"He Didn't Build That"...I Did (Part 7): Solar Cost Analysis and Payback Calculations

Total Solar Project Cost

Following are the comparative costs of the solar panels and components for our small-scale solar project. The prices may vary depending on the suppliers and locations of our sources. Also, prices tend to go down (at least in my observation) as time passes by and depending upon the competition. These are the current prices at the time of this writing, and are used merely for computational purposes and any future changes should not reflect upon the author or the suppliers.

OPTION I

Grape Solar 400-Watt Off-Grid Solar Panel Kit
Item # 776092
Manual
Your Price$1,399.99
Shipping & Handling included *

The Grape Solar 400-Watt Off-Grid Solar Panel Kit is ideal for a variety of applications, including emergency backup systems, RVs, boats, 12 Volt battery charging, small pumps, charging small electronic devices and operating LED lights. Made with high efficiency crystalline solar cells for years of service, this solar kit is easy to install and virtually maintenance free! An anodized aluminum frame and a sealed junction box make the panel weatherproof for outdoor use. A two-diode bypass minimizes power drop caused by shade. This system will provide approximately 1,200 Watt Hours or 100 Amp Hours of charge per day. The kit includes: 4pc 100-Watt polycrystalline solar panels, a 35 Amp charge controller, 2,000-watt inverter with two outlets and 1 USB port, cables and manual.

Ideal for running small pumps and lights or charging your portable electronic devices
Polycrystalline panel with anodized aluminum frames and tempered glass for outdoor use and superior performance
Two diode junction box for enhanced performance
2,000-watt pure sine inverter with two outlets and a USB port allows you to plug in small devices
Kit comes with all cables and connectors for quick and easy set-up
Battery not included, a minimum of one 12Volt deep cycle battery is necessary to use this kit
MFG Model #: GS-400-KIT
MFG Part #: GS-400-KIT

OPTION II

Item Description                                           Quantity  Unit Price    Total Price
Solar Panel, 100 watts, polycrystalline                4         $180.00 $720.00
Solar Charge Controller, 60 A, 12/24 VDC        1         $150.00      $150.00
Pure Sine Wave Inverter, 1,000 watts                 1         $185.00       $185.00
Deep Cycle Lead Acid Battery, 250AH, 12V     6         $397.50    $2,385.00
                                                         
Over-all Total Price = $3,440.00

Above cost does not include cost of cables and connectors, which would be in the vicinity of around $200.00 more. Also if we factor the cost of the inverter at double the size, from 1,000 watts to 2,000 watts which cost $450.00 each, I suggest that we buy the kit instead, (OPTION I) at $1,400.00 because it’s easier to set-up. Needless to say about compatibility issues and shipping problems when components are coming from different vendors/suppliers.

Therefore our price options would be the following:

1. Over-all total cost without batteries = $1,400.00 (P56, 000.00 @P40/dollar)
2. With at least 2 batteries, total cost   = $2,195.00 (P87, 800.00 @P40/dollar)
3. With 6 batteries, per computations  = $3,785.00 (P151, 400.00 @P40/dollar)

Without the storage batteries, our solar panels will provide electricity only during the daytime. I suggest that we consider option 2, using at least 2 batteries for lights at night and light loads such as TV, computers and cell phone charging.

For simple computational purposes, I’m going to round off the total cost to:

Total solar project cost = $2,200.00 (P88, 000.00 @P40/dollar)

Again, I’m emphasizing that above costing reflects not the actual cost, but merely being presented for purposes of giving the readers a bird’s eye view of what it would be like to own a solar system based on their load requirements at my approximate price evaluation at the time of this writing. Based on the price table above, you can try to configure your own system and just follow the computations as a basic guide for your total cost and payback calculations. You can still lower this cost by purchasing cheaper storage batteries. Just make sure they are of the deep cycle kind that can hold a charge longer.

Next time, we will discuss payback calculations. Hang in there, guys!

Solar And Wind Energy (Excerpt From My Open Letter To A Municipal Official)

(photo source: istockphoto)

First of all, I would like to greet you and all our townmates a happy fiesta, an annual town celebration which brings back a lot of childhood memories.

Going back to my childhood days in OMPSA, I saw a young and bright student who vowed to himself that never again will he let the future generations of his beloved town suffer the same experience he had while studying under a dimly-lit room and literally burning his eyebrows every time his head accidentally touches the gas lamp (made out of empty coffee jar), which provided the much needed light. To pursue his dreams, he studied Electrical Engineering in college hoping that someday after gaining some expertise in his chosen field, he would be able to alleviate if not totally eliminate the problem of having no electricity or lack thereof, that currently besieged our town and the whole province of Marinduque.

That young and bright student is now a successful and experienced Electrical Engineer; ten years away from his retirement is no other than yours truly, Engr. Victor Perlas Vizarra, at your service. I could not believe that we still have the same power and energy problems thirty-nine years ago, after I left our town to pursue my dreams and seek for greener pastures in a far away land, they called the land of milk and honey. I could not wait for another ten years, for me to be able to give back to my beloved town of Torrijos. I believe the time has finally come for me to get out of the sidelines and take the necessary actions to help your good office and with all honest intentions tackle the immense task of preventing brown-outs.

Why don’t we harness the power of the sun and wind (which are bountiful in our area) to provide us with the much needed source of electrical energy? If given the opportunity, I propose the following solutions to our power and energy problems which consist of four stages:

I.   Installation of a prototype solar panel

       A)  In public buildings such as hospitals, puericulture centers, municipal hall, etc.
       B)  Funding of this project may come from non-profit organizations and private citizens or this could be a joint venture between the local government and private citizens.

II.   Providing a classroom or some sort of building structure for solar panel manufacturing

       A) Training our out-of-school youth and jobless members of our community learn the basic skills of soldering and practical electricity.
        B) Once they become knowledgeable and proficient, they will provide the needed manpower to assemble the solar panels that we need. In return we are not only giving them jobs but quite literally, a bright future.
        C) This portion could be tied-up to the local government’s livelihood program.  

III.   Installation of solar panels on rooftops or ground structures of private residences

       A) Those more fortunate and well to do members of our community can do this on their own by buying directly from our self-manufactured solar panels or get their panels from a third party vendor.
        B) This privately installed solar panels shall be tied-up to the local electrical grid, so that in cases of excess power generated by the solar panels, they will be able to supply power back to the grid which will enable them to sustain the diesel generators used to supply power to the less fortunate members of our community.
        C) The government shall provide subsidies to private homeowners in terms of credits earned by supplying excess power to the local grid to entice the private sector to participate in these efforts. This would be subjected to your discretion.

IV.   Rural electrification using both solar panels and wind turbines

        A) Solar power and wind power are an ideal combination of providing non-conventional or renewable forms of energy sources. The solar panels work best in day time and wind turbines will provide the much needed boost at night time to charge the storage batteries that we need to store the energy generated by both solar and wind power.
        B) Wind turbines are noisy and require strategic positioning that’s why I do not recommend them for installation in the town proper. They should be installed in individual homes in the rural areas.

For details of my proposals, please feel free to contact me anytime. To start with, I would like to request your good office to send me an electrical plan of your public hospital complete with power and lighting loads so I can start my feasibility studies. You can give the plans to Architect Glee Rosas who will be there during the town fiesta or send the plans directly to my home address above. It would be great if you can also include the perspective drawing of the hospital.

I hope you agree with my proposed approach to providing solutions to our power and energy problems instead of building whole arrays of solar power plants and fields of wind turbines which would require a lot of financial funding; I believe we could not afford to provide. My approach to solving our problem is not complex at all. All we need is active participation from each member of the community. If we work hand-in-hand, we will accomplish great things even beyond our wildest imaginations.

Thank you for your precious time and once again, Happy Fiesta to ALL…Mabuhay tayong lahat!


Sincerely,


Engr. Victor Vizarra


Note: I wrote this letter last year to a town official in our beloved province. Unfortunately, I did not get any response at all. I will not stop until my vision of rural electrification - that is for every household, even the poorest of the poor in remote areas shall be provided with power and lighting. I know this is a big task and a real challenge, that's why I'm asking for every one's help and cooperation. We need to start somewhere, and I'm glad some of you are already doing it, while others are interested and willing to do it. Now, for those of you who are interested in my proposals, you can contact me at engr.vizarra@yahoo.com.

                                                         
                         
                   

"He Didn't Build That" I Did...(Part 3)

Solar Panel Array: Number of Panels Needed

Solar-powered bahay kubo (original photo from: Hagikhikan)

Before proceeding with cost savings and payback calculations, let us discuss some important topics such as solar panel sizing, electrical loads and Ohm’s Law which is the basic formula that we are going to use.
In its simplest form, Ohm's law states that the current in an electrical circuit is directly proportional to the applied voltage and the resistance of the circuit. The three (3) most common mathematical expressions are:

 P= V * I                    I = P / V        V = P / I = I * R

Where:
P = Power : the product of the voltage times the current in an electrical circuit measured in watts
V= Voltage : the electromotive force (pressure) applied to an electrical circuit measured in volts
I = Current : the flow of electrons in an electrical circuit measured in amperes
R = Resistance : the opposition to the flow of electrons in an electrical circuit measured in ohms

Example Only: ( Based on a daily usage)

LOAD DESCRIPTION                  RATING     HOURS     WATT-HRS.   
_____________________________________________________
LAPTOP                                             75 watts     4          300  
LIGHTING (4x15-watt CFL)               60 watts     5          300
ELECTRIC FAN                                 120 watts     6          720
TELEVISION                                     100 watts     6          600
REFRIGERATOR (35% run-time)       120 watts     8          960

TOTAL DAILY WATT-HOURS REQUIRED = 2,88O WATT-HOURS

In the Philippines which is a tropical country and has plenty of sunshine we can get at least 8 to 10 hours of daily sunshine. Use 5 hours daily average sunlight for mid-latitude in the US.

NUMBER OF SOLAR PANELS NEEDED:

Although I used a 45-watt panel for my experiment last year, I recommend using a 100-watt  solar panel currently available at Home Depot as of this writing, at $199.00 each with free shipping within the US except GU, PR and VI. This is the Grape Solar 100-Watt Monocrystalline PV Solar Panel. This is a whole lot cheaper and more efficient. I got mine on sale last year for $149.99 from Harbor Freight Tools and their regular price is $299.99. You will need two of these, as compared to one from Home Depot, and still you are 10 watts below capacity. Let's stick to our example load description for computational purposes, as follows:

Grape Solar 100-Watt Monocrystalline PV Solar Panel

Using a 100-watt solar panel and assuming 8 hours of sunshine, that would give us 800 watt-hours per day per panel.

Total number of solar panels = 2,880 watt-hours/800 watt-hours per day = 3.6 = approx. 4

Therefore, use: 4 solar panels with a capacity of 100 watts each.


Based on our example daily load requirements, our total solar panel cost would be:

          Total solar panel cost = 4 panels x $200.00 = $800.00 + tax

This cost does not include the DC batteries needed for storing solar energy during night time and extreme weather conditions without sunlight. The inverter needed to convert DC power to AC power (power coming out from your regular power/lighting outlets) is also not yet included in our cost.

Basically, if you live in the rural areas and just need power for electric fans, some lighting at night and some juice for charging your I-pads, I-phones, notebooks and other portable devices, all you really need is a 100-watt solar panel and a solar charge controller which usually come free with the kit. Otherwise, you can buy the controller below $20.00 from Amazon.com. Connect your solar panel in parallel with wind turbine and your electrical needs 24/7, 365 days a year, are all set. You don’t have to worry about brown-outs anymore.

Every year the cost of solar panels are going down and the designs are becoming more efficient brought about by technology advances. Direct savings is realized if you actually connect your DC appliances and other DC power requirements directly to the solar charge controller and you’re off-grid, meaning not connected to any utility power company. That means all your appliances and light bulbs should be rated either 12-volt DC or 24-volt DC. The solar panel can generate as high as 27.8 - 29.5 volts DC, that’s why you need a charge controller to regulate the voltage at either 12 or 24 volts depending upon your needs.

This is just a bird’s eye view of how much is involved in owning solar panels. If you really need to know how much it would cost you to have solar panels installed in your homes, it would need an in-depth analysis of your actual monthly electric usage for a period of 12 months, and also actual survey of your house location to determine the best location and efficient utilization of your solar power system.

For a more detailed information, take a look at Wall Street Journal’s study on the economics of installing residential solar in 5 US cities.

What I can say right now, with the government incentives and rebates, as well as lease options being offered by companies such as SolarCity,  SunPower Corporation and other solar companies, there is no better time than now, to start using solar energy. Right now, you don’t have to shell out $20,000 - $30,000 as initial investment for your solar panel system. Instead, you just pay for usage of the solar panels which are owned by the solar companies. You will have considerable savings and significantly lower monthly payments than your electric bills from your current utility providers. Utility companies bill you for transmission and distribution charges which will be eliminated when you use solar. Another advantage is helping your environment to become free from pollution caused by diesel and fossil-fuel generating power plants.

Is it not a good legacy for our grandchildren and their children in the future to have a pollution free environment?

"He Didn't Build That" I Did... (Part 2)

My finished tool/storage shed with solar panel on the right side

How To Install A Solar Panel

Before proceeding to our topic of installing solar panel, let me give you a brief introduction about solar panels and their types.

A solar panel (also solar module, photovoltaic module or photovoltaic panel) is a packaged connected assembly of photovoltaic cells. The solar panel can be used as a component of a larger photovoltaic system to generate and supply electricity in commercial and residential applications. Each panel is rated by its DC output power under standard test conditions, and typically ranges from 100 to 320 watts. The efficiency of a panel determines the area of a panel given the same rated output - an 8% efficient 230 watt panel will have twice the area of a 16% efficient 230 watt panel. Because a single solar panel can produce only a limited amount of power, most installations contain multiple panels. A photovoltaic system typically includes an array of solar panels, an inverter, and sometimes a battery and or solar tracker and interconnection wiring.

A solar panel or photovoltaic module, is composed of individual PV cells. This crystalline-silicon panel has an aluminium frame and glass on the front.

A solar cell (also called a photovoltaic cell) is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect. It is a form of photoelectric cell (in that its electrical characteristics-- e.g. current, voltage, or resistance-- vary when light is incident upon it) which, when exposed to light, can generate and support an electric current without being attached to any external voltage source. (Source: Wikipedia)

Types of Solar Panels:

1. Monocrystalline silicon (mono-silicon or single silicon) - the most efficient type of solar panels. They convert sunlight into more electricity than the other types below. As a result of their high silicon content, they’re also more expensive, but you need fewer of them. That’s the reason why they’re ideal for roofs, because fewer solar panels means lesser load bearing weight.

2. Polycrystalline silicon (multicrystalline or multi-silicon) - have lower silicon levels than “mono” panels. In general, that makes them less expensive to produce, but they’re also slightly less efficient. Their overall construction design can often make up for the efficiency loss, so they’re also good for roofs.

3. Amorphous silicon (thin film) - inexpensive to make and can absorb sunlight even on a cloudy or rainy day, but not efficient as compared to the first two above. They are usually installed on ground structures and not on roofs. This is the type of solar panel that we are going to install.

There are two more types of solar panels: BIPV (building integrated photovoltaics) and solar hot water (thermal) panels. BIPV’s look like real roofing tiles such as solar shingles. They have good aesthetic looks, but good looks cost a lot more. Also, they are less efficient than conventional PV.

Now that we're done with the crash course on solar panels, let's get down to business.

Tools You Need:

1. Electrical Pliers/Wire Cutter
2. Flat Head and Phillips Screwdrivers
3. Electric Drill/Screwdriver (optional)
4. Wire Stripper/Terminal Crimping Tool - this is a must have tool if you are a novice

Schematic/Wiring Diagram:

Wiring diagram from solar panel to junction box

The solar panel kit comes in 3 pieces, rated at 15 watts each for a total of 45 watts with its own connecting wires, 20 feet in length (gauge #16). This is good for short distance only from solar panel to solar controller/voltage regulator because as you go farther, there is a higher voltage drop along the wires. Here is what you need to do to minimize voltage drop:

1. Cut/splice the wires to desired length using wire cutter/splicer.

2. Connect positive to positive (red wires) and negative to negative (black wires).

3. Attach the connected wires to wire connectors/terminal block and place them inside a PVC junction box.

4. Use an insulated 3-wire extension chord (gauge #12), usually comes in standard 25-foot and 50-foot length, and cut to desired length from the PVC junction box to the location of the solar controller/voltage regulator.

5. Connect the positive wire (red) from the junction box terminal to the positive terminal of the solar controller/voltage regulator. Then connect the negative wire (black) to the negative wire (black) of the same component.

6. Use gauge #4 wire, 3 feet in length for connecting the solar controller/voltage regulator to 12-volt DC battery and from battery to inverter (see wiring diagram). Make sure the positive wires and negative wires do not touch each other, as this will cause short circuit causing damage to your expensive components, especially the inverter.

The color of the wires vary depending upon the source or manufacturer, so pay close attention to what kind of terminal you connect the wires to. Simple rule is: positive to positive and negative to negative. I can't emphasize well enough about this simple rule, but this is very important.

Before starting any of the above instructions, make sure you cover the solar panels first to prevent electricity from flowing through the wires while you are working, and to prevent damage to solar panels just in case the wires accidentally come in contact with each other.

The inverter (left side) which converts DC to AC power is connected to two 12-volt deep cycle lead acid battery (2nd battery not yet connected) with a rating of 105 amphours. The battery is connected to the solar charge controller or voltage regulator that came with the kit, as well as two light bulbs. 

On the left side is a 1000-watt pure sine wave inverter which I bought from Amazon.com and on the right side is a 7-amp solar charge controller that came with the kit. As you can see the output voltage is 12.5 volts DC. 

The front panel of the solar charge controller is equipped with USB port and three other ports (6-volt, 9-volt, 12-volt) for charging cell phones, laptops, car battery and other portable DC devices. You only need a 300-watt inverter for this particular set-up, but I opted for a higher output size for future use, as I plan to install more solar panels in the near future.

There you go folks, you have just learned how easy it is to install a solar panel. Maybe next time, we can build the solar panels ourselves from new or recycled solar cells. You will be surprised how easy and simple it is to build one.

Next time I will cover cost benefits and payback calculations of solar panels based on my experiment. Hope I shed some light on this topic, as I tried to discuss this in layman's terms as much as I could. If you have some questions, you can post them under the comments section of this article below.