Hafslund Nett owns and operates the regional grid in Oslo, Akershus and Østfold and is the distribution grid owner in Oslo, most of Akershus and parts of Østfold. In 2011 the total electricity consumption in Hafslund Nett’s area amounted to 21.3 TWh, a reduction of around 9 percent from 2010. In the reporting period Hafslund’s distribution grid distributed 15.2 TWh of electricity, a year-on-year decrease of just over nine percent.
A future-proof grid
With several thousand new electricity customers each year and major ongoing city centre development, Oslo needs more power. Hafslund Nett is therefore continuing its work to upgrade the electricity grid in Oslo to 132 kV. Increasing the grid to this voltage will reduce grid losses by a volume corresponding to the annual consumption of almost 3,500 households. After upgrading, the grid will be able to cater for future load increases, and the risk of outages will be reduced due to the grid’s increased capacity. The upgrading is planned for completion in 2018.
Significant infrastructure already in the ground
One of the largest challenges regarding the upgrade to 132 kV is posed by the presence of much existing infrastructure in the ground. When laying cables certain requirements apply with regard to distances that need to be maintained between water, waste and district heating pipes, existing high voltage and telecommunication cables and tram tracks etc. Electromagnetic fields from the cable installations must also be taken into consideration. Wherever possible Hafslund and Hafslund Fjernvarme are using shared ditches in the upgrade in order to reduce the inconvenience for the public to the greatest extent possible.
Focus on information and dialogue
Many people are being affected by the extensive grid expansion, which unfortunately at times restricts general traffic and limits parking spaces and access to property and stores. Hafslund Nett is attaching great importance to providing accurate information and engaging in a clear dialogue with all concerned parties both prior to and during construction.
Advice and guidelines from the authorities
In connection with the introduction of the 132 kV cables in Oslo Hafslund Nett has registered increasing concern about magnetic fields in the vicinity of homes, schools, nurseries and outdoor areas. The company is very conscious of public concern about potential health effects of magnetic fields from electricity lines and cables. The company is one of 140 grid companies in Norway with high voltage lines, and monitors health-related issues relating to power lines very closely. In doing so Hafslund Nett adheres to established facts, and the advice and guidelines issued by the Norwegian Radiation Protection Authority and other authorities.
In the week between Christmas and New Year Storm Dagmar raged over Hafslund Nett’s operating area, cutting power to nearly 50,000 customers. Hafslund Nett reinforced staffing levels at the operating centre, and deployed significant manpower throughout the entire period to reconnect power supplies. On the three busiest days, between about 200 people were all working in the field rectifying faults. 12,000 customers had their power restored within an hour, while after 18 hours just under 2,500 customers were without power. A small number of customers were without power for more than three days.
In 2011 Hafslund Nett started a project to introduce advanced metering systems (AMS) following changes in the Norwegian regulation governing metering, settlement and invoicing. The project requires AMS to be installed and commissioned with all customers by the end of 2016. In November 2011 pre-qualified suppliers of AMS were invited to tender for an end-to-end solution. The agreement is due to be signed in the third quarter of 2012. The project will implement a pilot installation before AMS is installed on full scale with all grid customers.