How Iceland Uses Geothermal Energy: From Hot Springs to Greenhouses

Iceland sits directly on the boundary where the North American and Eurasian tectonic plates are slowly pulling apart, and that restlessness has quietly reshaped daily life on the island for centuries. Roughly nine in ten Icelandic homes are heated by water drawn straight from the ground, farms grow tomatoes through months of near-total winter darkness, and outdoor swimming pools stay open in towns where a Nordic climate would otherwise make it unthinkable. On Odyssey’s small group tour of Iceland, Iceland’s geothermal energy isn’t something you read about in a museum display case — it’s the hot water in your hotel shower, the warmth radiating from a Reykjavík footpath in midwinter, and the reason a farm at Fríðheimar can serve a bowl of tomato soup grown a few dozen metres from where it’s poured.

A Landscape Still Being Built

Iceland is one of the few places on Earth where you can watch the planet’s crust being made in real time. The island straddles the Mid-Atlantic Ridge, and the volcanic and geothermal activity that produces its geysers, lava fields and hot springs is the same force behind the fissures, craters and glaciers explored in depth on our wider look at Iceland’s volcanic geology. It’s the same subterranean heat, in fact, that gave the Snæfellsjökull glacier its role as the fictional entrance to the centre of the earth in Jules Verne’s novel — a story our Snæfellsnes and Jules Verne article explores in more detail. What sets Iceland apart from other volcanic regions isn’t just the geology — it’s what Icelanders have done with it. Rather than treating geothermal heat as a hazard to be managed, the country has spent the past century turning it into the backbone of its energy supply.

Deildartunguhver and the Hot Water That Heats a Country

On day three of the tour’s route around the Iceland ring road itinerary, the group pauses at Deildartunguhver, Europe’s highest-flow hot spring. Water surfaces here at close to boiling point, and for the farms and villages of the Borgarfjörður region it has done far more than provide a striking photograph — it has heated homes for generations. A pipeline built in the 1970s still carries the spring’s water more than 60 kilometres to Akranes and Borgarnes, arriving at people’s taps still warm enough to be useful without any additional heating.

This is district heating on a national scale. Around nine out of every ten Icelandic households are connected to a geothermal hot water network of exactly this kind, and the model is simple: instead of burning fuel to heat water, towns pipe naturally hot groundwater directly into homes for space heating and washing. It’s a large part of why Iceland, despite its far northern latitude, has some of the cheapest domestic heating costs in Europe.

How hot is the water at Deildartunguhver?

It surfaces at around 97°C, just short of boiling. Visitors stay well back from the spring itself on a raised boardwalk, and the steam is often visible before the spring comes into view. The site is flat and paved, with only a short, level walk from the car park.

The Blue Lagoon and Iceland’s Geothermal Spas

The most photographed expression of Iceland’s geothermal heat is also one of the tour’s early stops. On day two, after a morning exploring Reykjavík, the group visits the Blue Lagoon, where the water sits at a steady, bathing-friendly temperature and is rich in silica and minerals that Icelanders have long considered good for the skin. It’s a fitting introduction to the theme of the whole tour, though it’s really just one geothermal spa among many scattered across the island — a subject our dedicated Blue Lagoon guide covers in far more depth, including its origins as a by-product of a nearby geothermal power station rather than a naturally occurring pool.

Is the Blue Lagoon natural or man-made?

Neither, exactly. The water itself is pumped from deep underground, but the lagoon that holds it formed after run-off from the adjacent Svartsengi geothermal power station collected in the surrounding lava field in the 1970s. Bathers found the mineral-rich water soothing long before it was developed into the spa it is today.

Growing Food Through the Dark Months: Fríðheimar’s Greenhouses

Toward the end of the tour, on day sixteen, the group visits Fríðheimar, a horse and tomato farm south of Reykjavík that has become one of the clearest demonstrations of what geothermal heat makes possible. Iceland’s growing season is short and its winters offer only a few hours of daylight, yet Fríðheimar’s greenhouses produce tomatoes year-round, heated by geothermal water piped directly beneath the growing beds and lit through the darkest months by electricity generated, in turn, by geothermal steam. Visitors walk through the working greenhouse itself, surrounded by vines, before sitting down to a lunch built almost entirely around what’s growing around them — a very direct link between the island’s underground heat and the food on the table, one we explore more broadly in our article on Icelandic food.

Capturing the Power: Hellisheiði and How Iceland Turns Geothermal Energy into Electricity

Not every use of Iceland’s underground heat is as simple as piping hot water into a house. At Hellisheiði, one of the world’s largest geothermal power stations, wells drilled deep into the volcanic bedrock draw up high-pressure steam that spins turbines to generate electricity, exactly the way a conventional power station does — except the steam here costs nothing to produce and never runs out. The tour visits Hellisheiði on its final full day, immediately after Fríðheimar and the Gullfoss waterfall, which makes for a neat piece of sequencing: guests see geothermal heat used for growing food in the morning, then see it converted into the electricity that powers the greenhouse lighting they walked through only hours earlier.

Geothermal sources currently generate around a quarter of Iceland’s electricity, with the remainder coming almost entirely from hydropower — meaning the country’s electricity grid is, in practical terms, powered almost completely by renewable sources drawn from its own landscape.

Can you drink Iceland’s geothermal water?

Not the hot water — it’s typically drawn from a different, mineral-rich groundwater source than the cold tap water and isn’t intended for drinking. Iceland’s cold tap water, by contrast, is some of the cleanest in the world, drawn from glacial and spring sources and safe to drink straight from any tap on the tour’s route.

Lake Mývatn: Where the Ground Still Breathes

Further along the route, at Lake Mývatn, the tour visits a landscape where geothermal activity is close to the surface in a rawer, less engineered form — bubbling mud pools at Námaskarð, steaming vents, and the eerie lava formations of Dimmuborgir. It’s a useful counterpoint to Hellisheiði and Fríðheimar: a reminder that everything Icelanders have built around geothermal energy started with a landscape that was already doing exactly this, unassisted, for millennia before anyone thought to put a pipe in the ground.

How much walking does a geothermal site visit involve?

Very little at any single stop — Deildartunguhver, the Blue Lagoon and Fríðheimar are all reached by short, level paths or boardwalks from the car park. The tour overall is rated Level 2 – Moderate, meaning participants should be able to manage 3 to 5 hours of activity across a full touring day and up to 8 kilometres on uneven ground, though no individual geothermal stop on this itinerary requires anything close to that on its own.

Travelling this route with a small group, rather than working it out independently, means someone else has already solved the logistics of getting to each of these sites, timed the visits around opening hours and daylight, and can put the science in context as you go. It’s one of the reasons Odyssey keeps groups on this tour to a maximum of 14 travellers, with solo travellers welcomed and comfortably accommodated throughout. For a country that runs so much of its daily life on heat drawn from underground, there’s something fitting about experiencing it in person — hand against the boardwalk rail at Deildartunguhver, feet in the Blue Lagoon, or a tomato still warm from a greenhouse vine at Fríðheimar.