Solar Energy refers to electricity and heat generated from sunlight, and includes Photovoltaic (PV) systems and Solar Thermal.
Solar Photovoltaic (PV) The most widespread application of solar power is in the form of photovoltaic, or PV, panels, which can be seen on roofs and arrays around the world, takes the suns energy. The suns’ energy creates an electrical charge in the silicon-based solar cells in the PV panel, creating electricity that powers homes, businesses or whole communities.Residential or commercial PV panels are typically tied into a house or building’s electrical supply in an arrangement called net metering, which feeds any excess power generated back to the local utilities — actually running the solar panel owner’s electric meter backwards. See all Solar PV Members
Solar PV History and Usage
Solar PV was first discovered in 1952 by scientists at Bell Labs, and saw a first wave of investment, development, and installation during the 1970′s energy crisis. With the long-term costs of fossil fuels now widely recognized, PV is being seen as a go-to solution for commercial and residential power needs.
A highly flexible form of renewable energy, solar PV grew 53 percent worldwide from 2008-9, ending 2009 with approximately 20 Gigawatts of capacity installed. With technological advances, economies of scale and feed-in tariffs, PV efficiencies and costs have become increasingly competitive. Meanwhile, researchers are exploring applications beyond domestic and commercial power. Alternatives to silicon are being pursued, producing flexible solar panels that can be used on backpacks, cars, planes, boats, even highways.
Solar Thermal Solar Thermal technologies capture the sun’s energy in the form of heat. The two most common applications are residential hot water systems, and much larger utility-scale high-temperature collectors. Residential systems can be seen on roofs around Vermont. Generally consisting of a collector, a liquid medium, and a holding tank, these systems rely on the sun’s energy to heat the liquid medium, which in turn heats water, supplementing or supplying the hot water needs of the building. See all Solar Thermal Members
Solar Thermal History and Usage
Worldwide, solar thermal hot water heaters reached 180 Gigawatts of thermal capacity by the end of 2009. Utility-scale solar thermal projects, called concentrating solar thermal power, typically take the form of an array of reflectors that concentrate the sun’s energy onto a liquid medium. The resulting super heated liquid is used to generate electricity though a variety of project-specific methods, including steam engines, heat engines, or pumping water uphill for hydro power generation.
Solar PV and Thermal in Vermont
Here in Vermont, solar PV and hot water comprise the fastest growing form of renewable energy, and there are many in-state incentives, including the recently passed Vermont Energy Act of 2011, that make these technologies more affordable than ever. PV is proving to be an adaptable and easy-to implement power solution for Vermont homeowners and businesses, with several international solar PV companies basing their operations and technical innovations on PV usage right in the state.
Read more about how easy it is to go solar with the Vermont Solar Consumer Guide, below.
Utility PV projects are being undertaken by utilities like Green Mountain Power. Many more projects are slated to come online in 2011, while robust, precedent-setting Vermont incentives like the “Standard Offer Program” are opening the door for increased utility-scale PV. Given our severe, cold winters, Solar Thermal is quickly expanding as the primary way to heat water without relying exclusively on heating oil, and installations can be seen on homes, apartment complexes and larger buildings throughout the state.
Vermont Solar Consumer Guide
Now that you’ve learned about solar technology, take a look at how easy, and affordable, it is to go solar in Vermont. Follow the links below to our Vermont Solar Consumer Guides on Solar Photovoltaic and Solar Hot Water. In each of our Guides, we break the installation process and costs down into simple, understandable steps. Check it out and see how you can eliminate or reduce electric and hot water bills, protect yourself from rising energy costs, and lock in monthly payments that make sense.
Learn More About Solar:
- Download REV’s Solar Energy Educational Factsheet (pdf)
- Union of Concerned Scientists Solar Energy page
- Assess your solar energy potential at the Vermont Renewable Energy Atlas
- US Department of Energy, Energy Efficiency and Renewable Energy
- Find a REV Partner installer, or find out how to become a REV Partner installer at our Partnership Program Page.
- How do I know if I have enough sunlight for PV?
- How big a solar energy system do I need?
- How much energy savings can I expect?
- What is the average time before my system pays for itself, and begins to save me money?
- How does net metering work?
- Why should I make my project net metered?
- I’ve heard solar power is highly subsidized. How can solar ever become competitive compared to fossil fuels?
- What are the incentives I can take advantage of to offset the costs of installation?
- Where can I find a reliable installer?
- Where can I find out more about becoming a Partnership Program installer?
- What are the benefits of using solar energy to heat water in my home?
- Can a solar water heater replace an electric or gas water heater?
- How much does a solar water-heating system cost?
- How much money will a solar water-heating system save on my utility bill?
A photovoltaic (PV) system needs unobstructed access to the sun’s rays for most or all of the day. Climate is not really a concern, because PV systems are relatively unaffected by severe weather. In fact, some PV modules actually work better in colder weather. Most PV modules are angled to catch the sun’s rays, so any snow that collects on them usually melts quickly. Therefore, there is enough sunlight to make solar energy systems useful and effective nearly everywhere in the United States. U.S. Department of Energy
The size of solar system you need depends on several factors, such as how much electricity or hot water or space heat you use, how much sunshine is available where you are, the size of your roof, and how much you’re willing to invest. You can contact a system designer/installer like those listed in our PV Directory or other solar industry directories to determine what type of system would suit your needs. And remember: an energy-efficient building requires a smaller system. U.S. Department of Energy
Checking the Vermont Renewable Energy Atlas and contacting a REV member specializing in residential-scale installation work is a great place to begin assessing the potential for solar power at your site, and what size system might fit your needs.
Unfortunately, there is no single or simple answer. But a solar rebate and other incentives can reduce the cost of a PV system. This cost depends on a number of factors, such as whether it is a stand-alone system or is integrated into the building design, the size of the system, and the particular system manufacturer, retailer, and installer. For solar water heaters and space heaters, you also have to consider the price of the fuel used to back up the system. In most cases, you would have to add the cost of natural gas or electricity to get a more accurate estimate of how much you can expect to pay for a solar energy system.
It is also difficult to say how much you will save with a solar energy system, because savings depend on how much you pay your utility for electricity or natural gas, and how much your utility will pay you for any excess power that you generate with your solar system. You can ask your solar system provider how much your new system will produce on an annual basis and compare that number to your annual electricity or hot water demand to get an idea of how much you will save. U.S. Department of Energy
It depends. The break-even point for a system depends on financing and incentives, which vary from place to place, and it depends on your solar resources and what you would pay for another source of energy and energy inflation over time. A system designer who has information about your location, the amount of energy you typically use, how much land or roof area you have for the system, etc., could give you a more accurate answer. You can obtain a very good estimate by contacting a reputable REV member system designer or installer. U.S. Department of Energy
Net metering is a policy that allows homeowners to receive the full retail value for the electricity that their solar energy system produces. The term net metering refers to the method of accounting for the photovoltaic (PV) system’s electricity production. Net metering allows homeowners with PV systems to use any excess electricity they produce to offset their electric bill. As the homeowner’s PV system produces electricity, the kilowatts are first used for any electric appliances in the home. If the PV system produces more electricity than the homeowner needs, the extra kilowatts are fed into the utility grid. U.S. Department of Energy
Net metering allows homeowners to receive the full retail value for the electricity that their solar energy system produces. Off-grid systems can provide a solution to generating energy in remote locations without the expense of bringing in power lines. However, the savings on power lines should be balanced against the cost of battery storage systems that must be installed to store what energy is not used directly by the household’s wind installation. With net metering the energy produced is fed into the gird, and paid for against the utility bill. Additionally, several incentives and rebates require the solar system to be net metered. Learn more about net metering here.
I’ve heard solar power is highly subsidized. How can solar ever become competitive compared to fossil fuels?
The cost of producing PV modules, in constant dollars, has fallen from as much as $50 per peak watt in 1980 to as little as $3 per peak watt today. This causes PV electricity costs to drop 15¢-25¢ per kilowatt hour (kWh), which is competitive in many applications.
In the California market, where state incentives and net metering are in place, PV electricity prices are dipping below 11¢/kWh, on par with some utility-delivered power. Moreover, according to the U.S. PV Industry Roadmap, solar electricity will continue this trend and become competitive in the near future for most domestic markets.
The energy payback period is also dropping rapidly. For example, it takes today’s typical crystalline silicon module about four years to generate more energy than went into making the module in the first place. The next generation of silicon modules, which will employ a different grade of silicon and use thinner layers of semiconductor material, will have an energy payback of about two years. And thin-film modules will soon bring the payback down to one year or less. This means that these modules will produce “free” and clean energy for the remaining 29 years of their expected life. U.S. Department of Energy
There are several federal, and state tax credits and/or rebates offered for solar PV and Thermal, depending on the application, and if it is residential or commercial. Please see our Incentives page for more information and links to online resources,
Full Solar Partner installers accredited through REV’s Partnership Program must meet a standard of performance and experience, as shown through a variety of criteria. REV does not endorse these installers, but their workmanship has been reviewed, approved, and they have access to the Vermont Small Scale Renewable Energy Incentive Program, making them a good place to start. As with any type of contractor, recommendations and proof of experience should be verified independently before engaging in a solar system installation.
Please see our Partnership Program page for criteria and application forms.
First, the fuel is free! Once you recover the higher initial costs of a solar system through reduced or avoided energy costs (that is, lower utility bills), your solar system will require expenditures only for maintenance. And when you include the cost of a solar water heater in a mortgage on a new home, the system often provides a positive monthly cash flow from the first day of ownership.
Second, solar water heaters and other solar technology applications do not pollute. They do not add to the carbon dioxide, nitrogen oxides, sulfur dioxide, and other air pollutants and wastes produced by most of today’s power plants, even those that run on natural gas. And they allow you to burn less natural gas in your home, as well. U.S. Department of Energy
Not completely. Conventional electric or gas water heating systems are still necessary as a supplement to the solar water heating system, largely because the sun might not shine in a particular area for several days at a time. However, because solar water heaters are designed provide hot water directly to the tank of a gas or electric water heater, they reduce the need for the water heater to run on conventional fuels. And this in turn reduces your gas or electric bill. Depending on where you live, solar water heaters can provide up to 80 percent of your home’s annual water-heating needs. U.S. Department of Energy
Solar water heating technology is effective regardless of the outside temperature. In colder climates, more energy is required to heat cold incoming, municipal ground water, so using solar energy in such conditions could dramatically lower a consumer’s utility bills. In addition, colder incoming, municipal ground water helps solar water heaters to operate at higher efficiencies. U.S. Department of Energy
While there aren’t any pre-engineered residential solar space heating systems available on the market, solar energy professionals could engineer a system for you. However, these types of systems are considerably more expensive “stand-alone” water-heating systems and, depending on the size of the heated space, could range from $15,000 to $20,000. A solar energy professional in your area can help you understand what would be involved in this type of solar system purchase. These systems tend to work best when tied into a radiant type slab heating system that has lower (more efficient) temperature requirements than, say, forced hot water systems that can approach 170F temps. U.S. Department of Energy
Unfortunately, there is no one answer to this question. The cost of a solar system depends on a number of factors, such as the size of the system and the particular system manufacturer, retailer and installer. However, any solar rebates and other incentives available in your area will reduce that total cost, often by 30-50 percent. For solar water heaters and space heaters, you will also be taking into consideration the price of the fuel used to back up the system. In most cases, you will have to add in the cost of supplemental natural gas or electricity to get a fairly accurate estimate of how much you can expect to pay for a solar system. Installed costs vary widely, from $8,000 to $12,000, before rebates/credits. Some homebuilders are beginning to list solar water heaters as an option for their homes. Others include them as a standard feature in every home. In some cases, the builder or mortgage company may offer a lower interest rate when solar water heaters or other energy-efficient features are built into a new home, because the buyer can expect to save a significant amount of money on future energy bills. Although a solar water-heating system still costs more initially than a conventional electric or gas water heater, some states and utilities offer rebates that can reduce the total cost appreciably. U.S. Department of Energy
It is difficult to say how much you will save with a solar system. That depends on several factors, including how much you already pay your local utility for electricity or natural gas. You can ask your solar system professional how much heat your new system will produce on an annual basis and then subtract that number from your current annual consumption—the total amount of electricity and gas you use—to get an idea of how much you will save. Data on your current annual consumption should be available from your utility. U.S. Department of Energy