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THE HISTORIC RUBICON HYDROELECTRIC SCHEME By Dr David Maddison Very few people would have heard of the historic Rubicon Hydroelectric Scheme – it’s not in the national consciousness like the Snowy Mountains Scheme. But at one time it was a significant source of power, supplying almost 17% of Victoria’s electricity. L ocated about 140km east of Melbourne, construction of the entire scheme was completed in 1929 (but some parts became operational in 1928) and it is still in operation and largely original condition, although now it generates just 0.2% of Victoria’s electricity. It is an early example of a system using remote control and fault monitoring technology. It had a number of automatic features to shut the system down to prevent damage in the event of a fault condition. At one time it coexisted with major logging operations in the area and it has survived numerous bushfires. In addition, its environmental impact is relatively low. The Rubicon Scheme has very much a rustic “steampunk” aura to it and was built in a time when engineering infrastructure was built to last and remain productive for an almost indefinite time. One might surmise that the reason for this was that the rate of technological progress was much slower then than now. It made sense to build infrastructure that lasted the long 16  Silicon Chip periods of time expected until new technological developments had been made. In any case, some engineering solutions are universally applicable and at the macro level, if this scheme was constructed now it may not be much different to that implemented. The scheme includes four hydroelectric power stations ranging in capacity from 300kW up to 9.2MW, for a total capacity of 13MW as shown in the table below. The maximum output is achieved during winter. Until becoming privately owned (by AGL), the Rubicon Scheme was the oldest publicly-owned hydro scheme on Power Station Royston Rubicon Falls Rubicon (two turbines) Lower Rubicon TOTAL Total Capacity (MW) 0.8 0.3 9.2 2.7 13 siliconchip.com.au A closer look Inlet side of the Royston Power Station showing penstock. As power stations go, it’s not the largest in the world . . . the Australian mainland. The 2MW Duck Reach Power Station in Launceston, Tasmania was an older publiclyowned scheme but is no longer operational, having operated between 1895 and 1955. To put the Rubicon Scheme’s capacity into perspective, consider that the total installed hydroelectric capacity in Australia is currently 8,186MW which is about 16% of total electricity generating capacity. However the total power produced by hydro is about 5% as it is not operating at capacity. This scheme represents about 0.16% of Australia’s hydroelectric capacity. How the scheme works The hydroelectric scheme involves two rivers (Royston and Rubicon, both tributaries of the Goulburn River), four power stations, three dams, various aqueducts, penstocks (the pipes that convey water to the turbines), roads, power lines and switchgear and associated (but now unused) infrastructure such as an industrial tramway and trestle bridges. The first (most upstream) power station is the Royston (0.8MW). The water for this is supplied by the Royston Dam on the Royston River and is conducted to the station via about 2km of aqueduct and then a penstock of 549m in length. The outlet side of Royston Power Station with water discharged into aqueduct. Yes, it really is a big “tin shed”. siliconchip.com.au For those people interested in taking a closer look at most of this system they can go on a 15km bush walk starting at Rubicon Power Station. Along the trail it is possible to view the Rubicon Falls Power Station, the Rubicon Falls Dam, the Royston Power Station, beautiful scenery, aqueducts, old sawmilling and power station tramways and historic sawmill sites. The walk can be completed within one day. Note, that as with any bush walk you should only attempt it if you are suitably equipped and experienced. It is not the easiest of walks for the inexperienced, especially the final descent. Unfortunately, the power stations can be viewed from afar but no internal access is permitted. (See a suitable bushwalking guide book for the specific route.) The area can also be visited by an appropriate off-road vehicle, subject to seasonal road closures. See www.dse.vic. gov.au/–data/assets/pdf–file/0017/101744/Rubicon–Valley– Historic–Area.pdf Map courtesy of Department of Sustainability and Environment, Victoria February 2013  17 An 8.8km aqueduct delivers water to the Rubicon Power Station. Note part of the disused industrial tramway track (2ft gauge) to the left. The forebay at the end of the aqueduct that delivers water to the Rubicon Power Station. The function is to collect the water and ensure debris is trapped and removed before the water is discharged into the penstock. The water discharged from Royston enters an aqueduct, the flowing water from which is also used to power a saw mill which is no longer in regular use except for historic demonstrations. Rubicon Falls (0.3MW) is the second power station downstream in the scheme. Water is supplied to this via the Rubicon Falls Dam by a 420m long penstock. The Rubicon Power Station is the third downstream and most powerful power station in the scheme with two turbines generating up to 9.2MW. Water for this station comes via the Rubicon Dam on the Rubicon River. To reach the Rubicon Power Station the water travels along an aqueduct for a total of 8.8km. Along the way, the discharge water from the Royston Power Station (the first of the power stations) also flows into this aqueduct. A disused industrial tramway track (2ft gauge) follows the aqueduct’s path. This track could not now be used without major works as the track has been warped in places from the heat of bushfires and log-falls, among other causes. It operated until the 1990s. The forebay At the end of the aqueduct the water is discharged into a “forebay”. This consists of a water-collecting pool and grates to trap logs, sticks, leaves, rocks and other debris that has fallen into the open aqueduct, to prevent it from The Pelton wheel The Pelton wheel is a highly efficient type of water impulse turbine. Its efficient design means that nearly all the useful energy (>90%) is extracted from a water jet that impinges upon the turbines’ buckets (the impulse) transferring kinetic energy from the water jet and causing the turbine to spin. After the main work has been done, just enough kinetic energy is left in the water to remove itself from the bucket. This is achieved by causing the impinging water jet to be deflected a nominal 180° (a “U-turn” but in practice, a little less) within the bucket which results in most of its Diagram of typical Pelton kinetic energy being transferred wheel from original 1880 US Patent US000233692. to the wheel. Based upon mathematical considerations, for optimal efficiency, the velocity of the water jet is designed to be twice that of the bucket. 18  Silicon Chip Pelton wheel on display at Rubicon Power Station. This power station has two generators, each of 4.6 MW capacity and each using a horizontally mounted Pelton wheel. Note the side-by-side bucket arrangement and the heavy structure of the wheel. This was one of the original wheels used at the station and was removed when the station was upgraded for increased power in 1954-55. Often, in order to achieve better mechanical load balancing, two buckets are mounted side to side on the wheel as is the case for the Rubicon Power Station. The Pelton wheel is a commonly used type of turbine in hydroelectric installations and excels in cases of relatively low volume flow with a high head. siliconchip.com.au Hg The penstock leading to the Rubicon Power Station. The elevation drops 443m over a pipe length of 1305m. Note the riveted pipe construction. As the pipe descends toward the bottom, more rows of rivets are installed to cope with the extra pressure. Modern penstock pipe would be of seamless construction with welded joints if made from steel or be of a composite construction such as fibreglass. going into the penstock and then damaging or destroying the turbines. It also has an important safety function to prevent people who may have fallen into the fast-flowing aqueduct getting sucked into the penstock. At the forebay they presumably could safely extricate themselves from the pool of water. The forebay discharges water into the penstock, where it falls a vertical distance of 443m over a pipe length of 1305m, after which it is directed into twin Pelton wheel turbines (see box). mercury free SEE FEATU THIS IS RE SUE Lower Rubicon The final power station in the scheme is the Lower Rubicon Power Station (2.7MW). It utilises the discharge water Remote control and fault monitoring The remote control and fault monitoring functions implemented within the system were remarkably advanced for the time. Remote control was possible for opening and closing circuit breakers, starting and stopping a station and changing the electrical load of a station. There were also safety interlocks to prevent starting of a station under a fault condition; shutting down a station if a fault was detected; only allowing as much power loading as the available quantity of water could generate and prevention of power loading beyond operational limits. Automatic station shutdown would be initiated under the following fault conditions: bearing overheat, generator field failure, electrical overload, electrical insulation failure, over-voltage, single or reverse phase generator operation and generator over-speed. Remote monitoring of water parameters was also possible including stream flow, aqueduct flow, pondage water level and water flow at the turbine. siliconchip.com.au February 2013  19 Rubicon Power Station showing penstock running down the hill, the corrugated steel shed containing generating equipment and the switchyard at left. The discharge aqueduct and control gates are in the foreground. View (from afar) through the window of the Rubicon Power Station showing some of the equipment. from the Rubicon Power Station which travels 3.2km along an open aqueduct before entering a 320m long penstock. After this, water is discharged back into the Rubicon River, most of its useful energy having been extracted by the hydroelectric system. In recent times there has been a shift from large-scale hydro-generation to small-scale generation because most areas suitable for large scale generation have been fully exploited (eg the Snowy Mountains Scheme) or there are environmental concerns with further large-scale development. Also, since Australia is topographically reasonably flat, there are limited opportunities for hydro-generation compared with many other countries. Nevertheless, there remain some opportunities for exploitation of hydro resources at smaller scales, where the environmental impacts are of much less concern. Hydroelectric power can be economical and comparable to the cost of coal and gas-fuelled electricity production as well as nuclear. However, no political party in Australia is prepared to consider nuclear electricity in a serious manner. Hydro is still cheaper than “green” alternatives such as solar and wind. Perhaps for economical electricity production in the future, a choice has to be made for further limited hydro production with environmental impacts versus a nuclear option with few environmental impacts but significant political contention. Old disused tram car which was once used for conveyance of goods and equipment precariously poised at the top of the hill above the Rubicon Power Station near to the forebay. Access to the Scheme infrastructure is now by dirt roads. Author’s note: The owners of this power scheme, AGL, were invited to participate in this story but unfortunately were unable to provide any personnel familiar with the system and so information has been obtained from various other sources. SC Smaller Scale Hydro Commercial hydro-electric generation does not need to be large in scale (of the order of hundreds of megawatts). There are many small scale commercial (and also grid-feed) hydro generation projects in Australia ranging in capacity from a few kilowatts to a number of megawatts such as the Rubicon Scheme. According to one definition, “small hydro” refers to any hydro scheme below 30MW in size. Examples of some randomly selected smaller scale systems of different vintages and different areas of Australia and New Zealand include: 20  Silicon Chip The Future of Hydro in Australia Steavenson Falls at Marysville, Vic. This employs a unique cross-flow turbine. Australian Anthony Michell patented this invention in 1903. This recently rebuilt installation has a typical output of 3.3kW. Paronella Park, Qld, 25kW. Tinaroo Hydro Power station, Qld, 1.6MW. Terminal Storage Mini Hydro on the Mannum/Adelaide pipeline, SA, 1.9MW. Wellington Dam Hydro Power Station, WA, 2MW. Arnold Power Station, NZ, 3MW. Cardinia Dam Power Station, Vic, 3.5 MW. Brown Mountain Power Station, NSW, 4.5MW. Rowallan Power Station, Tas, 10.5MW. siliconchip.com.au