January 2008 Archives
Because of my engineering background and my interest in the topic of renewable energy, people sometimes ask me how much it would cost to install enough photovoltaic (PV) solar panels to generate all of one’s own electrical energy. There are websites to help with this, but they can sometimes be confusing unless you’re a technologist so I’ve developed some simple guidelines that will help to put a PV solar system’s cost in perspective.
In the U.S., a rule-of-thumb is that an average house consumes electricity at the rate of 1 kW. Since there are about 730 hours in each month and the average price of a kW-hour of electricity is about $.10, an average monthly electric bill should be around $73 for 730 kWh of electricity. I will say that this can vary considerably if you have some non-standard items like a hot-tub or some electrical appliances running continuously. It will also increase significantly in months when you run an air conditioning unit. The cost of electricity varies widely across the U.S. as well from a low of $.07/kWh in West Virginia to a high of $.24/kWh in Hawaii, so you’d need to adjust my guidelines accordingly because what I’m writing about here applies to an average home with average electricity costs.
A conservative value to use for a solar panel’s generating capacity is 10 watts/sq. ft. This represents a panel conversion efficiency of about 12% which is typical. That means that for every kW you need to generate, you’d need about 100 sq. ft. of solar panels. If the sun would shine 24 hours a day, you could put up 100 sq. ft. of panels and you’d have enough to power an average home. But as we all know, the sun doesn’t shine all the time. The sun is only available during the day and the amount of sunshine per day is very dependent on cloud cover. Also, the length of each day is dependent on the season. Fortunately, there are resources on the web to help you figure out how many hours per day on average you can count on the sun to shine based on where you live. The numbers across the U.S. vary from an average of around 3 hours per day in places like Seattle, Chicago, and Pittsburgh to 5 or 6 hours per day in states like Colorado and California to a high of 7 hours a day in Arizona. What that means is that the size of your solar panel array can vary from around 400 to 800 sq. ft. (i.e., 4 kW to 8 kW) respectively, depending on where you live. You’ll need more panels if you live in a location that gets less average sunshine per day and fewer if you live in a location that gets higher amounts of average sunshine.
If your utility company allows you to have net metering, that is, they supply you with a special meter that will spin backwards when you generate more electricity than you use, your annual bill can average out to be zero. Because of the change in the length of the day in the winter months, you’ll likely be a net purchaser of electricity in those months and in the summer months, you may be a net producer. A grid-tied system like I’m describing is different than off-grid systems, such as those used in remote locations with no electrical service, since those require batteries and that can significantly increase the overall system cost.
At the time of this writing, the installed cost of solar panels runs between $7 to $9 per watt, so a 5 kW system would cost on the order of $35,000-$45,000 and an 8 kW system would be anywhere from $56,000 to $72,000. Many utility companies are offering incentives with some subsidizing as much as 50% of the cost of the system. Even so, a system that generates an average of $73 of electricity per month would take a long time to pay for itself even if you could get it at half cost. For example, a system that cost $18,000 would have a payback period on the order of 20 years. The panel cost today is around $4 per watt and the extra cost that brings it up to $7 to $9 installed is to cover the installation labor and the electronics needed to tie it into your existing electrical system.
The good news is that the installed cost of PV solar panels is expected to continue to drop as thin film panels from companies like First Solar, Nanosolar, and AVA Solar become available to the residential market. Right now, First Solar is only selling to commercial customers. Nanosolar and AVA Solar have yet to ramp up their production facilities. It will be interesting to see where this all goes in a year or two since these companies are talking about very aggressive price targets and volumes, on the order of $1-2 per watt and volumes that are several times today’s total output. Assuming that the installation and auxiliary equipment costs can be reduced to around $1 per watt, then a 5 kW system may cost as little as $10,000 and the payback would be on the order of 10 years even without subsidies, which begins to make PV solar much more attractive. Of course, all this assumes that electric rates stay constant. However, if anything, electric rates are likely to continue to rise as fuel and other infrastructure costs increase so payback periods for solar panels are likely to become even shorter in the future. I expect we will begin to see many more of them being installed on roofs, especially in areas with favorable solar conditions or higher than average electricity rates.
(above: Electron microscope view of an array of nanoantennas.) “Because of their size, the nanoantennas absorb energy in the infrared part of the spectrum, just outside the range of what is visible to the eye. The sun radiates a lot of infrared energy, some of which is soaked up by the earth and later released as radiation for hours after sunset. Nanoantennas can take in energy from both sunlight and the earth's heat, with higher efficiency than conventional solar cells.”
"I think these antennas really have the potential to replace traditional solar panels," says physicist Steven Novack, who spoke about the technology in November at the National Nano Engineering Conference in Boston.”
The researchers believe that the nanoantennas can be produced using a continuous roll-to-roll process. One of INL’s partners, Microcontinuum, Inc., specializes in this manufacturing process. Although the process has not been perfected yet, they have demonstrated the imprinting process using a six inch circular stamp that contains 10 million nanoantennas.
Why is this new technology so exciting? Researchers believe that the nanoantennas can absorb up to 80% of available energy, a vast improvement over a typical solar panel which absorbs less than 20%. The antennas can also absorb energy radiated back from the earth after the sun has set.
The materials used in production will help keep the price low. Demand for silicon, the semiconductor used in the majority of photovoltaic panels, continues to grow, which keeps the price high. The nanoantennas can be produced with semiconductors other than silicon, and they can be printed on the same plastic that’s used in bags and plastic wrap. “By focusing on readily available materials and rapid manufacturing from inception, Novack says, the aim is to make nanoantenna arrays as cheap as inexpensive carpet.”
Although the research team has made great progress, there are still issues that need to be worked out before the nanoantennas can be mass produced. One problem the team faces is the complex interaction when you combine millions of the antennas. They are using computers to model these interactions and fine-tune the efficiency of the entire array of nanoantennas. The antennas can also produce a large electromagnetic field which may damage the production materials. There are also problems with storing and transmitting the generated electricity. “Although infrared rays create an alternating current in the nanoantenna, the frequency of the current switches back and forth ten thousand billion times a second. That's much too fast for electrical appliances, which operate on currents that oscillate only 60 times a second. So the team is exploring ways to slow that cycling down, possibly by embedding energy conversion devices like tiny capacitors directly into the antenna structure as part of the nanoantenna imprinting process.”
Despite these problems, the researchers at INL are positive the issues can be overcome. Promising exploratory research is under way, and they believe that in a few short years you will be using nanoantennas to charge portable batteries and coat the roof of your home.
Solar Powered Battery Charger Video Overview - Solio Magnesium
The most popular Solio product has been the Hybrid Solar Charger that works almost like a Chinese accordion fan. It expands from a compact egg shape into a tri-fin PV solar collector. With the recent introduction of the magnesium version of the Hybrid Solar Charger users will get 30% to 50% more battery life, increased durability, and better biodegradability once the product is disposed of at the end of it's life. The Hybrid Solar Charger can be charged directly from a wall outlet or using it's PV energy collectors situated on the fan blades.
The coolest part about this solar charger is that it has so many interface options for charging electronics. It's perfect for charging an iPhone or as a solar iPod charger or any other cell phone including the Blackberry, a PSP, just about anything you can think of. The magnesium version has a more universal power outlet which enables users to buy dongles and other attachments from RadioShack, Fry's, or Best Buy. This is definitely one of the most versatile chargers we have seen, we are doing a more extensive test/review in the next couple of weeks which will include more feedback and video.We got a special rate at Mac World on the Magnesium but if you're interested we have a discount offer through Solio for their portable chargers Take 10% of at Solio.com today! Use coupon code: EcoGift10
Video Transcript: The Mag is our latest and greatest, it has the biggest internal battery, it recharges itself faster and will actually charge your cell phone about three to three and a half times before you have to recharge back to the Solio itself, our new Magnesium Solar Charger is actually going to work with iPhones now which makes it really cool, you can actually just pop down the street and get more tips (from Radio Shack) and it increases our compatibility by double so thousands of devices are going to work and are compatible with the Magnesium Solio Hybrid Charger, it's got magnesium outside casing for increased strength...it actually regulates at about 1.5 to 8 watts, while our classic Solio Hybrid Charger is about 1.5 to 5 watts so you get the most power out of the new Magnesium (what is the price difference between the magnesium solio and the classic?) the magnesium solio hybrid battery charger retails for $199 and the classic solio hybrid charger retails for $99 (thank you very much!)
PG&E installed the billboard to promote their new campaign, titled “We Can Do This”. The campaign highlights the California utilities’ commitment to the environment. “As a leader in the fight against climate change, we’re always looking for new ways to educate our customers,” said Greg Pruett, senior vice president of corporate relations at PG&E Corporation. “With this solar-powered billboard – the nation’s first – we increase the amount of clean, renewable energy we provide our customers. We also hope to capture the imagination of Americans about the actionable steps one can take to reduce their environmental impact.”
Nedbank Solar Billboard Video - South Africa Solar Bill Board
The PG&E billboard joins two solar powered billboards in Canada and two in South Africa. Nedbank installed the world’s first solar powered billboard in Johannesburg in June 2006. The billboard supplies power to a local school. The second billboard, erected in December 2007, provides power to a youth center in Cape Town.
For most companies, advertising is a means of creating awareness and growing a customer base. For Ned bank, it’s both these things, but it’s also far more. The bank that promises to ‘Make Things Happen’ has done just that with the recent unveiling of its second ‘solar billboard’ in Athlone in the Western Cape.
The initiative follows the success of Nedbank’s first solar panel billboard that generates electricity for the kitchen at MC Weiler Primary School in Alexandra Township in Gauteng. The electricity generated by the billboard feeds more than 1,400 children each day, and saw the bank scooping South Africa’s first ever outdoor Grand Prix Award at the 54th Cannes Advertising Awards earlier this year. The newest billboard takes the technology a step further and combines solar panels with a wind turbine to provide much needed power and hot water to the Athlone Youth and Family Development Centre in Cape Town.
Unlike the South African and American billboards, the billboards in Canada are not connected to the grid at this time. The billboard shown below belongs to Vancity which is a financial institution in Canada that is trying to become completely carbon neutral. Learn more about their campaign at http://www.weallprofit.vancity.com/
Video speaks louder than words so we decided to sign up for Citizenre on our own and video tape the experience. Below you will find an actual sign up for Citizenre's REnU offering. Also, in order to further assist our readers we've posted a few files that are mentioned during the video review below:
- Citizenre General Terms and Conditions - Dec 2007
- Citizenre Forward Rental Agreement (FRA) Terms and Conditions - Dec 2007
- Citizenre Sample Forward Rental Agreement (FRA) - Dec 2007
Citizenre Video Walkthrough - Citizenre Video Review
A 1998 Japanese project installed 350 schools in PNG with solar systems, so the concept was not unique in these areas. Mandatory training alleviated technological fears stemming from the school systems and enabled the teachers to maintain the units themselves. The GEF support was used to provide low-cost, long-term financing. The teachers’ salaries generally do not allow for much disposable income and with the rising cost of kerosene, which is used for lighting, the salary deductions help many more teachers afford a solar system. It is expected that teachers can save one or two months of salary each year.
The project has been very successful. There are now over 9,000 teachers on the waiting list to receive the solar kits, which have decreased in price by half. The solar kits are now priced at approximately $618 (USD). Click here to learn about other World Bank funded solar energy projects and the International Finance Corporation's involvement and here for their recent article.
Nanosolar Ships First Panels by Martin Roscheisen, CEO Nanosolar. After five years of product development – including aggressively pipelined science, research and development, manufacturing process development, product testing, manufacturing engineering and tool development, and factory construction – we now have shipped first product and received our first check of product revenue.
We are grateful to everyone who supported us through all these years
and the many occasions where there appeared to be mile-high concrete
walls in our path; the unusual intensity and creativity of our team
deserves all the credit for achieving this major milestone today.- the world’s first printed thin-film solar cell in a commercial panel product;
- the world’s first thin-film solar cell with a low-cost back-contact capability;
- the world’s lowest-cost solar panel – which we believe will make us the first solar manufacturer capable of profitably selling solar panels at as little as $.99/Watt;
- the world’s highest-current thin-film solar panel – delivering five times the current of any other thin-film panel on the market today and thus simplifying system deployment;
- an intensely systems-optimized product with the lowest balance-of-system cost of any thin-film panel – due to innovations in design we have included.
Today we are announcing that we have begun shipping panels for freefield deployment in Eastern Germany and that the first Megawatt of our panels will go into a power plant installation there.
As far as the first three of our commercial panels are concerned:
Panel #1 will remain at Nanosolar for exhibit.
Panel #2 can be purchased by you in an auction on eBay starting today. [auction canceled].
Panel #3 has been donated to the Tech Museum in San Jose.
[These are obviously not the first three we ever produced – we have produced loads for testing – but these are the first three of what we consider our commercial panels.]
Popular Science magazine — which many of us read when we were little — just came out with its annual innovation awards.
Our solar electricity technology was named the top Innovation of the Year 2007. Ranked #1 overall, we even came out ahead of the Apple iPhone and many other great technologies (and companies with much larger marketing budgets too in particular).
It’s great to see our hard work — and greentech in general — recognized so enthusiastically! Now we have no choice but to actually make sure that there’s going to be a solar panel on every building in the future.
A few words of an answer to this very frequently asked question:
We are presently a private company and therefore have no stock symbol and no shares available for purchase by the public. In fact, in the past, we have very carefully controlled our selection of investors, and it has been very good for us as a company to work with such a distinguished group of long-term committed stakeholders.
As to the question of when we might offer shares to the public, our board of directors has not yet had a chance to discuss this; we’re simply too focused on product development and company building right now.
In general, note that silicon cell manufacturers (whether based on crystalline silicon or equally capital-intense vacuum-deposited silicon thin films) require so much capital per MW of production capacity that they pretty much have to go public as quickly as they can. Nanosolar is different: Our technology is extremely capital efficient and has such a low cost structure.
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