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New Wireless Sensor Uses Light to Run Nearly Perpetually

The race to create tiny wireless sensors that could monitor anything from pressure in the eyes and brain to the stability of bridges appears to be heating up. Earlier this month, IEEE Spectrum reported on two approaches to creating an almost-indefinitely-running sensor using piezoelectric systems to convert tiny vibrations into power. Now, another team from the University of Michigan has created an alternative approach that uses solar power to keep the sensor running autonomously for many years.

The new sensor checks in at less than 9 mm3, and utilizes an ARM Cortex-M3 core processor. The system allows the sensor to consume only about 100 picowatts when in sleep mode, and only 2.1 µw upon waking up to take sensor measurements. The average power consumption comes out to less than 1 nanowatt. To provide that power, the sensor has a thin-film lithium-ion battery and two 1 mm2 solar cells. It need only be exposed to even mild lighting conditions periodically; in fact, one of the researchers, professor of electrical and computer engineering David Blaauw, said in a press release that it can even be indoor lighting to power the sensor.

The U of M researchers, who presented their work at the International Solid State Circuits Conference in San Francisco last week, said they are working with doctors to come up with potential medical applications for their device. Such internal versions of their sensor could be modified to harvest power from heat or movement, much like the microelectromechanical systems described above. They could be used to monitor pressure in the eyes or brain, or even inside tumors in cancer patients. Blaauw said in a phone call that the intraocular pressure monitoring application could actually still use solar power even when implanted within the eye.

"There is one piece that's missing from our system, and that's the communication," Blaauw said. "That still needs to be added, but we have some prototypes." He said the communications system will not substantially change the sensor's size. Other systems that incorporate a real microprocessor clock in at around 1 cm3, Blaauw said. "Ours is almost 100x smaller."

Image credit: Daeyeon Kim, University of Michigan

Shortcomings in South African Energy Policy

Chris Yelland, a well-informed electrical engineer in South Africa and a director of the country's EE Publishers, delivers a scorching critique of Pretoria's energy policy in a recent EE post. He decries the government's failure to formulate a 20-year integrated plan and its issuance instead of an improvised three-year interim plan, "a shoddy and inadequate piece of work" done without consultation with relevant parties such as independent power producers. Further, says Yelland, despite a government 1998 white paper calling for the electricity system to be restructured along the usual lines, "in the subsequent twelve years, nothing concrete materialised from this grand vision." Meanwhile, he continues, Eskom, the country's main energy company, "no longer has the wherewithal to continue as the sole builder, owner, operator, and maintainer of generation in South Africa on an exclusive basis."  Plans for construction of coal and nuclear plants have been scuppered, without any credible planning for substitute generation.

In fairness, South Africa is by no means the only country or region to have back-tracked on plans to "unbundle" transmission, generation, and distribution, and to establish a single grid operator or regulator. Many others have had second thoughts about the wisdom of trying to introduce competition into electricity, which traditionally has been considered a natural monopoly, and not only because of vested interests getting in the way. Deregulation has not consistently produced lower consumer prices, concerns about reliability and market rigging have surfaced, and there are valid worries about whether companies eying mainly their short-term balance sheets will invest adequately for a long term that can be as long as 60-75 years in the power sector. In the United States, only about half the states have opted to restructure, and it's no accident that those retaining old-fashioned integrated electricity companies are looking most seriously at nuclear, which has high up-front costs but very attractive long-range operating costs.

None of that detracts, however, from the force of Yelland's concerns about South Africa's energy planning, which indeed appears to be woefully unsatisfactory.

POSTSCRIPT (Feb. 26, 2010): A radically different perspective on South Africa's energy dilemmas has been drawn to my attention. A coalition of organizations has launched a global campaign to block the World Bank's plan to lend the country US$ 3.75 billion for construction of a South African coal-fired power plant, with a possible follow-on loan of $1.25 billion. The coalition comprises (among others) Climate Justice Now, groundWork and the Federation for a Sustainable Environment, and has backing from the National Union of Metalworkers of SA, the SA Council of Churches, and other organizations in the United States, India and Bangladesh.

South African opponents of the coal plant project and the World Bank's financing proposal argue that it will drive up consumer electricity rates, impose a long-term debt burden the country cannot afford, further bloat the country's vulnerable "minerals energy complex," and add to the country's "climate debt" as well. (South Africa, with 6 percent of Africa's population, accounts for 40 percent of its carbon emissions.)

The campaign against the Medupi coal plant project comes in the context of growing tension between the U.S. Treasury and the World Bank over its program to fund coal electricity generation in developing countries. The U.S. government has issued a "guidance note" to multilateral development banks saying they should tighten conditions for Third World coal projects. The World Bank's decision on Medupi, expected at the end of March, will be a test of that guidance.


First U.S. Loan Guarantees for New Nuclear Plant

President Obama announced this week that the government will provide $8.33 billion in loan guarantees to support construction of two 1100 MW reactors at a site near Waynesboro, Georgia, where the two Vogtle units already are operating. The reactors will be the Westinghouse AP 1000 model, which is one of the designs developed in the last two decades to serve as a safer, pre-approved template for a new generation of power plants.

The 2005 Energy Policy Act authorized loan guarantees for technology that reduces pollutants or greenhouse gases. Previous grants have supported wind, solar, energy storage, and carbon projects. Obama said the new nuclear units would help "meet our growing energy needs and prevent the worst consequences of climate change." He also stressed immediate employment benefits, making his announcement at a job training center run by the International Brotherhood of Electrical Workers in Maryland.

The Georgia plants are likely to be the first new nuclear construction project initiated in the United States in a generation. But does the announcement amount to a "groundbreaking," as initial radio reports suggested? No. The New York Times points out that because some regulatory hurdles remain, construction will not likely begin before the end of next year. The total cost of the project is estimated at $14 billion, but the direct projected costs shouldered by Southern Company and its partners will be lower, according to a Wall Street Journal analysis.

Buying a Car Minus the Engine - and Fuel

Carmakers have been toying with a novel marketing strategy to take the sting off the electric vehicle's punishing price premium: selling EVs batteries-not-included. The idea is to lease the lithium batteries separately, shaving a third or more of an EV's $30,000-plus package cost. Nissan poured some cold water on the idea last week but EV observers think the idea is just getting started, even for Nissan.

Nissan thinks car buyers are ready for its LEAF EV (see teaser ad above) but not for battery leasing. It closed out a pre-sale national tour of the LEAF with news that the compact will be offered as a complete package. As Energywise reported last month, the package includes installation of a home battery charger. Now we know buyers will own the battery too. “Based on the data we have, consumers prefer to buy the full car with batteries,” Nissan Americas chairman Carlos Tavares told the New York Times.

Greentech Media's Michael Kanellos calls leasing a "conceptual leap" too far: "Imagine if you went to a car dealer today and they offered to sell you the car and lease the engine." But his analogy may be missing a cog, if one considers the comparative cost of charging an EV versus fueling that internal combustion engine. Per mile, charging the EV will cost roughly a third the cost of gassing up. Imagine if you went to a car dealer and they proposed selling you five years' worth of fuel up front!

"The EV minus the battery and charge is like an [conventional car] minus the gas," says Pitt Moos, who runs Daimler's development program for an EV version of the Smart ForTwo. Moos thinks leasing may ultimately succeed if consumers can be educated on the difference in charging and fueling costs. "It will need explanation," says Moos.

That will be the challenge for leasing components: educating consumers to recognize the EV battery and charge as a fueling package. This is the business model for Project Better Place, the Palo Alto-based EV infrastructure firm that picked up $350 million in financing last month. Who is working most closely with Project Better Place to test the concept in Denmark, Israel and other selected markets? The Nissan-Renault partnership.

Smart Grid Promises Substantial Carbon Abatement

The Pacific Northwest National Laboratory  has issued a report in which carbon savings from introduction of smart grid technologies are estimated, looking ahead to the year 2030. PNNL, located in Richland, Washington and operated by Batelle for the U.S. Department of Energy,  puts direct carbon savings from equipment like smart meters at 12 percent, and indirect savings from things like stronger grid support for renewable electricity generation at 6 percent.

Studies like PNNL's must of course be treated with a degree of skepticism, first of all because their estimates depend on a large number of uncertain factors, and second, in this particular case, because the whole subject of the smart grid gives rise to a certain breathlessness. "With smart grids, there should be no need to send out lorries and ring door bells when the power fails," Britain's Economist predicted. "A few mouse clicks may do the trick, or the equipment may even fix itself."

Tell that to the Philadelphia linesmen who risked their lives last week restoring power to homes, following what was in that part of the world the snow storm of several centuries.

Still, the PNNL report meticulously explains its methodology and procedures, and is useful if only for the rather complete laundry list it provides of smart grid technologies and connections. Positive aspects of the smart grid include energy conservation resulting from real-time consumer feedback; more effective efficiency and demand response programs; building diagnostics; load shifting to lower-carbon generation; charging support for electric and plug-in hybrid vehicles; advanced voltage control; and enabling of wind and solar generation.

Of the 6 percent reduction in energy and carbon that the report credits as an indirect effect of smart grid technology, 5 percentage points are from greater use of wind and solar. Support for EVs and hybrids is expected to account for a quarter of the 12 percent carbon reduction from direct effects, that is, 3 percent.

The report's estimates assume that smart grid technologies are "fully implemented by 2030. For equipment like smart meters, which are being installed by the tens of millions in the United States and many other advanced industrial countries, that assumption seems warranted. But for technologies such as EV and hybrid charging, high obstacles must be surmounted if the technology is fully implemented, even assuming that electric and hybrid vehicles mature as hoped.

In an article that appeared last year in the March-April issue of IEEE's Power and Energy magazine, Ali Ipakchi and Farrokh Albuyeh pointed out that "plug-in vehicles will represent a significant new load on the existing primary and secondary distribution networks, with many of these circuits not having any spare capacity and no monitoring and automation capability." Typically, they say, charging a vehicle will more than double an average household's electric demands on the grid.

The PNNL report itself concedes on p. 76 considerable uncertainties in its estimates for hybrid and electric vehicles, because of factors such as choice of reference vehicles, postulated duration and intensity of charging, and assumptions about demands on baseload versus peak generation.

In detail, the PNNL report contains many insightful observations. On p. 52, for example, it points out that considerable carbon savings can be realized if smart grid technologies facilitate load shifting from peak to baseload generation. This is partly because, it says, natural gas peaking plants are about as carbon-intense as coal-fired plants--even though, as is well known, large baseload gas plants emit only about a third or half as much carbon as baseload coal plants.

Will the PNNL's estimated carbon savings largely materialize by 2030? If you had asked me fifteen years ago whether technologies based on the new high-temperature superconductors would be revolutionizing power generation and distribution by 2020, I would have answered in the affirmative, with confidence. But here we are in 2010, with little sign that any of the HTSC technologies are market-ready.

Wind Turbines Cause Radar Cone of Silence

In 2009, about 10,000 megawatts of wind power were installed in the United States, bringing the total capacity in the country up to around 35,000 MW. An interesting technical problem, though, has already slowed the development of wind power and prevented some proposed wind farms from being built. That problem is radar.

Spinning wind turbine blades create a “cone of silence” above the turbines, making it difficult for 2-D radar systems to see aircraft as they fly overhead. It can also create false positives on radar that can look like weather systems (photo). According to Gary Seifert of the Idaho National Laboratory speaking at the RETECH conference in Washington, close to 10,000 MW of wind power has been held up or abandoned completely because of conflicts with FAA, DoD or Department of Homeland Security radar system concerns.

There is ample reason to believe, however, that this type of problem can be overcome. In the United Kingdom, Raytheon was recently awarded a contract by the British National Air Traffic Services (NATS) to develop “clutter erasure” algorithms whereby radar can differentiate between a spinning turbine and an airplane. The company has already completed a feasibility study began in 2006, in which they determined five methods that could now or with future radar systems eliminate the turbine-generated noise.

One of these methods, called concurrent beam processing increased the chances of detection of an aircraft by more than 16 percent in tests at the Altamont Pass wind farm in California. Dual beam radar systems alternate between a lower-angle and higher-angle radar signal, but by processing the two beams at the same time a higher degree of accuracy was achieved.

Radar’s uneasy relationship with wind power doesn’t stop solely at the ability to track aircraft. The much more high-profile complaint about wind farms has been their potential for bird and bat deaths. In order to track bird populations especially around offshore wind farms where simply counting is difficult, the use of radar has been proposed; but radar, of course, doesn’t do so great around the turbines.

A paper by researchers with the radar systems developer DeTect published in Marine Pollution Bulletin in October outlined a wide array of problems radar tracking of birds will face in offshore locations, and a major one is “turbine shadow,” or the turbine’s own radar reflectivity hiding the birds the radar is meant to track.

One of the proposed solutions for such a problem is similar to one of Raytheon’s methods: the use of tracking algorithms. This would allow birds that entered a turbine’s “blackout zone” to be tracked until they left the zone; technical issues do still remain with this fix.

Although wind power installations have increased dramatically in recent years, clearly the radar issues will have to be resolved in order to meet the standing goal of having 20 percent of U.S. electricity come from wind by 2030.

Images via NOAA and Wikimedia Commons.

Inquiry Clears Climategate Researcher

A three-person panel at Pennsylvania State University has cleared faculty member Michael E. Mann of charges that he destroyed or misused data, or engaged in a conspiracy to distort climate science. Mann, a central figure in the so-called climategate scandal, is the person behind the controversial "hockeystick" graph (above) that shows a sharp rise in global temperatures in the last century. The graph, reproduced prominently in the 2001 IPCC climate assessment report, has been a lightning rod for global warming skeptics. Some scientists such as John Christy, see the 20th century temperature record as critically important, but others place more emphasis on the long-term temperature record or on modeling results. In effect there are within climate science several scientific subcultures: some put the most faith in theory, others in simulations, and yet others in empirical results--and even among the empiricists, opinions differ as to what kind of evidence is most compelling.

Image: This chart is Figure 1(b) from the Intergovernmental Panel on Climate Change Third Assessment Report, (c) 2001 The Intergovernmental Panel on Climate Change. The source of this image is a PDF file that can be downloaded here:

UN Posts Post-Copenhagen Pledges

The frustrations and hardships of the Copenhagen meeting--the long and slow lines endured by members of NGOs, the tortured negotiations that increasingly seemed to make a mockery of the "Hopenhagen" posters seen all over town--have been amply documented here and elsewhere. The adequacy or inadequacy of the Copenhagen Accord adopted during the meeting's 11th hour and 59th second will be debated until the end of time. So it's a relief to see the much-maligned UNFCCC posting, as scheduled, two lists of pledges: one of mid-term carbon reductions promised by advanced industrial countries; the other mitigation actions proposed by developing countries.

The schedule of industrial country emissions cuts is short and straight-forward: The box for each country contains a number or range of numbers, plus usually a few lines of text qualifying or elucidating the pledge. The numbers correspond generally to negotiating positions taken before Copenhagen and come as no surprise. Thus, Europe promises to cut emissions 20-30 percent by 2020, subject to a strong follow-on agreement being reached, and Japan 25 percent, subject to the same reservation. Canada and the United States each promise cuts of about 17 percent, Australia 5-25 percent, and Russia 15-25 percent..

The list of statements by developing countries looks more ominous, in that each box instead contains a link to a letter or memorandum, which one naturally opens with dread. But many of the letters turn out to be short and to the point. China's letter, for example, consists of  just four paragraphs, of which the operative one is this:

"China will endeavor to lower its carbon dioxide emissions per unit of GDP by 40-45% by 2020 compared to the 2005 level, increase the share of non-fossil fuels in primary energy consumption to around 15% by 2020 and increase forest coverage by 40 million hectares and forest stock volume by 1.3 billion cubic meters by 2020 from the 2005 levels."

India's letter says: "India will endeavour to reduce the emissions intensity of its GDP by 20-25% by 2020 in comparison to the 2005 level."

Explicitly and implicitly, virtually all statements quoted in the two lists are contingent on future progress in negotiations. The best account I've seen of developments leading up to Copenhagen, the conference and its outcome, and what comes next,  is in Earth Negotiations Bulletin.





U.S. Energy Budget Highlights

The president's 2011 budget, posted yesterday on the White House/OMB website, triples Federal loan guarantees for new nuclear power plant construction, to $54.5 billion. That compares with $3-5 billion in loan guarantees for innovative energy efficiency and renewable energy projects, and $144 million to support grid enhancements. In addition, the Energy Department will invest $4.7 billion directly in development of clean energy technologies, including almost $2.4 billion for efficiency and renewables, $545 for "advanced coal climate change technologies," $300 million for ARPA-E, and $793 million for clean energy activities and civilian nuclear energy programs.

The content and composition of the 2011 energy budget is all the more significant because, as the administration appears to be resigning itself to enactment of what will be at best a weak carbon cap-and-trade bill, the weight of meeting carbon reduction goals will fall more heavily on direct support for green tech. Bearing in mind the U.S. Copenhagen pledge to reduce carbon emissions 17 percent by 2020 and 80 percent by 2050,  the budget allocates $2.6 billion in research on climate change and impacts. The government will invest in registries to account for greenhouse gas emissions and issue regulations to improve energy efficiency, lower consumer bills, and reduce emissions.

Especially considering the more than $10 billion the energy department will be spending on activities associated with nuclear weapons--$2.7 billion to secure materials, $8.1 billion for weapon stockpile stewardship--the budget is bound to dismay advocates of renewable energy and carbon reduction. But bear in mind that the administration already spent very aggressively in 2010 in hot areas like the smart grid and advanced batteries. Even so, green tech advocates in the United States and abroad will be watching like hawks in the coming year to see whether developments are living up to promises.

WSJ Calls China’s Electric Bicycle Craze a Killer

Mainstream media have finally noticed the electric bicycle craze that's swept China — where there are now 120 million e-bikes on the road — and is now making inroads in Europe and North America. This weekend the New York Times examined what it called China's “accidental transportation upheaval”, and the Wall Street Journal devoted a coveted cover slot to China's e-bikes in January. The latter, unfortunately, paints an unduly dark picture of this energy-efficient and relatively affordable urban transport option.

“Because they are so silent, fast and heavy they've become a traffic menace,” says WSJ China correspondent Shai Oster in the video that accompanies his piece on e-bikes, unwisely shot while riding one through Beijing (video embedded below). Oster says this is why there is a “new backlash” against e-bikes, with various levels of Chinese governments trying to squelch the e-bike. What I see is ongoing harassment that China's e-bike community has endured for the past 6-7 years.

Early on the official complaint was that rapid replacement of the lead acid batteries most Chinese e-bikes carry  fueled pollution (According to the Times a typical Chinese e-bike uses five lead batteries in its lifetime, each containing 20 to 30 pounds of lead). Today the complaint is that deaths have “soared” from 34 in 2001 to over 2000 in 2007 (not too surprising given that e-bike use was exploding exponentially over that period). My take — reinforced by alternative-transport and urban design activists in China — is that these complaints are a smokescreen for car-oriented industrial and urban planners.

I stand by that analysis, argued for Spectrum in the 2005 feature “China's Cyclists Take Charge.” But I also ran the issues by Chris Cherry, a transportation engineer at the University of Tennessee-Knoxville who wrote his dissertation on the environmental, safety and mobility impacts of China's e-bike phenom.

Cherry responded yesterday with a back-of-the-envelope comparison that reveals e-bike fatalities — about 3.8 per 10,000 vehicles in 2007 — about as high as you'd expect for China's dangerous streets. In the same year fatality rates for riders of conventional bicycles, motorcycles and cars were roughly 1.5, 12.1 and 81 per 10,000 vehicles, respectively. In the U.S., by contrast, the road fatality rate is about 1.8 per 10,000 vehicles. “An ebike on crazy Chinese streets is only twice as dangerous as me driving to get a gallon of milk in the US”, says Cherry.

He is more sanguine about e-bikes role in Chinese lead pollution. The problem, he says, is that many small, poorly regulated smelters recycle used e-bike batteries and they make a mess in the process, and it is largely the e-bike's explosive growth that keeps them open. “The rate of new high tech facilities can’t keep up with consumption,” says Cherry.

That said, Cherry tells me I'm “right on” as far as the best role for Chinese officials. They could do more good, he agrees, by trying to solve the lead problem than trying to snuff out the e-bike. His proposal is that they use economic rather than traditional regulation (which clearly isn't working): “I think that it would be more cost effective to subsidize clean batteries (as a larger part of their e-vehicle initiative) or [to] heavily tax lead.”


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