THE BASICS

Solar is a zero emission energy source; including both pollutants (CO2, SO2 and NOx) and noise. This makes it the most environmentally sound energy source.

Solar offers long term savings on energy bills and is cost efficient when analyzed on a cost per kilowatt hour (kWh) delivered basis (when rebates and incentives are included).

A solar photovoltaic system will enable the homeowner to effectively fix a substantial portion of electricity costs over the expected life of the solar system (+30 years).

A solar system will increase the value of a home as it reduces the ongoing annual running costs of the property. Installing a solar electric system also enables the homeowner to capture federal, state and local solar rebates and tax incentives.

Solar panels typically last more than 30 years and have manufacturers guarantees of 25+ years. Solar power systems have few, if any moving parts and once installed, require very little ongoing maintenance; they typically need washing to remove dust every few months.

The size of the system depends on individual household energy usage, and whether you want to completely replace the local utility with a solar PV system. There are essentially 3 options when sizing a solar PV system.

  1. Optimized system size: An “optimized” solar system will cover only the most expensive tiers of power purchased from your utility. Most lower cost tiers of power will remain for you to pay. (With solar you’ll only have one electric bill annually after installation). The lowest tier of power stays historically low, in California it is legislatively protected for low income people. All customers have an average of 340 kilowatts of electricity a month of low cost, Tier 1, electricity available for use. The “Optimized” system size theoretically has the quickest “payback time”: time that it takes for the monies that were going to pay utility bills to pay off the cost of the solar PV system.
  2. Go Simple Energy “Optimized Plus”: This system covers all but the lowest cost Tier (as described above). This system will have a slightly longer payback, but greater long term returns. Due to economy of scale and lower installation costs per solar panel, the installation of a medium size system which covers high and middle cost power may payback in a time period equal to or just slightly higher than the “Optimized” system, yet the long term returns much greater. If site conditions make for an simple installation, and it fits in the customer’s budget, this size system proves the most popular.
  3. “Zero Electric Bill”: The customer’s goal is to replace all of their electric bill down to zero payment to the utility. It’s a bit of a misnomer, the utility will always have a “interconnection charge” which is typically between $5 and $12/month, depending on the utility rate selected post project. This Zero Electric Bill option will have the longest payback time, but also the highest total return on investment. Some customers choose this option because of their “green tendencies”, or because they have the cash and “just don’t want to pay for any electricity from the utility.”

Solar panels generate peak power when electricity demand is at its highest and most expensive (midday). Using a time-of-use tariff and under Net Energy Metering, homeowners are able to produce and sell electricity back to the utility at high rates (midday) and purchase electricity back at low rates (evening). For a more detailed description on Net Energy Metering (NEM) visit our How it Works page.

Solar installations offer partial protection against grid failure, particularly if (battery) storage capacity is also located on site. Learn more about the energy storage market here.

The solar systems we install typically have a payback period of five to seven years. Considering the system will generate electricity for 30 years, an Internal Rate of Return (IRR) of 15% is not unusual. A $15,000 investment in solar could save you over $150,000.

The main incentive that all tax paying Americans qualify for is the 30% Federal Tax Credit that will be available until December 31, 2016. See detailed Federal 30% Tax Credit info here.

There are other local incentives that you may qualify for. New homes automatically qualify for the New Solar Homes Partnership program rebates and many fully remodeled homes also qualify for this excellent incentive. We’ll make the effort to ensure that your project will qualify for all possible incentives available.

TECHNOLOGY

Solar electric or photovoltaic (PV) power is a term used to describe the process of converting sunlight into electricity using solar cells. These cells are constructed from semiconductor materials and are grouped together to form a solar module. Modules are typically enclosed in a glass to protect them from the elements and mounted in a frame to provide strength and a means of attachment. Most home systems consist of 10-30 modules connected together to form the solar PV system.

Solar cells are (semiconductor) solid-state devices (no mechanical action) in which photons (or packets of light) collide with atoms transforming the resulting energy into electrons. These electrons flow into wires that connect all the individual cells in a module and all the modules in a system.

The electric current that flows from the solar PV system passes through an inverter which converts the direct current (DC) to alternating current (AC); the type of electrical energy used in the home.

A Solar PV system typically consists of solar panels, an inverter (to convert electric power from DC to AC), wiring (to collect the electricity from each of the panels and feed it to the inverter and meter), mechanical support structure (to hold and attach the panels) and an electric utility meter (to measure the performance of the system).

Consider the fact that you can’t really control the output of your solar power whether the grid is operational or not. The power output of the solar array is dependent on the amount of sun’s rays impacting it. If your home is consuming all the power when connected to the grid, the extra power goes to the grid. If the grid is down, the inverters auto shutdown to prevent “islanding”. If a solar array were allowed to produce it’s own power while connected to the grid, any excess power travels to the grid. When the grid is non-operational, it’s safe to assume that utility personnel may be working on the grid in order to repair it. It’s necessary when the utility personnel work on the grid, the utility lines are unpowered for their protection. Therefore, in order to protect utility workers, solar systems are not allowed to operate interconnected to the grid when the grid is down. For a solar system to continue to operate during grid outages, they need to be “bimodal” systems. To properly accept excess power from a solar array, when attached to the grid, the grid accepts that power. The grid acts as a “battery”. In the absence of a grid connection, a real battery bank has to be available for acceptance of the excess power, or to provide additional power when the electricity provided by the solar array is not sufficient. Without a battery bank, a solar array can not operate properly without potentially causing damage to the equipment it is powering because of the inability of the equipment to self regulate it’s electric output. A “bimodal” system that will operate without utility interconnection has additional equipment to regulate power output such as charge controllers, batteries, and a critical load panel. Bimodal systems are much more expensive than utility interactive systems because of this additional equipment.

There are multiple answers to this question. To continue to provide power in the case of utility outage, a solar system must be designed as a bi-modal system, as described in the previous question. Back up power in the case of a grid outage (especially for long periods of time) is a very valid concern. Generators are a good, relatively inexpensive solution. However, fueling that generator for the long term (potentially over the course of weeks or months in the case of a very serious outage) will ultimately be expensive, and perhaps the fuel itself will become hard to come by. There are solar rechargeable generators that are worthy of investigation. Very simply, depending on it’s storage capacity and output, it can be a relatively small unit. These solar rechargeable generators consist of a couple of small solar panels, batteries, a charge controller and an inverter. These units allow the plugging in of standard household items for critical loads such as refrigeration, medical equipment, etc. These systems are “stand alone, charge controlled solar PV systems” and are available on the EBay and Amazon websites, amongst others.

Yes – solar panels work more efficiently in cooler weather although they are designed to withstand the harshest summer conditions. High (altitude) desert regions are optimal.

Quality Tier 1 solar panels such as those from SolarWorld USA will last over 30 years. Panels that are not quality made will fail well before this; a study was conducted by DuPont Labratories which determined that the seal between the frame and the solar cells will fail in cheap solar panels at about year 12; making them much less efficient and reducing their life significantly.

Irradiance refers to the power of solar radiation per unit area on a surface. Global irradiance on a horizontal surface is comprised of direct irradiance and diffuse irradiance. On a tilted surface, the reflected irradiance from the ground also contributes to the total global irradiance. Generally, solar irradiance is called insolation.

Solar radiation affects many systems in the house and can vary considerably within the same town. On-site, solar irradiance is a particularly useful measurement if there is a photovoltaic (PV) system or solar thermal system installed at the field test location. Also, if space conditioning is a focus of the field test, solar irradiance is an important measurement as solar radiation has a large effect on heating and cooling load requirements, electrical lighting demand (daylighting), and envelope performance.
(Source: nrel.gov)

INSTALLATION

It will typically take 3-5 days to fully prepare a site and install the system, depending on size and installation type. On most residential projects the whole project will be complete in 3 days, with building permit sign off from the local municipality on the 4th day.

Ideally, the solar panels should be mounted on a roof, building or piece of land, where the panels have maximum amount of unobstructed sunlight. This is typically on a tilted, south facing surface where the solar panel is perpendicular to sunlight.

Because our solar systems are guaranteed for 25 years you wouldn’t want to install one on a roof older than 30 years. If you want to re-roof before installing your system, we have a team of licensed roofers that guarantee their work for life. Another option is to re-roof the section of roof under the solar system and re-roof the rest later on.