Exploring The Ins and Outs Of Micro-Hydropower
Jan 7th, 2013 | By Andrew | Category: Energy, Water | Print This Article
Solar and wind energy are the alternative energy options most often chosen by those seeking an off-ramp from the grid superhighway. But while solar and wind may indeed be the most reasonable choices for many, it is always best to keep an open mind, and post-grid adventurers should strive be as flexible and creative as possible when searching for methods to increase their energy independence and self-sufficiency.
Many back-to-the-land pioneers and off-the-grid enthusiasts have sources of running water passing through their homesteads; or perhaps they have ponds or similar types of reservoirs whose placid waters could conceivably be made to flow with just a little bit of engineering ingenuity. Some folks who are lucky enough to have been thusly blessed know of the energy potential that lies hidden beneath the rippling surface of the stream, creek, or river that winds its way through the adjacent landscape, and they may have already taken steps to exploit that tremendous bounty. But others remain blissfully unaware that the flowing waters that run through their property could be used for something more than just raft rides or cooling dips on hot summer days.
In the minds of many, hydropower is exclusively associated with large-scale mega-dam projects named after former presidents. But scale really has no natural connection to this technology – hydropower can be a viable option anywhere that water runs freely (downhill), and micro-hydropower systems can help off-the-gridders supply their homes and outbuildings with a steady and extremely reliable supply of electricity or mechanical power. Just as a river runs wild and free, so too can the home owner who has legal access to that river harvest its latent energy freely and without restraint, if he is willing to invest the blood, sweat, tears, and dollars required to install a fully functioning micro-hydropower system.
Going With The Flow
While there are ways to get standing water to flow for the purposes of generating electricity, in most instances micro-hydropower set-ups will rely on waters that have already been sent in motion by nature. This is the most economical and practical method for getting the job done, and in this presentation we will concentrate exclusively on the “run-of-the-river” style of micro-hydropower system.
If there is a running stream on the premises, and if the place it crosses the property line is at a noticeably higher elevation than the point where it leaves, micro-hydropower could very well be viable. Such a system once installed will start with a channel, pipeline, or most likely a pressurized pipeline known as a penstock, which will deliver the water diverted from the stream to a turbine located inside of a power shed. In response to the force of the falling water the turbine will spin on its shaft, and in honor of Thomas Alva Edison the spinning shaft will power up an alternator or generator and cause it to produce a steady flow of low-voltage DC current. If the generator is being used to provide electricity to a home, an inverter will be used to convert the DC into 120 or 240 volts of AC power, which will then be carried to the living quarters through a conventional electrical wiring arrangement. In some cases, the power collected may be stored in battery banks for later usage, although this option generally is not the best if water flow is seasonal and the micro-hydropower system does not function well during certain parts of the year. (Since running water will generally not freeze, the off-season for a micro-hydro set-up will usually be in summer, when it is dry.)
In order for a micro-hydropower system to work, there must be adequate head and flow. Head is the measurement of the vertical distance that running water falls from the entry point of the system to the place where it hits the blades of the turbine, while flow is a function of the volume and speed of the water as it moves past a given point.
A ten-foot vertical fall on a homestead is the demarcation point that separates high head from low head, and not surprisingly, high-head micro-hydropower set-ups are to be preferred when the option is available. But low-head systems are also viable, as long as the vertical drop exceeds two feet. Output ranges vary based on the available head, but just because a micro-hydropower system is not able to deliver a maximum jolt does not mean the electricity it produces will not be enough to help meet a good share of a homestead’s power needs.
Flow, meanwhile, is measured in gallons per minute, and while a high flow rate is of course preferable, if a stream is able to fill a small two-gallon pail of water in sixty seconds, it should be potent enough to meet the needs of a standard micro-hydropower system.
The exact amount of power a new micro-hydropower system will be able to produce can only be determined by careful measurement and calculation. But in most instances, micro-hydro will deliver a payload that is more than sufficient to meet the power requirements of a home or commercial enterprise, as some relatively modest set-ups are able to generate as much as 100 kilowatts of usable electricity at any given time.
Questions About Micro-Hydropower
Micro-hydropower may be a legitimate option for many off-the-gridders. But installing one of these systems will involve a significant amount of research and physical work, not to mention hefty investments in both time and money. Fortunately, in the final analysis, micro-hydropower is rather simple in its operation and relies on the most basic kind of technology, so no one who is intrigued by the possibilities should be intimidated by fears of being overwhelmed.
Nevertheless, before diving into the deep end of the river, there are some questions that must be answered first, so that any prospective homesteader who is thinking of going the micro-hydro route will know exactly what he is getting himself into.
How much is it going to cost to install a system?
This question is obviously of critical importance to most everyone. Unfortunately, there is no way to answer it definitively except to say that it depends on various factors: the size and type of turbine used, the distance the water and/or electricity must be transmitted after generation, whether or not professionals are brought in to help with the installation process, how much electricity will be required to meet the power needs of a particular homestead, and so on and so forth. A micro-hydropower set-up could cost anywhere from $1,000 to $20,000 (the higher amount would apply primarily to commercial settings), so clearly a lot of in-depth research and comparison shopping would need to be done before any final buying or contracting decisions were made.
What about maintenance? Will it cost an arm and a leg to keep a micro-hydro system operating smoothly?
Great news here – while the initial investment in micro-hydropower can be a real wallet-stretcher, once in place, one of these systems will run crisply and efficiently in perpetuity while incurring very few extra costs for repair or maintenance. Because the wear and tear on micro-hydro set-ups is so limited, relatively speaking, a properly chosen and installed system can last for as long as fifty years, give or take a decade.
Is there any financial assistance available from the government to help those who would like to install micro-hydro on their properties?
Say what you will about our government, but bureaucrats everywhere are clearly infatuated with alternative energy, and government agencies at all levels do a lot to help encourage consumers to purchase off-the-grid technologies of all types. Tax credits, state sales tax exemptions, special grant and loan programs, and property tax exemptions are just a few of the possibilities that may be available to help lighten the load on those interested in micro-hydropower (or solar or wind, for that matter).
How are head and flow measured?
A professional surveyor can certainly be brought in to do the job, but these measurements can also be made directly using some relatively simple methodology. Once numbers have been attained for these two measurements, the amount of power a new micro-hydropower system would be able to theoretically produce could be calculated using this mathematical formula:
[net head (feet) x flow (gpm)] / 10 = Watts
(Net head = vertical distance available after adjusting for losses caused by pipe friction; gpm = gallons per minute; 1000 watts = 1 kilowatt).
What happens to the water that is diverted after it is used to spin the turbine?
This is one of the really neat aspects of a run-of-the-river micro-hydropower system. After water is piped in to the turbine, it can then be sent right back out to where it came from, into the adjacent stream or river. The power shed should be built as close to possible to the river – at a spot that is lower than the original diversion point, of course – so that the water can be channeled back into the running stream quickly and efficiently. This approach dramatically reduces the chances of a streambed being inexorably altered by a hydropower diversion project, making the overall environmental impact of a run-of-the-river micro-hydropower slight at best.
Are there any problems associated with acquiring permits or water rights?
Generally speaking, run-of-the-river projects will run into few obstacles from regulatory agencies. The county engineer will be the first person to contact if plans are being made to install micro-hydropower, and he will be able to guide the interested homeowner through the process of acquiring permits and securing full approval for the project. In drier climates, there may occasionally be some limitations placed on summertime water diversion, and it may be necessary to occasionally shut a system down completely during times of drought. But run-of-the-river set-ups which return used water back into the stream from whence it cam generally don’t face too many restrictions.
Can micro-hydropower be combined with other types of alternative energy?
Micro-hydropower complements solar energy beautifully because it delivers the most electricity during the winter months, when solar is much less effective because of the shorter days and lower sun angles.
Is micro-hydropower really an energy-efficient choice?
Micro-hydropower operates without any extra power input required, and it does not rely on sophisticated technology or heroic intervention to help facilitate the capture of the energy contained in running water. Initial investment costs aside, once it is up and running, a micro-hydropower installation will pay for itself over and over again, making it one of the most energy-efficient technologies available anywhere in this solar system.
Inheriting The Earth
When flowing waters meet the natural contours of the earth, rivers, streams, and creeks form to wind eternal paths through the quiet landscapes of the peaceful countryside. Amazingly, the same energy that allows flowing water to carve an ever-widening and deepening chasm into the earth beneath it can also be harnessed to produce electricity, through a non-violent form of intervention and re-direction that will not permanently alter the course of a stream or compromise its ecological integrity in any way.
A quintessential illustration of the principle that “nature always provides,” run-of-the-river micro-hydropower is one of the most elegant of all the alternative energy solutions, and off-the-gridders and other homesteaders who have access to running water on their properties would be wise to start investigating the possibilities it offers in the very near future.
©2013 Off The Grid News