Great age of steam ready to rise again

Greg Raasch is overseeing the boom in geothermal exploration. Picture / Alan Gibson

American Greg Raasch used to eagerly await the speeches by New Zealand geothermal researchers at conferences in the 1970s.

Our engineers and scientists were at the forefront of the industry, pushing the boundaries of geothermal power development and generation.

Then, slowly but surely, New Zealand started fading from the geothermal scene. Cheap natural gas from the Maui gas field meant money and effort was no longer spent exploring and developing geothermal energy.

Now, with Maui declining and the days of big hydroelectric schemes seemingly gone, New Zealand is again turning to the energy resource bubbling beneath the surface. And we are now turning to people like Raasch, who were once inspired by our researchers, to prod the New Zealand geothermal industry out of its slumber.

As Mighty River Power's new general manager of geothermal, Raasch, 54, is helping oversee a massive growth in exploration, development and spending on new wells and stations in the central North Island.

After working on schemes in the US, the Philippines, Indonesia and most recently Chile, Raasch was recruited by Mighty River as part of a massive push to expand its geothermal exploration and production team.

New Zealand has 450 megawatts of geothermal capacity, contributing about 7 per cent of the country's electricity needs. State-owned Mighty River has spent around $200 million on geothermal exploration and development in the past two years, with another $200 million due to be spent in the next two.

Mighty River and the NZX-listed Contact Energy are leading the geothermal charge, last year drilling 12 wells between them. Forecasts are that 20 wells will be drilled before the end of this year, an exploration rate not seen since the mid-1950s.

Across the industry, there are high expectations that the amount of electricity coming from geothermal stations will double over the next decade.

What makes geothermal so special - when done right - is that it is both renewable and reliable. A lot of political and public attention is focused on windfarms, which at their absolute best can produce electricity 50 per cent of the time. Even then, not all turbines on a windfarm are spinning, meaning that power supply is sporadic and unpredictable.

Raasch, showing off Mighty River's Rotokawa geothermal station near Taupo this week, demonstrates how a seemingly jumbled maze of pipes, tubes and tanks add up to a fiendishly ingenious method for extracting energy from hot water and steam.