A grid tie solar electric system – also referred to as grid-tied or utility intertie photovoltaic (PV) – uses solar panels, a power inverter and other components to turn sunlight into electricity for your use, while your home remains hooked up to the local utility. This is different from an off-grid or stand alone solar system, where your structure is not hooked up to utility power.
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.
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.
- 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.
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.
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 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 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.
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.
There is a lot to consider before investing in renewable energy, and we hope the information here provides the help you need to feel comfortable when making your decision. But more than likely you will still have some questions, and we welcome the opportunity to help you find the answers you need.