Thursday, 29 January 2009

Clean Energy Innovations - An Overview

Original Article - MIT Technology Review

As the energy debate rages in political and scientific circles, investment in clean energy technologies continues to rise. Clean Energy Trends 2008, published by research firm Clean Edge, estimates that fuel cells, solar PV, wind energy, and biofuels — a combined $77.3 billion market in 2007 — will increase to $254.5 billion (or 229 percent) within a decade. Even ocean energy research, which once ebbed due to its costly nature, has enjoyed a resurgence, attracting $250 million in global capital expenditure since 2004, according to ABS Energy Research. Yet, it remains to be seen which clean energy technologies have the brightest commercial future.
Is ocean energy the next wave?

A recent report completed by Greentech Media and the Prometheus Institute for Sustainable Development estimates that the annual market size for ocean energy in the next six years will total $500 million, with installed capacity growing from less than 10MW today to about 1GW during the same period. However, ocean energy remains largely uncharted compared to the progress made on other renewable energy fronts.

The Florida Atlantic University Center for Ocean Energy Technology (COET) is working to change that by focusing on ocean energy permitting and policy development, education and workforce development, public outreach, standards development and economic analysis.

[More ...]

Cheap, super-efficient LED lights on the horizon

Original Article - New Scientist

Incandescent tungsten-filament light bulbs face a global switch-off as governments push for energy efficient fluorescent lamps to become the standard. But the light could soon go out on those lamps too, now that UK materials scientists have discovered a cheaper way to produce LED bulbs, which are three times as efficient as fluorescent lamps.

Although the ultimate dominance of LED lights has long been predicted, the expense of the super-efficient technology has made the timescale uncertain. The researchers now say LED bulbs based on their new process could be commercially available within five years.

Gallium nitride (GaN) LEDs have many advantages over compact fluorescent lamps (CFLs) and incandescent bulbs. They switch on instantly, with no gradual warm-up, and can burn for an average of 100,000 hours before they need replacing - 10 times as long as fluorescent lamps and some 130 times as long as an incandescent bulb. CFLs also contain small levels of mercury, which makes environmentally-friendly disposal of spent bulbs difficult.

Cracking up

The cost of production has kept the LEDs far from homes and offices, however. Gallium nitride cannot be grown on silicon like other solid-state electronic components because it shrinks at twice the rate of silicon as it cools. Crystals of GaN must be grown at 1000°C, so by the time a new LED made on silicon has cooled, it has already cracked, rendering the devices unusable.

One solution is to grow the LEDs on sapphire, which shrinks and cools at much the same rate as GaN. But the expense is too great to be commercially competitive.

Now Colin Humphreys's team at the University of Cambridge has discovered a simple solution to the shrinkage problem.

They included layers of aluminium gallium nitride in their LED design. These layers shrink at a much slower rate during cooling and help to counteract the fast-shrinkage of pure gallium nitride. These LEDs can be grown on silicon as so many other electronics components are. "They still work well as LEDs even with those extra layers inside," says Humphreys.

Early switch-over

A 15-centimetre silicon wafer costs just $15 and can accommodate 150,000 LEDs making the cost per unit tiny. That levels the playing field with CFLs, which many people only ever saw as a stopgap solution to the lighting problem.

Humphreys reckons that the UK government encouraged consumers to drop tungsten bulbs too soon. "We should have stayed with tungsten for another five years and then switched to LEDs," he says.

Humphreys's team was funded by the UK Engineering and Physical Sciences Research Council. The UK government's Technology Strategy Board will now provide the funding to turn the new technology into a commercial process.

Monday, 19 January 2009

Balloon power isn't just a load of hot air

Original Article - New Scientist

For those who dislike the sight of wind turbines on the horizon, would a spectacular hot-air balloon farm be more acceptable?

Ian Edmonds, an environmental consultant with Solartran in Brisbane, Australia, has designed a giant engine with a balloon as its "piston". A greenhouse traps solar energy, providing hot air to fill the balloon. As the balloon rises, it pulls a tether, which turns a generator on the ground. Once the balloon has reached 3 kilometres, air is released through its vent and it loses buoyancy. This means less energy is needed to pull the balloon back down again, resulting in a net power gain (Renewable Energy, DOI: 10.1016/j.renene.2008.06.022). "It is like a huge two-stroke engine, with a capacity of 45 million litres, a stroke of 3 kilometres, and a frequency of one revolution per hour," says Edmonds.

For roughly the same cost as wind power, Edmonds has calculated that a large 44-metre-diameter recreational balloon could generate 50 kilowatts, enough to supply energy to about 10 homes. Doubling the diameter of the balloon would increase power production tenfold, substantially reducing costs, he says.

Using air heated by the sun to generate power has been attempted before: solar towers use the rising air to turn turbines. But a prototype solar tower in Manzanares in Spain proved too short even at 200 metres, limiting the amount of energy that could be captured from the rising air. Building towers of 500 metres or more has so far proved too expensive.

Science Direct

Wednesday, 14 January 2009

Cut power costs with DC power

Original Article - InfoWorld

(Note: The AC.vs.DC discussion below, while centered around dense data center applications, has relevance to the New City Design discussion as we attempt to rationalize the integration of micro generator capability, DC motors, devices which currently rely on low amperage DC power bricks and the AC transmission grid. Where is the most appropriate AC/DC boundary and how to we make it flexible and capable of evolution as our social structures change and as public spaces and private spaces arrange themselves?)

Our recent article "10 power-saving myths debunked" generated a lot of interest and controversy. One topic that sparked plenty of discussion was the use of DC power in the datacenter. Because all computers use DC power internally, the basic concept is to limit the number of energy-wasting AC-to-DC conversions between the utility pad and the servers and to make those conversions as efficient as possible.

In a typical datacenter environment, power conversions abound along the path from the outside utility pad to the servers. With each conversion, some power is lost. The power starts at the utility pad at 16,000 VAC (volts alternating current), then converted to 440 VAC, to 220 VAC, then to 110 VAC before it reaches the UPSes feeding each server rack. Each UPS converts the incoming AC power to DC power, then back to AC. The UPSes then distribute that AC power to their respective servers -- where it's converted back to DC. As much as 50 to 70 percent of the electricity that comes into the datacenter is wasted throughout this long and winding conversion process.

There's a more efficient approach, one promoted by Validus DC Systems: taking the utility-supplied 13,000 VAC and converting it directly to 575 VDC (volts direct current) using an outdoor-rated conversion unit, then running power into the datacenter over 1.5-inch cabling. Each rack in the datacenter then has a 575-to-48-VDC converter that is 95 percent efficient. The direct DC approach can save users 50 percent or more between cooling savings and elimination of conversion losses, according to Ron Croce, COO of Validus.

It might be tempting to place an AC-DC conversion unit outside the datacenter so that heat dissipation occurs outdoors and to run 48 VDC into the datacenter. However, long runs at 48 VDC suffer from voltage drop, which means that a good deal of power is lost before it gets to the servers -- about 20 percent for every 100 feet of cabling.

One of the common arguments against using DC power in the datacenter is that machines don't support it: Most servers run on 110 VAC, which is then converted internally into 5 VDC and 12 VDC. However, with the use of DC power gaining some traction in datacenters, a number of server vendors, including HP, IBM, and Sun, are making DC power supplies available on some or all of their server lines, such that the machines can run on 48 VDC. HP's next generation of server chassis will be the same for all AC- and DC-powered systems, with modular power supplies.

Moreover, some large systems, such as the IBM P Series, are already designed to use 575 VDC. Although there is no current standard for high-voltage DC power in datacenters, Panduit and other companies are working on a standardized 400-VDC connector and cabling solution. General Electric is currently working on listing 600-VDC circuit breakers with the Underwriters Laboratories. These breakers already function at 600 VDC but were not previously rated because there was no demand.

In addition to providing cost savings through higher efficiency, DC systems may also provide an opportunity to expand datacenter capacity: Many existing datacenters are using only part of their available square footage because they can't get more power or cooling capacity. Some telecommunications centers are finding that newer rack systems require 100 watts per square foot rather than the old standard of 40 watts per square foot. Due to lack of space, their buildings can't support the 4-foot-thick bundles of cabling necessary for that much 48-VDC power. Moving to high-voltage DC could get around these limitations, because the required cabling would be just 1.5 inches thick.

In many areas, including New York, the San Francisco Bay Area, and Los Angeles, companies are unable to get additional power from the local utilities. Increasing the efficiency of existing systems could also allow companies to continue to use existing buildings and still expand datacenter capacity.

A high-voltage power system like that from Validus requires substantial installation and investment, including running large diameter cabling from the utility pad outside into the datacenter, installing the 575-to-48-VDC converters for each rack, and converting servers to 48 VDC. However, saving 50 percent or more on power over many years represents a big return. For companies that are unable to increase datacenter capacity by buying more power capacity, turning to DC may be the only solution.

Monday, 5 January 2009

Report: Toyota developing solar powered green car

By YURI KAGEYAMA, AP Business Writer

TOKYO – Toyota Motor Corp. is secretly developing a vehicle that will be powered solely by solar energy in an effort to turn around its struggling business with a futuristic ecological car, a top business daily reported Thursday.

The Nikkei newspaper, however, said it will be years before the planned vehicle will be available on the market. Toyota's offices were closed Thursday and officials were not immediately available for comment.

According to The Nikkei, Toyota is working on an electric vehicle that will get some of its power from solar cells equipped on the vehicle, and that can be recharged with electricity generated from solar panels on the roofs of homes. The automaker later hopes to develop a model totally powered by solar cells on the vehicle, the newspaper said without citing sources.

The solar car is part of efforts by Japan's top automaker to grow during hard times, The Nikkei said.

In December, Toyota stunned the nation by announcing it will slip into its first operating loss in 70 years, as it gets battered by a global slump, especially in the key U.S. market. The surging yen has also hurt the earnings of Japanese automakers.

Still, Toyota is a leader in green technology and executives have stressed they won't cut back on environmental research despite its troubles.

Toyota, the manufacturer of the Lexus luxury car and Camry sedan, has already begun using solar panels at its Tsutsumi plant in central Japan to produce some of its own electricity.

The solar panels on the roofs add up in size to the equivalent of 60 tennis courts and produce enough electricity to power 500 homes, according to Toyota. That reduces 740 tons a year of carbon dioxide emissions and is equal to using 1,500 barrels of crude oil.

Toyota is also likely to indirectly gain expertise in solar energy when its partner in developing and producing hybrid batteries, Panasonic Corp., takes over Japanese rival Sanyo Electric Co., a leader in solar energy, early next year.