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EarthEnergy Blog: Information to help "make your home wherever you go."

Basic Renewable Energy System Diagram

To learn more about all the parts of a basic renewable energy system, just scroll your mouse over any of the labeled components in the diagram below. A text box will pop up on the right-hand side of the page, with an explanation of what each item does, and how it works with the rest of the system. (Apologies to mobile visitors, but this diagram requires a large screen.)

Wind Turbine

Wind turbines are one of the three primary alternative energy sources (along with water and solar power). Think of them as wind-powered battery chargers.

Their propeller blades rotate an alternator, delivering power to a load-diverting charge controller, which sends the power either to a battery bank or a diversion load (when the batteries are fully charged).

Wind generators generally require a wind speed of 10 MPH or higher to generate power. Check your annual average and maximum local wind speeds to make sure you are buying the right wind turbine for your location.
Solar Panel

Photovoltaic solar panels are one of the three primary alternative energy sources (along with wind and water power). Think of them as solar-powered battery chargers. Solar panels are very durable, low maintenace, and can easily last for 20-30 years.

Their silicon crystal layer converts sunlight to DC electricity, which is used to charge a storage battery bank, through a solar charge controller.
Hydro Turbine

“Micro-hydro” water generators are one of the three primary alternative energy sources (along with wind and solar power). Think of them as water-powered battery chargers.

Their propellers/turbine blades rotate an alternator, delivering power to a load-diverting charge controller, which sends the power either to a battery bank or a diversion load (when the batteries are fully charged).
Wind Turbine Tower

Wind generators are generally installed on tower mounts, and should have at least 15 feet of vertical clearance above any obstructions within 200 feet (such as trees, buildings, etc.). Some towers allow smaller turbines to be mounted to a roof or the side of a building, but these mounts can cause vibration noise in the building frame.
Solar Array Mount

Installing multiple solar panels (a solar array) requires a mounting rack to secure them. Array racks can be roof mounted, mounted on a freestanding pole/tower, or ground mounted.

Arrays should be positioned to avoid any shading of the panels during the day, and preferably should be angled to maximize direct sun exposure. Tracking array mounts are designed to allow the array rack to turn throughout the day, keeping the panels faced toward the sun for maximum power output.
Lightning Arrestor

Wind turbines must be mounted on tall towers to take advantage of the best possible wind speeds. These tall metal towers have the potential to attract lighting strikes. Lightning arrestors help protect your valuable system components from damage caused by lighting strike power surges.
Load Diverting Control

Wind and water turbine generators need to have an electrical “load” attached at all times while they are running (the current they produce must have somewhere to go), or the turbine generator and batteries can be damaged.

Load diverting charge controllers prevent damage by only sending power to the batteries until they are fully charged, then diverting excess electricity to a “diversion load” that can consume the excess power. Some wind generators have a load diverting controller built-in, but others need an external model.
DC Fuse or Breaker

DC fuses or breakers are installed at key points in your system, to protect system components and wiring from damaging excess current. Both fuses and circuit breakers perform the same function. Fuses, while initially cheaper, must be replaced each time the circuit overloads. Circuit breakers can be reset after an overload. Circuit breakers are available in manual and automatic reset styles.

DC fuses and breakers are often installed in the power source (solar, wind or water) circuits, the inverter DC input circuit, and each circuit in the DC panel or breaker box. The fuse or breaker should be rated for the correct DC voltage, and the maximum amperage the circuit is designed for. For maximum protection, use UL listed fuses and circuit breakers with insulating protective covers.
Load Diverting Control

Wind and water turbine generators need to have an electrical “load” attached at all times while they are running (the current they produce must have somewhere to go), or the turbine generator and batteries can be damaged.

Load diverting charge controllers prevent damage by only sending power to the batteries until they are fully charged, then diverting excess electricity to a “diversion load” that can consume the excess power. Some wind generators have a load diverting controller built-in, but others need an external model.
Diversion Load

A diversion load is connected to a load diverting charge controller. When your battery banks are fully charged, the load diverting charge controller will send extra power from your wind or water turbine to the diversion load, to prevent the batteries from over-charging. When designing your system, make sure the diversion load is able to handle the maximum amount of power the wind or water generator can create.

Some diversion loads are simply large resistors, designed to release excess current as heat. These must be installed away from any possible fire hazards. Other systems use a DC water heater element, or a heating and/or ventilation system, to use the excess power.
Solar Charge Control

A solar charge controller monitors your battery bank charge level, and prevents over-charging by stopping the flow of electrical current when the batteries are fully charged. Most solar controllers will use Pulse Width Modulated (PWM) charging circuitry, regulating the amount of current for faster and more efficient battery charging. Maximum Power Point Tracking (MPPT) controllers go a step further, and adjust charge voltage to maximize charging current.

Make sure your controller matches the voltage of your battery bank and solar panels, and has enough amperage capacity for the maximum output of your solar array. If you plan on adding panels to your array, you may want to buy a controller with “room to grow,” rather than buy a new one when your array output increases.
Diversion Load

A diversion load is connected to a load diverting charge controller. When your battery banks are fully charged, the load diverting charge controller will send extra power from your wind or water turbine to the diversion load, to prevent the batteries from over-charging. When designing your system, make sure the diversion load is able to handle the maximum amount of power the wind or water generator can create.

Some diversion loads are simply large resistors, designed to release excess current as heat. These must be installed away from any possible fire hazards. Other systems use a DC water heater element, or a heating and/or ventilation system, to use the excess power.
DC Fuse or Breaker

DC fuses or breakers are installed at key points in your system, to protect system components and wiring from damaging excess current. Both fuses and circuit breakers perform the same function. Fuses, while initially cheaper, must be replaced each time the circuit overloads. Circuit breakers can be reset after an overload. Circuit breakers are available in manual and automatic reset styles.

DC fuses and breakers are often installed in the power source (solar, wind or water) circuits, the inverter DC input circuit, and each circuit in the DC panel or breaker box. The fuse or breaker should be rated for the correct DC voltage, and the maximum amperage the circuit is designed for. For maximum protection, use UL listed fuses and circuit breakers with insulating protective covers.
DC Fuse or Breaker

DC fuses or breakers are installed at key points in your system, to protect system components and wiring from damaging excess current. Both fuses and circuit breakers perform the same function. Fuses, while initially cheaper, must be replaced each time the circuit overloads. Circuit breakers can be reset after an overload. Circuit breakers are available in manual and automatic reset styles.

DC fuses and breakers are often installed in the power source (solar, wind or water) circuits, the inverter DC input circuit, and each circuit in the DC panel or breaker box. The fuse or breaker should be rated for the correct DC voltage, and the maximum amperage the circuit is designed for. For maximum protection, use UL listed fuses and circuit breakers with insulating protective covers.
System Meter Shunt

An electrical shunt is a precision resistor, which creates a tiny voltage drop relative to the current flowing through it. When used with a battery/system meter, the shunt is wired to intercept the overall system current flow. The meter measures voltage drop at the shunt, and uses it to calculate the overall performance of the power system.
DC Fuse or Breaker

DC fuses or breakers are installed at key points in your system, to protect system components and wiring from damaging excess current. Both fuses and circuit breakers perform the same function. Fuses, while initially cheaper, must be replaced each time the circuit overloads. Circuit breakers can be reset after an overload. Circuit breakers are available in manual and automatic reset styles.

DC fuses and breakers are often installed in the power source (solar, wind or water) circuits, the inverter DC input circuit, and each circuit in the DC panel or breaker box. The fuse or breaker should be rated for the correct DC voltage, and the maximum amperage the circuit is designed for. For maximum protection, use UL listed fuses and circuit breakers with insulating protective covers.
Auxillary Battery Charger

Battery chargers convert the AC electricity from a source such as an engine generator into DC current suitable for recharging batteries. Battery charger/generator sets are often used in conjunction with renewable energy sources (solar, wind and water), for supplemental power when electrical load consumption exceeds the output of the renewable sources.

Many inverters have built-in battery charging functions. However, if inverter battery charging is not adequate (or not available), an auxillary battery charger is a solution. When sizing the auxillary battery charger, the AC and DC voltage of the system, optimal battery charging rate and generator output capacity need to be considered.
Power Storage Batteries

Your battery bank stores excess electricity until it is needed. Your solar panels, wind generator, or water generator will produce power regardless of current need, and the batteries will store excess power so you can use it later. Although a battery bank can be a big expense, buying the best batteries you can afford is the best investment for long term use.

Storage batteries come in many different styles and sizes, but all home power models are “deep cycle” batteries, meaning they can charge and discharge repeatedly for years. Make sure your battery bank has enough amp hour capacity for your needs, and is the right voltage for your system.
Battery/System Meter

A battery/system power meter is connected to your system wiring through a shunt. The meter can tell you how much power your system is producing, how much power your household is using, and how well-charged your batteries are staying.

A good battery system meter will monitor system voltage, amperage flows and battery state-of-charge. A large battery bank should have a meter that calculates state-of-charge from the net battery bank amp hours. Many system meters can be connected to a computer, so you can download your power system data and analyze its performance over time.
Engine Generator

For off-grid power systems, engine-powered generators provide a source of supplemental power for your alternative energy system. When the renewable energy sources (wind, solar or water power) are not producing enough power to keep the battery bank charged, an engine generator will supply AC power and recharge the battery bank.

Generators are also practical if you need to operate very large electrical loads, such as welding equipment or other large machinery. AC generators come with either gasoline, diesel or propane engines. Diesel and propane are usually the longest lasting. Get the highest quality, lowest RPM generator you can afford, for the best long term value.
DC Fuse/Breaker Box

The DC electrical system transfers electricity from the battery bank to the DC electrical loads. The DC panel provides a safe and organized means of splitting the DC power system into multiple circuits (wires), each providing power to a different room or set of appliances. Most DC Panels allow fuses or circuit breakers to be installed on each circuit to protect the system from electrical overload.

The DC panel should be rated for the correct voltage and maximum amperage that the system will need to handle. Wire gauge depends on maximum amperage for each circuit, and the length of the circuit wiring. If you have both AC and DC circuits, their wiring should be completely separated, with separate breaker boxes and outlets in different colors or styles, to prevent injury or damage to appliances.
DC Electrical Loads

Anything that uses electricity (either AC or DC) is referred to as an “electrical load.” There are many types of electrical loads: household appliances such as microwaves and hair dryers, electronic equipment like stereo or computer equipment, as well as lighting, shop equipment and portable devices like cordless drills and cell phones. Even unwanted things like shorts in the wiring system will consume electricity and count as electrical loads.

DC electricity is the type stored by batteries. DC electrical appliances (lighting, refrigerators, etc.) are available from specialty dealers, and often provide better efficiency than their AC counterparts. Most renewable energy systems include both AC and DC electrical loads.
DC-AC Inverter

To use DC battery power to run AC appliances, an inverter must change the DC electricity to AC. Your inverter should produce the correct AC voltage, and have enough output capacity to power all the AC appliances and electrical loads you plan to use simultaneously.

Inverters produce either True Sine Wave or Modified Sine Wave (MSW) AC current. True Sine Wave power is identical to utility power. MSW is a simulated Sine Wave that will operate most electrical loads adequately (with some exceptions, like laser printers), but can cause interference on TV and radio signals (snow or static), and variable speed appliances may not operate properly.
AC Fuse/Breaker Box

The AC electrical system transfers electricity from an AC source (inverter, generator or utility power) to the AC electrical loads. The AC panel provides a safe and organized means of splitting the AC power system into multiple circuits (wires), each providing power to a different room or set of appliances. Most AC Panels allow fuses or resettable circuit breakers to be installed on each circuit to protect the system from electrical overload.

The AC panel should be rated for the correct voltage and maximum amperage that the system should encounter. If you have both AC and DC electrical circuits, their wiring should be completely separated, with separate breaker boxes and outlets in different colors or styles, to prevent injury or damage to appliances.
AC Electrical Loads

Anything that uses electricity (either AC or DC) is referred to as an “electrical load.” There are many types of electrical loads: household appliances such as microwaves and hair dryers, electronic equipment like stereo or computer equipment, as well as lighting, shop equipment and portable devices like cordless drills and cell phones. Even unwanted things like shorts in the wiring system will consume electricity and count as electrical loads.

AC electricity is the type provided by the local utility company, and is what operates common household appliances and shop tools. To power AC loads in a renewable energy system, you will need either an engine generator (which produces AC power) or an inverter (which changes DC power to AC).
AC Transfer Switch

When more than one AC power source is used (ie: an inverter and an AC engine generator), a transfer switch must be incorporated into the system. This switch keeps the sources from operating at the same time and damaging each other.

Some inverters have transfer switch functions built-in, but others do not and some systems may require an external transfer switch anyway. Transfer switches can be manually operated or automatic.
DC Wiring

DC cables and wiring must be sized correctly to prevent excessive voltage drop. If your DC wiring is not sized for the right voltage, maximum amperage, and distance the current must travel, you will lose efficiency in your system. Know the maximum output of your power source, and measure the distance the wire must cover before buying your DC cables. DC wiring should always be stranded copper cable or wire.

Use only DC rated components in your DC electrical system. All system components must be rated for the correct voltage and maximum anticipated amperage. For best performance and safety, use UL listed components and install the electrical system according to all manufacturers instructions, the National Electrical Code, and any applicable local, state and federal regulations.
AC Wiring

All of the components needed to distribute and control electricity are commonly referred to as the “electrical system” or “power distribution system.” AC and DC electricity are very different, so your AC and DC electrical systems must be kept entirely separate. (see AC Loads or DC Loads for more info).

Use only AC rated components in your AC electrical system. Check your system components owner manuals for specifications. For optimal performance and safety, use UL listed components and follow all manufacturers instructions, the National Electrical Code, and any applicable local, state and federal regulations. It is strongly recommended that the electrical system be installed or inspected by a licensed electrician.