PHOTOVOLTAIC DEFINED

Photovoltaic means capturing the light from the sun and converting that light energy into usable electricity. This is possible with the use of solar panels. These solar panels contain "cells" made of silicon, which are designed to create energy in 3 steps. First, the cells absorb the sunlight. Second, the cells knock the electrons loose from the sunlight just absorbed. Third, these electrons are directed into a single stream, called a "direct current", or "DC". This is electricity we can use in a number of ways.

You may be familiar with the electrical term "Direct Current", also known as "DC", as well as "Alternating Current", also known as "AC". The most practical explanation of these two currents is that most devices that use batteries operate with "Direct Current". This includes car batteries, cell phones, and notebook computers. When you charge your phone or notebook, you are plugging an "AC Adapter" into the wall, which does exactly that, adapts the AC current from your home into DC current so your device gets the power it needs.

The same thing happens with PV. The DC produced by the solar panels can charge batteries directly. However, if you want to use solar panels to power a home, you must first convert this energy to Alternating Current, or AC. Fortunately, this is very simple to do using Inverters. Inverters change the current from DC to AC. They do this safely and efficiently. Some inverters will provide you a display on your personal computer, showing the power you generated by your system for a given time period.

What's really great about PV is that the systems are installed quickly, use your existing roof space, and last well over twenty years. For most types of buildings, we use stainless steel and aluminum mounting hardware on your roof to hold panels in place. Any penetrations of the roof are done professionally and guaranteed not to leak. The systems are easy to dismount if you need roof work done.

Our PV systems are also physically strong. There are documented cases of hurricane force winds blowing a roof off, but not the photovoltaic system. The system remained firmly in place, fastened to the house frame. And because there are no moving parts and the panels are self cleaning, even with a light rain, the maintenance required is minimal if any. PV panels will produce 85% of their original energy for at least 25 years.

With a fixed installation cost, you can secure your energy future and avoid paying ever-increasing prices for electrical power. In Hawai‘i, by taking advantage of state and federal tax credits, your payback on the system will typically be less than six years. Combine that with an additional 20 years of solar electricity, and your long-term profit, depending on system size, will be tens of thousands of dollars. Make a solid investment in your energy and financial future. In an uncertain world, one thing we can be certain of is that the sun will shine brightly in Hawai‘i.

 

The PV Experience

When you partner with Solar Cool Hawai‘i on your venture into Solar Photovoltaics, you can rest assured we’ll guide you successfully every step of the way!

Your first encounter with us is likely to be with one of our Consultants. Our team is comprised of well-educated solar professionals, who will happily share their knowledge with you.

We’ll start by reviewing your HECO bill. In order to size your system appropriately, we need to understand your energy use. Electricity is sold in kilowatt-hours, more commonly referred to as kWh. On your HECO bill, you’ll find a column of data which tells you what your average kWh usage was per day during any given month. We’ll look at an entire year’s data to find your average kWh usage. Let’s use 25 kWh’s per day as an example.

In order to make the correct system sizing calculation, we need to know how much sun your home sees on average over the course of the year. There’s a sun zone map which helps us determine this. The highest sun zone on Oahu is the 500 zone. Houses in this zone average 5.81 hours of direct sunlight.

If we need 25 kWh of energy per day, and we get 5.81 hours of sunlight, we can divide 25,000 (25 kWh) by 5.81 to see how big our system needs to be. That figure is approximately 4303 Watts. So we need a PV system that will generate 4303 Watts at full power.

Our next decision will be what PV panel to use. There are a couple of choices. We sell many types of PV panels, but our most popular are made by SolarWorld and Sanyo. SolarWorld panels are the most popular panels for a number of reasons. They are made in the United States, they offer great value for every dollar spent, they have a 25-year warranty, and they are available on-island. That means you don’t have to wait for panels to be shipped from the mainland.

Sanyo panels are another big seller. They have a smaller footprint, which is great for tight roof spaces, and they use a hybrid thin-film technology that performs exceptionally well in low-light or cloudy conditions. They are more expensive however, and unless you need the smaller footprint, or your home is in a low sun zone, you might not want to go to the extra expense.

Panels come in many sizes (power ratings) and currently we’re seeing panels in the 215W to 245W range. For the sake of our example above, let’s go with SolarWorld 245W panels. To finish our sizing calculation, we divide the 4303 Watts of power we need, by the panel capability, which is 245W. That tells us we need about 18 panels to meet our needs.

Next, we’ll inspect your roof to see if we have enough room for the 18 panels, and where on the roof they should go. Generally the most south facing roof is best, but your Consultant will help you decide.

We’ll also take a look at your current electrical system to make sure you have enough capacity to handle the PV installation. Even if you don’t, no need to worry. We are a fully licensed C-60 and C61 Solar contractor.

After gathering all of this information, your Consultant will prepare a quote for you. We have financing options and we’ll also help you find a way to take advantage of state and federal tax credits that will pay for up to 65% of your new PV system!

 

Installation

Our Project Coordinator will contact you within two days of signing your agreement with us.

He will schedule a convenient time for you to meet with the licensed electrician and lead installer for your job. They will go over the entire process with you, and answer any additional questions you might have about the installation process. This meeting ensures that we know exactly how you want things done. You’ll be communicating directly with the installation professionals, so there won’t be any misunderstandings.

The Project Coordinator will then work with you to choose an installation date. If the materials you’ve chosen are available locally, you can expect installation to begin within 1 – 2 weeks.

On installation day, the crew will arrive between 8:00am – 8:30am. There will also be a delivery of materials: solar panels, inverters, mounting racks, etc.

The first step is laying out the system design on the roof. Then our crew will begin installing the hardware that supports the racking which holds the solar panels.

Your roof type determines the way we mount your panels, but generally with shingle and tile roofs we use hangar bolts that are secured to your home’s structural beams. Metal roofs use special clips that provide strength without penetration of the roofing material. Either way, we stand behind our work and guarantee a leak-free installation.

After the hardware is installed, our workmen will begin assembling the racking that holds the panels. After that, we’ll install the micro-inverters on the racking and begin assembly of the grounding system.

Then, electricians will run the electrical conduit to your service panel and install disconnect boxes to allow you to shut off the system if it’s ever necessary.

The next step is mounting the solar panels on the racking and making all the connections to the electrical service. At that point, we will turn on your system for testing.

Once the system is operational, you will begin reaping the benefits of your solar power system right away. If you have an analog meter, you can actually watch the wheel turn backwards!

At this point, we will call for an electrical inspection from DPP (Department of Planning & Permitting). An electrician will meet the inspector and answer any questions he might have. You do not need to be home for either of these inspections.

Once the permit has closed we will notify HECO. They will come out to your house and change your electric meter to a special digital version that tracks your solar power generation. This is part of a net metering agreement you enter into with the utility. Information about the HECO Net Metering Agreement is available online at Hawaiian Electric's website.

Give Solar Cool Hawai‘i a call or click today! We will send one of our expert consultants to give you a free site inspection and quote. We are here for you and look forward to helping you get the most out of your photovoltaic system!