Hydropower, generated mainly from hydroelectric dams, is a clean, renewable, non-emitting source of energy that provides low-cost electricity and helps reduce carbon emissions. U.S. hydroelectric generation is the second largest in the world, providing 7% of domestic electricity production and much larger percentages in the western states. It is more efficient than any other form of electricity generation and offsets more carbon emissions than all other renewable energy sources combined.
Republicans in Congress support expanding the use of hydropower and it is an essential part of an all-of-the-above energy approach to improve the environment and meet our country’s energy needs. Republicans on the Natural Resources Committee are also working to make all hydropower officially recognized as a renewable energy source by any legal or regulatory standard established by the federal government.
Gravity water wheels as a micro hydropower energy source: A review based on historical data, design methods, efficiencies and modern optimizations.
Nowadays, due to the need for clean energy and sustainable electricity production, hydropower plays a central role in satisfying the energy demand. Particularly, use of low head micro hydropower plants is spreading worldwide, due to their low payback periods and good environmental sustainability. Gravity water wheels are micro hydropower converters typically used in sites with heads less than 6 m and discharges of a few cubic meters per second. Although water wheels were scientifically investigated as far back as the eighteenth century, they were largely ignored throughout the twentieth century, and only in the last two decades has there been a renewed interest in their use among the scientific community.
In this paper a review on gravity water wheels is presented, distinguishing between undershot, breastshot and overshot water wheels. Water wheels technology is discussed focusing on geometric and hydraulic design; data and engineering equations found in historic books of the nineteenth century are also presented. Water wheels’ performance is described examining experimental results, and modern theoretical models for efficiency estimation are presented. Finally, results achieved through experiments and numerical simulations were discussed with the aim of optimizing the performance of gravity water wheels. The results showed that maximum efficiency of overshot and undershot water wheels was around 85%, while that of breastshot water wheels ranged from 75% to 80%, depending on inflow configuration. Maximum efficiency of modern water wheels can be maintained at such high values over a wider range of flow rates and hydraulic conditions with respect to older installations. Hence well designed water wheels can be considered as efficient and cost-effective micro hydropower converters.
Using renewable energy sources for electricity generation at large scale has become an important way of meeting renewable energy targets and for reducing greenhouse gas emissions. Indeed, it is estimated that only 8% of the world energy consumption is generated from renewable sources, while 92% comes from non-renewable ones .
Table 1 shows the installed power of renewable energy sources in terms of GW at the end of year 2013. It can be seen that among renewable energy sources (like biomass heating, solar heating system, wind power plants), hydropower plays a significant role in supplying the electricity demand, and large hydropower plants (installed power higher than 10 MW) are the biggest contributory renewable energy source. Furthermore, Asia, Africa and South America still have large technical potential for hydropower which has not been exploited yet, equal to about 12,000 TW h/year; in Europe the hydropower technical potential has been estimated at 1000 TW h/year .
Table 1. Global installed capacity of renewable energy worldwide and diffusion percentage with respect to the total installed capacity of renewable sources.
|Type||Power (GW)||% on the total|
|Solar Photovoltaic grid connected||13||1%|
|Solar thermal power||10||1%|
Hydropower exhibits some advantages over the other renewable solutions, like wind and solar power plants (Table 1 shows wind and solar plants are the second and third most diffused renewable sources). For example, hydropower is more responsive to load management requirements, while pumping plants can consume electricity in low demand and low price periods, and provide it during periods with high energy demand. Furthermore, hydropower output can be predicted more easily than solar and wind power plants, because hydro plants can be managed by human control, except in the case of long dry periods .
There are, however, a number of difficulties which impede the expansion of large hydropower. It is difficult to further expand large scale hydropower in industrialized countries, especially in Europe, because it has already been almost exhausted. Another problem is that the environmental impacts caused by dams of large hydropower plants in emerging countries are generally not accepted: these include flooding of large areas upstream, interruption of longitudinal connectivity of a river and problems with trapped sediments . To solve these problems, two main strategies can be identified for the future of hydropower development. The first is better management of the output of existing big plants, with the installation of pumping stations for load management . The second strategy consists in the installation of smaller hydropower plants, like micro hydro plants . In this context, UNIDO, the USA Organization for the Industrial Development, classifies hydropower plants into the following categories: large for installed power over 10 MW; small for installed power under 10 MW; mini for installed power under 1 MW; micro for installed power under 100 kW; pico for installed power under 5 kW.
Micro hydro plants exploit sites with heads of the order of meters or few tens of meters, and discharges of a few cubic meters per second or less, as can be observed in Fig. 1 (the range ≤100 kW). Sites suitable for micro hydro are present in almost all countries ; for example, it is estimated that in Europe 350,000 sites suitable for micro hydro plants are available . Micro hydro plants are very attractive because of their eco-sustainability and wide applicability on the territory, especially in rural and decentralized areas . Indeed, the installation of micro hydro plants is considered as the most economical option for rural electrification. When existing structures are used, few new works are required, so that infrastructure costs can be reduced .
Micro hydro technology is a reliable and easy operation technology; the estimated life cycle is of more than fifty years and the global efficiency ranges from 60% to 90% . In industrialized countries, micro hydropower can contribute to meet the non-fossil fuel targets imposed by public authorities. In emerging countries it can help to satisfy the increasing request of decentralized electricity. The additional advantages of micro hydropower plants are numerous and include grid stability, reduced land requirements, good opportunities for technology export and economic development at the local scale .
Three main types of gravity water wheels can be identified: overshot, where the water enters from the top, breastshot and undershot, where the water enters from the upstream side. Depending on the water entry point, breastshot wheels can be distinguished in high, middle and low. High breastshot wheels receive water over the rotation axis; middle breastshot wheels near the axis, and the low ones under the axis. Low breastshot water wheels can be also called undershot water wheels. Schematic historic representations are depicted in Fig. 2. The most efficient kinds of undershot water wheels are Sagebien water wheels with forwards flat blades and Zuppinger water wheels with curved blades. Sagebien wheels are optimized for minimizing the inflow power losses, ensuring a gentle entry of blades into the upstream water. Zuppinger wheels are designed with blade shape to reduce the outflow power losses, reducing the portion of water that is uplift over the downstream water surface. Schematic historic pictures are depicted in Fig. 3. Gravity water wheels are the subject of the present paper.
Hydropower accounts for approximately 75% of the nation’s total renewable electricity generation, making it the leading renewable energy source of power.
Hydropower turbines are capable of converting more than 90% of available energy into electricity, making it the most efficient form of electricity generation. By comparison, fossil fuel plants are only approximately 50% efficient.
In addition to providing low-cost electricity, multi-purpose dams provide water for irrigation, wildlife, recreation and barge transportation and flood control benefits.
A medium size water wheel electric generator can provide enough electricity for one house (3 bulbs, one TV and one radio all running at the same time). Not only you will no longer dependent on the power grid, but you’ll have electricity when SHTF and more important: absolutely FREE. Unlike solar panels, a water wheel electric generator can produce electricity 24/7.
Hydroelectricity is the world’s largest and cleanest source of renewable energy. But despite lively interest in renewables generally, there is an information vacuum about the smallest version of the technology dubbed “the simplest, most reliable and least expensive way to generate power off grid.”
SIMPLE HOME BUILT WATERWHEEL
Turbines–All of the commercial micro hydro generators available today use a small turbine connected to an electrical generator or alternator. Water is collected in an intake pipe upstream, travels down to the turbine in plastic pipe, and is forced through one or more nozzles by its own gravity pressure. No dam is needed; systems without a dam are called “run of river” systems. Power is generated by a generator or alternator directly connected to the turbine wheel (no gears or pulleys needed). All of the factors below must be calculated correctly for your micro-hydro equipment to make power most efficiently. All commercial micro-hydro setups are custom-made by the manufacturer for your specific application. For proper operation, you must supply the manufacturer with specific data about your site, most importantly the vertical drop in feet (called “head”), the amount of water flow available during different seasons in gallons per minute, and the length of pipeline required to get a sufficient head.
In general, for a water turbine you need at least 3 feet of fall and at least 20 gallons per minute of flow. If you have more fall (head), less water is required. You can calculate potential head with a water level, a contractor’s level and stadia rod, or with just a string level attached to a measuring stick. The more fall and flow that you have, the more potential power you can generate. You can measure flow by building a weir in the creek and measuring how fast it will fill up a 5 gallon bucket.
Your pipeline must be of a big enough diameter to minimize friction loss in the pipe. Your micro-hydro supplier can give you specific information regarding this.
Nozzle size and turbine wheel type are all interrelated to your total head and flow. Again, your hydro supplier will customize these for your specific application. Often, different size nozzles are designed to be switched in and out as stream conditions change throughout the year.
There are two main types of turbines, impulse and reaction. With impulse turbines, a jet of water is created by the nozzle and squirted onto the wheel. Reaction turbines are more akin to propellor that spins INSIDE the pipe, generating power.
The 3 primary impulse turbine wheel types are Pelton, Turgo, and Cross-flow. Pelton wheels are used in low flow, high head conditions, and Cross-flow wheels are for high flow, low head installations. Turgo wheels are somewhere in the middle. Francis and propellor turbines are the most common reaction type; the Francis design is very similar to the innards of a centrifugal pump. A Kaplan turbine is also similar to this design.
Home built reaction turbines have been built using centrifugal pumps running in reverse (generating power with moving water instead of using power to move the water). We hope to have more information about experimenting with this soon.
In order to generate electricity from the kinetic energy in moving water, the water has to move with sufficient speed and volume to spin a propeller-like device called a turbine, which in turn rotates a generator to generate electricity. Roughly speaking, one gallon of water per second falling one hundred feet can generate one kilowatt of electricity.
The composite system powers communications equipment, three freezers, propane furnace/hot water, well pump and all electrical requirements of my barn thereby reducing my utility bill by 50%.
You can build it from any material but the lighter, the better. Most water wheels are built from wood.
Step by step instructions on how to make your own decorative yet functional 4 ft diameter water wheel out of old scrap redwood deck lumber using common carpentry equipment. This design utilizes mostly short scrap pieces (under 24″) so as to maximize the re-use of available scrap which would most likely otherwise be discarded or used as firewood kindling. Also the age-weathered deck boards make the wheel look old and add to the genuine look of the feature. This eight-spoke design is also the easiest to layout, cut, and assemble without needing expert carpentry skills or experience.
First we have to build the wooden wheels. You can do it by using the top and bottom of the barrel or you can build it from scratch. Here is a video tutorial (3 parts):
Don’t wait until food becomes scarce; start preparing for the future now by becoming as self-reliant as possible. Your long-term chances of survival could very well depend on your ability to feed yourself and your family without relying on someone else.
Homemade wooden garden waterwheel
Carnivore’s Bible (is a wellknown meat processor providing custom meat processing services locally andacross the state of Montana and more. Whether your needs are for domestic meator wild game meat processing)
The Lost Book of Remedies PDF ( contains a series of medicinal andherbal recipes to make home made remedies from medicinal plants and herbs.Chromic diseases and maladies can be overcome by taking the remediesoutlined in this book. The writer claims that his grandfather was taughtherbalism and healing whilst in active service during world war twoand that he has treated many soldiers with his home made cures. )
The Lost Ways (Learn the long forgotten secrets that helped our forefathers survive famines,wars,economic crisis and anything else life threw at them)
LOST WAYS 2 ( Wordof the day: Prepare! And do it the old fashion way, like our fore-fathers did it and succeed longbefore us,because what lies ahead of us will require all the help we can get. Watch this video and learn the 3 skills that ensured our ancestors survival in hard times offamine and war.)