Its proximity to nature has given Norway an enormous, green advantage with renewable energy. While many countries were industrialised with the help of fossil sources, hydropower became the mainstay in the development of Norwegian industry. More than 1600 hydropower plants and 1000 reservoirs are spread throughout the country.

Hydropower accounts for around 20 per cent of the world’s total electricity production. In Norway, hydropower dominates with 90 per cent.

Wind accounts for approximately 10 per cent of Norway's electricity production. When the wind does not blow and clouds block the sun’s rays from reaching solar panels, reliable hydropower delivers the renewable energy needed.

The day after the ceremonial opening of Kvilldal power plant, 1800 members of the public are admitted to see the brand new, state-of-the-art facility.

In the crowd stands a boy with wide-open eyes.

"I was eight or nine years old at the time and remember being excited by the tunnels and the fact that they had to blast underwater. It was cool stuff," recalls Bjørn Sandvik.

Four decades later, Sandvik is a power plant manager in charge of a gigantic energy project. The Ulla Førre power plant group in Western Norway utilises hydropower from the Kvilldal power plant, among others. The four generating units in Kvilldal have a combined power of 1 240 megawatts, or 1.7 million horsepower.

Most of this power comes from Lake Blåsjø, Norway's largest reservoir.

"Even without a drop of new water, Blåsjø could still supply Haugesund with electricity for 18–20 years," says Sandvik.

Blåsjø is located at the top level of the Ulla-Førre complex, approximately 1000 metres above sea level. The lake stretches across three municipalities in the counties of Agder and Rogaland and covers an area of 84 square kilometres.

Lake Blåsjø is known as a multi-year reservoir. This means that the reservoir is large enough to store more water than what falls as precipitation in a normal year. In this way, hydropower production becomes less vulnerable to changes in precipitation patterns.

In years of little precipitation, wind and sun, the Lake Blåsjø reservoir constitutes an important safeguard for Norway's power system. Lake Blåsjø could be referred to as a power storehouse.

Hydropower has a number of unique properties. It is:

• Renewable

• Emission-free

• Flexible (it can be turned on and off)

• Predictable

And hydropower helps to counteract flood damage by controlling the amount of water in regulated waterways and reservoirs.

Producers of renewable power from wind, solar and water are all dependent on weather conditions; enough wind, enough sun, enough inflow of rain and snow...

But what makes hydropower unique is that it is flexible and can be switched on and off.

Norwegian reservoirs vary in size and in how much inflow they receive from precipitation and snowmelt, i.e. the amount of water that flows into the watercourse, making it challenging to correctly manage water resources through storage and production.

Norway's largest water reservoir, Lake Blåsjø, holds three years of inflow. The purpose of reservoirs as large as Lake Blåsjø is to store water for use in years with low levels of precipitation. The reservoir helps to compensate for precipitation deficiencies and makes the power system in Norway more robust.

At the same time, the weather affects supply and demand in the power market; the more precipitation, the greater the supply of power, and the colder the weather, the greater the demand for electricity.

Moreover, an increasing proportion of renewable power reinforces the relationship between weather and electricity prices. When demand increases and there is a shortage of wind and hydropower, the price of power increases as a result of expensive production from fossil energy sources.

In addition, this year's war in Ukraine and Russia's cut in gas deliveries are creating extremely high energy prices in Europe and Norway.

Norway and the Nordic countries have long had a power surplus – in other words, power production is higher than consumption. Statkraft's analyses suggest that this surplus will continue.

In a normal year, Norway has a power surplus of around 10 terawatt hours (TWh). Most of Norwegian power production comes from hydropower, which today can vary by just over 20 TWh above or below normal.

This means that Norway will have a power deficit in dry years and be dependent on imports from neighbouring countries.

Why upgrade hydropower plants?

Over the past 20 years, around half of Norwegian hydropower plants have undergone some form of rehabilitation, according to the Norwegian Directorate of Water Resources and Energy (NVE).

It is called upgrading when the power plant does not need to increase water flow or height of fall. Upgrading helps to increase efficiency of the hydropower plants while having limited environmental impact. Statkraft has spent over NOK 20 billion on upgrading hydropower plants over the past 15 years. Among other things, the company has invested significantly in upgrading hydropower plants in Høyanger Municipality in Vestland County and Rana Municipality in Nordland County.

At Kvilldal power plant, a turbine runner and a turbine were recently upgraded. This resulted in an increase in generation of around 75 GWh without the need for more water. The increase corresponds to the production from five to six wind turbines.

Upgrading power plants often leads to significant positive spillover effects for local communities in the form of jobs.

Statkraft has plans to expand five hydropower plants in Norway by 2030. At Mauranger power plant in Kvinnherad Municipality in Vestland County, near the Folgefonna glacier, Statkraft has submitted its most comprehensive licence application in 40 years.

With upgrades, we will get the hydropower plants to supply the country with clean energy for many years to come.