Renewable Energy 101

We have put together the following step-by-step guide to help you go through the process of bringing Renewable Energy into your home.     

STEP 1

Falls Brook Centre Renewable Energy Information Group

The Falls Brook Centre Renewable Energy group is made up of individuals and organizations interested in demonstrating, promoting, and developing appropriate renewable energy technologies with a focus on the province of New Brunswick, Canada.

To become part of the group go to http://groups.google.com/group/fbc-re/subscribe.

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STEP 2

EnerGuide for Houses Evaluation

EnerGuide for Houses was created by the Government of Canada to help homeowners get independent, expert advice about the energy efficiency of their homes.  By reducing the energy used in our homes, we support Canada's goal of reducing the production of greenhouse gas emissions that contribute to climate change.

The EnerGuide for Houses evaluation service provides homeowners with information on energy-efficient improvements for their homes. Many service organizations across Canada offer this service. They can provide independent expert advice on the different systems of your home and what can be done to improve comfort and reduce energy bills. By assessing your home, an EnerGuide for Houses advisor can analyze how it uses energy and where energy is being wasted. The evaluation includes the following:

• a "blower door" test to identify air-leakage points

• a comprehensive walk-through of your house to collect data for modelling your home's energy use

• an EnerGuide for Houses Report, with customized energy upgrade recommendations for your home

• an estimate of annual energy consumption, along with an EnerGuide for Houses rating and label.

Home Energy Advisors Serving Carleton County, New Brunswick:
Home Energy Savings Inc: 1-866-855-3025
Enerplan Consultants Ltd: 1-866-363-7752

Get more information at the EnerGuide for Houses Website

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STEP 3

Determine Your Energy Budget

To help you determine the size of your system you should do an energy budget on your living space.  An Energy Budget will give you the average amount of energy that your home uses over a specified period of time - one week in this example.  To do an energy budget, you first list all of the electrical appliances that you home uses then their power consumption.  You can determine the power consumption from looking at back or bottom of the appliance for an electrical label, if you can't access to it, try the appliance user manual.  You are looking for the input wattage at 60 Hz and AC 120V.  If the wattage is not given like in Example A below but there is a current given in Amps (A), multiply the A by 120V to get the power.  If there is an input and output given like in Example B, use the input wattage.  

Next estimate how many hours per day and days per week you would use the device.  After you have determined all of these, multiply the three numbers together to get weekly watt-hours and add all the watt-hours up to get your total weekly energy use in watt-hours.  

Your daily energy use can be found by dividing your weekly Wh by 7.   Our example gives us 4756 Wh or 4.756 kWh. 

When completing your energy budget you should also consider your usage intensity pattern. Will you only use the system on weekend or all week?  This will impact decisions regarding the sizing your generation and storage systems.

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STEP 4

Plan Your System

The following sections may help you to understand the various considerations involved in planning your home renewable energy system.  A trained professional can also help guide you through this process.  See our local contacts section for more details.

1. Selecting your System Voltage

This is one of the most important decision making stages when building your system. Changing system voltage later is a costly and very disruptive process. Forethought into your system design and future expansion possibilities will save you money in the long run.

Here are a few guidelines in regards to system voltage. Remember that these are only guidelines and that there are countless exceptions to these rules.

12 Volt Systems:

• Suited to small systems with limited requirements for future expansion
• Charging sources (renewable energy source) are within 50’ wire run of the batteries
• Maximum inverter capacity is 3 kW
• The lower the voltage, the higher the amperage. The higher the amperage, the greater the resistance and the more expensive the wire will be to carry that higher amperage.
   

24 volt Systems:

• Most common voltage with lots of room for expansion
• Inverters up to 4 kW
• A 24 volt system will use half the amperage of a 12 volt inverter of the same size and operate more efficiently
• Longer transmission distances possible
• Wire costs reduced
   

48 Volt System:

• For larger, higher performance systems
• Single inverters up to 5.5 kW
• Transmission of electricity over much longer distances

Higher Voltages:

• For specialty projects such as water pumping and grid intertie
• High voltage systems can move power economically over many miles
• Contact a professional renewable energy dealer to discuss these types of set-ups

2. Choosing a Renewable Energy Technology: 

1. Photovoltaic Panel:

Photovoltaic power is generated when sunlight is absorbed by solar panels and transformed into electricity. The following sections should give an overview of the factors involved in considering array size.

Sunshine and Shading

PV modules produce electricity in proportion to the amount of sunlight falling on them. In full overhead sun (1000 Watts/m2) they will produce their rated power. Reduced sunlight caused by clouds or location will diminish the amount of electricity generated. Modules will produce electricity even when there is no direct sunlight. A Cloudy sky with an occasional blue patch will often be equivalent to approximately 50% full overhead sun. A cloudy day with rain in the forecast will produce approximately 10% to 15% peak sun. Snow or water adds to the output of the solar panel by reflecting sunlight.

Temperature

It is a common misconception that heat is required for PV modules to produce electricity. High temperatures actually decrease the power output. Warmer climates require PV modules with higher maximum voltage that those used in colder climates. Cold temperatures decrease resistance and increase voltage.

Insolation

Insolation or sunlight intensity is measured in peak sun hours. A full sun hour is equal to the amount of sunlight striking the earth in one hour when the sun is directly overhead in a clear sky. Bright sunshine hours do not equal peak sun hours. Bright sunshine first thing in the morning or just before sunset is not the same as bright sunshine at noon from a PV module’s perspective.

The lower the sun in the sky, the more atmosphere the light must pass through. Water molecules and other gases in the atmosphere reflect and absorb some of the light passing through it, reducing the insolation. Most of the sun’s energy is delivered from 10 am to 3 pm when the sun is highest in the sky.

The insolation differs from one location to another.  This is a factor in determining average daily energy output for an array of a given size.  A good rule of thumb is to multiply the power rating of your array by two during the winter and four during summer to get your daily Watt-hour output.

Typical daily 100W Solar Module Output in Watt-hours:

Location	Avg	Min (December)	Max (July)
Fredericton	334	232	408
Halifax	317	199	387

Location and Orientation

To achieve the best performance from your array it should be aimed in the direction of the most sunlight and angled correctly for the season. The array should be adjusted to the latitude plus or minus 15° from summer to winter for optimal output. If your mounting structure is not seasonally adjustable the modules should be mounted to achieve maximum output during the period of highest usage. For example, if you use your cottage during the summer months your array should be angled accordingly.

PV modules should always be aimed in the direction where they receive full exposure to sunlight. In areas with little or no shading, modules should face true south (not magnetic). True south is calculated by using the magnetic declination information for your site (available on most maps) and adjusting your compass accordingly.

Technology

There are three main technologies available; single crystal, multi crystal and amorphous. These mainly impact the power per unit area.  Single crystal panels will require less area for the same output power than multi-crystal.  Multi-crystal less than amorphous.

Connection

Panels can be connected in parallel or in series to make up your required voltage, charge current, and power requirements.  Voltage can be added when connected in series: current when connected in parallel.  Power numbers can be added when connected in series and/or in parallel.

Mounting

There are several options for mounting PV panels. The following discusses the most common:

Roof Mounts:
This is the most popular and cost effective method of mounting solar panels but is limited to locations that have a suitable south facing roof. By mounting on the roof you easily locate your panels in a location which is above most objects that would cause shading. The large roof surface often provides a surface which makes it easy to attach the mounting structure and also located the modules out of way and out of sight, reducing the possibility of theft or vandalism.

Ground Mounts:
Similar to roof mounts, these structures mount on the ground, typically on concrete footings. These mounts are usually taller than a roof mount, to avoid grass and shrubs blocking the sun. Ground mounts are easy to install and provide an easy means of seasonal angle adjustments and snow removal in the winter.

Pole Mounts:
Pole mounts are easy to install and allow the angle to be adjusted after installation. The mounting frame fits on a length of schedule 40 pipe (available at any metal shop) set securely in a concrete form in the ground.

Tracking Racks:
There is no question that moving your panels throughout the day to follow the sun will notable increase the energy produced. An ideal use for an old-style satellite dish is converting it into a low-tech tracking unit for the project types. Zomeworks and Wattsun offer factory assembled tracking racks that have proven to be a popular choice. However, a fixed rack will require less maintenance than a tracking rack.

Charge Controller/Regulator

A charge controller will protect your battery from over charging, which leads to water loss and decreased battery life. A charge controller is an inexpensive device for preventing accidental damage to your expensive batteries. It should be sized for your current requirements (charging Amps) and number of system battery banks.

2. Solar Thermal:

Over a horsepower of energy per square yard falls on your roof on a sunny day. You can take advantage of this and capture this energy to heat your domestic hot water using a number of different methods.

If your motivation is to use alternative energy to save money on your fuel costs, this is the first place to start. There are many possible ways to use solar hot water. In general, anything that requires water to be heated can benefit from solar energy. Some projects make sense, some do not. Pool heating and domestic hot water are the most common uses of solar thermal and offer the most appealing return on investment.

In a solar hot water system, heat from the sun is transferred directly to water or a glycol mixture circulating in a collector. There are two types of circulating systems in common use: the open-loop and the closed-loop.

Closed Loop

A closed-loop system circulates a water and glycol mixture through the collectpr, where it absorbs heat. It then passes through a heat exchanger, where it transfers the heat to the water in a storage tank or pre-heated hot water tank The pre-heat tank becomes the cold water supply for an existing domestic hot water tank.

There us no need to drain a closed-loop system in the winter because the glycol mixture does not freeze, so total hot water production will be higher than with an open-loop system. If your home is already equipped with an electric or gas-fired hot water heater, a closed loop hot water heater will work the best.

Open-Loop

An open-loop system circulated the solar heated water directly into the hot water tank. Customers who use a wood stove with a water jacket in the winter may easily add a solar collector to use the sun for hot water in the summer. This system is the simplest to install, but it must be drained in the freezing weather.

Thermo-siphon or Pump

A thermo-siphon occurs when the hot water tank is located above the collector. Heated fluid has a lower density than cold fluid. Natural convection causes the heated liquid to flow into the water tank. This system is most similar to the hot water coil found in many wood or oil stoves and requires no circulation pump.

A thermo-siphon system is often not practical especially if you want your collectors mounted on the roof. This configuration requires a circulation pump in the system. This type of pump draws very little energy and is often powered by a small solar electric module. When the sun is shining, it is heating and pumping water. A solar electric powered circulation pump means no complicated differential controllers are required.

Solar Collectors

There are many different collectors used in solar hot water systems, the most common being a flat plate grid collector. This is a series of pipes connected to a top and bottom manifold. These collectors are usually glazed and insulated. Typically a 4ft x 10 ft collector will produce as much energy in full sunlight as a 2kW hot water tank element.

However, no form of solar hot water heating will be 100% effective in the Canadian climate. For cloudy periods a backup water heating system is required. If you have an existing electric or natural gas hot water tank or wood stove, your backup is in place. Solar water heaters may be used for space heating. In space heating systems the solar heated water circulated through a radiator or pipes laid in the floor of the area to be heated.

3. Wind:

Wind energy has been used for centuries, for grinding grain, pumping water and generating electricity. Today we are seeing wind gaining tremendous popularity in generating significant amounts of power both off-grid and as a source of energy for large utilities. European countries are leading the way in wind generation while Canada generally lags behind.

How it Works

Wind turns the blades of the turbine which spins a shaft within the turbine structure. The shaft drives a generator to produce electricity. The electricity that is generated can be used, stored in batteries or sold to the Utility under a clause called net-metering (see section Considering a Net-metering (Grid intertie) system for more information).

Types of Wind Generators:

Small-Scale Units (under 3 kW): used to charge batteries or direct use (such as pumping water or power household devices).

Medium Sized Units (up to 50kW): used in a grid-intertie environment to generate power and feed it to the utility grid. Due to the unique nature of these projects and their related expense, each system requires a detailed assessment by a professional before proceeding.

Large-scale Units (megawatts):  large, towering units that cost millions of dollars and generate power to run hundreds or thousands of homes or businesses. These systems are generally suited to large utilities and power co-operatives.

Maintenance

Wind turbines, unlike PV modules, have moving parts and thus require periodic maintenance of bearings, brushes and shafts. It is important when installing a wind generator to consider how easy it will be to access the generator to conduct maintenance.

Towers are a critical component of wind power systems. Proper location and height of your tower is necessary to get maximum energy from a wind turbine. Improper tower design or installation may result in personal injury, property damage or a damaged generator. It will also likely result in less-than-satisfactory performance from your wind turbine.

Tower Height

Wind generator operation is dependant on the quantity and quality of the wind hitting the blades. Turbulent wind will reduce the power output as the turbine swings back and forth hunting for wind. The unequal stresses caused by turbulence and the variation in wind speed between the upper and lower blades of a wind turbine installed too close to the ground will reduce power output and wind turbine life.

Wind speed increases rapidly with tower height. Doubling tower height increases the available wind power by about 40%. It is often more economical to install a higher tower rather than purchase a larger generator. A wind generator should be installed a minimum of 33 feet (10 meters) above any obstruction within 100 meters of the generator.

Resource Assessment

There are three primary ways of determining how much wind is available on your site:

1. Installing an anemometer:

• The most accurate way to determine wind speed
• Can take several years of readings and some expensive equipment to compile accurate data- unless you plan on spending $15,000 or more on a wind system, this is usually not a necessary nor cost effective path
• Some people install a small wind generator and use it as an anemometer if they are planning for a much larger installation.

2. Using existing data:

• Local airport or meteorological stations
• Universities, colleges or radio stations
• There may be some data from local Environment Canada stations, but unless a weather station is nearby the data may not be accurate for the site
• Wind speeds can vary a great deal within a small area, so this information should be correlated with another method such as visual observations.

3. Visual observations:

• The simplest and quickest method of determining average wind speed is to observe the effects on vegetation at the site
• If the trees or shrubs are growing with a definite slant to one direction, or only branches on one side of the tree, you will have a good wind site. It takes constant, prevailing winds to affect vegetation in this way.
• If you have a flag at your site and the flag is stiff in the wind for a few hours a day then the site is a good candidate for wind power. It is a good idea to keep a log of these observations over the course of a few months and in different seasons before proceeding with wind power development.

4. Micro-Hydro:

If your site has running water, you simply must investigate its potential as a source of electricity. Experience has demonstrated that water power will produce between 10 and 100 times more power than solar or wind for the same capital investment. Since water flows day and night, a micro-hydro system requires far less battery storage than other technologies.

Electricity is produced from the energy in water flowing from a high level to a lower level. This change in elevation is called “head” and supplied the pressure which drives the turbine. “Flow” is the other factor contributing to power production. It is usually limited by the size of the creek. The amount of electricity produced is directly related to the head and the flow. If the head or the flow is increased the power output increases proportionally.

Site Considerations:

Many factors work together to make a successful micro-hydro site. In order to have optimal performance your equipment must be neither too big nor too small. A turbine can be up to a couple of kilometers away from where the power is being used and still be cost effective. It is far cheaper to run wire lines than it is to extend the pipe length. Correctly-sized transmission lines and high-voltage generators can deliver significant amounts of power a great distance with acceptable losses and in a cost effective way.

To do an initial assessment of your micro-hydro potential you must know how to calculate your head and flow.

Measuring Flow:

Flow is the volume of water per unit of time available to the turbine. It varies seasonally and may also vary along a creeks length if tributaries flow into it. Measuring the flow at different times of the year helps estimate the maximum and minimum usable flow. Most micro-hydro systems use less than a hundred gallons per minute. These flows can be calculated by timing how long it takes to fill a bucket. A hundred gallons per minute will take three seconds to fill a five gallon bucket.

Measuring Head:

Modern handheld digital altimeters can be used as a survey tool with great accuracy. Modern GPS receivers can also provide good data depending on signal strength. Record the elevation at the bottom. Move to the top and record the altitude again. The difference in feet is your gross head. Repeat the process and average the results for better accuracy.

Equations:

 A good approximation of the power available to a battery charging micro hydro system is given by:

Power [watts] = Net head [ft] x Flow [USGM]
                          -----------------------------------------
                                                   14

Hydro turbines and generators for AC only micro-hydro systems are more efficient, so the above power equation need to be modified:

Power [watts] = Net head [ft] x Flow [USGM]
                          -----------------------------------------
                                                   9

SAMPLE:

The total distance between where we wish to draw the water from the creek and where the turbine will be located is 600 feet. Thus the length of pipeline must be 600 feet long. Along this 600 foot pipeline there is a drop in elevation of 80 feet. Thus the static head is 80 feet. The flow available from the creek is measured to be 48 US gallons per minute.

Total power =  64 feet x 48 USGM
                       -------------------------                     =  219 watts
                                    14

The power generated would be approximately 219 watts. Over 24 hours more than 5 kWh of energy would be produced. In a nominal 12 volt system the turbine and generator would deliver approximately 15 amps continuously or 360 amp/hours per day.

5. Ground Source Energy (Geothermal energy and Heat Pumps):

The Falls Brook Centre has very little experience working with ground source energy and would not feel comfortable answering questions or giving advice in this area until we are more experienced. If you would like information in this regard, please contact organizations that are more experienced in this field such as:

The Canadian Association for Renewable Energies www.renewables.ca

3. Battery Storage

   Charge storage capacity is quoted in Amp-hours.  This value varies with average load current and is usually listed for a 100 h discharge period.  A battery with an 400 amp-hour rating @ 100 hour discharge duration is capable of supplying a load current of 4 amps for 100 hours.  Faster discharges with higher average currents typically reduce battery capacity rating (eg. The same battery might have a 350 amp-hour rating @ 80 hour discharge => 4.375 amps)

   Depth of discharge specs for battery cycling will also limit the effective charge storage capacity (many batteries do not recommend discharging below 50%)

   Required days of autonomy will have to be considered in sizing your battery bank; Insurance against long periods without good sunlight/wind/water flow.

   Batteries can be connected in parallel or in series to make up your voltage, current, and storage requirement.  Total amp-hours can be calculated by adding the amp-hours of all batteries in the system that are connected in parallel.

    

4. Inverter Selection

Inverters are a basic component of any independent power system that requires AC power. An inverter converts DC power stored in batteries into AC power used to run conventional appliances like computers, refrigerators, power tools and entertainment systems. Inverters differ in the quality of electricity that they produce. Quality can vary in waveform, frequency and voltage. The types of appliances that can run off an inverter depend on the quality of the electricity being generated.

Types of Inverters:

1) True Sine Wave Inverter

• Produces electricity similar to or better than utilities
• Virtually no harmonics
• Will run any appliance-typically used to run appliances sensitive to other waveforms like computers and electronic entertainment equipment.
• More expensive than modified sine wave inverters

2) Modified Sine Wave Inverter:

• Popular option with slightly compromised wave (some harmonics) at a lower cost
• Approximates a true sine wave with low harmonics that do not cause problems with household equipment
• Main disadvantage is peak voltage varies with battery voltage. Inexpensive electronic devices with no regulation of power supply may behave erratically when a battery voltage fluctuates.

3) Grid Intertie Inverter:

• Designed to “sell power back to the utility when there is a surplus (see Considering Net-Metering section of this document for more information).

5. Considering a Net-Metering (Grid Intertie) System:

Net metering is a simplified method of metering the energy consumed and produced at a home or business that has its own energy generator, such as a wind turbine. Under net-metering, excess electricity produced by the local generator will spin the existing home or business electricity meter backwards, effectively banking the electricity until it is needed by the customer. This provides the customer with full retail value for all electricity produced.

I am a resident of New Brunswick or Nova Scotia, can I net-meter my electricity?

In New Brunswick and Nova Scotia, customers are permitted under their respective electricity acts to net-meter their electricity. Under the New Brunswick agreement, NB Power allows there customers to net-meter there electricity as long as the generator is smaller than 100 kW.  The Falls Brook Centre is a pioneer in New Brunswick Net Metering.  Check out the details of our demonstration site at http://www.fallsbrookcentre.ca/technology/net_metering.htm or http://www.fallsbrookcentre.ca/technology/re_demonstrations.htm