Lead

“You know, Japan is rich in geothermal resources but isn’t using them.”

You’ve probably heard that line for years.

But if you’ve ever worked with hydropower in the mountains, you also know this: Japan still has a lot of energy it simply hasn’t tapped yet.

In this article, writing from the standpoint of a person living with an acquired severe disability and still involved in mountain infrastructure, I’ll try to tell the story of “next-generation geothermal power” not as some faraway national project, but as a realistic, hopeful energy option that works beautifully together with hydropower.

Three ideas run through the whole piece:

1. Next-generation geothermal was invented to loosen location constraints.


2. Once you combine it with hydropower, Japan’s renewables can cover daily, seasonal, and yearly rhythms.


3. Because it keeps work in the mountains, it connects really well with local tourism, welfare, and even jobs for people with disabilities — in other words, it can become a renewable that people want to support.




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Table of Contents

1. Why Japan’s geothermal didn’t grow


2. Why people working in hydropower should be excited about next-gen geothermal


3. The three pillars of next-generation geothermal
　3-1. EGS (Enhanced Geothermal System)
　3-2. Closed-loop geothermal
　3-3. Superhot / supercritical geothermal


4. Looking at it as “keeping the culture of making energy in the mountains”


5. Rhythm design of renewables with hydro × geothermal


6. Why “social acceptance” matters so much in Japan


7. How to design local benefits people actually feel


8. Mountain jobs that even people with disabilities can do


9. Five things the government, utilities, and local communities should agree on first


10. A 10-year roadmap Japan should follow


11. FAQ


12. Conclusion — Don’t let being a volcanic country stay a burden




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1. Why Japan’s geothermal didn’t grow

First thing to be clear about: Japan’s geothermal didn’t stall because we don’t have resources.
It stalled because the places we want to drill are hard to drill.

Most of Japan’s promising geothermal spots are:

inside or right next to national / quasi-national parks,

right under famous hot spring resorts,

or in areas where tourism and nature conservation are the lifeline.


If you try to do conventional geothermal (take hot water/steam from an underground reservoir and generate power) there, you will always be asked:

“Will our hot springs dry up?”

“Will the landscape be ruined?”

“Are you going to drill too much?”


On top of that, in Japan it can easily take 10 years from exploration → environmental assessment → drilling → power plant construction. A normal private company can’t keep money tied up that long.
So even though Japan is always introduced in reports as “one of the world’s top geothermal countries,” installed capacity kept hovering around 0.5–0.6 GW.

That’s where “next-generation geothermal” comes in.
It’s not “let’s slowly extend the old way,” but “let’s increase the number of places we can actually use.”
That’s why the growth curve can finally look different.


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2. Why people working in hydropower should be excited about next-gen geothermal

If you work with hydro, you already have a kind of “sense”:

you look at a mountain shape and water flow and you can tell where the head might be taken,

you look at seasons and inflow and you can roughly tell the output,

you know both the hardship and value of placing equipment in the mountains.


That sense transfers almost as-is to geothermal.

Why? Because geothermal is also, at its core, a job of “reading the land.”
Hydro reads nature horizontally (upstream → downstream).
Geothermal reads nature vertically (surface → deep underground).

So people in hydro already own an “OS for making energy in the mountains.”
Next-generation geothermal is just a new app you install on top of that OS. Suddenly, the number of renewable options you can propose from the same mountain increases.

Hydro also has its pains:

output must be reduced in droughts

just refurbishing dams/powerhouses doesn’t always keep local jobs

winter patrols and snow-related work are heavy and seasonal


Geothermal is the opposite in an important way: it has almost no seasonal fluctuation and can produce day and night.
So you can build a set like this:

Base load: geothermal

Adjustment / peak / seasonal follow: hydropower


For utilities, local governments, and businesses that already have bases in the mountains, this is a very clean combination.


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3. The three pillars of next-generation geothermal

Let’s go through the technologies one by one so that even someone who lands here from search can read this part alone.

3-1. EGS (Enhanced Geothermal System)

EGS is a method for places that “have heat but not enough water.”
You artificially create fractures underground so water can circulate and pick up heat.

Two key points:

1. Unlike conventional geothermal, you don’t have to find a natural hot-water pocket.


2. You can turn “likely-hot” locations into resources.



In Japan, there are many stretches along the volcanic front where the rock is hot but there isn’t a usable hot spring reservoir.
If we open those spots up with EGS, we can increase the number of sites that don’t collide with national parks or hot spring aquifers.

Of course, EGS comes with the issue of induced seismicity.
So in Japan the realistic way is to make seismometers and real-time data disclosure part of the package. Only then will people accept it.

3-2. Closed-loop geothermal

Closed-loop geothermal is, very simply, “we put a pipe loop underground, circulate our own working fluid, and take only the heat from the surrounding rock.”

Because it doesn’t touch the groundwater, the impact on hot springs is extremely small. That’s the biggest advantage.

You can explain it even in tourist hot spring areas

Easy to combine with binary power and heat use

Civil engineering / tunnel / oil & gas drilling skills can be reused


So in Japan we can start to imagine small, distributed geothermal in tourist and mid-mountain areas.

3-3. Superhot / supercritical geothermal

Superhot / supercritical geothermal means you drill deeper to 400–500°C class zones and pull out a lot of energy from one point.

This is more demanding — drilling, materials, instrumentation all need to withstand high temperature and pressure — but because you can get big output from one spot, it’s perfect for Japan’s “we can’t use big areas here, but maybe we can drill one point” locations.

If you’re in hydro, imagine a high-head plant taking a big drop in a very narrow valley — it’s that kind of idea.


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4. Looking at it as “keeping the culture of making energy in the mountains”

Hydropower plants and dams in Japan are also a mechanism to keep people going into the mountains.

Patrols, brushing, equipment inspection, snow damage response, emergency response…
Because there’s work, there’s an economic reason to go up there.
Because there’s an economic reason, other mountain industries (forestry, tourism, road maintenance) don’t collapse so easily.

But with population aging, automation, and rationalization, the amount of work we can leave in the mountains is shrinking.

That’s why it’s meaningful to add new work to the very same mountains in the form of geothermal:

geothermal monitoring

environmental observation

tourist explanation

maintenance of heat-use equipment


Then the mountain economy gets one size thicker.

This is not just “good for CO₂.”
It’s about “passing on the Japanese lifestyle of living and working in the mountains.”
If you work in hydro, this should resonate.


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5. Rhythm design of renewables with hydro × geothermal

When talking about renewables, what really matters is how you align the output rhythms.

Solar PV: only in the daytime

Wind: fluctuates with season and time of day

Hydro: can adjust daily/seasonally to some extent

Geothermal: almost no seasonality, runs at night too


So geothermal is the renewable that supports the yearly bottom,
and hydro is the renewable that fills the daily and seasonal dips.

Put them together and you can raise the regional renewable ratio without making system operation too hard.

If you then add on-site heat use (hot springs, farming, welfare facilities) on top, you can avoid wasting the part that can’t be efficiently turned into electricity.

This logic — “show it, use it, return it” — is the same as hydropower using discharge for tourism and disaster prevention.
Once those three are there, the power plant is seen as a local asset.


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6. Why “social acceptance” matters so much in Japan

Why is geothermal treated so carefully in Japan?
Basically because of three worries:

1. “Will it affect our springs?”


2. “Will it damage park landscapes and ecosystems?”


3. “Will the drilling cause small earthquakes?”



Conventional geothermal had to take all three head-on.
Next-generation geothermal was invented to thin these issues out with technology.

Closed loop → easier to separate from hot spring aquifers

EGS → easy to disclose real-time monitoring

Supercritical → can take high output from a single point, so you can choose sites carefully


Also, in Japan, we already know from dams and rivers that just making things public — “here’s the water level / here’s the release / here’s the camera” — raises acceptance a lot.

So for next-gen geothermal, right from the start, operators should:

prepare a system to disclose subsurface temperature, flow, pH, and seismic data

prepare easy-to-understand geological cross sections for briefings

prepare an evaluation flow that allows hot spring operators to say “no impact so far”


Do this and the chance of being supported goes way up.


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7. How to design local benefits people actually feel

“Okay, sounds nice, but what do we get?”

Every municipality asks this.
So it’s quicker if we make a “visible benefits” menu from day one.
I recommend this 3-part package:

1. Use the heat locally
Don’t stop at power generation. Feed the leftover heat into hot spring inns, tourist spots, greenhouses, welfare facilities. Decide the priority order together with the municipality and operator in advance.


2. Decide the money routes first
Decide in advance how to distribute property tax, usage fees, and contribution money to the tourism association, environmental conservation, and local NPOs. Also decide on a “hot spring impact fund” just in case — this provides huge reassurance.


3. Leave jobs for local people
List from the beginning the jobs that can be done locally: monitoring, guidance, tourist content, SNS. If you include tasks that the elderly or people with disabilities can do, it becomes much easier to work with the welfare sector.



Once these three are there, discussions shift from “we oppose it” to “we’ll accept it if you do X, Y, Z.”
That’s all it takes to make a renewable “supported.”


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8. Mountain jobs that even people with disabilities can do

When you acquire a disability midway through life, you really do think for a moment,
“Maybe I can’t go to sites anymore,”
“Maybe I can’t do mountain work anymore.”

But when next-generation geothermal comes in, the number of “mountain protection” jobs you can do without going there every day actually increases.

checking daily drilling logs and seismic data and flagging anomalies

uploading environmental monitoring results to a public website

creating panels and digital guides for tourists like “Here’s the heat under this mountain”

doing online classes for local elementary and junior high schools


These can all be done at home, with a PC, even with physical limitations.

As Japan spreads out energy sources — hydro, geothermal, small hydro, biomass — it will definitely need people who remotely “keep an eye” on them.
So next-gen geothermal is also an entrance for people with disabilities to stay involved in mountain infrastructure.
That’s a point we can say louder.


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9. Five things the government, utilities, and local communities should agree on first

1. Priority of sites
Map national parks, surrounding areas, existing hot spring belts, closed mine sites, and agree where to start.


2. What data to disclose and how often
Decide up front the granularity for temperature, flow, seismic, noise, and power output.


3. Emergency contact and compensation flow
Put on paper: “If there is any change in hot springs, who does what by when.”


4. Priority for heat use
Locally decide what comes first — tourism > welfare > agriculture > industry.


5. A window for employment and education links
Connect to special needs schools, work-continuation support (Type A/B), technical colleges, and high schools, so local kids can visit and help.



If you do these, you won’t get stuck at “Geothermal? We don’t really know, so let’s be cautious…”


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10. A 10-year roadmap Japan should follow

1. Do 1–2 “visible demonstrations” in Japan for each of the three types (EGS, closed loop, supercritical)
→ publish data online, allow tours, publish environmental procedures


2. Create a national platform to share drilling data
→ lower the cost for the next developer


3. Set up a “mountain renewables desk” in each prefecture for hydro, mini-hydro, geothermal, and biomass
→ one-stop for mountain access, road use, and grid connection


4. Make it a bundled product with tourism, hot springs, and agriculture
→ build “use all the heat” into subsidy requirements from the start


5. Make participation slots for seniors and people with disabilities a standard menu
→ make monitoring, PR, education, and archiving mandatory tasks



Do this, and next-gen geothermal stops being “Sorry, it’s inside a national park, so no” and becomes “It’s in a national park, but with these conditions, yes.”


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11. FAQ

Q1. Is next-generation geothermal really safe?
A. It depends on the method. Closed loop doesn’t touch groundwater, so the impact on hot springs is minimal. EGS can cause small induced quakes, so putting seismometers and disclosing data is a must. In Japan, “showing what we’re doing” is the realistic way to secure social safety.

Q2. What if the hot springs are affected?
A. It’s hard to make the risk literally zero, so the practical way is to decide in advance on monitoring + compensation rules. It’s just like deciding intake/discharge rules for dams.

Q3. I’ve heard drilling is expensive. Can it pay off?
A. The first well looks expensive. But costs drop with the second and third well in the same field. That’s why the key is not “drill once,” but “how many wells we’ll drill in this field.”

Q4. Why does it work so well with hydro?
A. Hydro is good at adjustment and seasonal response. Geothermal is good at steady output with almost no seasonality. Put them together and you can add more solar and wind without breaking the grid.

Q5. Can people with disabilities be involved?
A. Yes. Especially with monitoring data整理, public updates, tourism content, and educational materials. These are doable remotely and connect geothermal projects with local welfare.


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12. Conclusion — Don’t let being a volcanic country stay a burden

Japan has volcanoes, earthquakes, hot springs, steep mountains, and even heavy snow.
From an energy-infrastructure angle, it’s a pretty “troublesome” country.

And yet we’ve made power from falling water in such a country for more than 100 years.

“Because nature is troublesome, there is work for people.”
That’s what Japanese hydropower teaches us.

Next-generation geothermal is a way to turn that very Japanese “troublesomeness” into energy one layer deeper.
Like hydro, it leaves work in the mountains, it overlaps with tourism/welfare/education, and it lets people with disabilities take part.

To hand over the culture of “making energy in the mountains” to the next generation, geothermal is a very good card.

If you work in hydropower, please look at geothermal as your business, not someone else’s.
This isn’t just a topic for some ministry.
It’s a question of “Will Japan keep its ability to live from the mountains, or not?”

When more people feel that way, Japan’s next-generation geothermal will become **a renewable people actually cheer for.**