FAQ: How do I compare a proposal from Solaflect with one from another solar installer?

The tradition in the solar industry is to compare system costs according to their “cost per watt” of capacity. “Capacity” is the ability of the solar panels to produce a certain amount of electricity when exposed to light. More specifically, it is a measure of how much electricity the panels will create when they are at a specific temperature and are exposed to light of a specific intensity. For example, a solar array rated at 4 kilowatts (kW) will produce 4 kW of direct current electricity under standardized conditions. The amount of electricity created by the panels will vary if the temperature or intensity of light change. Read more

FAQ: What is net metering? How does it work?

Net metering is a system of accounting on your electric bill to give you credit for the solar energy your system generates. The specifics can vary from state to state and from utility to utility.

Basic net metering works like this. First, think of a home that does not have a solar array. It gets all of its electricity from the utility. Whenever an electric device is on in the house, electricity is pulled in from the utility grid. The utility meter measures how much electricity is passed into the house. For each kWh passed into the house over the course of the month, the utility will charge a certain cost. Read more

FAQ: Will a Solaflect PV Tracker zero out my electric bill?

A Solaflect PV Tracker will produce a certain amount of electricity, based on its capacity (4 kW) [update: beginning Summer 2016, the Tracker has an increased capacity of 4.24 kW], how open the view of the sky is at its location, the time of year, and the weather during the billing period. We offer free site visits to assess the conditions at your property, including measurement of “solar access,” the term for how much of the sky the Tracker can see without trees, buildings, ridge lines, etc., in the way. A Tracker will be more productive in late spring and summer months when the days are longer, and less productive in late fall and winter months when days are shorter. (See “How does solar production vary over the year?“) As for weather, the sunniness or cloudiness of any particular month or year varies, and may change by 5% or 10% from year to year. Whenever we estimate production, we base that on the average conditions over the long term. Read more

FAQ: Will I get backup power from my Tracker if the utility grid is down?

Solaflect installs standard grid-connected systems. You will not get power from it when the utility grid is down. This is a National Electric Code safety feature built into the inverters. The inverter senses if the grid is operating normally. The moment the grid goes down, the inverter stops solar power from flowing through it. This is to prevent power backflowing into the grid where it might harm line crews that are fixing the grid.

For those who would like a degree of solar backup power when the grid is down, we offer an upgrade option to the SolarEdge StorEdge inverter. This inverter is fully compatible with the Tesla Powerwall battery system. We do not currently offer the Powerwall batteries directly, however with the StorEdge upgrade your Tracker system will be ready to “plug and play” with the Powerwall when it becomes more readily available.


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FAQ: What is Group Net Metering?

Group net metering means that more than one account with the utility can share the benefit of a single solar array. The specifics of how group net metering work depend on the laws and regulations of the state.

In Vermont, utilities are required to allow customers to use group net metering. All of the customers and the solar array have to be connected to the same utility. How the credit from the array is shared depends on specifics of the group arrangement. Read more

FAQ: What about future advances in solar technology?

Standard solar modules, which are based on crystal silicon, are 15-20% efficient. That means that 15-20% of the energy in the sunlight that lands on them is converted into electrical energy. The most efficient crystal silicon PV cell in the laboratory has achieved 25% efficiency. That record has hardly changed in the past 20 years. While manufacturing techniques have improved so that commercially available modules approach the laboratory maximum, and simultaneously lower costs, there is not all that much room for improvement in this most-common PV chemistry.

There are alternative PV technologies that achieve much better efficiencies, as seen in the National Renewable Energy Lab chart below. The panels that are in widespread use today rely on “Crystalline Si Cells,” specifically “Single crystal (non-concentrator)” and “Multicrystalline,” also without concentration. Read more

FAQ: What is the “solar adder”?

Vermont state law requires that utilities provide at least a minimum level of value for solar net metering. The way the law is put into effect depends on the utility involved and its rate structure.

If your utility is Green Mountain Power, then the solar adder functions as bonus credit on your electric bill for each kWh of solar you produce. You receive the solar adder for the first 10 years of your solar array. Read more

FAQ: What’s the difference between kW and kWh?

Let’s start with the terminology. A kilowatt (abbreviated as kW) is the same as 1,000 watts (or W). A kilowatt-hour (abbreviated as kWh) is the same as 1,000 watt-hours (or Wh).

A watt is a measure of the amount of power flowing at one moment in time. If a solar array has a capacity rating of 4 kW, then it is capable of putting out a flow of 4 kW of energy under the right conditions.

If that solar array produces at a rate of 4 kW for one hour of time, then it has created 4 kWh of energy. Read more

FAQ: What’s the situation with the Federal tax credit for solar?

The “Residential Renewable Energy Tax Credit” is a Federal income tax credit available worth 30% of the total cost of the solar array. This is available for solar installed for primary and secondary residences. For a Solaflect PV Tracker, this is worth nearly $6,000. The tax credit is available for solar installations that are in place and operating by the end of 2016. UPDATE: in December 2015, Congress extended the tax credit. It will be 30% through the end of 2019. After that the credit steps down over a few years. In the final year, 2021, the credit will be 22%.

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FAQ: What happens to the Tracker when it is windy?

Solaflect PV Trackers include anemometers that are constantly measuring wind speed. If the wind speed gets high enough, the Tracker will “stow” in a horizontal orientation. By going flat, the Tracker presents only a thin edge to the wind, which can slide by easily.

Once the wind has calmed, the Tracker automatically returns to its normal orientation. While in the stowed position, the panels are facing upward. If this happens during daytime, they will still produce energy, even if not quite as much as when facing directly at the sun.

A Solaflect PV Tracker at dawn on a windy day.
A Solaflect PV Tracker at dawn on a windy day.

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