Category The Homeowner’s Guide to. Renewable Energy

ASSESSING THE POTENTIAL OF A MICROHYDRO SITE

Once you have determined your fam­ily’s electrical energy demands, it is time to assess the potential of your site. You’ll need to determine how much electricity a microhydro system could produce and the percentage of your needs that it could meet. Before you do this, you should be aware of the difference between continu­ous power and daily power production and use.

Unlike other renewable energy systems, microhydro systems can produce electric­ity 24 hours a day, 7 days a week, 365 days a year, A system, for instance, might pro­duce 200 watts of continuous power day in and day out. So, over a 24-hour period, this system would produce 4,800 watts – hours, or 4,8 kWh. To determine monthly output, multiply the daily output by 30...

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Analyzing Your Electrical Energy Needs

Before you assess the electrical generating capacity of a stream, however, it is impor­tant, indeed essential, to analyze your electrical energy needs. This process is described in Chapter 8, so I wont repeat it here, other than to offer a few remind­ers. First and foremost, when determining your electrical demand, it is important to be accurate — and generous — in your assessment. Accuracy is vital to your suc­cess, but it is often difficult to achieve.

Generous estimates are important because most people use a lot more electricity than they think they do.

Why?

When estimating electrical consump­tion for a new home, people often begin by listing all of the components of their load, that is, their household electrical demand...

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Low-Head Microhydro

Low-head microhydro systems are a bit simpler than the high-head systems just described* As illustrated in Figure 10-4, they require a screened intake or a small dam across part of a stream or river with a settling basin to allow grit and silt to pre­cipitate out* The intake structure empties into a fairly short diversion canal that deliv­ers water to a vertical draft tube often only ten feet long* A draft tube sends diverted water back into the stream and is where the turbine is located* The water flowing through the system turns a propeller-like turbine* It is connected to a generator that produces electricity* Water is returned directly to the stream* Such systems are often built near small water falls*

ASSESSING THE FEASIBILITY OF YOUR SITE

Before you decide to purchase a micro­hydro...

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THE ANATOMY OF A MICROHYDRO SYSTEM

Microhydro systems are electrical gen­erating systems for use on a small scale, usually for residential power in remote

mountainous terrain* Microhydro is usu – ally“installed” along small streams or rivers close to the buildings where it will be used — the closer the better! To protect the stream and those creatures that depend on it, microhydro systems generally divert only a small portion of the current from the waterway* This water temporarily bor­rowed from the stream is diverted into a pipe or specially built channel or canal (that typically runs alongside the water­way) to a turbine some distance below the water intake...

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AIM INTRODUCTION TO HYDROELECTRIC SYSTEMS

Hydroelectricity is based on some pretty simple concepts. If you have read the wind power chapter in this book or have studied conventional electrical production by coal, nuclear, or geothermal energy, you’ll see the similarities instantly. In a microhydro system, moving water turns a turbine. The turbine spins a generator. The generator (or alternator) produces electricity. These components are common to all of the elec­trical generating equipment discussed in this book, except PV modules.

“Many other components may be in a system, but it all begins with the energy… within the moving water,” says Dan New, author of’Tntro to Hydropower” published in Home Power magazine, Issues 103-105. (This information can also be found on

Dan News website canyonhydro...

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GENERATING ELECTRICITY FROM RUNNING WATER

H

umans have been tapping the power of flowing water for centu­ries, Early New Englanders, for instance, tapped the power of water flowing in the streams that ran through their towns by installing small dams and water wheels. The water wheels powered the machin­ery of textile factories and grain mills where wheat was ground into flour used to make bread, a staple of early American life. Hydropower continues to play a piv­otal role throughout the world today. Its primary value, however, is as a source of electricity. Today, hydroelectricity con­stitutes 7 percent of the total electrical generation in the United States, and 21 percent in Canada.

But that’s not hydropower’s only claim to fame.

Hydropower is not only a significant source of energy, it also has the distinction of rank...

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WIND POWER WITHOUT INSTALLING A WIND GENERATOR

If a wind generator is not right for you, don’t fret. Many utilities offer green power to their customers. Green power is elec­tricity generated from renewable sources, mostly gigantic wind turbines on commer­cial wind farms, like those shown in Figure 9-13. Green power may be produced by other renewable sources as well, but wind is the dominant source. It’s the cheapest and most widely developed commercial renewable energy source in the world, other than hydropower from hydroelec­tric plants on rivers. In Colorado, the local utility offers its customers an option to purchase blocks of wind energy from ever – expanding wind farms. Customers can opt to buy as many blocks as they want, pro­vided the company has enough to sell.

Even if the utility company in your area does not have its ow...

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FINANCIAL MATTERS

Like a good salesperson, I’ve given you the scoop on wind power before I drop the cost bomb. How much does it cost to install a wind turbine?

As noted earlier, wind generators for household use vary from the smallest 1,000-watt turbines to the largest 20,000- watt unit. If you simply want to supplement your electrical energy from the grid, a wind turbine of 1,000- to 3,000-watt rated out­put might be ideal. When buying, look for models in this range, then compare them using swept area, weight, AEO, and costs, A 1,000- to 3,000-watt wind gen­erator might also work if you live in a tiny cabin, or you are extremely efficient. And it might suffice if you are installing a hybrid system — a combination of wind and PVs — or some other renewable resource such as microhydro (see Chapter 10).

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