail premises where a heavier loading or larger sized cover may be required. A small commercial application of a new energy storage system rarely becomes a hot topic, but the sand battery has attracted attention for its potential to even out the power supply from renewable sources (see The search for steady supply box). Any configuration of ducts and branches can be created to provide a tailor-made floor access solution for your application.Third party CERTIFIRE fire rated to BS 476 Part 22 for stainless steel covers. Fire rated for 2 hours on integrity, and up to 2 hours on insulation depending on the floor access cover fill specification. Howe Green is a leading UK manufacturer of fabricated metal access covers which are designed to provide easy and safe access to concealed services. Established in 1983, we have over 35 years experience in the building services sector. In 2017 we were acquired by Bilco UK to support their proposition "safe access all areas". An extensive range of standard and custom made access covers satisfies the requirements of all the stakeholders in a building. We are aware of the impact on building owners of their duty of care and their obligation to ensure compliance with Health and Safety regulations and legislation. At Howe Green we understand the desire of architects and designers to produce aesthetically pleasing buildings that inspire and motivate, whilst justifying the cost of their choices. We appreciate the need for building services professionals and facilities managers to be able to access concealed services easily and cost effectively with minimum disruption. Together with Ylönen, he started developing the sand battery prototype. Having successfully tested their pilot battery in Eronen's grandfather's garden near Tampere, the pair recruited their childhood friends from the athletics club to start Polar Night Energy. In July, they installed the first commercial sand battery at the Vatajankoski power plant in Kankaanpää. Any configuration of ducts and branches can be created to provide a tailor-made floor access solution.

In the wake of the Ukraine war, Finland is urging the EU to increase its renewables output. "The only way out of the energy crisis is to invest heavily in renewable and emission-free energy production," Finland's prime minister Sanna Marin said in September. Visedge VR Series Aluminium Securing Edge Joint is used in commercial locations such as walkways in kitchens where the safety flooring may adjoin quarry tiles under the ovens, swimming pools where safety flooring on the poolside adjoins tiles around the pool, and wetrooms where safety flooring adjoins a tiled area. MANUFACTURED TO REQUIREMENT Visedge DS Series Aluminium Securing Edge is for use in commercial locations such as kitchens, hospitals, shopping centres, supermarkets and retail outlets, where two different types of flooring meet.At the moment, the sand battery remains a Nordic solution at heart, says Pongrácz. "It's very useful in Finland where we have cold winters and need heating pretty much from September to May, [due to] an average annual temperature of under 10C (50F)," she says, adding that half of Finland's 5.5 million people are connected to a district heating network. Any situation where regular access to concealed services is required. Performance Standards Howe Green | HSE 75 SUITABILITY