Net metering is a terrific advantage of having a solar energy system. For those without a solar energy technology background, net metering is when you provide excess power to energy companies for use on their grids. For example, if your home or business produces more energy than consumed, that excess energy is sold back to your local utility providing you with decreased electric bills or, in some cases, even a refund.

There are currently no national standards for net metering, but Maryland solar experts can tell you the state’s standards are at that top of the table.  Any of our energy auditors can easily explain your available options depending on where you live and any local regulations. Once you have a net metering monitor installed with your solar energy system, it’s almost as simple as “set it, and forget it!”  Your metering system will monitor your daily consumption use, and compare it toward your daily energy production while keeping a record of the differences. It will also track the date and times of your energy use and any spikes or drops.

The benefit of tracking this information allows utilities, and yourself, to develop the best energy rates. Solar energy systems will naturally produce more energy and power during daytime hours while the sun is out, which also coincides with the highest demand times for energy. If your system produces more energy than you need during that time, you can “sell” that excess energy at a premium rate since energy demand is high. At night time, when demand is low and your system isn’t producing as much energy, you are then “buying” electric at a decreased amount since demand is normally lower. Net metering provides for a simple way to monitor your rate exchange with your utility company.

The US Energy Policy Act of 2006 requires utilities to provide each residential and commercial end energy user with net metering. This dramatically helps to streamline opportunities to work with your local utility and ultimately provide you with the cheapest energy in today’s market.

The tied inverter can take the DC energy and convert it into electricity that is phased matched. The local solar energy system is also phase matched allowing for electricity to be interchanged when needed.

A grid tied system works in conjunction with the existing grid.  In the most simplest terms pulling energy from the grid when needed and supplying energy to the grid when energy is not being used at the solar site.

Post written by: David Zamostny, Solar Energy World Intern

Grid tie inverters – are used to convert DC energy into alternating energy used to power businesses and homes. Once loss of utility supply occurs, grid tie inverters shut down automatically for safety reasons and do not provide backup during power outages.

Battery back-up inverters – special inverters designed to draw energy from a battery and export excess energy to the utility grid. These inverters can supply AC energy during a utility outage, and are required to have anti-islanding protection.

Solar micro inverters – convert DC energy from a single panel the AC energy. The energy from all of these panels can be combined and sent to the specific consuming devices. This allows for each inverter to separately monitor its own panel. This makes it easier to add components to the system rather than add one panel and changing the characteristics of the whole system.

Stand-alone inverters – normally used in isolated systems, stand-alone inverters draw DC energy from batteries that are powered by a solar array. Typically, these inverters are not tied into a system and don’t require anti-islanding protection.

Anti-islanding – the process that prevents circuits from remaining powered after all power is cut off from the grid source.

How do I know I am getting maximum production from my system?

Maximum power point tracking is a technique that is used by inverters to get the maximum output from the photovoltaic array. The inverters will sample the output of the photovoltaic array and apply a resistance load to obtain the maximum power for any specific environmental conditions in order to achieve maximum possible power.

Post written by: David Zamostny, Solar Energy World Intern

Photovoltaics can involve a single cell however this is typically not the case, since a single cell cannot produce enough power. Generally the cells are electrically connected to form photovoltaic modules, or as we know them, solar energy panels.

Photovoltaic Effect – this involves the creation of voltage when a specific material is exposed to light. In this process, generated electrons bounce between different bands in the material causing a buildup of voltage (the junction of two substances exposed to light). This effect first observed by Alexandre-Edmond Becquerel.

Initially photovoltaics were used to power satellites and space stations orbiting in space, recently the majority is used for grid connected power generation for homes and businesses. With the development and implementation of electric cars, photovoltaics technologies continue to expand.

While there are many positives there are a few negatives. These would include cost and the fact that photovoltaics produce only DC current that must be converted. Secondly, current cannot be produced at night or when it is significantly cloudy. Solar power is also dependent on the limited power density of a locations insolation, a topic discussed in an earlier blog post.

Post written by: David Zamostny, Solar Energy World Intern

Commercially, solar power made its debut in the late 1800’s. After black boxes started dotting the rooftops of Baltimore, Charles Kemp patented the first solar water heating system. The original systems were basic: the back boxes held water that were heated throughout the day. Kemp combined this style with the scientific principle of a hot box and the Climax was born.

Known as the simple batch system, the Climax cost $25 and would save homeowners around $9 a year. Sales to wealthier Marylanders supported the business originally, but Kemp would later move to the sun-rich grounds of California. By 1900, the Kemp had sold over 1,600 systems.

By 1909, William Bailey transformed the solar heating system, fixing one of the major flaws of the Climax. Since Kemp’s system was entirely housed outside, it meant hot water was only possible during sunlight. The water would cool off as soon as the sun sank below the horizon.

Called the Day and Night, William Bailey invented and patented a thermosyphon system, which kept the heating component outside to reach the sun, but stored the heated water inside so it would retain heat. Bailey also targeted sunny California to sell his solar energy system, and soon put Kemp out of business. The Day and Night sold over 4000 units from 1909 through 1918.

As production of the solar thermosyphon system prospered during the 1920’s, economics soon made the solar heat irrelevant. With the discovery of large amounts of natural gas in California, the cost to heat water plummeted and solar energy systems could no longer compete for business. Bailey did invent a gas version of the Day and Night that flourished in Florida, but the mass production of electricity made the new system obsolete as well.

Today, the tides have changed. While solar energy is still requires an upfront investment, new technology, financial incentives, and the increasing cost of oil make solar once again a financially viable option (see how much you can save with our Solar Savings Calculator).

The first of these variables involves calculating how much power in watts your household uses on a daily basis. Using your electrical bill and/or a kWh (watt-hours) load tool you can calculate total watts you use per day or month.

The next step would be to calculate the amount of useable sunlight in your area or insolation, when your solar panels will produce their rated voltage. This can be done using a solar calculator to find the tilt and size of a suitable system, and total hours of usable energy or you can use solar insolation table to determine the average hours of sunlight.

Determining the size of the system

To then calculate the size of the system in kW (kilowatts), divide watts-hours by your insolation value. In order to account for average energy losses and inefficiencies you can increase this number by 30%. This will give you the size of the solar energy system needed in kilowatts.

What type of solar panel is right for me?

This all depends on how much energy you need to produce and how much space you have. It is possible to have one bigger solar panel that produces the same watts-hours as six smaller ones. It is also possible that one type of solar panel is more aesthetically pleasing than another. This may be the case with the new SunPower solar panels.

The best way to determine how many solar panels you need would be to have a professional come to your property to survey the proposed area. This is done as part of a solar assessment.  During the solar assessment, you’ll discover all the financial benefits that come along with solar too.

Photovoltaic effect

The photovoltaic effect is the basic physical process through which a photovoltaic cell converts sunlight into electricity. Sunlight is composed of photons which are packets of solar energy. These photons contain different amounts of energy that correspond to the different wavelengths of the solar spectrum. When photons strike a photovoltaic cell, they may be reflected or absorbed, or they may pass right through. The absorbed photons generate electricity.

Post written by:  David Zamostny, Solar Energy World Intern

To be truly off the grid, your home would be completely independent of public utilities and would not be impacted by outages. You have the option to choose a system that will lessen your dependence in varying degrees. It should be noted that if power goes out – for safety reasons – your solar system will automatically shut off.

Solar energy can help America become more independent of international fossil fuels. Because solar energy is generated locally, once the initial installation is complete, there is minimal upkeep and you’ll be freed of the rising cost of public energy companies. Living off the grid can also trickle into other areas of your life; you learn to only use what you’re producing, and no more.

One of the greatest perks of solar energy is being energy independent and not relying on public utilities – or paying into them.

You’ll want to contact your energy company to determine your average kilowatt hour usage for the past year.  Once you have this information, it helps in choosing a solar system that will eliminate your energy usage.

Once we’ve provided you with a free cost/benefit analysis and you’re ready to move forward, we’ll send our technician to your home to confirm the measurements and energy savings.

We understand that all of the rebates and incentives can be confusing, so we’ll complete the tax credit and rebate paperwork to ensure that you’re getting all the financial support that is available.

The installation is usually complete within 2-3 days depending on the size of your system.  Once your system is installed, we set up the final inspection with the appropriate municipality and/or utility company.  Then we make sure you’re connected to the grid so you can start receiving the rewards for going solar.

We’ll complete the final paperwork for the appropriate Renewable Energy Credits (SRECs) so you’ll start seeing savings and earnings immediately!

You can easily calculate the ROI of your solar panel system. Here’s the formula we use when we do a solar analysis:

Average Monthly Solar Savings / Net Investment (cost after tax credits, grants and SRECs)

In other words, we figure out how much you save on your electricity bill each year, and compare that to what you actually have to spend to install a system. Compare that with any other investment you might make. When the stock market is good, we’re usually happy to be earning more than 10 or 20 percent return. When the stock market is bad, we hope we’re not losing money, and that we can get a modest 3 – 5 percent return.

An average solar panel system, though, provides an average return of twenty-eight percent! And that’s only after 3 – 5 years!

Here is a great return on investment comparison from SunPower:

* Solar ROI based on 3kW system in San Jose, CA with a $265 monthly electricity bill
**  Traditional investment returns based on average nominal returns between November 1983 and November 2008