With oil prices finally seriously expensive, it’s time to rethink the old boring residential energy management business. Our industry is in a key position to take advantage of new technology that when combined with automation products we already install, can finally take your customer’s house off the grid. And as you’ll see, it has some unexpected side benefits for other home electronics as well.
A little Background
There are only two ways to get energy consumption in the U.S.â€”and the world for that matterâ€”under control. Generate power way more efficiently (and cleanly), or drastically reduce demand. Historically, reducing demand is the only way that average consumer can practically contribute to the solution.
Utility companies have been working both side of the problem for decades. I worked with utility companies for years on load side management technologies using home network technologies like CEBus. The utility installed remotely controlled devices in the home to disconnect loads or set back thermostats to control peak usage. While some of these projects are still kicking around, most went nowhere. Too little, too late, and way boring.
Back in the late 80’s I developed a home automation system (Archinetics, Inc.) that had, among it’s many features, the best state-of-the-art energy management capability. It could monitor and control various electric loads in the home, systematically reduce electric use over time based on living patterns, turn loads off when no one was home, etc. It was great. But in reality, even if this technology was installed in millions of homes, it’s impact would be minimal and too complicated. I know, I know, it adds up, but not enough. It’s just not that serious.
Similar capability exists today in stand-alone energy management products and as part of home automation systems (although not as good). While reducing demand and load management are good, it’s not going to solve anything long term as long as homes are connected to the â€œpipe”. However, when power generation is done on-site, these techniques take on new significance.
Getting serious about energy management and reducing our dependency on nasty stuff like coal and oil (foreign and domestic) means making energy on site (the central distribution systems we use now, not only have too many problems, but would take lifetimes to convert). The best way I know to do this, until small residential nuclear generators are available, is PV (photo voltaic) solar.
Solar electric power for the home is nothing new. It’s been around at least since the 1980’s, but historically too expensive for even close to break-even, even over decades. Like many people, after researching it about 5 years ago, I shelved the idea as a not- ready-for-prime-time solution. It was kind of like high-end home theatre: technology toys for the rich. This has all changed while I wasn’t looking.
A recent news item and NY Times article about Solar City (www.solarcity.com), a “custom electronics installation company” was a real wake-up call. To quote the NY Times article describing the recent incredible increase in solar
installations: “They point to companies like Solar City, an installer of rooftop solar cells based in Foster City. Since its founding in 2006, it has grown to 215 workers and $29 million in annual sales. â€œIt is hard to find installers,” said Lyndon Rive, the chief executive. â€œWe’re at the stage where if we continue to grow at this pace, we won’t be able to sustain the growth.”
Check out their site at www.solarcity.com. These guys have put together a great design/field installation business specializing in solar systems. The company offers:
* A lease package with lease payments less than the previous electric bill
* Little or no installation charge
* Free repairs/service
* Free performance monitoring via internet
I’m not the only one impressed. The company’s sales are backed up for at least 18 months in CA alone.
So what’s changed to make solar electric now so hot? Three things.
* Lower cost solar panels due to incredibly increased demand and competition
* Higher cost of energy, big time over the last two years
* Dramatically increased state and federal subsidies
Companies that make solar panels are seeing the largest increase in demand in their history. To paraphrase another NY Times article:
“SunPower, which makes silicon-based cells, reported 2007 revenue of more than $775 million, more than triple its 2006 revenue. The company expects sales to top $1 billion this year. SunPower, based in San Jose, said its stock price grew 251 percent in 2007, faster than any other Silicon Valley company, including Apple and Google.”
Many solar panel manufacturers are beginning to use materials like copper indium gallium selenide, or CIGS, an alternative to the conventional crystalline silicon, the dominant technology. CIGS, while less efficient than silicon, can be made far more cheaply than silicon-based cells. Nanosolar’s (a startup that makes CIGS “panels) factory looks more like a newspaper plant than a chip-making factory. The CIGS material is sprayed onto giant rolls of aluminum foil and then cut into pieces the size of solar panels.
And it gets better. One of the most expensive and bothersome part of a solar electric installation has been batteries for storing electric power to use during night time. The yare big, expensive, and not that efficient. A familiar story in the electric car business which has pushed the technology hard over the last few years. The results have been enormous progress in high capacity battery development for the electric car industry and it’s spilling over into the solar electric industry. Just google â€œbattery breakthrough” and you’ll see what I mean. Check out nanowire batteries.
And just last month, a major breakthrough occurred in fuel cell technology. Danial Nocera and Matthew Kanan at MIT have developed an unprecedented process using new catalysts and a minimum amount of electricity to split water into hydrogen and oxygen gases at room temperature. Later (at night), the oxygen and hydrogen are recombined in a fuel cell to recreate the electricity. Overnight, fuel cells went from a not-so-great energy storage device to something that could actually change the world. No joke. Check it out at: web.mit.edu/news office/2008/ oxygen-0731.html
And, oh yes, Federal and State governments and electric utilities are currently offering tremendous financial incentives to motivate home owners to switch to solar. Current rebates can cover 30-35% of the total solar system cost.
Even without all the new technologies coming online, the existing equipment is highly reliable. It’s been through 25+ years of field installation debugging so it’s just a matter of sizing the equipment for the home load and average sunlight.
There is not enough space in this tip to cover the details of a solar system, so this is just the highlights for those not familiar with these systems. The diagram below illustrates atypical installation. The PV silicon panels generate a relatively fixed output voltage even in low light levels. The more sun on the panel, the more current they can generate. They are usually connected in parallel to combine the current. The DC output of the panels is applied to a power inverter. The inverter serves several tasks. It generates
240 V AC (split phase) for connection to the house load center. It also acts as a battery charger, storing excess panel output. If the load is more that the panels can supply(such as at night), the inverter draws from the batteries. If you remove the solar panels, this is really just a big UPS.
Solar panels are designed for various DC output voltagesâ€”12, 24, 48 volts DC are typical. Higher voltages are needed if they need to be located a long distance from the inverter. Crystal Silicon panels, currently the most efficient at converting light to DC, are capable of outputting about 12 watts per square foot and currently cost about $4.50 a watt. In a typical residential installation, they should last 25 to 30 years. The output of solar panels decreases as they age and after 20 years, begins to gradually drop off. While newer technologies like amorphous silicon and CIGS mentioned earlier are much cheaper, they are much less efficient and thus require a larger “footprint”. The size of the panels and total area depends of course on how much energy the customer is willing to pay for and trade off from the electric service.
The batteries (and charge controller) are optional. A system without it is referred to as a grid tie system. Obviously it only supplies power when there is adequate sun. Most practical systems will need some sort of batteries. Most batteries used in current solar systems are fairly traditional, deep discharge, lead acid. But as the price of new battery types is pushed down by the electric car industry, this should change quickly to more efficient types meaning smaller and fewer for the same storage. The batteries not only store charge for discharge during the night, but act as reserve source of power for peak loads, reducing the total panel space required.
The inverter is a powerful DC powered 240V AC oscillator. It has to match frequency and phase of the generated AC with the incoming grid AC. They come in an almost infinite variety of powers and features. To be off-the-grid, they have to be able to supply the largest peak load the house is capable of demanding (with load management), this could be anywhere between 10,000 and 12,000 watts. They can be paralleled for larger loads. Fortunately, current designs are between 85-95% efficient. When loads are low, they direct panel DC to charge the batteries.
A solar power installation has some interesting side benefits to our industry.
1. UPS – by definition, the house is running off a big uninterruptible power supply (UPS). No need to install extra ones for computers or AV equipment.
2. Clean power – the inverter, by design, is a power conditioner. It provides a well regulated source of AC. Unless it malfunctions, no threat of over/under-voltage from the grid, no spikes, surges, or other noise from outside sources. Cool!
3. Readily available low-voltage DC – back in the 1980’s some of you might remember the NAHB Smart Home project. At the core of the project was a plan to establish a new wiring system for the home that would include the distribution of low-voltage DC at most outlets. The idea was that it would eliminate the proliferation of low-voltage power supplies for electronic equipment. A nice idea but needless to say, it didn’t fly. Too complicated, too expensive. But a solar power system already has the low-voltage supply built-in. You just need to supply wiring from the batteries to low-voltage equipment. Hey, it’s an idea.
So, why is this such a great opportunity for our industry? Let me list just a few of the reasons:
* We’re already in the residential custom electronics business. This becomes an add-on. We have all the basics.
* If your customer can afford what you are offering now, they can easily afford a solar system installation. Even so, the economic model is only going to get better.
* Installation is not rocket science but it requires engineering skill. These systems must be designed and professionally installed. Something you should be good at now.
* Nearly infinite demand. It’s like retrofit, every home is a potential customer.
* If Solar City is any indication, customers will be calling you. What better way to introduce the customer to other products and services you offer.
No, it isn’t as glamorous as home theatre. But it IS something that you can make money at that is actually beneficial to the customer and the world. AND you can combine it with your other work, especially automation. Nowhere on the Solar City site does it mention anything about load management. The cost saving figure they give appear to be based on standard grid-based electrical usage in the home. But, if you couple on site generation with on-site load management through a good home automation/managment system…bye-bye grid! And you CAN do it.
If you have any questions about anything in this TIP or VoIP story to relate, drop me an
e-mail at firstname.lastname@example.org I will actually answer it!
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