Sustainable energy production

A cooling resource that is drawn up from the depths of a lake SUSTAINABLE ENERGY PRODUCTION District cooling for Aalborg University Hospital Client Aalborg Forsyning Photo Aalborg Portland

When the new Aalborg University Hospital is completed, it will be cooled with water from the chalk lake at Aalborg Portland. This is a solution that results in massive savings economically and in the carbon balance.

The cement manufacturer Aalborg Portland uses massive quantities of chalk in its production process. Many excavations have over time formed a chalk lake at the company's facilities, and this will now provide district cooling for the new Aalborg University Hospital.

The water near the bottom of the more than 30 metre deep lake has a temperature ranging between 4 and 14 degrees throughout the year. This is a resource that in the future will provide electricity savings of approximately 80 % compared with an ordinary cooling system. The 170,000 m² hospital at Gistrup will make use of the cooling for patient rooms, personnel and clinical facilities and medical equipment.

Moreover, a total of 500 to 700 tonnes of carbon dioxide will be saved per year by using a climate-friendly solution.

How cold water travels MOE is the consultant to the client Aalborg Supply for the lake water heat exchanger building and the cooling distribution centre, each of which plays an important role in the comprehensive system. The cold water from the bottom of the lake is pumped up into the lake water heat exchanger building first. The heat exchanger uses the cold from the lake to cool the water in the piping that runs to and from the cooling distribution centre at the hospital. The systems are thus separate, and the water in the piping contains corrosion protection and is softened, so that the pipes do not corrode or become blocked by lime deposits etc. The water is transported approximately 3.5 km to the hospital's 800 m² cooling distribution centre. The water is delivered at a temperature of 12 degrees, and is returned in the direction of the lake water heat exchanger station at a temperature of 18 degrees. The cycle is completed when the heat is diverted by the heat exchanger into the surface water of the chalk lake.

The plant is expected to become operational in mid-2021.

A green energy source that can be harvested year after year SUSTAINABLE ENERGY PRODUCTION Halskov straw-fired heating plant Client SK Varme A/S Architect Arkikon Photo Martin Schubert

The residents of Halskov now have access to district heating by means of a new straw-fired heating plant, which also supplies large parts of Korsør.

Straw is an annual crop and can thus be sown, harvested and burned in a recurring annual cycle. It is also a local resource, and straw as a fuel is therefore close to being 100 % carbon neutral.

One of the places where straw is converted into green energy is at the Halskov straw-fired heating plant in northern Korsør. Before the plant opened in the spring of 2019, the residents of Halskov had to do without district heating, and now the new plant supplies a considerable portion of Korsør. Since agriculture is abundant in West Zealand, there are many suppliers of straw in the local area.

MOE has participated on several fronts in the creation of the new plant that SK Varme is responsible for. We were the lead consultant for the building, client consultant for machinery, and construction manager for the overall project. Pipeline under the harbour Since central and southern Korsør were also to benefit from the new heating plant, it was necessary to establish a connection between the city's existing district heating network and the new network in Halskov. However, Halskov and the rest of Korsør are separated by water, and MOE was tasked with studying different approaches to the connection. The solution was to lay a transmission line under Korsør Harbour by directional boring. This was a task that resulted in a lot of curious onlookers along the harbour, since the 225-metre-long district heating pipe was pulled through in one piece.