Posts tagged solar power

Lessons From Today’s Economy

When making a commitment to switch to renewable energy in your life, the factor most often cited for delaying the switch is the upfront cost of installing an alternative energy generating system.  This is understandable, especially given the large amount of press coverage from the days when solar panels were VERY expensive and no tax credits existed to help a homeowner out of the financial hole created by purchasing fifty grand worth of panels.  However, these days it is possible to jump start your energy generation renovation without breaking the bank.

Of course, when you’re struggling just to keep up with this month’s gas bill, any additional expenses can seen like an insurmountable burden.  This is the case with many homeowners today, who are just trying to stay afloat with huge mortgage payments and utility bills.  Which brings me to my lesson of the day.  You see, there is a paradox in today’s world that goes something like this: when times are good, you don’t look for alternative solutions to problems because you have the leeway (read cash) to do things in the relatively inefficient way that you’ve always done them without breaking your bank account.  When times start to get bad, people don’t invest in alternative solutions because our natural human tendency is to imitate the ostrich, complaining about the squeeze but doing nothing to change the paradigm which produces said results.  The head in sand approach carries us through until Phase Three, the collapse of market sustainability.  Did we really think that our financial woes started yesterday with the mortgage crisis?  No, it’s been coming on for years, while we all sipped margaritas by the heated pool and pretended we could really afford the cars in our driveways. At this point, survival becomes king and all innovation gets laid by the roadside unless it costs practically nothing to implement.

This is the situation we find ourselves in now.  Another winter looms dark and cold in front of us, but in the struggle to keep up with growing bills and shrinking wages and savings, we feel we can no longer AFFORD to make the investments required by alternative energy, regardless of their future value.  Which is a shame if you ask me, because this is potentially the BEST time to get into generating alternative energy.  Not only have the renewable energy tax credits been renewed and expanded at a national level, local solar and wind initiatives are cropping up across the country that offer innovative ways to finance the switch.  Here in Los Angeles, Mayor Villagarosa announced a couple weeks back a new solar initiative which calls for installing 500 Mw of solar power on city-owned rooftops, a huge investment in concentrated solar power generation out in the Mojave desert, and a residential solar rooftop program that together promise to make the program the largest municipal solar program in the country, if not the world.  Home efficiency products like computer-run zone control systems are also experiencing a renaissance of innovations which are bringing the price down into the reach of the masses.  But alas, most homeowners are so deep in the hole that we risk losing many of these innovations to crippling financial woes within the small business sector as no one implements their ultimately sensible technologies.

Where does this leave the individual investor?  Well, let me say this.  Our inability to seek change when we have the financial capabilities to do so undermines the entire potential for distributed alternative energy generation.  If you are having trouble with your mortgage today, the time to invest in solar was a few years back when you still had cash in your bank account.  If you’re still sitting relatively pretty today, now is the time to invest, not a year from now.  You see, there are several alternative energy technologies which are eligible for tax credits and also have a relatively fast breakeven point.  Take solar hot water heating, which costs little to install and in most climates can easily provide most of your home water heating needs.  The federal tax credit allows for a 30% rebate on the total cost of installing the sytem.  This no-cap rebate is by far the best offer that the federal government has ever made to homeowners wishing to adopt alternative energy.  So take them up on their generous offer BEFORE everyone, nation included, runs out of funds to support the program.  Those who installed their systems years back are now enjoying minimal heating bills while the rest of the country shivers up to their fireplaces hoping heating costs go down.   (Which, incidentally, they have recently, but only due to total financial collapse, and that’s no prize!)

Housing starts are at an all-time low right now, but for those considering building a place, radiant heating is another option which makes imminent sense for a small up-front investment.  By heating water using solar power which is then pumped through pipes within the flooring material, your cold winter morning runs to turn on the shower will be replaced by a nice warm stroll over to the tub across your new radiant heat floor.  All for adding a few extra pipes in the concrete foundation you already planned to pour.   To me, with my childhood memories of shivering in bed and calling out to my bro to turn on the shower and let it heat up before I would venture out of the covers, that alone would raise the quality of life immensely. And for those who already have a structure in place, you can use the same concept for radiant wall heating for far less upfront expense than retrofitting a floor.

But back to the lesson at hand.  If you have been lucky enough to plan your finances well enough not to be irrevocably hurt by this impending crisis, you are in a uniquely great position to further the market for alternative energy here in the US.  As it stands right now, though the US is the largest producer of solar panels and wind turbines in the world, most of the product produced is shipped abroad to places with a stronger national investment in alternative energy than our domestic programs.  As the incoming administration plans to shift some traditional manufacturing sectors over to producing more renewable generation equipment, we need to uplift the market here in the US so that it becomes cost effective for emerging US companies to sell to US customers rather than simply shipping abroad.  If you can afford it, making the switch to alternative energy will not only help your pocketbook in the long run, it will help our nation’s crippled financial system learn to walk again.  And this time, we can take green steps toward to future instead of our previous dirty footprints.

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QUICKIE: Solar Powered Christmas Lights

Looking for an easy way to integrate a little alternative energy into your holiday festivities?  There are a lot of exciting solar products coming out of Asia these days, as several eastern countries have gotten the jump on the US in terms of R&D and product development.  Which isn’t so good for the US’ current energy market, but it is good for solar energy enthusiasts!  Why don’t you try a string of solar powered Christmas lights in your front yard?  They turn themselves on automatically at dusk (if you want them too), similar to existing solar lawn lamps, they have solid light or blinking options, and they can easily be strung around fences, eaves, railings and wreaths to create a cheerful effect that’s also effortlessly green.

I have a set of white fairy style lights of this type, and they are great.  Not having a yard, I simply place the receiver in the window each morning and come sunset, I have a 60-LED solar powered flashlight for late night reading that lasts several hours! They throw a surprising amount of light for their tiny size.  If you’re interested in these or any other solar power accessories such as solar powered flashlights for emergency or off-grid use, head to ebay today and search for solar lights.  Finally, sunshine you can hold in your hand!

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Solar Power Class: Semiconductors and the P/N Junction

Holiday’s over, class, and it’s time to get back to our solar power lessons.  Today, let’s talk about semiconductors, and a slew of other things along the way!

What is a semi-conductor?  Pretty much what it sounds like.  If a substance which conducts electricity (think copper wires) is a conductor, and one that does not (rubber) is called an insulator, then a semi-conductor is right in between. Basically, atoms with only 1 or 2 electrons in their valence (outermost) orbit conduct electricity more easily than those which have a full or almost full outer valence (7 or 8).  The first are conductors, the latter are insulators.  So semiconductors are those with 3, 4, or 5 valence electrons, which means that they are neither particularly inclined nor disinclined toward conductance.

By taking silicon (which has 4 valence electrons) and doping it, as it is called, with an element which has either 3 or 5 electrons, materials with a net positive or negative charge can be created. This has to do with silicon’s natural crystal forming tendencies.  If the material used had 3 valence electrons, then the overall material has a positive charge and it is called a P-type material.  If it had 5, then the material holds a negative charge, and is called an N-type material.

All interesting enough, but things really get going when you place the two together.  The P/N Junction is the innovation that pretty much ushered in the electronic age.  The particular application of this material to solar power was actually one of the first experiments done with it, by Bell Labs back in the 50s.  When a P-type material and an N-type material are placed back to back, and a circuit is completed wiring the two pieces together, the sun excites electrons in the negatively charged layer (remember, this layer has extra electrons) and as the voltage (or pressure) builds to a point at which they overcome barrier resistance, they begin to jump to the positively charged layer where holes in the crystal structure await them.  From there, the circuit exits the P-type material and travels back to the N-type material via the wire circuit to restore the electron balance in each material.  If we hook up a battery amongst the wire circuitry, it is those bounced electrons which we store and call energy.

Okay, time for a break.  Join me back here tomorrow for the next installment of our solar power class.  In the meantime, for your reading pleasure, check out The Light Revolution, a great book about the necessary influence of the sun in our health and buildings.  Full review soon!

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Solar Panel Primer

Looking to buy a solar panel for your home, or maybe build your own? It can be confusing trying to sort out the actual capacity of a panel and what it will or won’t power. So here are a few facts about solar panels to get you started on your way to energy freedom.

Solar panels are composed of individual solar cells, wired in some combination of series and parallel to achieve the desired voltage and amperage that produces the wattage you need for operation. In order to charge a 12 volt battery, you need a panel that outputs 18 volts. Here is a fact you’ll want to know: a solar cell, no matter how large or small, puts out a total voltage of 0.55 volts. For the sake of making math easy, let’s call it 0.5 volts.

So in order to get 18 volts, you need to create a voltage multiplier circuit (which for those of you not following the photovoltaic course on this site means a SERIES circuit). Between 34 and 36 cells wired positive to negative will achieve this. (0.5 * 36 = 18 volts) Let’s say you have a bunch of cells that have 0.5 volts each, and 1.5 amps each. If you simply wire 36 in series, as is recommended, you will end up with a panel that puts out 18 volts with total amperage of… 1.5 amps. All together, this means you will get 27 watts (per hour of full sun).

If you’ve checked the back of any of your appliances recently, you may realize that this wattage is not enough for your needs. After all, even a compact fluorescent 12 volt bulb will probably use at least 9 or 10 of those watts each hour it operates, which is 1/3 of your total available power. (For the sake of this example we will ignore the fact that you probably wouldn’t need a light while the sun is shining!) Use three bulbs, and your power will run out with the sunshine at dusk. So how do you increase your available power?

Most photovoltaic system batteries are designed to operate at 12 volts (similar to a standard car battery), so you don’t want to up the voltage unless you want to start upping the number of batteries as well. If wattage (available power) is equal to voltage * amps, and you can’t change the voltage, then it stands to reason that upping the amps is the way to go. To do this, you wire groups of cells together in parallel. In order to wire things up in parallel, the things wired together should be the same, meaning you will be wiring together groups of 36 cells (wired in series). To double the amperage, you would wire two sets of 36 cells together, for a total of 72 cells, 18 volts, and 3 amps (1.5 amps * 2). Now, you have an available 54 watts (18 * 3) per hour of full sun. For every additional set of 36 panels in series that you add (in parallel) to your array, you get an additional 1.5 amps, and your total wattage is increased by 27 watts per hour of full sun.

There are a few other things to remember when choosing a panel for your needs. The first is kind of obvious: the sun only shines so many hours per day. In most places, you can expect between 5 and 8 hours of “full sun” (the conditions under which your panel produces its maximum output) per day. So if you have a 50 watt panel and 6 hours of full sun, you can expect around 300 watts of power production daily sent to your battery (or perhaps a little more from a few hours of partial sun production). On cloudy days, or if you live in an area of high particulate pollution such as a large city, you will get less.

Which brings me to fact #2: to get the full output from your panel, they must be kept clean. Over time, dust settles on the panels and reduces the amount of light hitting the surface. Or in the winter, in cold areas, you will have snow to contend with, and in the fall, you’ll have to keep an eye out for leaves falling atop the panel. Birds are another common culprit. We’ve all seen the ground under areas where birds congregate… it isn’t pretty. Basically, your panel will output at the level of the cell getting the LEAST sunlight. So if you have one cell in full shade (or fully covered with something), and others in the sun, your total output will be reduced more than you’d intuitively think. Save yourself some grief and locate the panels in a place easy to access for cleaning, and outside the regular path of avian neighbors.

Lastly, since solar panel setups are Direct Current (DC) systems, and since most household appliances run on Alternating Current (AC), you will usually need an inverter to convert DC to AC power your appliances can use. But there is a good reason to consider investing in some 12 volt appliances and lights. In the process of inverting the power to AC, about 15% of the power is lost. So if you have a total of 500 watts to use, and you invert it all to AC, you will have about 425 watts available for powering loads (appliances). There is an increasing variety of 12 volt appliances on the market, from light bulbs and radios to refrigerators. The more 12 V appliances you use, the more use you get for your available power.

This is by no means a complete list of considerations when buying a solar generation system, but it should be enough to help you sort through the eBay flotsam and find a panel that meets your particular needs. Stay tuned for next time, when we’ll be discussing batteries!

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Celebrating Labor Day

What better topic for Labor Day than reduction of necessary labor by moving off the grid? When you make the decision to cut the power lines, you are making a contract with yourself: to do whatever labor is necessary to keep your alternative energy system running to provide your necessary power. Luckily, whether with solar, wind, or micro-hydro power, once you’ve invested in the initial construction phase, you’ve gotten a lot of that work out of the way and you can let nature take it from there.

However, all systems do require upkeep. Solar panels need dusting and readjusting, wind towers need tuning, and hydro systems must be cleared of debris.  This upkeep is one thing that turns a lot of people off about off-grid power. It SEEMS like a lot of work when one is addicted to simply having on-demand power by signing a check every month.  However, when you see the bigger picture of your energy consumption scheme, things make more sense.  The majority of the power generation in an off-grid system is generated by nature.  This is also true in a utility power generation system, but there, workers must transport the raw materials (usually coal) to the power generation site and physically feed the burners.  Between the labor costs of mining the materials and getting them to the power station, and then the labor required to string and maintain power lines to transport the electricity to you, you’ve racked up a lot of human capital for each kilowatt hour you consume.  By taking a pledge to do minimal maintenance on your own system, you are freeing up human capital for other tasks, like designing new generations of alternative energy delivery or other such noble tasks.  (I won’t expound on humanity’s likelihood for picking such noble professions over, say, sleeping on the couch on a holiday like today.  There are limits – enjoy your time off!)

In fact, this discussion underlines a concept that interweaves into a lot of simple living theory.  In order to see your real savings, you should be able to see outside your own life to the greater good of our neighborhoods, nations, species, and planet. By investing a small amount of time, you can count yourself a philanthropist.  Go ahead, put it on your resume! After all, time is a luxury of which each of us only has so much.  You’ll probably find that you end up freeing more time by not having to work to pay certain bills than you will spend in upkeep.  In conclusion, if you want to save energy, your fellow man, and the planet all at once while building your karmic bank account, start planning a way to get off the grid today.  That way, by Labor Day next year, you might celebrate by DOING some labor for a change, instead of needing a break from your daily grind. Happy holiday!

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Cool Gadget: Solar Icemaker Prototype

It’s not portable, or even available yet, but the solar icemaker prototype created by students at San Jose State University (see full story on the icemaker here) is literally cooler than cool.  They used pressure differentials created by rise and drop in daytime temperatures to create a “zero carbon footprint” ice maker.

At something like 5 feet cubed for dimensions, and only capable of producing ice at night, it’s not going to replace the ice tray any time, but it could be really important in places that don’t have easy access to a power grid for food refrigeration and space cooling. Best of all, it looks like something that the dedicated DIYer could put on his or her “To Build” list without having to hit the books much beforehand.

They are currently at work on the product, as well as several others related to solar energySee the San Jose State U program site here, it looks very interesting, and it’s great to see renewable energy being taught in higher education.

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Solar Power Class: Combined Circuits

The next installment of our electrical theory class is about combined circuits. Though studying all the simple circuits of the past few posts (see Ohm’s Law, Kirchoff’s Laws the Formulae Roundup if you’d like a review) is well worth the effort so that you understand the reasons why your power system is or is not working, most often in a power generation setting, you’ll be dealing with things hooked up in combined circuits, which means in combinations of series and parallel that produce the required output wattage to run a house circuit.

So how do you deal with the laws we just learned when you see a circuit that doesn’t seem to fit either category?

Solving Combo Circuits:

For the above example, can you show the remaining measurements for each resistor, and also calculate the total resistance for the circuit? To do this, we must reduce the circuit to a simple circuit of only one type. Before we get started, let me share one more little formula with you. Don’t worry, this one is designed to make your life easier. In a parallel circuit with only two resistors, instead of solving for total resistance in the usual way, you can find it using the following formula, also known as the “product over sum” method:
Rt = (R1 * R2) / (R1 + R2)

First, let’s work on the total resistance measurement. For a combination circuit, you use all the knowledge you’ve been storing up about simple series and parallel circuitry, and simply solve from the outside in, treating each circuit as though it is independent of the rest.

The outermost two resistors are hooked up in parallel (R5 and R6). Because there are only two resistors in this circuit, we can solve for the “equivalent” resistance by using the formula above. Therefore, R5-6 = 30*60 / 30 + 60 = 20Ω.

The next step “into” the center of the circuit is a series circuit composed of R3, R4, and the equivalent value for R5-6. Since in series circuits, we can simply add the partial resistnaces to get the total, we arrive at: 20 + 10 + 20 = 50Ω

This leaves us with a simple series circuit with three resistors – R1, R2, and the equivalent of R4-5-6. Again, we have a series circuit, so we simply add up the partial resistances to arrive at our final Total Resistance for the entire combination circuit. Therefore, 50 + 30 + 50 = 130Ω = Rt

Now that we know the total resistance, finding the total current through the circuit is as easy as using Ohm’s Law: E = I * R. Therefore, 240w = I * 130Ω, and I = 1.846 amps. Now we can use Ohm’s Law’s other formula to figure out the total power. P = I * E = 1.846 * 240 = 443.1 watts.

Now we know all of the totals for the circuit. They are as follows:
Rt = 130Ω
Et = 240v
It = 1.846 A
Pt = 443.1w.

From here you could go on to solve the current or voltage drops at any particular point along the circuits, or similarly figure out the work done at any point along the circuit’s path.

There you have it: you can now solve practically any circuit you’ll encounter.  And remember, practice makes perfect, so keep doing examples until you feel thoroughly comfortable with all these past few lessons.  If you’d like another explanation of combination circuits, check out the links below:

Physics Classroom Tutorial

Understanding and Calculating Combination Circuits

Electrical Engineering Training Series

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