Last month in Santa Rosa, CA, an electric-powered 4-seat light plane won the NASA/Google Green Flight Challenge by flying over 200 miles non-stop at over 100 MPH while achieving 403.5 passenger miles per gallon (mpg) using the equivalent of less than one gallon of gasoline. Compare that to the Chevy Volt—the current state of the art in electric (land-based) vehicles—which gets the equivalent of 112 mpg in all-electric mode while driving slowly over flat roads. And even with the benefit of wheels and a 435 lb. battery, the Volt can only keep that up for 35 miles, at which point it reverts to its gas engine, which gets 37 mpg.

The winner of the $1.65 million prize was Team Pipistrel from Penn State, flying a Taurus G4 manufactured in Slovenia. The G4 is a four-seat, twin engine plane with a wingspan of 69’2” and weighing 2,490 lb, slightly less than a Volkswagen Beetle. The two 145 KW (194 HP) motors can drive Pipistrel to about 114 mph, so it won the Challenge race running almost flat out.

Detailed data on the custom-built G4 is hard to come by, but not for the production model Taurus Electro G2. The body is a composite of epoxy resin, fiberglass, carbon fibers and Kevlar in a honeycomb structure. The motor is a high-performance synchronous 3-phase outrunner with permanent magnets, delivering 40 kW on takeoff and 30 kW continuous. The best glide ratio is 1:41, which really qualifies it as a powered glider. To put it in perspective, the typical glide ratio for a two-seat general aviation plane is about 1:10. Aside from getting unimpressive mileage, you really don’t want to run out of gas while flying your Piper Cub. Or in a 747 for that matter.

Electric gliders have been around for a while. The first commercial one was the AE-1 Silent, which first flew in 1997. Weighing a mere 430 lb., the AE-1 is easily powered by its 13 kW (17 Hp) electric motor, which in turn works from a 4.1 kW/77 lb. Li-Ion battery. If you’re so inclined the AE-1 is FAA certified as an ultralight aircraft and it’s still being produced.

More high powered is the Antares 20E from Lange Aviation GmbH, in production since 2004. The 20E is powered by a 42 kW (52 hp) BLDC electric motor weighing 64 lb. Energy storage consists of 72 Li-Ion cells each rated at 44 Ah at 3.7V, for a combined capacity of 12 kWh @ 266V. With a wingspan of 65 ft. and weighing in at 1,455 lb, this is a serious airplane—though still a one seater. The 20E can self launch and climb to 3,300 ft. in four minutes and climb to 10,000 ft., where it can fly for 1.5 hours. Assuming you’ve covered 93 miles at that point and a maximum glide ratio of 1:56 (!), the maximum range then becomes (93+(2×56))=205 miles.

Now let’s figure the mileage for just the powered portion of the flight. Assuming your flight fully depleted the 12 kWh batteries, that works out to 12 kWh/93 miles or 12.9 kWh/100 miles. Using the same formula the EPA applied to the Chevy Volt—where 36 kWh/100 miles = 93 mpg-e—the Antares comes in 2.8x better at 260 mpg equivalent! That’s a pretty energy efficient way to travel.

In an interesting twist Lange is now producing the Antares DLR-H2, which is powered by hydrogen fuel cells, with the tanks slung in pods under the wings. The actual motive force is a 42 kW BLDC motor. The 130 lb. fuel cells can generate 20 kW continuously, twice the 10 kW required for level flight. The DLR-H2 can attain a height of 12,000 ft and has a top speed of 105 mph and a range of 1,240 miles.

Using solar cells to recharge your batteries while in flight can greatly extend your range. In 1990 the solar powered plane Sunseeker flew across the U.S. powered by a 250W array of thin-film solar cells. Since solar cells obviously don’t work at night, it took two weeks to accomplish this task.

The first solar powered plane to complete a 24 hour flight was Solar Impulse. Claiming to have “the wingspan of an Airbus [208 ft.]…the weight of a family car [3,500 lb.]…and the power of a scooter [40 hp],” its designers plan to fly it around the world in 2012. The solar cells on the wings of Solar Impulse cover 650 sq. ft. and can generate 6 kW (8.2 hp), which is stored in Li-Ion cells during the night. All things being equal, this should be enough to keep the 1.6 ton plane aloft day and night while traveling at just over 40 mph.

Even electric commercial airliners are in the works. In Europe EADS, Airbus’ parent company, has proposed the VoltAir ducted fan engine that would power commercial airliners. To achieve the energy density required to move such a massive aircraft, the VoltAir motor would be constructed of high-temperature superconducting (HTS) materials, cooled by liquid nitrogen. HTS motors are expected to reach power densities of 7-8 kW/kg, comparable to 7 kW/kg for today’s turboshaft engines. The batteries will still be Li-Ion, which EADS hopes will become more efficient, or Li-Air should it become commercially viable by then.

Coming to an Airport Near You

While electric flight is both fun and interesting—especially to engineers—it may impact you sooner than you think. Every major city and most smaller ones have general aviation airports. The Taurus G2 and numerous others like it would make quiet, inexpensive air taxis practical. Not only are the planes inexpensive—about the cost of a high-end car—they’re extremely inexpensive to operate, highly reliable, quiet, and essentially non-polluting. Instead of fighting the traffic between New York and Boston or San Jose and Sacramento you would be able to hop a quick, cheap flight there and gaze smugly down at the congestion below.

So there you have it. Electric boats and cars—been there, done that. Stay tuned for electric aircraft. You hopefully won’t have to stay tuned for long, and it will be worth the wait.

By the mid-90’s automakers had pretty much given up on being able to go very far on batteries alone, which led Toyota to introduce the Prius—the first commercial hybrid—in Japan in 1997. In EV mode the Prius is powered by a sealed 38-module 6.5 Ah/274V NiMH battery pack weighing 53.3 kg. That works out to 1.78 kWh total capacity. According to the EPA’s formula, one gallon of gasoline is equivalent to 33.7 kWh—almost 20x what the Prius’ battery alone can deliver. So it’s hardly surprising that the Prius relies primarily on its internal combustion engine for propulsion.

The Chevrolet Volt features a much larger battery with a considerably higher energy density than the Prius. The Volt uses a 16 kWh (197 kg) manganese spinel lithium-polymer prismatic battery pack, which alone can power the Volt for 35 miles (56 km). The Volt’s lithium-ion battery is 2.5x larger in terms of energy density than the Prius’ NiMH battery (.0812 vs. .0319 kWh/kg). Considering that the energy density of NiMH is under 2x that of NiMH—140-300 Wh/liter for NiMH vs. 250-620 Wh/liter for lithium ion—that’s well on the high side of what you would expect.

In addition to having a greater energy density than NiMH—in terms of both weight and volume—lithium-ion batteries also display a much lower self-discharge rate; a greater maximum number of charge/discharge cycles (i.e., they last longer); a more linear discharge rate, which enables more accurate prediction of remaining capacity; and they perform better at low temperatures.

As far as durability goes, both battery types are about the same: NiMH batteries can be discharged and recharged 500-1000 times, with Li-ion batteries being good for 400-1200 cycles. Since replacing an EV battery pack can be a very expensive proposition—currently about $8,000 for the Volt—manufacturers typically guarantee them for an extended period. GM guarantees the Volt’s battery bank for 100,000 miles or eight years.

Not Your Dad’s Li-Ion Battery

OK, assuming your Dad had Li-ion batteries, the ones in the Volt are better. The Volt’s battery design is based on technology developed at Argonne National Laboratory. The Lab used x-ray absorption spectroscopy to study new cathode compositions. They came up with a manganese-rich cathode that resulted in a dramatic increase in the battery’s energy storage capacity while at the same time making it less likely to overheat, and therefore safer and easier to maintain. To complete the trifecta, the new cathode material is also cheaper to manufacture.

Even if there isn’t much beyond Li-ion in terms of energy density—unless you’re comfortable with a thorium-based energy source—there’s still room for improvement. According to Khalil Amine, an Argonne senior materials scientist, “Based on our data, the next generation of batteries will last twice as long as current models.” Chances are your car would give out long before your battery does.

Recycling

When your Volt battery bank finally sends you an End of Life notice, what can you do with it? For one thing you could keep it and use it to help recharge your new Volt battery. Or you might rig it to an inverter bank as a backup source of electricity during power outages or at least peak billing times.

If GM gives you a credit for turning in your old battery on a new one, what can they do with it? The EPA claims that rechargeable batteries are not an environmental hazard if they’re not dumped in landfills; European governments aren’t quite so sanguine, since Li-ion isn’t exactly something you’d like to wind up in your water supply. Both the cathode and anode material can be recycled, which is what most jurisdictions require.

In the end the Volt’s energy storage system turns out to be as high-tech as the rest of the car. Considering how much more reliable electric motors are than internal combustion engines, Volt owners could wind up owning their cars for a very long time.

[This article is part of a series on the Chevy Volt for the UBM/Avnet series Drive for Innovation.]

You Want Gas with That?

There are two basic types of hybrid drivetrains: series and parallel. Series hybrids have a gas engine that turns a generator that charges a battery bank that powers an electric motor that powers the car; the engine is not connected to the drivetrain. The Chevy Volt—which GM refers to as “an extended range electric vehicle (EREV)”— is essentially a series hybrid, though with a twist that we’ll describe in a moment.

In parallel hybrids both the electric motor and the gas engine are connected to the transmission through clutches that enable one or the other to power the vehicle.

Then of course there’s the series/parallel hybrid. In this configuration the two power sources are joined in a planetary gear set that enables either the motor or the engine to power the vehicle, or to share the burden as needs be. Despite being primarily an electric vehicle, the volt actually falls into this category. When you need rapid acceleration, the engine works in parallel with the motor until you let up on the accelerator. Also, the gas engine takes over from the motor when you exceed 70 mph. That’s an appropriate place for the motor – which has its greatest torque at low rpm – to hand control over to the engine, which generates maximum torque at high rpm. Besides, at 80 mph you’ve ceased being an ecopurist and are just in a hurry.

Both the Volt and the Prius are essentially series/parallel hybrids. The main difference is that on the open road the Volt relies more on electrical power and the Prius more on its engine. The Volt as a result has a considerably larger battery bank: 16 kWh for the Volt vs. 5.2 kWh for the Prius. Not surprisingly the Prius has a larger gas engine: a 1.8 liter/98 hp engine vs. the Volt’s 1.4 liter/80 hp engine. OTOH the Volt’s 111 kW (149 hp) electric motor can generate 273 lb-ft of torque, considerably more than the Prius’ 80 hp, 153 lb-ft motor. You might think of the Prius as a gas/electric hybrid and the Volt as an electric/gas hybrid.

Looking at the table, the Volt has about the same power as my Mazda 3, though it gets >3x better gas mileage—and infinitely more for trips under 35 miles, where it’s purely electric. It’s also a lot quieter and more fun to drive.

The Train is Leaving the Station

In late 2010 GM formally introduced the Voltec powertrain on which the Volt is based, though its roots go back to 2007. The basic design combines a small gas engine and a large electric motor that drives the vehicle, though they can work smoothly in tandem when it makes sense to do so. The large lithium-ion battery bank is designed to be recharged at home overnight—in 10 hours from a 110 VAC source or 4 hours from 220 VAC.

The table shows the basic specifications for the 2011 Chevy Volt. GM has announced plans to use the Voltec powertrain in other cars, SUVs, and even trucks, bring down the cost by using the platform across a much larger base of vehicles. Expect the Volt specs to scale for SUVs and trucks. Even Porsche is getting into the act, toying with the idea of an electric 911 (though not the Turbo GT2).

Maybe drivers won’t miss the roar of a big engine so much while they’re quietly zipping past yet another filling station advertising gas for $4/gallon.

Note: This article was first posted at http://www.driveforinnovation.com/get-on-the-drivetrain. Please check out the site if you’re at all into electric vehicles and follow Brian Fuller as he pilots the Chevy Volt across America–well, parts of it anyway. –JD

Ever since Intel hit the Power Wall in 2004—when the Pentium 4 drew 150W and approached 1000 pins—low-power design has come into its own. Over the past decade smart engineers have come up with a seemingly endless number of innovative tricks to stave off the frequently predicted death of Moore’s law, which was supposed to happen first at 90 nm, then 65 nm than 40 nm, etc. Still, when gate doping variations of several atoms can cause a transistor to fail, the laws of physics are finally asserting themselves. As one wit observed recently about Moore’s law, the party isn’t over but the police have arrived and the volume has been turned way down.

On one level better process technologies have gone a long way toward enabling low-power design. Smaller geometries enable lower voltage cores, which helps exponentially on the power front. Strained silicon, silicon-on-insulator, high-K metal gates and other clever process innovations have all enabled the continuing push to smaller geometries and more energy efficient designs.

On the system level design engineers have developed a long succession of power management techniques. Modern MCU’s typically rely on power gating, clock gating, and more recently dynamic (even adaptive) voltage and frequency scaling to minimize power consumption in both active and inactive modes. With the number of sleep modes and voltage islands proliferating, fine-grained power management becomes so complex that most CPUs now rely on separate power management ICs (PMICs). Since MCU’s are more self-contained, much of the power management burden is shifted from the embedded developer back to the chip designer.

Low Power –> Ultra-Low Power

If not the chips then the ‘race to the bottom’—in terms of power—between MCU vendors is getting heated. With the numbers they’re hitting, it’s hard to argue that the newest MCUs are indeed ‘ultra-low power’.

TI promotes its 16-bit RISC ‘ultra-low power’ MSP430 line in a wide range of applications, including a wireless sensor circuit that can operate from a single coin cell for up to five years (thanks in part to a very short duty cycle). The MSP430C1101—with 1kB of ROM, 128B RAM, and an analog comparator—draws 160 µA at 1 MHz/2.2V in active mode, 0.7 µA in standby mode, and 0.1 µA in off mode. This week TI announced its Grace software platform, a free plug-in for Code Composer Studio that provides a detailed graphical user interface to simplify low-level programming of MSP430 MCUs.

Microchip’s answer to the MSP430 is its eXtreme Low Power PIC Microcontrollers with XLP Technology.  XLP processors include 16 to 40 MIPS PIC24 MCU & dsPIC DSC families with up to 256 KM of memory and a variety of I/O options. On its web site Microchip emphasizes how low power its devices are in deep sleep mode, comparing the PIC24F16KA102 favorably to the MSP430F2252 LPM3 at 3V. Comparing power in active modes is considerably more complex, being highly application dependent. That’s what evaluation kits are for.

Silicon Labs claims that its C8051F9xx ultra-low-power product family includes “the most power-efficient MCUs in the industry,” with both the lowest active and sleep mode power consumption (160 µA/MHz /50 nA for the C8051F90x-91x) compared to “competitive devices.” Comparing data sheets is often and exercise in “apples and oranges,” but the numbers do justify the impression that ‘ultra-low power’ is a lot more than marketing hype.

NXP is definitely into green MCUs with its GreenChip ICs that “improve energy efficiency and reduce carbon emissions.” NXP’s recently announced LPC11U00—being a Cortex-M0-based MCU—is decidedly low power, but this one focuses more on connectivity, incorporating a USB 2.0 controller, two synchronous serial port (SSP) interfaces, I²C, a USART, smart card interface3 and up to 40 GPIO pins.

STMicroelectronics features 8- and 32-bit families of ultra-low-power MCUs, apparently skipping over the 16-bit migration path that Microchip needed to fill. The 8-bit STM8L15xx CISC devices can run up to 16 MIPS at 16 MHz but still only draw 200 µA/MHz in active mode and 5.9 µA down to 400 nA in various sleep modes. Like NXP, ST is into connectivity, including a wide range of options on different devices.

Connectivity and flexibility are the main selling point for Cypress’ programmable system-on-chip or PSoC. PSoC 5 is based on a 32-bit Cortex-M3 core running up to 80 MHz. Incorporating a programmable, PLD-based logic fabric, the CY8C54 PSoC family can handle dozens of different data acquisition channels and analog inputs on every GPIO pin. The chip draws 2 mA in active mode at 6 MHz, 2 µA in sleep mode (with RTC) and 330 nA in hibernate with RAM retention.

Grill the Gurus

If after reading all the datasheets you still have questions, this Thursday you can ‘grill the gurus’ online in real time as EE times presents the Digi-Key Microcontroller Virtual Conference: New Directions in MCU Designs, from 11-6 EDT. From 11:15-12:15 EDT I’ll be moderating the panel “Low-Power Design—Keeping Hot Designs Cool,” and questions from the audience are encouraged.

From 12:30-1:30 EDT Scott Roller, Vice President and General Manager, Microcontrollers at Texas Instruments will deliver the keynote, “What Will Make The Biggest Impact: Low Power? Connectivity? Simplicity? Yes.” TI sees the market for embedded MCUs exploding over the next several years, and it’s working on some interesting innovations that should open up new markets for developers.

Throughout the day there will be series of panels, webcasts, chats and exhibits at (virtual) pavilions of interest to the embedded design community. Click here to check it out. I hope to see you there.

The basic structure of the electric grid today is not much different than it was 100 years ago, other than the fact that it supplies AC rather than DC. Reasons for modernizing the grid include reducing costs; using more renewables; improving reliability; and supporting electric vehicle recharging.

The arguments on the cost side are compelling. Half of all U.S. coal plants are over 40 years old, and the cost of upgrading or replacing them is estimated at $560 billion by the year 2030. Smart Grid technology can reduce both peak and average electrical usage, reducing the required investment. There’s also considerable leeway for conservation. In the United States per capita annual electricity usage is 13,000 kWh. In Japan the per capita usage is 7900 kWh. By providing feedback to consumers on their usage patterns and enabling them to shift loads to nonpeak – and therefore lower cost – hours, smart grids provide the feedback loop to consumers both enabling and incentivizing them to conserve electricity.

The US has nowhere to go but up in the use of renewable energy sources. The vast majority of our electricity comes from coal-fired power plants. According to the Department of Energy renewables account for only 8.4% of US electrical generation, with Hydro contributing 5.95%, wind only 0.83% and solar even less.

On the reliability issue: the average U.S. utility customer experiences 125 min. of power outages per year; the average Japanese consumer only has to put up with that for 16 min. per year. The estimated cost of these power outages to the US economy according to the department energy is approximately $80 billion per year.

Turning to the demand side, where does the power go? Residential use accounts for 37%, commercial usage is 36% and industrial applications account for the remaining 27%. On the residential side 17% of your electricity goes to air conditioning, 15% to lights, 9% to heating and the balance to other devices. Getting your kids to turn off the lights will help, but only so much.

Arnold spent some time discussing smart appliances. Smart appliances will need home control systems in order to store your preferences for them; it won’t be up to the electric utility to determine when and which appliances you run. This event was heavily supported by numerous players in the smart appliance and home control markets, including the HomePlug Powerline Alliance, the HomeGrid Forum, the Z-Wave Alliance, the Wi-Fi Alliance and numerous semiconductor, system and utility providers. The stakeholders came to share ideas and hear what NIST had to say.

As well they might. As Arnold asked rhetorically, “With a dozen different communications interfaces, how do you do a national Smart Grid?” Good question. Right now just about every RF protocol you’ve heard of – and some you may not have – is vying to be part of the smart grid. Lacking any kind of standardization, and with plenty of money invested in proprietary solutions, utilities are understandably reluctant to move forward with Smart Grid implementations, and consumers are at least as confused.

NIST has now finished reviewing the various protocols and is now passing that information back to industry to work out standards. In Arnold’s words, “Things are about to become very contentious and argumentative” as standards are hashed out. As Bismarck once remarked, “If you like laws and sausages, you should never watch either one being made.” The same certainly applies to electronics standards.

There actually is real progress being made, and we’ll report on that shortly. Meanwhile don’t despair, the Smart Grid really is happening. It’s just not going to be happening next week.

Just as they have for the last several years, portable devices will continue to drive growth in the electronics industry. Far from just handsets, the mobile internet—also encompassing “the internet of things”—represents a huge expansion of the semiconductor application space to include a wide range of wireless home entertainment, automotive safety and autonomous industrial, military and medical devices. The mobile internet promises to be 10-100x larger in unit volume than the desktop internet ever was.

Amerasekera distinguishes between two types of portable electronics: performance “hub” devices such as computers, multi-media devices, wireless hubs and PDAs which have 1W to 5W needs today; and distributed, largely autonomous systems with micro and nano watt needs. A typical autonomous system—for example, wireless strain gauges in bridges and aircraft wings—has a life expectancy of up to 10 years. Assuming such a device is powered by today’s typical 100 mAh cell phone battery, the average power available from the battery is less than 1 µW. That isn’t possible with today’s technologies.

The problem is that battery technology has been scaling at about 2x every 10 years compared to semiconductor technology, which scales 2x every 18 months. The gap between what portable electronic devices demand and what batteries can deliver will continue to grow. Don’t expect much improvement from the battery camp any time soon. “The energy density of lithium-ion batteries is so high that they’re really like small hand grenades,” said Amerasekera. There isn’t much left on the atomic scale that has a higher energy density and isn’t radioactive.

How Do You Manage?

Lacking more capable batteries, silicon performance advances require power management. A lot of very effective techniques have been developed over the last several years. At 65 nm leakage power was reduced 300x vs. what it had been at 90 nm through a combination of SDRAM retention, logic power gating, channel length reduction, logic retention, process/temperature AVS and dynamic voltage and frequency scaling (DVFS). At 45 nm new techniques were devised—including adaptive body bias (ABB) and Retention ‘Til Access (RTA)—that resulted in 1000x reduction in active power. Still, Amerasekera—like Jan Rabaey in his keynote yesterday—is concerned that we’ve run out of tricks at the component level that will scale.

According to Amerasekera, future advances in ultra-low-power electronics will come at the system level. He gives the example of running an FFT in software, which requires 28 uW. Running it in hardware requires only 1.6 uW, an 18x improvement. Dropping the core voltage yields a further 1.8x power savings, for a total improvement of 28x. The SoC running the FFT now draws < 1uA.

3D chip techniques have finally evolved to the point where they can help optimize bandwidth, power and area. Currently 3D means package on package (POP) or stacked die. FinFET technology now enables more dense dies, and and die-to-die interconnects—vias connecting disparate digital, analog and RF layers—are becoming…viable.

Renewable energy—wind, solar, hydro and heating systems—has tremendous potential, though they’re all faced with economic as well as technical challenges. Energy harvesting also has a lot of potential, but efficiencies of such systems are quite low, as is the amount of energy they can deliver. Still, there’s a place for them going forward.

Divide and Conquer

Basically, the mobile internet will need a variety of energy sources:

• Batteries for general functionality
• Storage caps for high current functions
• Energy scavenging for extended battery life
• Wireless power sources for connection to the grid

The mobile internet will also require intelligent energy management and control, including

• Highly efficient on-chip power processing
• Control of energy sources and delivery
• Management of power demand and access
• Unreliable energy sources (aka wind, solar, etc.)

The challenge for the next decade will be coming up with another 2-3 orders of magnitude of power reduction to meet the demands of an increasingly wireless world.

Engineers always enjoy working on interesting problems, and this one should stay interesting for years to come.

Having long since been politicized, the debate over global warming has become yet another front in the political culture wars. With the climate change deniers being led by such flat-earth luminaries as James Inhofe and Darrell Issa, it’s easy for anyone with upwards of half a brain to dismiss their followers as a bunch of babbling idiots.

While some of them clearly are, unfortunately, fellow tree huggers, they have a point.

Leaky Data

The purported smoking gun is contained in the recently leaked emails and files from Climatic Research Unit (CRU) of the University of East Anglia, on whose research, dataset and algorithms the United Nations Intergovernmental Panel on Climate Change (IPCC) relied in its hugely influential 2007 report. The U.S. EPA in turn relied heavily on that report in determining that carbon dioxide emissions endanger public health and should be regulated. The Obama administration is relying on both the U.N. and the EPA’s findings in arguing for expanding cap-and-trade and in setting its agenda going into the Copenhagen climate negotiations. The underlying data is not nearly as tidy as has been assumed.

I’ve spent the last few days reading the leaked CRU documents and a lot of the commentary surrounding them. I’ve read their programmer’s README file and critiques of their code by a number of experienced programmers. I’ve had to go back to my college programming and math texts to assess some of the critiques, but like it or not they’re largely right.

It’s way beyond annoying to have to agree with Inhofe/Issa that “the books have been cooked,” but they have been. Climate change adherents—and I’m still strongly among them—don’t need to change their conclusions, but they need to know that the data on which they’re basing them isn’t nearly as conclusive as they’d like.

In the case of Inhofe and Issa—both of whom formed their conclusions long before any facts were in (isn’t that called prejudice?)—I take solace in what someone once said of Rush Limbaugh, “Even a stopped clock is right twice a day.”

Show Me the Money

Here are a few key excerpts from the CRU programmer’s README file:

I am seriously worried that our flagship gridded data product is produced by Delaunay triangulation – apparently linear as well. As far as I can see, this renders the station counts totally meaningless.

I am very sorry to report that the rest of the databases seem to be in nearly as poor a state as Australia was. There are hundreds if not thousands of pairs of dummy stations, one with no WMO and one with, usually overlapping and with the same station name and very similar coordinates. I know it could be old and new stations, but why such large overlaps if that’s the case? Aarrggghhh! There truly is no end in sight… So, we can have a proper result, but only by including a load of garbage!

Knowing how long it takes to debug this suite – the experiment endeth here. The option (like all the anomdtb options) is totally undocumented so we’ll never know what we lost.

22. Right, time to stop pussyfooting around the niceties of Tim’s labyrinthine software suites – let’s have a go at producing CRU TS 3.0! since failing to do that will be the definitive failure of the entire project.

Comments in leaked computer code—in addition to Harry’s README file—have sent a swarm of programmers to work critiquing the code. They didn’t have to look far:

A comment in the file briffa_sep98_d.pro says: “Apply a VERY ARTIFICAL correction for decline!!” and “APPLY ARTIFICIAL CORRECTION.” Another, quantify_tsdcal.pro, says: “Low pass filtering at century and longer time scales never gets rid of the trend – so eventually I start to scale down the 120-yr low pass time series to mimic the effect of removing/adding longer time scales!”

Equally damning were comments by CRU researchers, whose agendas—combined with a very dim view of their detractors—were beyond the pale. CRU director Phil Jones, in one email, warns that global warming skeptics “have been after the CRU station data for years. If they ever hear there is a Freedom of Information Act now in the UK, I think I’ll delete the file rather than send to anyone.” Jones was a contributing author on the IPCC’s report.

For its efforts the U.N. panel received a Nobel Prize. For its work the University of East Anglia CRU needs to be excoriated and purged, starting with Jones.

So What?

The only certainty in science is that there is no certainty, only varying degrees of uncertainty that you try to diminish by unbiased research. The rate of climate change and the relative importance of the reasons for it just became more uncertain, thanks to a bunch of wankers in East Anglia whose biases clouded their objectivity, and in the process handed a huge PR victory to their opponents. Thanks, jerks!

Beyond the vocal wall of political demagogues the programmers and climate scientists now finally able to critique the CRU’s model are doing everyone a service. It’s unconscionable that the CRU didn’t allow peer review of their work, especially knowing how dodgy it was. This is how the scientific method is supposed to work. It’s a damn shame it had to come about this way.

In addition to the CRU’s tainted model, there are dozens of other computer models from hundreds of scientists with impeccable credentials, models based on thousands of observations that all point to the same conclusion: the world’s climate does seem to be changing, and increasingly so in recent decades. It beggars belief that 6.8 billion people driving cars powered by fossil fuels and burning coal to heat their homes and generate electricity aren’t having a discernible effect on the environment, even the climate.

To put this in perspective, the earth’s mean radius is 3,959 miles. The breathable portion of the earth’s atmosphere (troposphere) extends out a mere six miles from the surface and the stratosphere out to 30 miles. About 99% of atmospheric gases are contained within these two layers.

The breathable portion of the atmosphere is a mere 0.76% of the radius of the earth—about the same proportion as the skin on a plum. The stratosphere merely supplies an efficient method of carrying pollutants pumped into the air from a coal-fired power plant in Texas, thousands of aging diesel buses in India and rain forest clearing fires in the Amazon to the rest of their respective hemispheres. Cleaning up our act is of paramount importance.

It’s shortly going to become much more important. According to the 2006 U.N. population report, “The world population will likely increase by 2.5 billion … passing from the current 6.7 billion to 9.2 billion in 2050. This increase is equivalent to the total size of the world population in 1950, and it will be absorbed mostly by the less developed regions, whose population is projected to rise from 5.4 billion in 2007 to 7.9 billion in 2050.” As Tom Friedman noted recently in the New York Times, “The energy, climate, water and pollution implications of adding another 2.5 billion mouths to feed, clothe, house and transport will be staggering.”

Sticking with just pollution for the moment, if you’ve ever visited major cities in China you know what pollution is; only one percent of the country’s 560 million city dwellers breathe air considered safe by the European Union. The Chinese government only cracked down on the coal-burning stoves that Beijing residents used to warm their flats and pollute their skies in advance of the 2008 Olympics. They ordered gas-burning heaters installed, which greatly alleviated the chronic smog problem.

After The Great Smog of 1952—caused by Londoners burning high-sulfur coal to keep warm during a temperature inversion—killed nearly 12,000 people, the British Parliament outlawed the burning of coal in open-hearth fireplaces and started pushing cleaner sources of energy.

Just Do It

People often do the right thing only after a situation has gotten so bad that they can no longer deny or ignore it. What matters is doing the right thing in a timely manner, before disaster strikes. It ultimately doesn’t matter whether or not you believe people are responsible for climate change; what matters is whether you support or oppose efforts to curb greenhouse gas emissions, stop polluting the environment and develop clean, renewable sources of energy—all of which lessen the impact of a swelling mass of human beings on the environment.

The bottom line politically is that the U.S. is borrowing from China to buy oil from Middle East dictatorships. This puts us in a weak position strategically and an untenable one economically. Supporting the development of clean, renewable, alternative sources of domestically-produced energy such as solar and wind power makes sense politically, economically and morally. Opposing it is a lot harder to justify.

Whether or not you believe that humans are responsible for climate change, those who do believe it are doing what needs to be done in any case. Those who don’t believe it need to get past “Just say no!” and support their efforts.

Status of Photovoltaic Technology

First up was Dr. Jeffrey Mazer, an engineer with the U.S. Dept. of Energy’s Photovoltaics Program, who spoke on the “Status of Photovoltaic Technology and the DOE / EERE Photovoltaics Program.”

Photovoltaic (PV) solar panels are in huge demand. The market grew 51% in 2007 and 81% in 2008. Seven gigawatts of PV panels were produced in 2008, mostly in India and China. The U.S., which in 1995 had 45% of that market, is now down to 8%. As Tom Friedman remarked recently, “So, if you like importing oil from Saudi Arabia, you’re going to love importing solar panels from China.”

Direct PV module manufacturing costs are now down to under $2/watt, which makes them increasingly attractive; the increasing use of cadmium telluride (CdTe) can drive that down to ~$1/watt. In 2008 about 86% of PV modules were made from crystalline-Si, thought the use of thin-film PV is growing fast due to it much lower manufacturing cost. More than half of U.S. production in 2008 was thin films. Thin films now make up 13-14% of the PV market worldwide and over half in the U.S.

You Got a Problem With That?

Photovoltaics aren’t without their problems. Dust builds up on the modules and obscures sunlight, creating a need for anti-soiling coatings. Inverters and chargers need to be more reliable–they currently suffer from thermal problems.

There are also problems with the basic physics. A solar cell must be able to absorb photons; separate the excess (photogenerated) carriers; and transport them to external terminals. This leads to two fundamental and several difficult challenges.

Fundamental problem #1 is the rapid cooling or thermalization of hot carriers. Energetic photons create carriers too far into the conductance band, where they lose kinetic energy through electron (hole) –phonon scattering mechanisms. The use of multijunctions can help conduct away excess heat, but the process is expensive.

Fundamental problem #2 is the inability to absorb low-energy (sub-bandgap) photons, which further limits their efficiency. For example, for crystalline-Si, infrared (> 1150 nm) is not absorbed.

Mazer’s suggested solution for addressing both problems is quantum dots, which slow down cooling dynamics, allowing impact ionization (inverse Auger process) to produce several e-h pairs from one photon. Quantum dots can be induced by creating a superlattice. For barriers < 4 nm, the wave functions overlap, and minibands form. Minibands might serve as electrodes for collection of hot carriers before they can cool, or absorb sub-bandgap photons in a p-i-n cell.

Difficult though not fundamental problems include high materials costs due to the large size of PV cells (–>use thinner wafers); balance of systems (–>more reliable inverters); and various issues with glass. Mazer predicts that solar will consume 5% of worldwide glass output by 2015-20; however, the low profit margins on such glass creates little motivation for new low-Fe glass plants. So expect to see a possible shortage of solar glass in 2015-2020 that will parallel the shortage of silicon when PV panels really took off a few years ago.

Mazer spent some time explaining different architectures for both silicon and thin film PV cells. The real imperative for the technology is to increase efficiency while bringing down costs. The bottom line, in short, is economic. Currently the cost for producing electricity from solar cells is about $.17/kWh; according to Mazer, that needs to come down to $.05-.10/kWh for solar to be competitive without requiring subsidies. We’re getting there, but we’re not there yet.

Chew On That For a While

On a closing note I had lunch at Dr. Mazer’s table where he fielded questions from fellow hungry engineers. One said he hoped solar could “help relieve our dependence on foreign oil.” Mazer pointed out that only 3-4% of U.S. electrical power is generated by petroleum, so that wasn’t in the cards. Considering that most U.S. electrical power comes from coal-fired and nuclear power plants, hopefully solar will reduce our dependence on those sources.

Reduce our carbon footprint and ‘uranium footprint’ at the same time. I could get behind that.

“Electricity use from power-hungry gadgets is rising fast all over the world… Americans now have about 25 consumer electronic products in every household, compared with just three in 1980. Worldwide, consumer electronics now represent 15 percent of household power demand, and that is expected to triple over the next two decades. To satisfy the demand from gadgets will require building the equivalent of 560 coal-fired power plants, or 230 nuclear plants… Most energy experts see only one solution: mandatory efficiency rules specifying how much power devices may use.”

According to the Natural Resources Defense Council, gaming consoles alone–which kids like mine often leave on all the time so they can pick up where they left off–now use about the same amount of electricity each year as San Diego, the ninth-largest city in the country.

This is both reprehensible and indefensible. It’s also completely unnecessary. Low-power design, when scaled to hundreds of millions of devices, amounts to green engineering. Designing a more power-efficient wall wart or game console is not rocket science. First you have to wake up to the fact that it’s important to do so–then just do it.

Raising awareness of the social (“green”) implications of power-efficient design and providing the tools to help implement such products is the whole mission of Low-Power Design. The Times article makes it clear why going down this path is so important.

Note to CEA: Get Over It

Since the consumer electronics industry hasn’t seen the importance of energy-efficient design, government regulation is the obvious card to play. Since 1990, when the Energy Star standards for appliances went into effect, refrigerators are 45% more efficient on average and washing machines as much as 70%. Scaled to the national level this has precluded the need for hundreds of nuclear or coal-fired power plants.

Appliance Effiency Gains

In 1987 Congress gave the Energy Department the power to set efficiency standards for televisions, which aren’t covered by Energy Star. With the advent of large, flat-panel displays, televisions can now consume more energy than refrigerators, making them Tier 1 energy hogs. Still manufacturers–aggressively lead by the Consumer Electronics Association (CEA)–have fought every attempt to increase energy efficiency in consumer electronics (CE) products. According to Douglas Johnson, the senior director of technology policy at CEA, “Mandatory limits, such as we see in California, threaten to raise prices for consumers and reduce consumer choice.”

Baloney. If I have to pay $100 more for a flat-screen TV that draws half as much power, my total cost of ownership drops dramatically; the payback time depends on your utility rates, but with the average household watching five hours of TV daily, the payback will take place in a matter of months, after which my new TV is putting money in my pocket each month. That’s the sort of choice consumers want and the CEA is fighting to avoid. It’s time to get past “Just Say No!”

It’s also time to get on with the real work of low-power, energy-efficient “green” design. Over to you on that note.

]]> http://low-powerdesign.com/donovansbrain/2009/09/20/low-power-design-has-a-high-power-payoff/feed/ 0 http://low-powerdesign.com/donovansbrain/2009/07/02/clean-energy-jobs-take-off/ http://low-powerdesign.com/donovansbrain/2009/07/02/clean-energy-jobs-take-off/#comments Thu, 02 Jul 2009 16:25:08 +0000 John Donovan http://low-powerdesign.com/donovansbrain/?p=13 Continue reading →]]> The Pew Charitable Trusts have released a study of clean energy jobs, the first hard count of that market. The Pew study shows that job sector grew by 9.1% between 1998 and 2007 compared to overall job growth of 3.7% during the same period.

The high growth rate is partly the result of the small number phenomenon. Pew researchers counted 68,200 businesses and 770,000 jobs across the U.S. tied to clean energy as of 2007–a mere 0.5% of the national total. But the Pew report predicts “explosive growth” in the clean tech sector over the next several years, due to a surge in private investment and the huge amount of money the federal government plans to plow into ‘clean energy’.

The Pew report defines the “clean energy economy” as:

• Clean energy development and production (wind power, solar, biomass, tidal, et al)
• Energy efficiency
• Environmental improvements in products and and manufacturing processes
• Conservation and pollution mitigation, including recycling
• Training and support

Not surprisingly, California came in #1 in terms of venture capital investment in green jobs (Table 1).

The number of clean tech job didn’t entirely follow the money, but they did grow fastest in California and Texas, both of which heavily promote the sector (Table 2).

Don’t Mess With Texas

According to Kil Huh, who led the Pew Study, “Texas is the sixth-largest producer of wind energy in the world. The state’s clean-energy economy is poised for incredible growth.” The state also ranked third in clean-energy venture investments and fourth in clean-energy patents. The Pew study attributed much of this growth to the state’s policies on fostering renewable energy enterprises. But there’s another side to that story, too.

In 2007 Texas had 40,167 jobs tied to conservation and pollution mitigation, accounting for over 70% of the jobs in the clean energy sector. Texas has always been a leading energy producer, and the state government is determined to be a leader in new energy sources, at which the Texas Emerging Technology Fund and Austin Ventures are throwing a lot of money. But if Texas were a nation, it would be the seventh largest producer of greenhouse gases, thanks largely to its fondness for coal-fired power plants and big pickup trucks. So it’s only fitting that as ‘green/clean tech’ catches on, Texas is profiting from cleaning up its act.

California–with its plentiful supply of hydroelectric power–may get snooty about this, but let’s give credit where credit is due. “Doing well by doing good,” etc.

[Full disclosure: I'm a Bay Area native happy to be living in a state that includes Austin, Luckenbach and great BBQ.]