Lake Coleridge drained into the Harper river just before its confluence with the Wilberforce river. This exit was impeded slightly, and the head was 490'. The initial capacity was 4·5 MW from three turbines, and a fourth was added in 1917. Additions and refurbishments followed.

In 1930 the Acheron river was diverted to flow into lake Coleridge's headwaters. A canal diverts the Harper river to flow into Lake Coleridge. In 1977 another canal captured part of the flow of the Wilberforce river. The intake for this is via a gravel berm, that is reconstructed after every flood.

See also http://www.ipenz.org.nz/heritage/itemdetail.cfm?itemid=58

The Molyneux worked from Clyde to the lower Kawerau river, ceasing in 1942 after poor returns.

The Austral-N.Z. worked the Lowburn (upper Clutha), ceasing in January 1952.

The Alexandra worked the Roxburgh gorge, Alexandra flats and Earnscleugh plains, ceasing in March 1963.

Although these last two could have continued, land available for disruption was becoming too expensive.

2007, June. 385 MW two-cycle system (gas-fired turbines, exhaust heat producing steam for a steam turbine) thereby wasting only half the fuel's energy while the single-cycle steam turbines (wasting two thirds) were relegated to coal firing.

In 1960 a steam turbine was installed to generate electricity, just after the opening of the Wairakei power station. This was a small part of the plant's complex processes. Around 1990, two ORMAT generators were installed on the periphery of the paper mill to capture heat from otherwise wasted hot water effluent to generate a few megawatts, and in 2008 outside the paper mill a 100 MW steam turbine was installed.

Dams on the headwaters of the Mangahao river (that drains to the Wairarapa at Mangahao near Pahiatua) form two lakes; from the lower there is a tunnel to a third dam and lake, but on the headwaters of the Tokomaru river (that drains to the Manawatu); thence a tunnel and pipeline down to the power house on the banks of the Mangatangi stream by Mangaore, all in the ever-clouded Tararua Ranges.

See also http://www.ipenz.org.nz/heritage/itemdetail.cfm?itemid=430

See also http://www.ipenz.org.nz/heritage/itemdetail.cfm?itemid=544

The Tuai power station discharges to lake Whakamarino, then, since its natural outlet is damned, and augmented by the capture of the Waikaretaheke that drains from lake Kaitawa, and the Mangaone diversion (any such canal is not indicated on the topographic map though the stream is named) of a stream to the south west, water flows to the Piripaua power station.

Over the decades, there have been multiple redevelopments, repeatedly extending replacing or drowning prior dams and power stations, and changing the nomenclature. This means that a stated capacity may be for a generator no longer in operation.

Meanwhile, more exploratory drilling found additional steam, so more turbines were added to the design and a second power house proposed with still more to bring the total to 190·6 MW.

Effluent from the stations was carried away by the Waikato river, to be reconcentrated in lake weed to the degree that arsenic levels rendered it unfit for stock feed. Current usage is to re-inject about a third of the warm water effluent into the borehole area. Even without Wairakei's discharge, arsenic levels in the Waikato reach or exceed the NZ standard for drinking water, which must therefore be treated. Other notable contaminants are mercury, boron, lithium and hydrogen sulphide, and the more modern concern, carbon dioxide.

In 2014 the Te Mihi station was completed, using steam from the Wairakei field but on the far side from the Waikato river. Generation from Wairakei is reduced, likewise discharge to the river.

From landfills, amongst the exotic contaminants of the methane are the silanes: silicon takes the same role as carbon does in hydrocarbons, so instead of methane CH₄, there is silane SiH₄. These burn to the corresponding SiO₂ but this is not a gas, it is quartz. Delicate engines such as gas turbines are not used, less-efficient piston engines are.

Because methane is rated about twenty times as potent a "greenhouse gas" than carbon dioxide, burning it can mean a gain in "carbon credits" and thus add lustre to a project. On the other hand, the electricity generated can be too much for the local network's capacity and even if not, involve one-sided "agreements".