District cooling infrastructure is a big ongoing project by Hafslund Oslo Celsio. Since having a total overview of the environmental impact of each such facility is crucial, NORSUS and Norsk Energi have developed an environmental declaration mapping the product's whole life cycle.
District cooling, also known as area cooling, is based on renewable energy resources, which contributes to reducing the need for electricity. When establishing a district cooling infrastructure, cooling production in each building is unnecessary; therefore, such measures are an essential part of the climate solution.
In brief, district cooling means that cooling machines cool down water while excess heat from the plants can be utilized for heating when possible.
The corporation Hafslund Oslo Celsio offers both district cooling and heating in Oslo municipality, and the areas of Økern and Ullern are now to be developed. As part of the process, Hafslund Oslo Celsio requested an Environmental Product Declaration (EPD).
An EPD is a document summarizing the total environmental impacts of a product.
Hafslund Oslo Celsio*s EPD NORSUS, in collaboration with Energi Norge, has prepared the Hafslund Oslo Celsio EPD. Energi Norge has contributed data about the infrastructure used for cooled water distribution, while NORSUS has calculated the environmental impacts and developed the EPD.
Environmental declarations relate the environmental effects to a functional unit. In this specific EPD, the functional unit is 1 kWh cooling delivered to the customer. The estimated environmental impact includes the manufacture and transportation of raw materials used in the infrastructure and the manufacture and transport of energy carriers used to cool the water. The infrastructure consists of the facility cooling the water and the pipe networks distributing the cooled water to customers. It is the infrastructure itself that is most important for the total environmental impact of district cooling.
An EPD divides the product's life cycle into modules. In the Hafslund Oslo Celsio EPD, the process is split into an upstream, a core, and a downstream module.
- The upstream module includes producing and distributing electricity used to cool the water.
- The core module consists of the production of the infrastructure for the energy plant where the water cooling happens. This module also includes infrastructure for dumping heat used for district heating.
- The downstream module includes the infrastructure of the pipe mesh distributing cold water, as well as heat exchangers and associated equipment at the customer's premises.
Yearly maintenance and waste disposal of the infrastructure are also included in the analysis.
For district cooling, the infrastructure is the most important contributor to greenhouse gas emissions and other environmental impact categories. The main factor is steel used in the energy plant, the customer unit and the distribution network.
In general, the core module accounts for approximately 50 percent of the total environmental impact of delivering 1 kWh to customers. The effects of the upstream and downstream modules depend on which environmental impact category is being analyzed.