Off-Grid Living Solutions - Micro Hydro
William George Armstrong, 1st Baron Armstrong and Cragside
Cragside the private residence of William George Armstrong, 1st Baron Armstrong, 26 November 1810 – 27 December 1900) was the first house to be lit by electricity in 1870.
The electricity at Cragside was generated from a Siemens dynamos driven by water from the artificial lakes. Cragside was, and still is, a spectacular residence.
Hydro electricity is produced as the water turns turbines which in turn drive the alternator (dynamo in old speak). The falling water is the prime mover.
Although Baron Armstrong build a small hydro a little close to 150 years ago, mini hydro is as much required to bring electricity to remote areas in South East Asia and Africa today. There are places which are remote from the grid and without innovative application of technology will continue in darkness.
This article looks at the possibility of using mini hydro to alleviate energy poverty is rural areas.
Hydro Power Generation
What Is Mini Hydro
Small hydro or mini hydro refer to small scale hydro electricity generation for small communities.
By the turn of the 19th electricity generation was taking root everywhere and the convention was to build large scale power stations using public funds or funded through private investments. Such facilities as public transportation, water supply and electricity were often centralized, and are still are.
The imperative of history is upon us; most rural areas in Africa and other Third World countries are still without electrical power. The result had been massive deforestation.
So important is small hydro that a whole new industry has emerged to carter to the needs of the new consumer.
It becomes important to define terms so that practitioners have the same perspective when discussing these matters.
Small hydro - often is an umbrella term used to define hydro power stations that generate electricity not exceeding 10MW, as expected these definitions vary.
Mini hydro are those that generate power between 100kW and 1MW.
Micro hydro generates between 5kW to 100kW - this puts Baron Armstrong's mammoth plant in the micro hydro class.
Those who are looking for really small scale are in the range of 5kW and are classified as pico hydro.
Electricity from water
Water is the driving force of all life.— Leonardo da Vinci
The Physics of Hydro Power
The Sun provides the energy that we derive from hydro power through its effect on the water cycle.
In (very) brief, the water cycle is a process whereby water evaporates from water bodies, goes up into the atmosphere before it condense and falls as rainfall or snowfall.
Water will percolate to ground and some runs off the surface along water ways back to water bodies.
Water that flows in water ways (rivers, streams, brooks, rivulets) do so from points at higher ground to lower plains.
At any two points the waters loses potential energy and gains kinetic energy. In physics potential energy is described as energy possessed by an object due to its relative position in a force field. Thus;
Potential energy of an object sitting at point A as viewed by an observer at point B is:
PAB = mg(hA - hB) where hA and hB are the heights of points A and B as measured from a common datum.
This is the potential energy that can be converted to electricity as a body of water of mass m falls from a higher level to a lower level. What remains is to device machines that can harness this energy. All this was done in last 150 years.
Where are Mini Hydro Plants Built
By definition mini hydro are of the order of 10MW and although is classified as such this is a very huge investment that can sustain a small town with a respectable cottage industry base. Moreover such a plant can be grid connected.
Investment in a mini hydro is huge in comparison to what ordinary people can be looking at when they say 'off-grid life'. So indeed for this hub, we must be talking about micro hydro and pico hydro.
These are people who can be interested in micro hydro and pico hydro:
Three Gorges Dam in China produces 22.5GW, i.e. 22,500MW, and a pico hydro in Vietnam produces in the order of 5kW. Such is the beauty of nature that both these facilities serve the interest of the owners.— Author