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Battery Backup System
The battery can be as simple as a 12 volt battery of moderate size, much like a car battery. The capacity, or the energy storage capacity, of the battery is directly related to its physical size. The larger the battery, the higher the capacity. A 7 Ampere Hour (AH) battery might be the size of an envelope box where as a 220 AH battery would be larger than a car battery. The battery bank is made up of several batteries connected together in series and parallel combinations to develop the voltage and current capacities needed for a particular system. Two 12 v batteries connected in series make up a 24 volt battery. This battery would have the same current capacity of either of the two batteries individually. If the 12 volt battery were to be rated for 12 v at 220 AH, then the series connected battery combination would be rated at 24 volts at 220 Ampere Hours. If we carry this out further, making a 48 volt battery by connecting the original two batteries in series with two more batteries in series (a total of 4 batteries) we make one 48 volt battery with a capacity rating of 220 AH. Once the battery voltage is satisfied, by connecting batteries in series, we then consider the total battery Ampere Hour capacity needed. To meet this requirement we connect the 4 series connected batteries in parallel with 4 more series connected batteries, making a 48 volt battery with 440 AH capacity. The process continues until the battery is sized to meet the load demand.
CAUTION – Even a single cell battery at modest AH ratings has the ability to supply very high currents for short durations. Shorting the terminals of a battery will cause maximum current to flow, and the power will be dissipated in the load. Resistance is the limiting factor in the power transfer process. Without resistance, as in the case of a short circuit, maximum current flows for the duration of the batteries ability to contain the power developed during energy transfer process. This is limited by the physical construction of the battery and the duration of the short circuit. The battery can, and most likely will explode causing the contents of the battery, to be sent in all directions. This is a very serious mishap often resulting in major physical injury or death.
Each piece of equipment or appliance in the home (draws) a specific amount of power expressed in Watts. Watts = the applied voltage expressed as E, times the current expressed as I, passing through the device (W= E x I or Watts= Volts x Amps for this example). While in operation this power is basically supplied by the systems batteries and the solar panel array which is sized to recharge or replace the energy drawn from the batteries during the normal periods of sunlight. Power is related to the current capacity of the batteries (expressed in Ampere Hours or AH) and determines the length of time the energy can be drawn from the battery at a rate to allow normal operation of the loads attached. The amount of energy consumed during the daily period must be put back into the batteries, or the batteries will eventually discharge below a usable level causing the system to fail. A 100 watt lamp consumes power at a rate of 100 watts per hour for the period of time it is on. If the lamp is on for 1 hour it consumes 100 watt hours. In order to make the power available later to turn on the lamp we must recharge that 100 watt hours back into the batteries plus about 12% (112 watts) for applicable system losses. The lamp consumes 100 watts at 120 volts so while the lamp is on the current required is relatively small (100W/120V = 0.83 amps). The power that comes from a battery is at a lower voltage, in this test case at 24 volts. Therefore, the current flowing from the battery for the period of time the lamp was on would be 4.67 amps (112W/ 24V = 4.67 amps). In Virginia we have 5 hours (annual average) of peak solar energy production to replace the power consumed by the lamp back into the battery. Therefore to size the solar panels required to charge the batteries at a rate to reflect the available hours of solar production is 112 watts / 4.8 hours = 23 watts/hour. So one 24 volt solar panel (typical panel voltage) rated at 28 watts can be used to keep the battery charged. Of course that battery capacity must be capable of supplying the power needed based on the total time that the devices are being used, and at the power supply rate to match the energy that is pulled out of the battery. With larger loads, like a window AC unit, more current is needed at a higher rate of power supply. This then requires a larger battery storage system. The inverter (converts the battery power from DC to standard AC power) also needs to be sized to meet the load demand, not only the constant load, such as a light, but also the surge load caused when starting motors such as those used in an air conditioner fan and refrigerator compressors. It takes about 3 to 7 times as much energy to start the motors as it takes to operate them. For instance a 5000 BTU WINDOW AC unit requires 1,465 watts to operate but it may require 4,395 watts for a short duration to start. If the battery systems demand capacity is not built large enough to start the motors the motor will not start.
The number of solar panels required is directly proportional to the daily power required to supply the home. Because the available energy to be harvested from the sun, it is calculated based on the daily average of available solar energy. The energy production per square foot of solar panel surface for that harvest must be known. If we require more solar energy to be harvested; the solar panel surface area is enlarged by the addition of more panels within the system. Typically, a solar panel that produces at 175 watts per hour represents about 14 square feet (1.3 m2) of solar panel surface area. A 100% efficient solar panel would convert the standard 1,000 Watts/m2 that strikes the surface of the earth into 1300 watts of solar energy. However, at 15% (typical efficiency for today’s solar panel technology) the same panel produces the manufacture’s rating of 175 watts. A 200 watt panel of the same quality is just physically larger (more surface area).Two 87.5 watt rated panels (physically smaller), would produce 175 watts under the same conditions. As a result the total number of solar panels needed is a ratio of available solar energy, and the daily power consumed by the system loads. If this ratio is not properly calculated, including the DC to AC conversion process and system losses, the solar panels will fail to supply the batteries with the energy required to replace what is consumed by the loads on a daily basis. The number of panels required depends on the energy harvest required to meet the needs of the system design.
In general, these systems are best for applications in which backup power must be instantly available without interruption (for example, to power computers). These systems are also good for areas where power outages are a frequent occurrence, or an area where blackouts and brownouts are relatively common such as after a hurricane.
Off grid systems typically require a larger up-front investment than grid-tie systems. This is, in large part, due to the greater demands on the system. Off Grid systems are typically used in remote applications in which utility power is not available, where running a line to the local utility grid is prohibitively expensive, or where a generator is not desirable.
A battery based system is made up of several different components. These include solar panels, batteries and a charge regulator or controller, an inverter which converts the DC current to AC current; wiring; and mounting hardware or a framework. Although a small amount of energy is lost in converting DC to AC (typical inverter efficiencies are in the range of 90 to 95%), an inverter makes solar generated electricity behave like utility power to operate everyday AC appliances, lights, and electrical equipment. Please note that you will need a special type of inverter if you want a battery backup system. For safety reasons most grid-tied inverters are designed to shut down completely if there is a power failure. The charge controller prevents the solar panel or array from overcharging your battery. Batteries are the energy storage for your system. Without batteries there is no way to store the energy your solar panels produce during the day and provide you with the energy you need at night. Typically loads receive their power from batteries instead of directly from the output of a solar panel. The solar panel is the basic building block of the system. This is your battery charger. If you have several solar panels wired together you have created a solar array. The size of the solar array determines the amount of power or energy that will be produced.
Hybrid systems typically require a larger up-front investment than grid-tie systems. Batteries are an additional expense, required maintenance, last 5-10 years, decrease system efficiency and result in a more complicated system. Many of our customers opt for a grid-tie system and purchase a standby generator with a properly installed manual transfer switch. For a given level of power output, generators are usually the least expensive option for backup power production. Generators provide the most reliable and cost effective source of extended backup power, eliminate the additional expenses related to batteries, and have backup power available for as long as they have fuel.
Different geographic regions provide various amounts of daily sunshine. It is recommended that an off grid system has enough battery power to account for five days of inclement weather. The American southwest averages 6 sunshine hours per day and the northeast receives about 3 hours of daily sunshine. More solar panels will increase the amount of power generated when the sun is shining. A solar generating system with batteries supplies electricity when it is needed. The amount of electricity that can be used after sunset or on cloudy days is determined by the output of the solar energy modules and the storage capacity of the battery bank. Including more modules and batteries increases system cost. Energy requirements (both in terms of peak loads and the average duration of the loads) are carefully studied to determine optimum system size. A well-designed system balances cost and convenience to meet the needs of the particular application, and can be expanded if those needs change.
To begin the design process, you must list all items you are considering to power using your battery backed system by the item name, the power rating of the device, and the length of time (hours) during the week the item will be in operation. The power consumption information can be found on the manufactures tag in the same locations as the model and serial number. The power consumption may be listed as watts or the amount of current draw in amps. Most appliances require 120 volts and some requires 240 volts (110 & 120 volts are considered to be the same in this instance as are 220 & 240 volts).
The Hybrid system takes advantage of the high efficiency of energy production of the On Grid system, but has a limited load demand battery storage bank to supply power to critical loads in the home like certain lights or a refrigerator. Normally these critical loads do not include the air conditioning unit. Hybrid systems are designed to supply critical loads without the benefit of a solar charge cycle period, referred to as the days of autonomy (3 days is typical). The autonomy period is based on the load demand of the appliances to be operated and the length of time those appliances are to be in operation. Of course the system can be built large enough to power any device as long as cost is not a consideration. If a generator is avaliable to provide recharging of the battery bank, then the days of autonomy can be shortened, as the generator would be called on to offset the loss of access to the sun’s power during extended cloudy periods.
The main difference between the On Grid (Grid Tied) and Off Grid system is the method of energy storage for later use. On Grid, we bank energy for later use by passing excess energy production back to the grid in reverse of the energy consumption accounting system, thus applying credits for the energy that will be used later when the power production is less than the local loads require during overcast times or at night. Off Grid systems are designed to meet 100% of the current demands of the attached appliances, and electrical loads, whereas the On Grid systems are designed to meet a portion of the energy consumed by the loads, On Grid systems allow the Grid to meet the high current load demand, such as high rush currents needed to start the air conditioner compressor, or other motor driven loads.This RUSH current can be 3 to 7 times the energy required to operate the appliance. In the Off Grid system capacity of the system needs to be large enough to meet ALL current demands of all appliances to reconnected to the solar power production system. If the current demand is not sufficient the connected load swill not function, or can be damaged.
Battery backed solar electric systems are elegantly simple. Maintenance includes:
• Checking your deep cycle batteries every few months to make sure they have enough distilled water
• Occasionally checking the connections between the solar modules and the inverter(s), and tightening them when applicable.
The batteries used in solar systems are similar to car batteries, but are designed for deep cycling use in which a larger percentage of the capacity of the battery is used each night (and then fully charged up each day). Batteries designed for solar projects pose the same risks and demand the same caution in handling and storage as automotive batteries. The fluid in unsealed batteries is highly corrosive. Levels should be checked periodically, batteries must be appropriately ventilated, and batteries should be protected from extremely cold weather. In practice we have found that when the batteries are maintained properly, they last for apporximately 5-10 years. After which, their capacity is significantly diminished.
The simplest solution is to install a relatively inexpensive generator in conjunction with a manual transfer switch. The transfer switch directs the source of power for critical loads from the utility (which is presumably down) to the generator – without back-feeding the electric grid. During a power outage the transfer switch is operated and the generator is started, thereby providing power to the critical loads in the house. Total costs for this type of installation are typically in the $3,000 to $7,000 range, with manual start gasoline generators at the lower end and auto-start propane/NG generators at the higher end. More durable diesel powered generators, such as a 10,000 watt auto-start unit, can be purchased for about $10,000. This generator has higher quality power output, requires less maintenance, and has a much longer life. Since they don’t require complicated carburetion, propane/NG generators are also good solutions for remote backup systems. With these higher price range generators one can install an automatic transfer switch and auto-start capabilities so that the generator automatically begins to supply your electrical loads in the event of a power outage. Most generator systems it will take several minutes for the generator to come online and provide adequate power.
During the charge cycle hydrogen is produced in the process. Different types of batteries handle the gassing process differently, and each process can be directly related to battery cost. The standard wet cell, commonly related to the car battery, just vents the gas into the air, normally the quantity is such that the concentration is not explosive. Sealed batteries will vent, but normally the gasses are contained, depending on the charge rate. In all cases one would want to consider a separated space for the batteries, certainly not within the living space. Ideally, storage batteries would be placed in cool, dry and vented locations (batteries release hydrogen gas). Sheds or garages are good places. The contents of batteries should not be subjected to boiling or freezing. Freezing will only occur when the batteries are in a state of discharge.
Grid Tie Systems
Overall value is important when choosing between the increasing number of professionals offering solar products and services. Often the low bid is from a company that is highly qualified and has a well-managed operation, but sometimes it comes from a company that will cut corners or that may not fully understand the job requirements. Main Street Solar has the experience and resources necessary to ensure your investment is a dependable, quality installation providing a lifetime of worry free savings. Guaranteed.
- When sunlight shines on solar panels they produce Direct Current (DC). That DC electricity is converted into household AC power by your power inverter, and it is then available for household use. This process happens silently and automatically every day.
When a grid-tie solar electric system generates more power than you are using in your home, the excess electricity is sent out into the utility grid. The excess power going into the grid spins your meter backwards, allowing your neighbors to use clean, quiet solar power. If you use more power than your system is producing, your inverter will automatically pull the needed power from the utility grid – and you will never notice a thing.
This is back and forth process is called “net metering”, and it means you are only billed for the “net” electricity purchased over the entire billing period. At the end of each billing cycle your meter will not have spun as far forward when compared to not having solar electricity, saving you money. If you produce more than you use during a billing period, your utility company will retain it as a credit, which will then be applied to future electric bills.
Sizing your solar grid-tie system is not as complicated as you may think. With only an electrical bill, you can determine the minimum system size you will need. Once you’ve determined that, you can determine how many solar panels you will need, and find compatible components from there.
To begin, you will need your 12 month average electrical use–which you should be able to find on your utility bill. This number will be in kWH (kilowatt-hours).
Then follow these steps to get a ballpark estimate of your minimum system size:
- Record average monthly kWH electrical use: __________kWH
- Multiply this by the percentage you want the solar system to produce: __________kW (ie: 1000kWH X 50% = 500kWH)
- Divide by 30 for the daily output from your solar power system: __________kW
- Divide by the daily average sun hours for your location: __________kW (use 5 hours in VA)
- Divide by 75% to compensate for system efficiency: __________kW
The simplest way though, is to let us help you. We can save you time and ensure you have accurate information to base your PV array sizing, as with any questions you may have about using renewable energy. Feel free to give us a call at 540-860-8036 or contact us on our request a quote form.
Once you know how large of solar array is required to meet your power demands, we can help you select the appropriate products for your specific needs.
The number of solar panels you need and how you want to mount them are just two of the factors that will affect the overall cost of your off-grid system. Another important factor will be which brand of products you choose.
At Main Street Solar we work hard to provide all the information and help you to select a renewable energy solution that gives you the best overall value for your investment. We don’t just look at the price of an item, though of course that is an important consideration. Sometimes the upfront cost of an item can be misleading. Though it may seem like a good deal at first glance, when you look more closely – at quality, dependability, efficiency and life expectancy – you may find a slightly more expensive product will offer a better value over the life of your system.
The Federal government, some cities and counties and many local utilities offer incentive programs. For more information on incentives available in your area, call Main Street Solar, or visit the Database of State Incentives for Renewable Energy (DSIRE) website atwww.dsire.org.
Main Street Solar does not recommend that a customer who is already hooked up to utility power disconnect and go off-grid. There are many reasons, but some key ones are:
- Grid tie systems are less expensive than off-grid because they require no storage batteries.
- Off-grid solar has some unique design limitations, which means most people will need to adjust their power use habits and may need to replace some appliances (such as an electric furnace or electric oven) to make an off-grid system practical and cost effective.
- Batteries, which are necessary in off-grid systems to provide power at night or at other times when power is not being produced, can be expensive and they require regular maintenance. They also have a shorter life expectancy than most other solar system components, which means that they not only add to the upfront cost of a system, but they add to the costs over time because batteries need to be replaced “regularly”.
- On-the-grid solar systems offer you the best of both worlds. You can have your system sized so that your 12 month average electrical bill next to nothing, but still have the flexibility to at any time draw more than your solar array is producing without having to do a thing.
Grid-connected PV systems are typically sized to eliminate part of your electric bill because of the higher upfront costs associated with purchasing a larger system. However, larger systems will cost less per kilowatt-hour generated due to the economies of scale associated with manufacturing processes. The utilities have adopted a rate structure that increases the cost of electricity as you use more of it. Many people choose a system that will only eliminate the most expensive electricity. This increases the return on your investment.
The number of companies offering solar equipment is rapidly increasing. Each solar professional you speak with will have certain products they recommend, and they usually have very convincing reasons for recommending those products. This can make it a challenge for consumers to know whose opinion to trust, and which products are truly the best.
So how do you choose? As with any major purchase, you will want to do your homework. With all the focus on renewable energy, it is easier than ever to get reliable information on manufacturers and specific technologies, but this can also leave you with an overwhelming pile of information to sort through.
Our best suggestion is to find a solar professional you trust, and allow them to guide you through the ever-changing maze of renewable technology. Because renewables are a major investment, it is always a good idea to talk with someone professional and experience to be sure you are receiving information that is accurate, pertinent and complete.
Once you have recommendations on products to choose, you can also do some research online to see what others are saying about those products. Check out each manufacturer’s website or give them a call. Check out one of the many industry blogs, the Better Business Bureau (BBB), and industry publications. (Remember, the manufacturer will naturally tell you the best about their products, so don’t rely solely on the information they provide to make your decision.) Because of the increased demand for renewable, third party testing agencies such as Consumer Reports are also starting to offer consumers with quality information.
From our experience, here are some things you’ll want to consider as you’re shopping for products and choosing brands:
How long has the manufacturer been making renewable energy products?
There are a plethora of new companies getting into the industry, and we have found many of them use “the new math” when they calculate their industry experience. Don’t just take their word for it – ask around to find out if they really know what it takes to make good products.
What is the track record of their products?
Ask around about a manufacturer’s reputation and about how their products perform in the field. You can find online sources for this information, or you can talk with consumers who are using their products. Main Street Solar can help you find end-users to talk with you about the products you are considering.
Is it proven technology, or will you be “field testing” something new?
We get calls all the time with people asking about the latest and greatest products available on the market. Though there are many new and exciting renewable energy products being introduced, we prefer to take a somewhat cautious approach when considering something we haven’t tried before.
So first we look at who is introducing the product. We are much more confident when trying out something new from the industry leaders like OutBack Power, SMA, Xantrex, Sharp Solar or BP Solar, than we are about trying something from XYZ Company, who we have never hear of. It doesn’t mean XYZ’s product isn’t good, it just means that we don’t have history with them to rely on. We know that OutBack, etc., will be there should their product not perform as they’ve expected, and we know they will make it right. We don’t know if XYZ Company will.
Another reason we are cautious is because sometimes a new technology has insufficient field performance data for us to be confident recommending it.
Another thought about new renewable energy technology: It often seems that the marketing and sales folks get all excited and start talking about new products that are either in the early stages of research and development and/or far from actual production. The most common one we hear about is new solar panel technology that will cost almost nothing and make gigawatts of power. So far, (unfortunately) none of those products have actually shown up in the market.
Is it the right product to do the job?
Sometimes you may hear of a couple of different products that have proven track records and that are made by reputable companies. So how do you know which one is right? Obviously the first consideration is whether or not they will do the job you need them to do. Again our best recommendation is to talk with the professionals, or at least chat with folks who are using the different products, to get their thoughts on the subject. Assuming each of the solar products you’re considering will do the job, then it naturally comes down to practical details such as price, warranty, and extra features.
Which products does your solar contractor use at their home and/or business?
This is a great question to ask. It not only tells you something about the products, but also helps you determine if your solar professional has practical experience with the products they sell.
The most common reason people install a solar grid tie system is to reduce their utility bills. Once your system is operating the power it provides is free. There is little or no maintenance required. While it runs, your PV system reduces your electrical bills. It decreases how much power you pull from your utility, but also because any excess power you produce is pushed back into the grid (net metering) effectively turning your meter backwards. Eventually your PV system will pay for itself, and your energy savings will continue long after.
In addition to what you save on your electric bill, having a grid tie system raises the value of your property. Solar also makes a home more attractive to potential buyers, particularly when compared to an otherwise identical home. This can make a big difference should you decide to sell your home in a tight real estate market.
Another great incentive for installing solar is that the Federal government, and many states and local utilities, offer rebates, tax credits, low interest loans and other incentives for adding solar power.
And of course, solar energy is a clean source of power. It reduces dependence on fossil fuels in a practical and effective way, and helps protect our environment.
System Payback. Payback is usually used to describe the time it takes for an investment to pay for itself, similar to Return On Investment. However, the basic assumption behind a payback calculation is that this is a discretionary expenditure, I can choose to invest in this energy equipment, or not, and if I don’t, I can put that amount of money in the bank and with no risk, make some interest.
Paying an electric bill is not a ‘discretionary’ expense for most people; they have no choice! By buying a solar electric system you are taking money that you would be “giving” to your electric utility and investing it in your home.
A residential grid-tie system in Virginia will typically pay for itself between 8 to 13 years (site specific). Considering that solar panels come with a 25-year warranty, and have a 30-50 year design life (depending on manufacture), that basically means that after the first 13 years they’ve paid for themselves. They then go on to generate ‘free power’ for the next 20 to 40 years. That’s 30 years of positive cash flow, money in your pocket in the form of avoiding electric bills. In addition to your reduced power bills, a home solar panel system increases the value of your home with out adding additional tax value.
Off-Grid System
If you are considering the off-grid lifestyle, you first need to fully understand your own power use habits, as well as exactly how an off-grid system works. To live off-grid you will likely need to make adjustments to when and how you use electricity so you can live within the limitations of your system’s design, and to keep the system cost reasonable. This doesn’t necessarily imply doing without, but rather a shift to a more conscientious use of electricity.
When designing an off-grid system it is critical that electricity consumption be determined for everything in your home or business, and to calculate for those cold, dark winter days and nights when energy consumption is at its peak and power production is at its minimum. Main Street Solar recommends taking energy conservation measures first, such as installing fluorescent or LED lighting and energy efficient appliances, before investing in an off-the-grid system. (Please go to our Energy Efficiency section for more detailed information on this subject.)
We also recommend that before you choose an off-grid lifestyle you talk with a few folks who are already doing it. This will give you practical information that you may not come across in your other research. We can also get you in touch with others living off-the-grid, and you may also be able to find some folks through local organizations that support renewable energy and green living.
Another great resource for seeing off-grid or on-grid solar systems that are actually in use is to attend the National Solar Tour in your area. The Solar Tour is organized by the American Solar Energy Society (ASES) and its member groups, such as Solar Virginia. The main tour is held the first Saturday of October all across the country, but in some areas tours are held at different times of the year. The Solar Tour is designed so that people just like you can visit homes and businesses in your area where renewable energy and other green living products and practices are in place. It is a wonderful opportunity to talk with end-users about the ins and outs, ups and downs, and all arounds of what they’re doing. For more information about the National Solar Tour please give us a call, or visit the ASES website at www.ases.org.
Remote homes and cabins, water pumping systems, livestock watering, telecommunications, RV’s, boats, sign lighting and traffic warning lights are just some of the places off grid solar and renewable energy are utilized.
From here on we will focus on off-grid solar, but keep in mind that the process of determining how much power you will need to produce and store in an off-grid application is basically the same no matter what renewable energy technology you choose. The main difference between types of RE technology is what size and how much equipment you’ll need. To answer those questions we recommend you give us a call, and we can help you determine exactly which products will make your off-grid life simple and comfortable.
Determining how much power your solar PV system needs to produce for off-the-grid living is similar to sizing a grid-tie solar system, except that there is no utility bill to refer to for historic usage. So the first step is to make a list of all the items you plan to power in your off-grid home. Just remember that the more power you use, the more you will need to produce.
To be very accurate, you can refer to the label on each appliance or piece of equipment, and then estimate the amount of time you will using them each day, then do some math. For some items it is reasonable to use a guesstimate, but for those that have higher power consumption we suggest actual ratings for off-grid calculations.
The simplest way though, is to let us help you. We can save you time and ensure you have accurate information on which to base your PV array sizing, As with any questions you may have about using renewable energy, feel free to give us a call at 540-860-8036 or contact us via our request a quote form.
The number of solar panels you need, how you want to mount them, how many batteries you need, and how far you need to run wiring are just some of the many factors that will affect the overall cost of your off-grid system.
At Main Street Solar we work hard to provide all the information and help you will need to select a renewable energy solution that gives you the best overall value for your investment. That means we don’t just look at the price of an item, though of course that is an important consideration. But sometimes the upfront cost of a piece of equipment makes it seem like a good deal, but when you look more closely – at quality, dependability, efficiency and life expectancy – you may find it is better to pay a little bit more up front because over time it will save you money.
Solar panels absorb solar energy from the sun and convert it to DC power. Your power consumption, as well as your geographic location, affects the type and quantity of panels you will need. Because each solar panel only produces a small amount of energy, most solar electric systems consist of multiple solar panels interconnected together in “strings.” This is called a PV (photovoltaic) or solar array.
Off-grid solar, will allow you to live independent from utility power, and/or off the beaten path. A well designed off-grid system also has an environmental advantage, helping you reduce your carbon footprint.
It is generally not cost effective or feasible to install a renewable energy system large enough to provide power for things like electric heat, air-conditioning, electric cooking or electric hot water. Geothermal, solar hot water, and of course, gas appliances, are just some of the alternatives available that will allow you to maintain a comfortable lifestyle without relying on utility power.
Now that you understand the purpose, benefits and limitations of going off-the-grid, let’s take a look at how to actually do it.
The Federal government, some cities and counties and many local utilities offer incentive programs. For more information on incentives available in your area, call Main Street Solar, or visit the Database of State Incentives for Renewable Energy (DSIRE) website at www.dsire.org.
Once you know how much power you use, you can proceed to sizing your solar PV system. In an off-grid application it is critical the system is properly sized, because you will not have utility power to draw from if your RE system does not provide enough to meet demand. That is why we recommend getting expert professional help sizing your off-grid system, so you can be sure that you have all the power you will need.
Solar panel mounts are important to maximize production, provide proper directional and latitudinal orientation, and to provide the stability needed to protect your investment from the force of the wind. Solar panels can be mounted on the roof, ground, or on a pole.
A solar tracker is a device for orienting a solar panel or solar array toward the sun. Solar trackers increase morning and afternoon exposure, which at the right latitudes and in the right climates can substantially improve the amount of power produced by your system.
The number of companies offering solar equipment is rapidly increasing. And each solar professional you speak with will have certain products they recommend, and they usually have very convincing reasons for recommending those products. This can make it a challenge for consumers to know whose opinion to trust, and which products are truly the best.
So how do you choose? As with any major purchase, you will want to do your homework. With all the focus on renewable energy, it is easier than ever to get reliable information on manufacturers and specific technologies, but this can also leave you with an overwhelming pile of information to sort through.
Our best suggestion is to let Main Street Solar, Virginia’s most trusted solar installation team, guide you through the ever-changing maze of renewable technology. Because renewables are a major investment, it is always a good idea to use a solar professional.
Once you have recommendations on products, you can also do some research online to see what others are saying about those products. Check out each manufacturer’s website or give them a call. Check out one of the many industry blogs, the Better Business Bureau (BBB), and industry publications. (Remember, the manufacturer will naturally tell you the best about their products, so don’t rely solely on the information they provide to make your decision.) Because of the increased demand for renewables, third party testing agencies such as Consumer Reports are also starting to offer consumers with quality information.
In our opinion, here are some things you’ll want to consider as you’re shopping for products and choosing brands:
How long has the manufacturer been making renewable energy products?
There are a plethora of new companies getting into the industry, and we have found many of them use “the new math” when they calculate their industry experience. Don’t just take their word for it – ask around to find out if they really know what it takes to make good products.
What is the track record of their products?
Ask around about a manufacturer’s reputation and about how their products perform in the field. You can find online sources for this information, or you can talk with consumers who are using their products. Main Street Solar can help you find end-users to talk with about the products you are considering.
Is it proven technology, or will you be “field testing” something new?
We get calls all the time from people asking about the latest and greatest products available. And though there are many new and exciting renewable energy products being introduced into the market, we prefer to take a somewhat cautious approach when considering something we haven’t tried before.
So first we look at who is introducing the product. We are much more confident when trying out something new from the industry leaders like OutBack Power, SMA, Xantrex, Sharp Solar or BP Solar, than we are about trying something from XYZ Company, who we have never heard of. It doesn’t mean XYZ’s product isn’t good, it just means that we don’t have history with them to rely on. We know that OutBack, etc., will be there should their product not perform as they’ve expected, and we know they will make it right. We don’t know if XYZ Company will.
Another reason we are cautious is because sometimes a technology is so new there is insufficient field performance data for us to be confident recommending it.
Another thought about new renewable energy technology: It often seems that the marketing and sales folks get all excited and start talking about new products that are only in the early stages of research and development and/or that are far from actual production. The most common one we hear about is new solar panel technology that will cost almost nothing and make gigawatts of power. So far, (unfortunately) none of those products have actually shown up in the market.
Is it the right product to do the job?
Sometimes you may hear of a couple of different products that have proven track records and that are made by reputable companies. So how do you know which one is right? Obviously the first consideration is whether or not they will do the job you need them to do. Again our best recommendation is to give us a call. Our job is to give you accurate, dependable information to base your decision on. If we don’t have the answers, we will help you find them. The assuming each of the solar products you’re considering will do the job, it naturally comes down practical details such as price, warranty, and extra features.
Which products is your solar contractor using at their home and/or business?
This is a great question to ask. It not only tells you something about the products, but also helps you determine if your solar professional has practical experience with the products they sell.
There are many reasons to be off-the-grid, but typically off-grid (stand alone) solar electric systems are used in remote locations where connecting to the local utility grid is impossible or prohibitively expensive, in areas where grid power is inconsistent, or due to the appeal of an independent lifestyle. With an off-the-grid system, solar panels, a small wind turbine, a micro-hydro system, or a combination of these technologies and others, is used to supply all of the power a cabin, home or business needs. In some off-grid systems a home backup generator may also be included, to supply power when the renewable technologies can’t produce enough to meet demand.
Off-grid living completely relieves you of dependency on the electrical utility, because the system provides all of your power. Due to this, off-grid systems are generally larger than grid-ties. To be fully independent, a system must have a larger wind generator or array of solar panels, and greater battery storage capacity than in applications where grid power is available. However, if done properly, living off-the-grid can save you thousands of dollars over the life of the system.