From what I've gathered from reading other articles before this one, the weather can get pretty choppy at times and when that happens those islands become cut off. So it might not be a case of tunnels being less expensive but rather tunnels being more reliable.
To put that into perspective: the tunnel cost roughly 175M euros, that's 3.5k EUR per inhabitant. I don't find this excessive. From the maps, it looks like basically every inhabitant benefits from those tunnels. Even if it just saves 100 EUR in gas per year and inhabitant, the tunnel is a societal net gain after about 35 years.
Also consider this:
> On the Eysturoy side of the tunnel house prices increased by 31% between 2019 and 2020 and have doubled between 2015-2020 [0]
Additionally, the tunnels are tolled [0]:
> Construction costs for the tunnel are being recouped through toll fees. Tolls start at 75 DKK for small cars (up to 3,500 kilograms (7,700 lb)) between Tórshavn and Eysturoy, and 25 DKK for local traffic between Saltnes (near Runavík) and Strendur. This price is for people who have a subscription (hald). Without subscription the price is 175 DKK between Eysturoy to Streymoy and 125 DKK between the two arms of Skálafjørður.
75 DKK are around 10 EUR. With an estimated 6,000 cars per day, thats 60,000 EUR per day. At this rate, the tunnel will have paid for itself (if maintenance cost is excluded) after 8 years.
That’s quarterly earnings type thinking, if you do the projections on a 50 year basis they almost certainly come out as a net gain, at least for Norwegian money. As they have lots of money looking for returns on investment overseas already.
The Faroe Islands were part of Norway for 800 years until about 200 years ago. Nordic territorial rivalries continue to exist as friendly banter (for now).
The Norwegian city of Tromsø has just 70k people, and a whole network of underground tunnels with two roundabouts. It's very useful given the weather, and less destructive to the island than new overland thoroughfares would have been. If that had been a failure, I'm not sure why it would be repeated.
Consider that the tunnels will encourage economic activity, which will encourage population growth at the nodes. I've always felt that the North American method of building transit between 'natural' urban centers is wrong, and that the Japanese have it right--demolish everything, build a rail line, and economic life will flourish around the nodes.
Not sure how you're computing benefits of the tunnels...
Those tunnels cut travel time to the capital from 1h14 to 16 min. Moreover, you don't have to travel by car+ferry+car, you simply drive.
I reckon the increased accessibility makes it worth them in one year.
If you only want to count in monetary terms, consider that a hospital in the capital is suddenly reachable in 16 min instead of over 1hr. So they don't need helicopters for emergencies; they don't need minor, unsustainable hospitals on the other island just to have healthcare accessible, etc. Same for other things: supplying the 2nd islands can be done by lorry from the first, instead of shipping. Et cetera, et cetera, et cetera.
In addition to what the other replies have said, it's also worth adding that these are as much to provide essential access (eg emergency services) as it is for convenience. In Europe, and particularly the Scandinavian countries, governments often provide services at a loss where safety concerns are considered.
