Sun-free photovoltaics

Materials engineered to give off precisely tuned wavelengths of light when heated are key to new high-efficiency generating system.

A new photovoltaic energy-conversion system developed at MIT can be powered solely by heat, generating electricity with no sunlight at all. While the principle involved is not new, a novel way of engineering the surface of a material to convert heat into precisely tuned wavelengths of light — selected to match the wavelengths that photovoltaic cells can best convert to electricity — makes the new system much more efficient than previous versions.

The key to this fine-tuned light emission, described in the journal Physical Review A, lies in a material with billions of nanoscale pits etched on its surface. When the material absorbs heat — whether from the sun, a hydrocarbon fuel, a decaying radioisotope or any other source — the pitted surface radiates energy primarily at these carefully chosen wavelengths.

Based on that technology, MIT researchers have made a button-sized power generator fueled by butane that can run three times longer than a lithium-ion battery of the same weight; the device can then be recharged instantly, just by snapping in a tiny cartridge of fresh fuel. Another device, powered by a radioisotope that steadily produces heat from radioactive decay, could generate electricity for 30 years without refueling or servicing — an ideal source of electricity for spacecraft headed on long missions away from the sun.

According to the U.S. Energy Information Administration, 92 percent of all the energy we use involves converting heat into mechanical energy, and then often into electricity — such as using fuel to boil water to turn a turbine, which is attached to a generator. But today's mechanical systems have relatively low efficiency, and can't be scaled down to the small sizes needed for devices such as sensors, smartphones or medical monitors.

"Being able to convert heat from various sources into electricity without moving parts would bring huge benefits," says Ivan Celanovic ScD '06, research engineer in MIT's Institute for Soldier Nanotechnologies (ISN), "especially if we could do it efficiently, relatively inexpensively and on a small scale."

It has long been known that photovoltaic (PV) cells needn't always run on sunlight. Half a century ago, researchers developed thermophotovoltaics (TPV), which couple a PV cell with any source of heat: A burning hydrocarbon, for example, heats up a material called the thermal emitter, which radiates heat and light onto the PV diode, generating electricity. The thermal emitter's radiation includes far more infrared wavelengths than occur in the solar spectrum, and "low band-gap" PV materials invented less than a decade ago can absorb more of that infrared radiation than standard silicon PVs can. But much of the heat is still wasted, so efficiencies remain relatively low.

An ideal match

The solution, Celanovic says, is to design a thermal emitter that radiates only the wavelengths that the PV diode can absorb and convert into electricity, while suppressing other wavelengths. "But how do we find a material that has this magical property of emitting only at the wavelengths that we want?" asks Marin Soljačić, professor of physics and ISN researcher. The answer: Make a photonic crystal by taking a sample of material and create some nanoscale features on its surface — say, a regularly repeating pattern of holes or ridges — so light propagates through the sample in a dramatically different way.

"By choosing how we design the nanostructure, we can create materials that have novel optical properties," Soljačić says. "This gives us the ability to control and manipulate the behavior of light."

The team — which also includes Peter Bermel, research scientist in the Research Laboratory for Electronics (RLE); Peter Fisher, professor of physics; and Michael Ghebrebrhan, a postdoc in RLE — used a slab of tungsten, engineering billions of tiny pits on its surface. When the slab heats up, it generates bright light with an altered emission spectrum because each pit acts as a resonator, capable of giving off radiation at only certain wavelengths.

This powerful approach — co-developed by John D. Joannopoulos, the Francis Wright Davis Professor of Physics and ISN director, and others — has been widely used to improve lasers, light-emitting diodes and even optical fibers. The MIT team, supported in part by a seed grant from the MIT Energy Initiative, is now working with collaborators at MIT and elsewhere to use it to create several novel electricity-generating devices.

Mike Waits, an electronics engineer at the Army Research Laboratory in Adelphi, Md., who was not involved in this work, says this approach to producing miniature power supplies could lead to lighter portable electronics, which is "critical for the soldier to lighten his load. It not only reduces his burden, but also reduces the logistics chain" to deliver those devices to the field. "There are a lot of lives at stake," he says, "so if you can make the power sources more efficient, it could be a great benefit."

The button-like device that uses hydrocarbon fuels such as butane or propane as its heat source — known as a micro-TPV power generator — has at its heart a "micro-reactor" designed by Klavs Jensen, the Warren K. Lewis Professor of Chemical Engineering, and fabricated in the Microsystems Technology Laboratories. While the device achieves a fuel-to-electricity conversion efficiency three times greater than that of a lithium-ion battery of the same size and weight, Celanovic is confident that with further work his team can triple the current energy density. "At that point, our TPV generator could power your smartphone for a whole week without being recharged," he says.

Celanovic and Soljačić stress that building practical systems requires integrating many technologies and fields of expertise. "It's a really multidisciplinary effort," Celanovic says. "And it's a neat example of how fundamental research in materials can result in new performance that enables a whole spectrum of applications for efficient energy conversion."

David L. Chandler contributed to this story.

RBI's rate increase may not be the last: Pranab

Govt to take steps to support RBI’s war on inflation.

Pranab MukherjeeFinance Minister Pranab Mukherjee on Wednesday dashed even faint hopes of a pause in the Reserve Bank of India’s (RBI’s) rate tightening cycle. Speaking to reporters a day after RBI stunned everybody with a 50 basis points (bps) increase in the repo rate, Mukherjee indicated this might not be the last increase.
I don’t think we have reached the end of the tunnel,” Mukherjee said, when asked if RBI was nearing the end of the rate increase cycle.

Yesterday’s rate increase has drawn criticism from companies worried about higher borrowing costs and prompted economists to revise their growth outlook. Standard Chartered Bank has reduced its gross domestic product growth forecast for this financial year from 8.1 per cent to 7.7 per cent. Kotak has cut its growth forecast to 7.3 per cent from 7.7 per cent, among the lowest in the market.

The benchmark 10-year bond yield on Wednesday hit its highest level in almost three years after rising 15 bps yesterday. Stocks continued their slide, losing nearly 0.5 per cent, and are down 10 per cent this year.

Mukherjee also sought to put a lid on murmurs over a finance ministry-RBI divide over steps to be taken to curb inflation, and pledged support to RBI in its fight against inflation.

RBI had said yesterday that its measure (repo rate increase) was expected to reinforce the point that there was an absence of complementary policy responses on both demand and supply sides.

Asked if he was surprised by the 50 bps increase, Mukherjee said, “I cannot say it surprised me. It is substantial no doubt, but given the situation it was necessary.”

Admitting that the 9.4 per cent inflation in June was “unacceptable”, Mukherjee said high prices were a global phenomenon and the whole world was reeling under rising prices of fuel and other commodities.

The government and RBI were taking steps to check inflation, he said, adding, “I am optimistic that the measures taken by RBI by adjusting the crucial rate will have an impact and inflation will come down.”

The inflation, Mukherjee said, might not come down to below 6-7 per cent by the end of the current financial year.

In an economy, Mukherjee said, “You cannot have a carpet under which you can keep all these things and at the same time expect these things will remain stable”.

He said crude oil prices went up from $89 per barrel when the Budget calculations were done to $107-110 a barrel.

He said he would take up the issue of volatility in commodity and crude oil prices at the international fora, including the G-20.

Meanwhile, the Financial Stability and Development Council, a body of the finance ministry and financial sector regulators, expressed confidence that the growth momentum would be maintained despite yesterday’s steep repo rate increase.

IBM net profit down 1% to $2.29 billion

US computer giant IBM on Monday reported that first quarter net profit fell one percent to $2.29 billion while revenue declined 11% to $21.7 billion.

Earnings per share were $1.70, up from $1.64 in the same quarter last year.

"IBM continued to perform well in a very difficult economic environment," IBM chief executive Samuel Palmisano said in a statement.

"This was due to our long-term strategic focus: shifting into software and services, divesting of commodity businesses, and creating solutions that help clients reduce cost and conserve capital.

"We are well-positioned to continue to move aggressively and leverage our strong cash performance to make the most of the opportunities that arise, including smarter planet initiatives and other strategic options," Palmisano said.

"We remain ahead of pace for our 2010 roadmap of 10 dollars to 11 dollars per share."

Sony Ericsson expects 340-390 mn euro loss in Q1 on weak sales

Cellular handset maker Sony Ericsson Mobile Communications AB on Friday said it expects to post a loss in the range of 340-390 million
euro in the first quarter of this year, due to continued decline in sales.

The company has estimated a net loss before taxes in the range of 340-390 million euro, excluding restructuring charges between 10 million and 20 million euro, Sony Ericsson said in a statement.

"..Net sales and net income before taxes in the first quarter of 2009 continue to be negatively affected by weak consumer demand as well as de-stocking in the retail and distribution channels," the statement added.

Besides, Sony Ericsson plans to ship about 14 million phones during the first quarter of 2009 with an estimated average selling price of 120 euro.

The company is due to announce its first quarter result on April 17.

Sony Ericsson had reported a net loss of 187 million euro in the fourth quarter of last year, against a net income of 373 million euro in the corresponding year-ago period.

Earlier in January, telecommunications firm Ericsson AB had said it would slash about 5,000 jobs as part of its cost cutting initiatives, while it had reported a substantial fall in net income for the fourth quarter ended December 31, 2008.

Worst yet to come for Indian economy: Moody's

The positive movement of the st"The positive sentiment is expected to be short-lived, as India essentially only started feeling the pinch of the global downturn in the December quarter and the worst is yet to come," Moody's economy.com said in a research report.

The industrial production growth slipped into negative territory for the third time in the current fiscal by 0.5 per cent in January while exports also dropped by 15.9 per cent on a year-on-year (y-o-y) basis in the month.

However, expectations of further monetary easing measures by the Reserve Bank increased after inflation fell to 0.44 per cent for the first week of March against 2.43 per cent a week ago.

Since October, RBI has infused over Rs 4,00,000 crore in the system by cutting ratios and signalling interest rate cut.

There is also some positive news from Dalal Street as the Bombay Stock Exchange benchmark index Sensex surged 245 points in this week.

Moody's added that the Indian economy is likely to grow by 6.3 per cent with some downward risk in the current fiscal against government estimate of 7.1 per cent.

For the year 2009, India's growth rate is unlikely to exceed five per cent, but a recovery in the opening quarter of 2010 due to expected rebound of the US economy in the December quarter, should lift annual expansion to about five per cent for fiscal 2009-2010, it said.

It further added that the market sentiment is still unstable in India and so far in 2009 there has been a net outflow from the Indian stock market.

Even businesses in India continue to be troubled by liquidity concerns and tight access to credit.

"As the current focus of many firms is to refinance debt and survive the financial turmoil, investment is expected to be subdued this year," the report added.

Moody's expects long-term investors to continue to value India's underlying growth potential, but speculators who are facing liquidity constraints, are likely to stay clear of emerging markets on signs of turbulence.

"As the current focus of many firms is to refinance debt and survive the financial turmoil, investment is expected to be subdued this year," it added.

Yahoo! CFO Blake Jorgensen to quit

Yahoo! has said its Chief Financial Officer (CFO) Blake Jorgensen will be quitting the company, amid reports that the internet major will soon be revamping its corporate structure.

In a regulatory filing with the US Securities and Exchange Commission on Thursday, Yahoo! said Jorgensen would be leaving the firm and added that the search has started for a new CFO.

Jorgensen would remain with the company as the CFO through a transition period, the filing added.

The development comes amid reports suggesting that the newly appointed Yahoo! chief Carol Bartz would soon be announcing a corporate reorganisation of the company.

Bartz took over the reins of the internet major in January.

On the other hand, Yahoo! India's CEO for Research & Development (R&D) Sharad Sharma has decided to quit the company.

Sharma would be replaced by Shoubick Mukherjee as the new R&D head.

Key rates unchanged; GDP forecast cut to 7%

The Reserve Bank of India (RBI) in its third quarter review of the Monetary Policy 2008-09, kept the key interest rates unchanged. The central bank also scaled down the GDP growth target to 7% with a downward bias from the earlier 7.5%-8%.

The repo rate under the LAF has been kept unchanged at 5.5%. The reverse repo rate under the LAF has been kept unchanged at 4%. The Bank Rate has been kept unchanged at 6%.

The review also reduced the inflation target to 3% in the medium term. The inflation projection is down keeping in view the global trend in commodity prices and the domestic demand-supply balance.

Money supply growth has been revised to 19% from 17% earlier. RBI expects fiscal deficit for FY09 at 5.9 per cent of GDP against earlier estimate of 2.5 per cent.

The Reserve Bank has allowed banks to avail liquidity support under the LAF for the purpose of meeting the funding requirements of mutual funds (MFs), non-banking financial companies (NBFCs) and housing finance companies (HFCs) through relaxation in the maintenance of SLR up to 1.5 per cent of their NDTL.

A special refinance facility for scheduled commercial banks (excluding RRBs) was provided by the Reserve Bank on November 1, 2008 under Section 17 (3B) of the RBI Act, 1934 up to 1% of each bank’s NDTL as on October 24, 2008. Both these facilities are currently available up to June 30, 2009.