ForTheDoers Blog

World’s oldest and newest energy storage side by side: hydropower and batteries

27 February 2017, 12:44

Hydropower is agile, but agility comes with a price. This is where lithium-ion batteries come into the picture.

Energy battery in Järvenpää

There is a big hype on lithium-ion batteries; they are enjoying the media spotlight alongside other cool ideas, such as demand response and electric vehicles. Fortum too has joined in the Nordic battery game: Batcave, the biggest lithium-ion battery in the Nordic countries, will be taken into use on Wednesday, 1 March, at Fortum’s Järvenpää power plant.

But what is this battery mania really about? Does Finland really need a cargo container full of cell phone batteries to be connected to the electricity network? And what will they actually be used for?

The basics on the battery hype

The big interest in energy storage, i.e. battery hype, has prevailed in energy markets for a long time. And there’s a really good reason for this hype: with the increase in the number of rooftop solar panels and windmills spinning in windy weather, the aim is to be able to store that renewable energy for later use when the sun is not shining and the wind is not blowing.

In addition to energy storages that store energy for hours, energy storages that are fast, reacting at the second- and minute-level, are also needed. Every day, the electricity network experiences sudden, unpredictable peaks in electricity consumption and production; at worst, these peaks can cause power outages and disruptions. The future may bring more potential electricity peaks and thus, even more, need for fast-reacting energy storages. When the sun suddenly emerges through cloud cover, a solar panel’s production shoots from zero to 100 per cent, and when hundreds of electric vehicles connect to charging stations at the same time, the balance between electricity production and consumption can sway dramatically in the electricity network.

So do we need batteries for this? Yes and no.

In terms of energy storage, things here in Finland are already relatively good: we have a lot of hydropower.

Hydropower: the wallflower of renewables

Hydropower is often the forgotten renewable energy form in the media hype, perhaps because of its long history – hydropower is one of the oldest energy production forms – and therefore it may be slightly boring alongside the media-sexy solar and wind power.

Hydropower also happens to be our best energy storage. Hydropower can solve both energy storage problems: water can be stored in lakes for hours, and, on the other hand, hydropower plants can quickly increase or decrease production, in under a minute. Despite its old age, hydropower can tranquilly store energy and, at the same time, can react very fast to the needed changes.

So then, why are batteries needed?

Hydropower is agile, but agility comes with a price. Fast changes at hydropower plants wear their mechanical parts, shortening their expected life-time. Big maintenance projects have had to be done at hydropower plants years earlier than expected due to the wear on the bearings and seals of the Kaplan turbine blades.

This is where lithium-ion batteries come into the picture.

Of the battery technologies, lithium-ion batteries have developed enough for commercial use: the price of lithium-ion batteries has dropped quickly in recent years, and it is believed that the price will continue to decrease as demand increases. Lithium-ion batteries can react in seconds, making them ideal for fast energy storages to support the growth of solar and wind energy in energy production.

In the Nordic countries, lithium-ion batteries can give hydropower a break. By having batteries (instead of hydropower) perform the fast adjustment, the premature wear of the machinery is prevented, and hydropower’s flexibility is used for longer-term energy storage.

Batcave battery and future outlook

The Batcave, the biggest battery storage in the Nordic countries, will be taken into use on Wednesday, 1 March 2017, at Fortum’s Järvenpää power plant. The fast-reacting 2MW/1MWh lithium-ion battery will offer the electricity network fast, second- and minute-level flexibility in frequency regulation. The Batcave project was launched in April 2016 after a bidding round and was ready for deployment in February 2017.

The Batcave battery will be used alongside hydropower. The battery’s primary role is to provide fast adjustment; when its output capacity is reached, hydropower will be engaged to support it. The best end result will be achieved by optimising the use of the battery and hydropower together.

Fortum is also thinking beyond the Järvenpää Batcave. Growth in use of solar and wind energy in the energy markets is not limited only to Finland: batteries will be needed elsewhere in the world, too, especially in places where hydropower is not available.

So could Finnish know-how in the optimal use of batteries be exported to other parts of the world? A good way to start capturing global markets is to start learning. The Batcave battery is, above all, a learning project towards the future energy market and new opportunities.

Roosa Nieminen
Project Manager for Batcave

Fortum Batcave PDF