Monthly Archives: July 2012

Tokelau: the first nation in the world to go (almost) 100% solar

The Tokelau islands will be the first nation in the world to switch over completely to solar power.

The little group of atolls in the South Pacific Ocean is momentarily depending on petrol that is being shipped in from New Zealand. Tokelau is burning about 2000 barrels a year of petrol at a cost of more than half a million euro. This petrol dependency also impacts Tokelau’s 1,400 residents, who can only count on 15 to 18 hours of electricity each day.

The solar power plant is spread across Tokelau’s three atolls – Fakaofo, Nukunonu, and Atafu. The custom-designed solar system will provide 150 per cent of the nation’s current electricity demand, allowing Tokelauans to expand electricity use without increasing petrol demand. In total 4032 solar panels and 1344 batteries, weighing 250 kg each, will provide electricity to the nation’s people. In overcast weather the generators will run on coconut oil and simultaneously recharge the battery bank.

The Tokelau Renewable Energy Project (TREP) is being headed by Powersmart Solar, a New Zealand company. If they succeed, Tokelau will be the first 100 percent solar electric nation in the world. The only fossil fuel that is still needed will be used for the three cars on the islands. Tokelau’s government estimates the country will save 12,000 tonnes of CO2 over the life of the solar power plant.

Via: www.nzte.govt.nz/features-commentary/success-stories/pages/tokalau-worlds-first-solar-power-nation.aspx

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London’s first hydroelectric turbine generates energy by using a screw

The first hydroelectric turbine in London has been installed at Morden Hall Park on Wednesday.

Morden Hall Park is a National Trust park located on the banks of the River Wandle in Morden, south London. It covers over 125 acres of parkland with the River Wandle meandering through it. The estate contains Morden Hall itself, Morden Cottage, an old Snuff Mill, and many old farm buildings, some of which are now a garden centre and a city farm. The turbine mentioned will be installed in the river, behind the Grade II listed Snuff Mill and the 18th-century east mill waterwheel, which was renovated last year.

The 8.5 kW turbine, manufactured in the Netherlands, acts as a modern waterwheel, harnessing the power of the river to generate electricity. The turbine has an Archimedes screw design which is a machine that has been used since ancient times to lift water to higher levels, for instance for draining water out of mines. In the Netherlands, Archimedean screws are used to remove water from polders to create dry land areas below sea level. The screw is turned usually by a windmill or by manual labour. As the shaft turns, the bottom end scoops up a volume of water. This water will slide up in the spiral tube, until it finally pours out from the top of the tube.

The visitors centre, a former stableyard, is made into a green technology centre that has been appointed the country’s most energyefficient historic building. It has won both the design and innovation category in this year’s Royal Institute of Chartered Surveyors awards and a Green Apple Award. The building hosts a range of green technology, including three different types of solar panels – PV, PV-thermal and solar slates – six types of insulation, an air source heat pump and heritage-sensitive double glazing, plus a wash basin in the cistern of a toilet, allowing water used to wash hands to then flush the toilet.

It’s estimated that the Archimedes screw, costing £350,000, will generate 59,000 kWh a year. Enough electricity to power 18 average-sized houses, the visitor centre and the Snuff Mill in the park. The estate expects to sell the surplus (about 20% of the generation) back to National Grid. The hydroelectric turbine is expected to start generating energy in September 2012.

Spaans Babcock, the Dutch company that manufactured the screw made this video to explain the technology.
Here you can watch a video of a Archimedes screw in a Dutch windmill pumping water.

Via: www.guardian.co.uk/environment/2011/oct/25/hydropower-turbine-river-thames and wikipedia

Researchers improve energy harnassing efficiency from waves

The energy generated from our oceans could be doubled using a new system for predicting wave power, according to researchers from the University of Exeter.

The research, co-written by Tel Aviv University, was published in the journal Renewable Energy and could, according to the scientists pave the way for significant advancements in marine renewable energy, making it a more viable source of power. Currently technologies that extract and convert energy from the sea are not yet as fully developed as solar or wind energy technology. They are as yet not commercially competitive without subsidies. Progress has been made by the leading device developers, but key challenges remain.

Over 70% of the earth’s surface is covered with water. The energy contained within waves has the potential to produce up to 80,000TWh of electricity per year, sufficient to meet our global energy demand five times over. Locations with the most potential for wave power include the western seaboard of Europe, the northern coast of the UK, and the Pacific coastlines of North and South America, Southern Africa, Australia, and New Zealand. In theory power available from wave energy is 1,000 megawatts per kilometer of coastline. In reality, however, only a fraction of this energy can be extracted, in part because wave intensity is highly variable based on the hour, day and season. This is making it difficult to improve the efficiency of energy capture from the waves. The prevention of damage to devices by the hostile marine environment also proves to be a big challenge. The need is to make sure the technology continues to operate in harsh weather circumstances.

According to Exeter scientists, the key to this is to enable devices to accurately predict the power of the next wave and respond by extracting the maximum energy. The team devised a system, which enables the device to extract the maximum amount of energy by predicting the incoming wave. This information enables a programme to actively control the response required for a wave of a particular size. Due to the fact that the device responds appropriately to the force of the next wave, it is far less likely to be damaged and wouldn’t need to be turned off in stormy conditions, as is currently the case.

Co-author Dr Markus Mueller said: “The next step is for us to see how effective this approach could be at a large scale, by testing it in farms of Wave Energy Converters.” There is need for a better understanding of how large wave-energy farms might alter the coastal climate and impact coastal ecology and marine life. Currently underwater noise studies are carried out at the European Marine Energy Center in Scotland.

Via: www.exeter.ac.uk/esi/news/title_216618_en.html
en.wikipedia.org/wiki/Wave_power

Human waste turned into electricity and fertilizer

In one of our earlier posts we wrote about pee power fuelling up hydrogen cars. Now, scientists from Singapore’s Nanyang Technological University (NTU) have developed a new toilet system that can convert the other, more solid human waste to electricity and fertiliser.

Singapore isn’t rich in natural resources, so the NTU scientists chose to do something with the waste material that was available in abundance. The team from NTU say the poo power toilet they developed ( also known as the No-Mix Vacuum Toilet) reduces the amount of water needed for flushing by up to 90% compared to existing toilet systems in Singapore. The existing conventional water closet is said to use about 4-6 lts of water per flush. If installed in a public restroom flushed 100 times a day, this next generation toilet system will save about 160,000 lts in a year – enough to fill a small pool 10m x 8m x 2m.

The toilet has two chambers which separates the liquid and solid waste. Using vacuum suction technology, such as those used in aircraft lavatories, flushing liquids would now take only 0.2 lts of water whilst flushing solids require just one litre. The No-Mix Vacuum Toilet then diverts the liquid waste into a processing facility where components used for fertilizers; nitrogen, phosphorus and potassium can be recovered. Meanwhile all solid waste is sent to a bioreactor where it will be digested to release biogas which contains methane. Methane is odourless and can be used to replace natural gas used in stoves for cooking or processed to electricity and used to fuel power plants or fuel cells. ‘Grey water’ (used water from the laundry, shower and kitchen sink) can be released back into the drainage system without further need for complex waste water treatment, whilst leftover food wastes can be sent either to the bioreactors or turned into compost and mixed with soil, resulting in a complete recovery of resources.

The No-Mix Vacuum Toilets will be useful for new housing estates, hotels, resorts and especially communities not linked to the main sewage system and so requiring their own sewage facilities. The systyem, that has taken one and a half year to develop, has already received some funding. NTU scientists are now looking to carry out trials by installing the toilet prototypes in two NTU restrooms.

Via: news.ntu.edu.sg/pages/newsdetail.aspx?URL=http://news.ntu.edu.sg/news/Pages/NR2012_Jun26.aspx&Guid=b00109d0-4a69-4db9-8dcb-3b4990f9539b&Category=All