SOLAR AND WIND ELECTRICITY WORKSHOP

THE FIRST RULE OF GOING RENEWABLE   CONSIDER YOUR CONSUMPTION   One of the most important things to remember when

considering going solar is your consumption. The more you use, the more you need to spend on your system. Change your light bulbs to compact fluorescent bulb, switch off lights and appliances when out, make sure the fridge shuts properly, and try not to use big power things like irons and hairdryers. If you can manage without these you can save thousands of dollars.

Renewable energy systems come in all shapes and sizes, most, but not all, of

them contain the same four components:

Solar panels / wind turbine/hydro Charge controller Batteries Inverter THE GOLDEN RULE – ALWAYS

CONSIDER YOUR CONSUMPTION

What are solar panels.

There are two main ways of using solar energy to produce electricity. These are through the use of solar cells and solar thermal technology.

Solar cells are photovoltaic cells that turn light into electricity. Solar cells are used in two main ways. They are used in homes small, electrical items, like calculators, and for remote area power supplies, like telephones and space satellites. They are also used on a larger scale to supply electricity through energy companies and authorities, and have even been used to a limited extent in the development of solar-powered vehicles.

Solar panels

Solar thermal technology uses heat gained directly from sunlight. The best known use of this technology is in solar water heating.

PV panels

Photovoltaic cells (PVs or solar panels) are a very different technology from solar water heating, and use light to generate electricity. They are particularly well suited to sites where a grid connection would be difficult or expensive or that are only used in the summer. For an independent power supply, solar works well with wind as there is a good balance of both over the year. Solar electricity, like electricity from other renewable energy sources, doesn't produce carbon dioxide or harm the environment.

Although start-up costs are higher than some other renewable technologies,

solar panels have key advantages as well as being good for the environment:

there are no moving parts to fix so they are relatively easy to install and maintain

they can be sited in town or countryside and are not restricted in the way that wind and hydro-power systems are

they can replace other roofing materials, for example tiles. The cells are embedded in a flat, waterproof material to form 'modules', which make ideal cladding material for walls and roofs

they need not take up any additional land space.

How does the sun create electricity?

Solar photovoltaic panels are made up of silicon cells which are surrounded by electron molecules and connected together by wires. The photon rays from the sun hit the electron molecules and break them away from the silicon cells, pushing them along the wires. Everything in front is a positive charge, and everything behind is a negative charge. The positive current is electricity

Renewable energy systems come in all shapes and sizes, most, but not all, of them contain the same four components

Solar panels / wind turbine/ hydro Charge controller Batteries Inverter

Getting the most Power from your system

Most solar panels and wind turbines make 12 volt electricity, and most systems use batteries to store the power, so that once the sun goes down, there is still power available to use.

  However, the first stop for the power,

after it travels down the wires from the panels or turbine, is the CHARGE CONTROLLER.

 

The positive charge from the panels or turbine passes down the wires to the controller. This has to a sensor which knows when the batteries are full, and switches off the current from the panels. When there is space available in the batteries, it opens and allows the current to pass freely once more.

  Thus preventing OVERCHARGING which

shortens the life expectancy of batteries.

The 12 volt power passes through some wires and is then stored in batteries until it is required.

The average renewable energy system makes 12 or 24 volt electricity, and the average person uses either 110 volts or 220-240 volts, depending on where in the world they live.

So to use the energy stored in the batteries in an average home it has to be converted to a useable voltage, 110 or 220-240. This is done very simply by using a power inverter (similar to a transformer), which converts the current to the desired voltage.

From there you have normal electricity, exactly as if it was from the local electricity supplier, just as useful; just as dangerous.

  Nature provides the earth with more

energy each minute than the world consumes in one year. It seems a waste not use a bit of it at least!!

Portable Solar Genrators

Small portable solar powered generators are now available at low cost for small homes with minimal power consumption. They range form 300 watt units to 1500 watt units, and are very practical for small isolated locations. The disadvantage is that the system cannot be greatly expanded like the standard system now in use here and at 3 rivers. These systems work out at around US$1000 including tax and shipping.

Renewable energy systems come in all shapes and sizes, but most of them contain the same four components

Solar panels / wind turbine/ hydro Charge controller Batteries Inverter

CONSUMPTION

One of the most important things to remember when considering using renewable energy is your consumption. The more you use, the more you need to spend on your system. Change your light bulbs to compact fluorescent bulb, switch off lights and appliances when out, make sure the fridge shuts properly, and try not to use big power things like irons and hairdryers. If you can manage without these you can save thousands of dollars.

WIND TURBINES

Wind turbines are simple and low maintenance. Once installed they need very little attention. Basically they act instead of, or as well, solar panels, and are wired in exactly the same order of basic components as the solar panels. An excellent solution to the changing weather problem is a solar / wind combination system.

When it is sunny you get good charge from the solar, and when the wind blows the batteries will charge.

Wind turbines

Also, once the sun goes down, your batteries get the opportunity to re charge at night too, thus being much more reliable. A wind turbine works just like a hydro turbine, or car alternator, except that it uses wind to turn the propeller instead of water of an engine.

Wind turbines operate on a simple principle. The energy in the wind turns two or three propeller-like blades around a rotor. The rotor is connected to the main shaft, which spins a generator to create electricity.

wind

Wind turbines are often mounted on a tower to capture the most energy. At 100 feet (30 meters) or more above ground, they can take advantage of faster and less turbulent wind.

Wind turbines can be used to produce electricity for a single home or building, or they can be connected to an electricity grid (shown here) for more widespread electricity distribution.

Air x 400

The Air-X has a charge controller which can manage any battery bank size from 25 to 25,000 amp hours. Periodically, battery charging is cut for a few milliseconds to check if the batteries are full. Therefore the lifetime of the batteries will be extended and overcharging is not possible as the turbine will slow to an almost complete stop when the batteries are full.The Air-X wind turbine is so quiet and simple to use it is practical to fit it to the rooftop, greatly reducing costs, but ideally you should fit it to a pole (with an outside diameter of 1.5"). With carbon fibre blades, aircraft quality aluminium alloy castings, and only two moving parts, there is little to go wrong.

How does a Wind Turbine work?

So how do wind turbines make electricity? Simply stated, a wind turbine works the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity. Utility-scale turbines range in size from 50 to 750 kilowatts. Single small turbines, below 50 kilowatts, are used for homes, telecommunications dishes, or water pumping.

Look at the Wind Turbine Close Up

Wind Turbine Glossary Anemometer: Measures the wind speed and transmits wind speed

data to the controller. Blades: Most turbines have either two or three blades. Wind

blowing over the blades causes the blades to "lift" and rotate. Brake: A disc brake which can be applied mechanically, electrically,

or hydraulically to stop the rotor in emergencies. Controller: The controller starts up the machine at wind speeds of

about 8 to 16 miles per hour (mph) and shuts off the machine at about 65 mph. Turbines cannot operate at wind speeds above about 65 mph because their generators could overheat.

Gear box: Gears connect the low-speed shaft to the high-speed shaft and increase the rotational speeds from about 30 to 60 rotations per minute (rpm) to about 1200 to 1500 rpm, the rotational speed required by most generators to produce electricity. The gear box is a costly (and heavy) part of the wind turbine and engineers are exploring "direct-drive" generators that operate at lower rotational speeds and don't need gear boxes.

glossery

Generator: Usually an off-the-shelf induction generator that produces 60-cycle AC electricity.

High-speed shaft: Drives the generator. Low-speed shaft: The rotor turns the low-speed shaft at

about 30 to 60 rotations per minute. Nacelle: The rotor attaches to the nacelle, which sits atop

the tower and includes the gear box, low- and high-speed shafts, generator, controller, and brake. A cover protects the components inside the nacelle. Some nacelles are large enough for a technician to stand inside while working.

Pitch: Blades are turned, or pitched, out of the wind to keep the rotor from turning in winds that are too high or too low to produce electricity.

Rotor: The blades and the hub together are called the rotor.

glossary

Tower: Towers are made from tubular steel (shown here) or steel lattice. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity.

Wind direction: This is an "upwind" turbine, so-called because it operates facing into the wind. Other turbines are designed to run "downwind", facing away from the wind.

Wind vane: Measures wind direction and communicates with the yaw drive to orient the turbine properly with respect to the wind.

Yaw drive: Upwind turbines face into the wind; the yaw drive is used to keep the rotor facing into the wind as the wind direction changes. Downwind turbines don't require a yaw drive, the wind blows the rotor downwind.

Yaw motor: Powers the yaw drive.

How to measure wind speed.

Wind speed is affected by many variables.  In the picture below, wind speeds are approximated and are depicted in miles per hour (MPH), using a standard wind sock.

CHARGE CONTROLLER

The Xantrex C Series offers the C35, C40 and C60 controllers which can handle 35, 40, and 60 amps of DC current. These can be used as solar charge controllers or load controllers or load diversion controllers.

PREVENTS OVERCHARGING PREVENTS POWER BACKFLOW

POWER INVERTER

Pure sine-wave inverters produce in many cases cleaner electricity than normal utility power from your local electric company and should be used when operating AC motors forlong durations such as: pumps, refrigerators compressors etc...The machine converts the power to a useable 240 volts or 110 volts..

The batteries

Our system is using 8 x Trojan L-16 deep cycle lead acid batteries. This sis where the power is stored, until you are ready to use it.

 

EXCEPTIONS TO THE FOUR COMPONENTS

Although most systems use the main four components, there are two that are not always necessary. If you are using all 12 volt appliances, an inverter is not required as the power is already at 12 volts.

Solar Footpath lights

Solar footpath lights are a stand alone 12 volt system. They each have their own solar panel, built in charge controller, which recharges the batteries inside daily. There is a built in sensor which turns the light on at night and off again the morning. They light down to show the way, but do not spoil the view of the night sky.

Direct charging ; no batteries

There are a few systems that do not require batteries..

A solar powered pump for example, can have a direct feed from the panels and controller to the pump, when the sun is up it pumps, when the sun goes down it stops, thus avoid the need for power storage and therefore batteries

THE GOLDEN RULE OF GOING RENEWABLE CONSIDER YOUR CONSUMPTION

One of the most important things to remember when considering going renewable is your consumption. The more you use, the more you need to spend on your system. Change your light bulbs to compact fluorescent bulb, switch off lights and appliances when out, make sure the fridge shuts properly, and try not to use big power things like irons and hairdryers. If you can manage without these you can save thousands of dollars.

SIZING YOUR SYSTEM

SPREADSHEETS

THANK YOU

THANKS FOR COMING TO THE DOMINICA INTERNATIONAL ECOFEST 2009.

JEM WINSTON MANAGING DIRECTOR

ROSALIE FOREST ECO LODGE jem@rosalieforest.com