In recent months, Landsnet has carried out extensive upgrades and improvements to its transmission system on the Suðurnes Peninsula, both related to Suðurnes Line 1 and in preparation for Suðurnes Line 2. On three occasions in recent weeks, these changes have required HS Orka to operate the region in island mode — a complex operation that is far from guaranteed to run smoothly.

The ability to switch to island operation significantly increases the security of electricity supply in Suðurnes. When the area is operated as an “island,” HS Orka effectively takes over Landsnet’s role, delivering electricity to the distribution utility, which then supplies end users.

Arnar Flókason, who oversees all electrical and control systems at HS Orka, says the operations were executed flawlessly thanks to coordinated efforts by staff at both HS Orka and Landsnet. “This is not the first time Suðurnes has been run as an island, but over the past decade HS Orka has planned around 20 such operations — all with good results.”

A Major Transformation Ahead for the Suðurnes Transmission System

A major milestone for energy security in Suðurnes was reached earlier this year when construction began on Suðurnes Line 2. For a region that is home to a tenth of the nation, hosts a diverse business community, and contains Iceland’s international airport, this development is nothing short of transformative. A new substation has been built at Njarðvíkurheiði, and new high‑voltage towers are rising rapidly, mostly alongside Suðurnes Line 1.

Everything Worked Seamlessly During Island Operations

Arnar and his team have had their hands full in recent weeks. “Landsnet’s work has mainly involved commissioning the new substation at Fitjar. Connections had to be moved from the original site to the new one. The largest task was relocating the connection point of Suðurnes Line 1 and linking it to the new substation at Fitjar, where the distribution utility receives electricity from HS Orka. The old switchgear at Fitjar is being phased out and replaced with new equipment.”

With this change, Suðurnes Line 1 will no longer enter the building as an overhead line but instead run underground as a cable, connecting to new gas‑insulated switchgear (GIS) installed in the expanded Fitjar substation.

The third and final island operation related to Landsnet’s upgrades on Suðurnes Line 1 took place in mid‑October and lasted seven hours. “During that time, HS Orka staff kept everything running in Suðurnes as if nothing had happened — lights stayed on in homes, data centers kept calculating, and fish farms continued caring for their stock,” Arnar says, clearly pleased with the outcome.

A Complex Operation With Many Moving Parts

HS Orka normally produces far more electricity than is consumed in Suðurnes, with the surplus fed into Landsnet’s transmission system for use elsewhere in the country. During island operation, however, production at both HS Orka power plants on the Reykjanes Peninsula must be significantly reduced — by as much as 60 MW.

“When the system is run as an island, at least one turbine must handle frequency regulation. In these operations, Turbine 1 at Reykjanes Power Plant took on that role. During the operation, a warning light in the control room read: ‘AREA ISOLATED OPERATION.’ This indicates that the plant is no longer connected to Landsnet’s system.”

Large‑Scale Landsnet Projects Bring Additional Challenges

The Suðurnes Line 1 upgrades are not the only Landsnet project affecting HS Orka’s operations in recent months. The connection of Reykjanes Power Plant to the transmission system has also been changed. “Previously, Reykjanes Power Plant connected to Rauðamel via Rauðamels Line 1, and from there Svartsengi and Reykjanes shared a single high‑voltage line, Fitjar Line 1, to Fitjar. That has now changed. Reykjanes Power Plant connects directly to Fitjar and no longer shares a line with Svartsengi. The line has also been renamed and is now called Reykjanes Line 1.”

To carry out this major project, the line had to be taken out of service twice — once for three full days and again for eight hours. As this is the only Landsnet line connected to Reykjanes Power Plant, all production at the plant had to be halted during the work — a significant undertaking.