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The golden years for micro-hydro were from 1888 to 1938, writes STEPHEN LOWE, and a new age in small hydro schemes could be the answer to our energy future. The principal of micro-hydro in the past was to generate power near to the load because it was plain common sense, and the presence of so many historic sawmills adjacent to rivers is testimony to this. Long haul transmission was not in the brief for early pioneers and a typical development was that of John Chambers who, in the 1880s, took a correspondence course in electrical engineering, ordered new and second-hand equipment from London, and by 1892 had commissioned a micro-hydro scheme at Mokopeka. Chambers constructed transmission lines and supplied the homestead, the workshop and the shearing shed. This heritage scheme generates power to this day. There’s been a marked revival of micro-hydro interest around the world in what could be an energy-scarce future where resilience relies on a small scale, modular and decentralised infrastructure. Rural villages, their paddocks irrigated by border dykes fed from a mountain stream, their satellite dishes powered by a micro-hydro scheme, and the water shared by mutual consent might sound like a utopian dream, but the idea of micro-hydro playing a part in the smart micro-grids of our future communities may be nearer to reality than we think. Entrepreneur and paradigm shifter Brendan Norris of Off Grid Eco Stay near Picton suggests an eco retirement village could be a good place to start, stepping back towards the energy conservation of old-fashioned village life. It’s about adapting, and smoothing the load, he says. If power usage peaks when the rugby comes on the residents can go to the village hall to watch it, turning off their lights at home. Shared wash houses of the type seen in camping grounds are both an energy saver and a community hub. Adam Harvey, in his book, Micro-Hydro Design Manual, introduces the formula “energy used over energy available”. Harvey gathers his data using ethnographic methods. If this formula does not produce a plant factor of 0.4 or better, the power is too expensive and the scheme will cause economic problems for the community it is designed to serve. Harvey and his co-authors write from wide experience of setting up micro-hydro schemes in villages in Peru, Nepal and Sri Lanka. Theirs is a human approach, and their interventions are highly contextualised. Management structures already exist in the host communities, the villagers meeting to share water resources for irrigation. Irrigation and power generation are inseparable, but the third user-group, the recreational users, are not present. Low-head run-of-the-river projects are the focus of Harvey’s accessible, practical and clear text. And these are exactly the kind and scale of projects that enterprising New Zealanders have been building since Victorian times. In just 374 pages, Harvey covers the subject from end to end. This is not just a book for engineers, it is a book for accountants and managers and community leaders too. It is a book for those people now wishing to build resilient communities that can survive disconnection from the national grid. It is about building weirs, but not dams. During the early years of this country, energy supply issues were resolved in isolation. Nobody waited for large centralised schemes to provide to their individual and pressing needs. Today, with transmission losses contributing 20 percent to the wrong side of the equation, there is an argument for a more rational approach of distributed generation. One that is taking a lesson from history, yet is enabled by today’s technology. Impacting less on the environment, small scale distributed generation attracts less opposition and can march a quicker more chartable path through the RMA process. John Chambers designed and built the Mokopeka scheme to test his new-found knowledge of hydro electricity. Now there needs to be a coming together of transition-town people and get-smart-think-small power people to build a micro-hydro smart micro-grid eco-village where we can learn by our mistakes, and amplify our successes. We need this model scheme to showcase new thinking and the benefits it brings in terms of energy saving and a more sustainable lifestyle.
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