Siân Green, Managing Editor

The tiny Norwegian island of Utsira is playing host to a world-first demonstration of a wind-hydrogen hybrid power plant. The project aims to show that a community can be self-sufficient with renewable energy, and investigate the feasibility of the ‘hydrogen economy’.

On July 1, 2004, ten households on the island of Utsira, Norway, became fully reliant on renewable energy when a new hydrogen and wind-based power plant was officially inaugurated. The plant, developed by Norsk Hydro (Hydro), is the world’s first full-scale autonomous renewable energy system based on wind power and hydrogen.

The power plant makes the small, windswept island a global showcase for the development of renewable energy systems. It will, says Hydro, show how a combination of wind and hydrogen can ensure a reliable supply of energy. “This is an incredibly exciting pilot project,” said Jørgen Rostrup, vice president of Hydro’s New Energy unit. “Utsira will be a showroom demonstrating how we can create sustainable energy systems based on renewable energy and hydrogen.”

“Given its westerly position in the North Sea, Utsira is a strong and independent community. This project will demonstrate how a local community can produce its own renewable energy, and represents one of the most innovative energy projects in the world,” said Thorhild Widvey, Norway’s petroleum and energy minister, at the plant’s inauguration. “With this project, Hydro and its partner Enercon are demonstrating how seriously they take the challenge of developing the future’s energy solutions.”

The two wind turbines began operating in September 2003. One turbine is dedicated to the standalone hybrid plant, while the other produces power for export to the grid
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Plant design

The power plant consists of two wind turbines, a fuel cell, electrolyser, a hydrogen generator set and grid stabilising equipment. It is designed to supply the electricity needs of ten households on Utsira, which with a total area of just 6.15 km2 and 240 inhabitants, is Norway’s smallest municipality.

Situated 20 km west of the coastal town of Haugesund, Utsira experiences just three or four days per year without wind. While the prevailing weather conditions on the island make it an ideal choice for wind power generation, electricity supply from wind turbines is periodical. The concept of the Utsira project is, therefore, to overcome this fundamental problem by storing any surplus electricity produced as chemical energy in the form of hydrogen.

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When wind conditions on Utsira are good, the wind turbines produce enough electricity to supply the ten households and to convert water into hydrogen in the electrolyser. Any surplus energy is exported to the island’s grid. When wind conditions are poor – i.e. when there is not enough wind or if there is too much wind for the turbines to operate – the stored hydrogen is used in the fuel cell and hydrogen generator engine to produce electricity. The ten households therefore have a constant and reliable supply of renewable electricity.

The NOK40 million ($5.8 million) project was developed by Norsk Hydro – Norway’s second largest power producer with an annual production of some 9 TWh – in conjunction with German wind turbine manufacturer Enercon. It received support from the Norwegian Pollution Control Authority and the Research Council of Norway. Enercon supplied the wind turbines, grid stabilising equipment and the control system, while Norsk Hydro Electrolysers delivered the hydrogen plant.

Feasibility and planning

The inspiration for the project came from the combined efforts of Hydro and the municipality of Utsira. Hydro was seeking an opportunity to demonstrate a hydrogen-based renewable energy project, while Utsira wanted to exploit its wind resources. Enercon was invited to become a partner due to the design of its wind turbines – which are suited to operation in weak grids – as well as its experience with standalone systems and research into storage systems.

Studies were carried out based on meteorological data collected on the island to determine the best location for the plant. Peak power consumption (winter) on the island is approximately 900 kW, while the annual consumption is around 2.5 GWh. The island is connected to the mainland via a 17.5 km, 22 kV subsea cable with a capacity of 5 MW.

As part of the planning studies, simulations were carried out investigating the feasibility of a system serving the whole island as well as one serving just a few households. It was important to the developers involved that the quality of the power delivered by the new plant should be comparable to that supplied by the island’s existing system.

For technical and financial reasons, it was finally decided that the plant should serve ten domestic consumers. Support for the project among the Utsira community has been strong, according to Hydro. Construction began in June 2003.

The total peak load of the ten households is approximately 40 kW. Hydro verified their load profile by installing measuring devices in the substation serving the selected group. A load profile for one year was constructed from three months of load monitoring as well as from a generic profile for typical residential electricity loads in Norway.

One of the main design criteria of the plant was that the plant should be able to serve the needs of the ten households as a standalone system. The peak power capacity of the system was therefore fitted to the selected load with an additional margin. The wind turbine, electrolyser, storage unit and fuel cell/hydrogen combustion generator were sized so as to avoid an overall dumping or exhaustion of energy. The wind data showed that the maximum period without sufficient wind for operation of the wind turbines was two days.

Integrated system

The wind turbines for the Utsira plant were supplied by Enercon. They were erected in the summer of 2003 and became operational in September 2003. Each wind turbine unit is rated at 600 kW with a rotor diameter of 40 m and a tower height of 46 m. They operate at wind speeds in the range of 2.5-25 m/s. From 25 m/s, their output declines until wind speeds reach 34 m/s, when they shut down automatically.

At optimum performance, the two wind turbines can provide more than enough electricity to supply the entire Utsiracommunity. One of the turbines is therefore dedicated to the standalone hybrid plant, while the other produces power exclusively for export to the grid. Any surplus power from the turbine linked to the hybrid plant will also be sold to the grid, and Utsira is therefore likely to become a net power exporter. An agreement has been signed with Haugeland Kraft, the owner of the network, to allow export of power.

The ten households in the island of Utsira will become self-sufficient with renewable energy when the hybrid plant becomes fully operational
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Power from one of the wind turbines is used to generate hydrogen in an electrolyser. Electrolysers produce hydrogen and oxygen by splitting water molecules by means of electricity. The gases are produced when an electric current flows from an anode to a cathode through water mixed with an electrolyte. The hydrogen produced by the electrolyser is compressed to 200 bar and stored in a container that can hold up to 2400 Nm3 of the gas – enough for two full days of energy supply to the ten households. The electrolyser is fully automatic and supplied with a state-of-the-art PLC control system, and is certified and approved in accordance with international standards for hazardous area installations. The whole hydrogen system at Utsira is operated by Norsk Hydro Electrolysers.

When the wind turbines are not operating, the stored hydrogen is used to produce power via a 10 kW fuel cell and a 55 kW hydrogen combustion generator. The fuel cell is a proton exchange membrane (PEM) type unit and was supplied by IRD, a Danish fuel cell manufacturing company based in Copenhagen. The combustion engine is a diesel engine which was converted for operation on hydrogen by Belgian engine manufacturer, Continental Energy Systems, a Brussels-based company. Hydrogen-fuelled reciprocating engines are not very common but are relatively easy to operate, according to Torgeir Nakken, Norsk Hydro project manager. Hydrogen combusts in the engine at a high temperature, but otherwise the engines operate on similar principles to natural gas fired engines.

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The hybrid plant is a standalone system and is therefore not connected to the grid. The customers which it supplies are therefore directly connected to the plant, but if the plant shuts down, they are automatically reconnected to grid supplies via a switch.

In order to ensure a stable supply of power from the plant, it is equipped with a flywheel with a storage capacity of 5 kWh.

The Utsira project is the world’s first full scale autonomous renewable energy supply system based on wind power and hydrogen

Testing times

The project is undoubtedly innovative but was not without challenges along the way. One of the key challenges, according to Hydro, was the number of interfaces between the standalone hybrid plant and the island’s electricity grid, and the fact that solutions had to be found that could be replicated in later projects. In addition, neither Enercon nor Hydro have any experience with fuel cells and hydrogen -fuelled generators.

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The power plant was officially opened at the beginning of July and will become fully operational in August after the Norwegian summer vacation period. Hydro Energy’s power production department will operate the plant on a day-to-day basis.

At the time of writing, just the wind turbines were operational but these had already achieved an impressive second place in the efficiency ranking of European wind turbines, with a production time of 97 per cent.

A strong foundation

Hydro has little operational experience with this hybrid plant so far, but will run it for a two-year demonstration period. During this time, it will monitor it closely, measuring various aspects such as wind speed, hydrogen consumption and so on. Hydro believes that it requires a full six months of continuous operation in order to gain a good understanding of the system and to have a strong foundation for further development work.

For Hydro, the Utsira project has a wide significance. If successful, the project could be expanded to incorporate all consumers on the island, or could be replicated elsewhere – even in urban environments. The company is keen to explore the possibilities of a hydrogen economy supported by renewable energy, including the use of hydrogen in transport and other applications. The company, a major oil and gas producer, has already invested in other hydrogen projects, including a filling station on Iceland.