Once the plague of miners, geothermal energy is now hailed as a resource bearing the promise of abundant, clean energy. EPTV investigates in the Ruhr region.

Reporter: From coal pits in the Ruhr, clean energy

Which energy is clean, CO2 free, readily  available and not reliant on the weather?

The answer could lie in Germany's  former coal mining district,

the crisis-ridden  black coal area of the Rhine and Ruhr.

For over 100 years the Ruhr region  in the West of Germany

provided energy for  industrialisation, railways,

The mighty headframes of the pits served  as beacons of the coal barons' power.

The unsung heroes of the black coal era  were the miners.

I reckon we were roughly  700 metres below ground.

When we walked or rode back  to the mine shaft,

We were completely soaked  as if we'd had a shower.

You have to consider  that without ventilation

the temperature down there  would be 50 to 60 degrees.

It's terrible if you're grafting,  as it goes deeper and deeper,

and the deeper it goes,  the worse it gets.

The wheels have stopped turning.  The last pit in the Ruhr is to close in 2018.

The coal that fires this plant  is being bought on the global market.

And where its pit once stood  there is now a barren wasteland.

But the heat that once plagued the miners  is now being recognised as a resource.

The water being pumped from Hans-Georg  Kerch's former mine is warm at 20 degrees.

Enough to heat this fire station and a  neighbouring school via a heat exchanger.

has come to be a centre  of this new form of energy.

There's no chimney smoke  coming from this estate.

Some 100 downhole heat exchangers,  hidden in the gardens, heat the 138 houses.

If gas prices continue to rise like this

the heat pump should pay for itself  in 8-10 years and then start making money.

Especially with energy prices  climbing at the moment,

this is ideal, considering the price  of water and geothermal power combined.

It's so low,  everybody should do it nowadays.

The technology was partly developed here,

at Bochum University,  in the heart of the Ruhr region.

Building on the mining sector expertise,  a Geothermal Centre is being established

In terms of heating, geothermal energy  currently accounts for

about 13-15%  of the overall market in Germany.

There, almost every other building  is heated by geothermal energy.

I can well imagine,  projecting towards the year 2020,

that by then geothermal  will account for 20% of heating.

This should be achievable,  moving on to 40% for 2030.

Engineers and politicians like geothermal  for its low risk and wide availability.

It complements other renewable energies  and provides a constant source of power.

Creating jobs is another important benefit  in this region undergoing restructuring.

there are over 250 companies  involved in the geothermal sector,

mostly working with near-surface  geothermal technology.

It will continue to be a growth industry,  presenting opportunities for the region.

Maybe the area's iconic headframes,  built as beacons of energy extraction,

and subsequently decried  as symbols of pollution,

will one day herald  clean energy from underground.