How To Extract More Energy From Running Water

Nidelva, the main river in the Arendal watercourse, has been a source of energy for more than a century. Arendals Fossekompani established the Bøylefoss hydropower plant in 1913 and added the Flatenfoss plant in 1927.

The planning of energy production, using a combined 10 turbines in two river-located plants with various water flows, is a tricky business. The variables are too many for the human mind to process when searching for the optimal production plan. And even a small miscalculation can lead to great economic losses.

Taking this into account, Arendals Fossekompani – the main owner of Volue – has been focused on optimising energy production, knowing that the upside is substantial. The upside became evident when the company identified that different operating teams achieved different results based on the same water volumes.

"One operating team could produce energy worth NOK 30,000-40,000 more per week than other teams. This made us aware that fully manual production processes have their weaknesses. We approached Volue to explore the possibility of digitising our power plant control systems. Volue came up with solutions that have helped us increase the utilisation rate of our water resources by approximately one percent. In an average year, this translates to an extra 5 GWh or NOK 1 million or more," says Jan Roald Evensen, Operation Manager at Bøylefoss power plant.

Production simulation to help maximise energy output

Power production is always planned one day ahead, based on the assumed amount of water in the river and the balance of the power supply. Decisions have to be made as to which turbines shall produce energy and when productions should start. Based on precise timing and by tuning the aggregates to the optimal output level, the efficiency level and energy output is increased. The trick is to have the power stations interact optimally, so that the maximum of megawatts is extracted from the water as it runs through the power plants.

The digital management system of Volue has proven to be a valuable tool for optimising energy production. A detailed simulation model of the two power plants has been created, including pipelines, aggregates, water flow in the water course, and inflow forecasts. Using the Nimbus software tool kit, next day's production pattern is calculated. The final output is a production plan telling operators how to run the plants.

"We are very pleased with the results we have achieved thanks to the Volue software and expertise. System data generated by Volue could also enable us to take a small share of the frequency market,” says Evensen.

Volatility in energy prices increases the value of optimisation software

According to Nils Olav Tangvik, Sales Manager Energy Solutions at Volue, the rising level and volatility of electricity prices have increased the value of Volue’s software solutions.

"With so much to gain from increased output, utilities are very much interested in how to make power production more efficient and profitable. With the help of Volue's software, all relevant data are processed. The result is a production plan that maximises output from the turbines," says Tangvik.

“Based on the same data sets, power producers can also reduce the risk of a difference between planned production and actual output. Such an imbalance is very costly for power producers,” says Tangvik.

So far, Volue has implemented production control systems to approximately 40 larger utilities in the Nordics and Europe. Tangvik says that the introduction of solar and wind in the energy mix will make Volue's control systems even more relevant and useful in the years to come.