Stockholm Moves Towards an Emission-Free Future with a Giant Drilling machine

A drill that is longer than the tallest skyscraper in Stockholm eats away at granite, gneiss and other rocks. After three years of work, the 1,000 ton machine named Elektra and has reached the halfway mark in its journey.

The hulking machine, which moves at a constant pace of 70 meters a week (230 feet), is slowly moving across the Swedish capital. It is digging a subterranean tunnel that will allow the city to upgrade its outdated electricity infrastructure, and finally go green. Once the tunnel is completed, it will solve a major problem not only for Stockholm but also cities around the world. While fast-growing cities have tried to reduce carbon emissions by electrifying, their networks were unable to meet the surging demand. Stockholm’s tunnel, which stretches 13.4 km from the wealthy suburb of Danderyd in the north to the middle class neighborhood of Hammarby Sjostad in the south, will be completed by late 2028. It is the latest element of a plan to upgrade the infrastructure that delivers power to the city, costing 15 billion Swedish kronors ($1.37billion).

During the transition period, the old overhead powerlines are being removed and replaced with new underground ones, increasing the overall capacity of the city to 6 to 6.5 Gigawatts. The national grid operator will drill a tunnel which will extend for over 13km

Stockholm’s network can only handle 3.5 gigawatts, despite the fact that Sweden is a powerhouse. It was Europe’s largest electricity exporter in 2017. This is not enough for the peak demand on the coldest winter days, or to power new subway stations, commuter tubes, electric vehicle chargers, or electrify ports and ferry services. This means that energy-intensive, large projects that need to be connected to Stockholm’s grid will have to wait until the resources are available.

In 2019, local grid manager Ellevio AB and supplier Stockholm Exergi AB struck a deal for emergency supplies to be provided during the coldest of days. The city’s plan to become fossil-fuel free by 2040, five years before the demand for energy is expected to reach a level of more than one third the current level, is adding to the pressure.

The need for grid upgrades becomes more evident as time goes on and the demand increases. On April 26, a combination human error and defective equipment knocked power out to trains and subways for an hour in the morning rush. This left tens and thousands of commuters stranded. Traffic lights went out and two nuclear power plants north of the city had to be temporarily shut down. Elektra has also been affected by the shortages. The shortages have affected even Elektrastrong> /strong>.

Per Eckemark is the head of Svenska Kraftnat AB’s grid division. This state-owned firm oversees the national network and tunnel construction. He acknowledged that many power lines and underground substations in Stockholm are nearing the end of their useful lives. He said that some overhead power lines were built in the 1940s. With modern technology, the risk of future power outages will be reduced. Around 20 years ago, plans to overhaul the grid began to take shape after outages struck the technology hub Kista and the residential areas north the capital. Eckemark explained that a proposal to build a submarine cable around Stockholm was discarded due to cost and reliability issues. The tunnel became the only viable alternative. The plan was finally approved in 2017 after years of legal disputes and red tape. After completion, nine aluminium cables will run along one wall of the tunnel to ferry electricity from the national network to the local grid.

Ellevio cannot wait for such reinforcements. Saira Aladin, the Head of Asset Management at Ellevio, said, “We are in a very acute situation. We shouldn’t be where we’re at.” “We need more capacity.”

It is vital to update the local grid for electrification. Ellevio will spend its annual revenue in the coming years on boosting capacity. Alladin noted that investment in Stockholm alone is expected to double, to around 4 billion Kronor per year.

Stockholm’s underground tunnel, while one of many cities that are working to strengthen their grid – Berlin and London also pursue similar projects – has recently gained international attention. The project was visited by US Congressional staffers in October last year, and officials from Nordic grid companies this month.

The entrance to the tunnel is not visible from the outside. It is concealed behind a substation, and is occasionally hit by golf balls from the adjacent driving range. The passageway underground is surprisingly smooth and five meters wide, except for those parts where concrete has been used to patch over the damaged areas. Tunnel boring machines, which are relatively new in Sweden, were previously dominated by dynamite – a Swedish invention. A conveyer belt near the ceiling ferries the rocks to the surface so they can be used in other infrastructure projects. A reporter was there on the day that several men were monitoring operations from a room with a control panel, while a man in white overalls and a yellow helmet shoveled mud. Others gathered together to discuss project notes at a toolshed. The 60-person team, which hails from a dozen different countries in Europe, will rotate shifts every two weeks, with two weeks of rest, until the project is completed.

Stockholm has borrowed time until then. The national statistics agency predicts that the population of Stockholm will increase by 16% in the next 17 year. In a decade or two, the city will look completely different. Electric ferries are set to transport locals and tourists between the city and the archipelago of islands that makes up Stockholm. Electric planes are set to buzz over the city and modern subway lines will link the rapidly expanding suburbs with the inner city.

The light at the other end of the tunnel is a welcome sight for both officials and residents.