Commercial wave farm a world first for Portugal
September 25, 2008
Posted in Renewable energy
The world’s first commercial wave farm started operating off the coast of Portugal at Agucadoura on Tuesday. It comprises three red “articulated sea snakes”, each about 140 metres long and 3.5 metres in diameter, which generate about 2.25MW of electricity – enough to power 1,500 homes.
Scottish firm Pelamis Wave Power made the wave converters. They are moored to the seabed about 5km offshore using a special system that allows the machine to float head-on into incoming waves. Each machine has a number of segments linked with hinged joints. As the machine moves with the waves, it extracts power from the motion of the joints. Each joint contains a hydraulic pump, which pumps high-pressure liquid through motors that drive power generators. (There’s a video of how it works on the Guardian’s website).
The energy is then transmitted to a substation on shore at Agucadoura by undersea cables. This energy is then supplied to homes via the national electricity grid.
Portugal has big plans for wave power. Another 22 “sea snakes” will be added to the Agucadoura project in the next few years, bringing its generating capacity to 21MW. This is enough for about 15,000 homes. “Portugal could be for wave power what Denmark was for wind,” a spokesman for Babcock and Brown, the company that built and commissioned the project, was quoted as saying.
As yet, wave power is too expensive to be competitive, reports say. The Agucadoura project’s first three wave converters reportedly cost 8.5-million euros. But the project was made possible in part by the Portugese government agreeing to a feed-in tariff which pays a premium for the wave-generated electricity. The developers envisage that in 15 years wave power should be as competitive as wind power is now.
Sources: Reuters, Power Technology.com, Guardian
Is it a wind turbine or is it art?
September 11, 2008
Posted in Renewable energy
The Energy Ball you see in the picture is a funky little home wind turbine from Home Energy International, of the Netherlands. Apart from looking good, it’s said to be less noisy than traditional propeller turbines and it works at wind speeds as low as 2 metres per second. They come in sizes of 1-metre or 2-metres in diameter and are installed on a pole in the garden or on your roof. The 1-metre ball can reportedly generate up to 500kWh a year and the 2-metre ball 1,750kWh a year. But, alas, they are pretty expensive – from around R24,000 to R56,000. Ouch. The one is the picture is at Schipol Airport in Amsterdam.
Via :: Live Science
The oil crisis and the search for a new way of living
September 9, 2008
Posted in Renewable energy, Transport
Saliem Fakir looks at SA’s energy options and what can be done to improve our energy security.
We live in interesting times that promise both peril and opportunity. Things have changed so fast within the span of just a year that it’s putting a strain on our ability to adapt.
It took five years from 2002-2007 for the oil price to go up by $60/barrel; but in the last 12 months, the price of oil surged by an additional $70/barrel.
The surge in oil prices is making life for everybody uncomfortable, as its ripple effects are being felt throughout the global and South African economies. It has, however, brought home the urgency to find solutions. The whole world is in the throes of a massive cycle of innovation. There lie two possible pathways before us. Read more
Eco-conscious Dutch clubbers light up the dance floor
September 8, 2008
Posted in Renewable energy
[youtube:http://www.youtube.com/watch?v=xoewlHwI3U4]
WATT, a club designed to save about the third of the energy and half of the water used in ordinary nightclubs, opened in Rotterdam last Thursday. The loos are flushed with rainwater, the food is organic, the drinks are served in recyclable cups … but WATT’s showpiece is its “sustainable dance floor” which generates electricity when people dance on it. The LED lights on the floor apparently become more dynamic as more people dance on it and there’s a meter that shows everybody how much electricity they’re generating. Watch the video to see how it works.
Sources: Planet Ark, Sustainable Rotterdam, SustainableDance Club, Watt
SA’s first electricity feed-in system being tested
September 1, 2008
Posted in Renewable energy
Nelson Mandela Bay could be the first municipality in South Africa where homeowners will be able to produce their own renewable electricity and sell the surplus to the national utility, reports The Herald online.
The report says that a pilot project aimed at checking the feasibility of the feed-in approach began six months ago. A one kilowatt solar panel package and a one kilowatt wind turbine on a 12m mast have been installed at a test home, the report says. The system has been up and running since July 28, says the municipality on its website. Read more
Small-scale wind power blows into SA
August 28, 2008
Posted in Renewable energy
I’d always thought that to generate electricity from wind you’d need a great expanse of open space that the wind could howl across to turn giant turbines, but you don’t. Recently, in South Africa, I’ve come across two types of turbine that prove that you don’t need to live on a farm to have a wind turbine. You could, in fact, generate wind power for your home or office. How exciting is that?
The first wind turbine system was installed on a billboard in Bryanston, Johannesburg, see right. It comprises lots of little round turbines joined together. James Lech, the director of Phieco, the local company that sells and installs these turbines says they are designed for urban and rural environments and the system can be scaled to suit your needs. They can be installed on buildings to generation power for lights or air conditioning, for example. What’s more, these little turbines start turning at wind speeds of 1m/s. They also come in different colours, so you could design your system to look like the South African flag, or some other picture, if you like. Go to Phieco’s website to find out more information.
The other turbine is the hybrid wind/solar generator that’s on trial at Cape Town’s N2 Gateway low-cost housing project. It’s known as the Little Wind House (LWH), see left.
From what I can gather, Swiss company Greentecno designed it specifically for developing markets as a cheaper and more sustainable alternative to diesel generators for small-scale electricity generation in rural/off-the-grid locations. It’s described as extremely sturdy, resistant to very high winds and extreme weather conditions, it’s easy to assemble, installation and construction costs are low, and it’s said to need nearly no maintenance.
The LWH’s average generation capacity is 15kWh/day. It’s peak capacity is 4,8kW. It stands 7m high, has a small, vertical-axis wind turbine and eight photovoltaic panels with a peak capacity of 170W each and a maximum power output of the solar component is 1,4kW.
The Times reports that the Cape Town generator will provide power to 10 houses. It sells for R310,000 and the housing department is assessing its cost-effectiveness.
Update (03.09.08): The LWH’s generating capacity is now 25kWh/day. They are also manufactured locally, says Maurits Perold of Greentecno Africa.
Sources: The Times, All Business.com , Stopbigfoot.com, Greentecno
Mystery of how wind turbines kill bats solved
August 26, 2008
Posted in Renewable energy
The number of bats killed by wind farms is higher than birds, researchers say. But many of these bat casualties show no signs of external injuries caused by the turbine blades, so the cause of their deaths has been a mystery. A Canadian researcher may have found the answer, though. She dissected 75 bats found dead around a wind farm in Calgary and found that they had ruptured blood vessels in their lungs. The pulmonary barotrauma, as it’s officially called, is caused by a drop in air pressure. It was found that wind turbines lower the air pressure as they cut through the air, especially around the tips of the blade. Bats flying within a meter of the blades get caught in the depressurised zone and suffer the lung trauma. Birds’ lungs apparently aren’t affected in the same way because they are more rigid. Now researchers are looking for ways to prevent bat deaths at wind farms.
[Via :: ScienceNow Daily News]
Solar-powered flight beats record
August 25, 2008
Posted in Business, Renewable energy
A solar-powered aircraft, the QinetiQ Zephyr, has reportedly broken the official world record for unmanned flight. It flew for 82 hours 37 minutes, exceeding the 30 hours 24 minutes set by Global Hawk in 2001, QinetiQ says.
The Zephyr is a fragile-looking ultra-lightweight carbon-fibre aircraft that is launched by hand. “By day it flies on solar power generated by amorphous silicon solar arrays no thicker than sheets of paper that cover the aircraft’s wings. By night it is powered by rechargeable lithium-sulphur batteries, which are recharged during the day using solar power,” QinetiQ says in a press release.
The flight trial took place at the end of July over the Sonoran Desert in the United States. It was flown via satellite communications to a maximum altitude of more than 60,000ft.
The Zephyr, which is officially known as an unmanned aerial vehicle (UAV), was designed for military use but it looks like it could have civilian applications.
Via :: Crave
Slow uptake for solar geysers. I’m not surprised.
August 22, 2008
Posted in Renewable energy
South Africans need incentives to replace their electric water heaters with solar water heaters because the conversion process isn’t going well, Dorothy Mahlangu of the Gauteng local government said at the Green Building Expo in Midrand this week. [Engineering News] Why am I not surprised? Last October when my electric geyser broke, I wanted to replace it with a solar geyser, but I didn’t and here’s why.
My insurance would only pay out about R4,500 to replace my geyser (because that is what it cost for a replacement electric geyser). I asked a plumber to recommend a solar geyser company – having heard that not all solar geysers are equal – this was before Eskom published its list of approved suppliers. I was told a new solar geyser, plus installation etc, would cost in the region of R18,000.
So, let’s just assume that I would have got a R3,000 consumer rebate from Eskom (which I suspect may be on the generous side), add to that the R4,500 from my insurance, and I would have been left needing R10,500 to pay for a new solar geyser. But I would have had to apply for the rebate after I’d paid for the geyser, so I would, in fact, have needed to have R13,500 handy. Compare that with getting a new electric geyser installed for basically no extra cash except the insurance excess, which I think was less than R1,000. Guess which option I chose?
I still would like a solar geyser, but I just can’t afford it.
Solar-hydrogen system powers a home
August 14, 2008
Posted in Renewable energy
An American civil engineer, who describes himself as a “self-sufficiency” guy, has knocked something together in his garage that produces all the fuel he needs to power his home and his car. Mike Strizki uses photovoltaic panels to turn sunlight into electricity that is then harnessed to extract hydrogen from tap water. He even has a hydrogen-powered lawnmower. See photographs of how he’s adapted his home on Scientific American
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