Tag Archives: Wind power

Offshore wind could calm hurricanes

FOR IMMEDIATE RELEASE US scientists say that very large wind farms could not only withstand a hurricane: they would also weaken it and so protect coastal communities. LONDON, 26 February – US engineers have thought of a new way to take the heat out of a hurricane. Fortuitously-placed offshore wind farms could make dramatic reductions in wind speeds and storm surge wave heights. Hurricanes are capricious consequences of peculiar sea temperature and wind conditions, while wind farms are the outcome of years of thoughtful design and investment, and not an emergency response to a severe weather warning. But, according to new research in Nature Climate Change, a giant wind farm off the coast of New Orleans in 2005 could have lowered the wind speeds of Hurricane Katrina by between 80 and 98 miles an hour, and decreased the storm surge by 79%. Katrina was a calamitous event that caught civic, state and federal authorities off-guard, and devastated the city. But an array of 78,000 wind turbines off the coast would, according to Mark Jacobson of Stanford University, and Cristina Archer and Willett Kempton of the University of Delaware, have defused its force dramatically – and turned a lot of hurricane energy into electricity at the same time. Wind turbines turn in the wind to generate energy. The laws of thermodynamics are inexorable, so a national grid’s gain is the wind’s loss, because wind energy is dissipated as it crosses a wind farm. One turbine literally takes the wind out of the sails of another.

Tempest models

One of the three Nature Climate Change authors, Cristina Archer, last year examined the geometry of a hypothetical wind farm to work out how to place turbines most efficiently to make the best of a gusty day, rather than have one bank of turbines turning furiously while the others barely stir. But this same translation of wind circulation to electrical circuitry suggested another accidental consequence. Mark Jacobson and his colleagues used sophisticated computer models to test the impact of a hurricane on a wind farm, and since the US has both cruel experience and highly detailed records of hurricane events, he and his Delaware partners decided to model three notorious tempests: Superstorm Sandy, which slammed into New York in 2012 and caused $82 billion damage in three US states, Hurricane Isaac, which hit Louisiana the same year, and Hurricane Katrina in 2005. “We found that when wind turbines are present, they slow down the outer rotation winds of a hurricane,” Professor Jacobson said. ”This feeds back to decrease wave height, which reduces movement of air toward the centre of the hurricane, increasing the central pressure, which in turn slows down the winds of the entire hurricane and dissipates it faster.” And Cristina Archer put it more vividly: “The little turbines can fight back the beast,” she said. Her colleague Willett Kempton added: “We always think about hurricanes and wind turbines as incompatible. But we find that, in large arrays, wind turbines have some ability to protect both themselves and coastal communities from the strongest winds.”

Double benefit

The conclusions are based entirely on computer simulations. Real world tests are for the moment unlikely, chiefly because wind farms tend to have dozens or, at the most, hundreds of turbines and the hurricane experiment was based on turbines in their tens of thousands, delivering hundreds of gigawatts. But Professor Jacobson and Dr Archer tend to think big anyway. They argued in 2012 that four million wind turbines in the world’s windiest places could generate at least half the world’s electricity needs by 2030 without interfering too greatly with global atmospheric circulation. The tempest-taming qualities of really big wind farms would deliver an added bonus: they could offer protection to vulnerable coastal cities. The costs of wind-farming on such a scale would be huge, but then the losses to coastal cities from flooding and storm damage in a rampant climate change scenario are expected to rise to $100 trillion a year by 2100. The three authors calculate that the net cost of such projects – after considering all the good things that could come from them – would be “less than today’s fossil fuel electricity generation net cost in these regions and less than the net cost of sea walls used solely to avoid storm damage.” A sea wall to protect one city might cost anything from $10 billion to $29 billion, and that is all it would do: protect that city. A really big wind farm would offer protection during cyclones, typhoons or hurricanes and generate carbon-free energy all year round. – Climate News Network

FOR IMMEDIATE RELEASE US scientists say that very large wind farms could not only withstand a hurricane: they would also weaken it and so protect coastal communities. LONDON, 26 February – US engineers have thought of a new way to take the heat out of a hurricane. Fortuitously-placed offshore wind farms could make dramatic reductions in wind speeds and storm surge wave heights. Hurricanes are capricious consequences of peculiar sea temperature and wind conditions, while wind farms are the outcome of years of thoughtful design and investment, and not an emergency response to a severe weather warning. But, according to new research in Nature Climate Change, a giant wind farm off the coast of New Orleans in 2005 could have lowered the wind speeds of Hurricane Katrina by between 80 and 98 miles an hour, and decreased the storm surge by 79%. Katrina was a calamitous event that caught civic, state and federal authorities off-guard, and devastated the city. But an array of 78,000 wind turbines off the coast would, according to Mark Jacobson of Stanford University, and Cristina Archer and Willett Kempton of the University of Delaware, have defused its force dramatically – and turned a lot of hurricane energy into electricity at the same time. Wind turbines turn in the wind to generate energy. The laws of thermodynamics are inexorable, so a national grid’s gain is the wind’s loss, because wind energy is dissipated as it crosses a wind farm. One turbine literally takes the wind out of the sails of another.

Tempest models

One of the three Nature Climate Change authors, Cristina Archer, last year examined the geometry of a hypothetical wind farm to work out how to place turbines most efficiently to make the best of a gusty day, rather than have one bank of turbines turning furiously while the others barely stir. But this same translation of wind circulation to electrical circuitry suggested another accidental consequence. Mark Jacobson and his colleagues used sophisticated computer models to test the impact of a hurricane on a wind farm, and since the US has both cruel experience and highly detailed records of hurricane events, he and his Delaware partners decided to model three notorious tempests: Superstorm Sandy, which slammed into New York in 2012 and caused $82 billion damage in three US states, Hurricane Isaac, which hit Louisiana the same year, and Hurricane Katrina in 2005. “We found that when wind turbines are present, they slow down the outer rotation winds of a hurricane,” Professor Jacobson said. ”This feeds back to decrease wave height, which reduces movement of air toward the centre of the hurricane, increasing the central pressure, which in turn slows down the winds of the entire hurricane and dissipates it faster.” And Cristina Archer put it more vividly: “The little turbines can fight back the beast,” she said. Her colleague Willett Kempton added: “We always think about hurricanes and wind turbines as incompatible. But we find that, in large arrays, wind turbines have some ability to protect both themselves and coastal communities from the strongest winds.”

Double benefit

The conclusions are based entirely on computer simulations. Real world tests are for the moment unlikely, chiefly because wind farms tend to have dozens or, at the most, hundreds of turbines and the hurricane experiment was based on turbines in their tens of thousands, delivering hundreds of gigawatts. But Professor Jacobson and Dr Archer tend to think big anyway. They argued in 2012 that four million wind turbines in the world’s windiest places could generate at least half the world’s electricity needs by 2030 without interfering too greatly with global atmospheric circulation. The tempest-taming qualities of really big wind farms would deliver an added bonus: they could offer protection to vulnerable coastal cities. The costs of wind-farming on such a scale would be huge, but then the losses to coastal cities from flooding and storm damage in a rampant climate change scenario are expected to rise to $100 trillion a year by 2100. The three authors calculate that the net cost of such projects – after considering all the good things that could come from them – would be “less than today’s fossil fuel electricity generation net cost in these regions and less than the net cost of sea walls used solely to avoid storm damage.” A sea wall to protect one city might cost anything from $10 billion to $29 billion, and that is all it would do: protect that city. A really big wind farm would offer protection during cyclones, typhoons or hurricanes and generate carbon-free energy all year round. – Climate News Network

Staggered turbines 'make most of wind'

FOR IMMEDIATE RELEASE
Wind farms, along with solar energy,  could soon provide enough energy to provide for half the world’s needs, researchers say. The only problem is working out how best to build them.

LONDON, November 6 – US scientists have worked out how to get 33% more power from an offshore wind farm – stagger the turbines rather than line them up in neat, orderly rows.

Cristina Archer of the University of Delaware and colleagues report in Geophysical Research Letters that they started with a real, working offshore wind farm – Lillgrund in Sweden – and then, using computer simulations and real weather data, hypothetically arranged the turbines to achieve the optimum results.

The problem is a real one. In April two US scientists calculated that spacing set practical limits to wind power: the impact of air on turbine blades set them turning but also set up eddies that took the wind out of the sails of the turbine downstream.

Land costs are huge, so there is a limit to the possibilities of spacing for onshore wind farmers. But offshore farms can spread themselves a little more comfortably. Dr Archer and her colleagues tried six simulated configurations, sometimes keeping the turbines at the same distance, sometimes further apart, and sometimes staggering them according to the prevailing wind, in the way theatre seats are staggered to give everyone a better view of the stage.

Hopes of huge potential

It was a combination of the two approaches – more generous spacing, and a staggered alignment – that gave the best results. In general, they argue, the right placement and arrangement could improve energy yields by 13% to 33%.

It all boils down to having the right attitude. Last year, in a display of the power of positive thinking, Dr Archer and a colleague from California calculated that wind turbines could deliver half the world’s energy demands by 2030 with minimal environmental impact. This would require four million turbines at 100 metres above ground level in all the windiest places.

Not everybody agrees: others argue that wind energy in particular cannot match coal, oil or nuclear, because the ratio of power to unit area is so much lower. A few days ago, commentators warned in Nature Geoscience that a world driven by renewable energy would create an enormous demand for metals and minerals – and energy to extract them.

But Dr Archer isn’t the only researcher at the University of Delaware to take a distinctly optimistic view of renewable resources. In January a different team from the same institution reported that a combination of wind power and solar energy could keep the US grid supplied around 99.9% of the time. – Climate News Network

FOR IMMEDIATE RELEASE
Wind farms, along with solar energy,  could soon provide enough energy to provide for half the world’s needs, researchers say. The only problem is working out how best to build them.

LONDON, November 6 – US scientists have worked out how to get 33% more power from an offshore wind farm – stagger the turbines rather than line them up in neat, orderly rows.

Cristina Archer of the University of Delaware and colleagues report in Geophysical Research Letters that they started with a real, working offshore wind farm – Lillgrund in Sweden – and then, using computer simulations and real weather data, hypothetically arranged the turbines to achieve the optimum results.

The problem is a real one. In April two US scientists calculated that spacing set practical limits to wind power: the impact of air on turbine blades set them turning but also set up eddies that took the wind out of the sails of the turbine downstream.

Land costs are huge, so there is a limit to the possibilities of spacing for onshore wind farmers. But offshore farms can spread themselves a little more comfortably. Dr Archer and her colleagues tried six simulated configurations, sometimes keeping the turbines at the same distance, sometimes further apart, and sometimes staggering them according to the prevailing wind, in the way theatre seats are staggered to give everyone a better view of the stage.

Hopes of huge potential

It was a combination of the two approaches – more generous spacing, and a staggered alignment – that gave the best results. In general, they argue, the right placement and arrangement could improve energy yields by 13% to 33%.

It all boils down to having the right attitude. Last year, in a display of the power of positive thinking, Dr Archer and a colleague from California calculated that wind turbines could deliver half the world’s energy demands by 2030 with minimal environmental impact. This would require four million turbines at 100 metres above ground level in all the windiest places.

Not everybody agrees: others argue that wind energy in particular cannot match coal, oil or nuclear, because the ratio of power to unit area is so much lower. A few days ago, commentators warned in Nature Geoscience that a world driven by renewable energy would create an enormous demand for metals and minerals – and energy to extract them.

But Dr Archer isn’t the only researcher at the University of Delaware to take a distinctly optimistic view of renewable resources. In January a different team from the same institution reported that a combination of wind power and solar energy could keep the US grid supplied around 99.9% of the time. – Climate News Network

Staggered turbines ‘make most of wind’

FOR IMMEDIATE RELEASE Wind farms, along with solar energy,  could soon provide enough energy to provide for half the world’s needs, researchers say. The only problem is working out how best to build them. LONDON, November 6 – US scientists have worked out how to get 33% more power from an offshore wind farm – stagger the turbines rather than line them up in neat, orderly rows. Cristina Archer of the University of Delaware and colleagues report in Geophysical Research Letters that they started with a real, working offshore wind farm – Lillgrund in Sweden – and then, using computer simulations and real weather data, hypothetically arranged the turbines to achieve the optimum results. The problem is a real one. In April two US scientists calculated that spacing set practical limits to wind power: the impact of air on turbine blades set them turning but also set up eddies that took the wind out of the sails of the turbine downstream. Land costs are huge, so there is a limit to the possibilities of spacing for onshore wind farmers. But offshore farms can spread themselves a little more comfortably. Dr Archer and her colleagues tried six simulated configurations, sometimes keeping the turbines at the same distance, sometimes further apart, and sometimes staggering them according to the prevailing wind, in the way theatre seats are staggered to give everyone a better view of the stage.

Hopes of huge potential

It was a combination of the two approaches – more generous spacing, and a staggered alignment – that gave the best results. In general, they argue, the right placement and arrangement could improve energy yields by 13% to 33%. It all boils down to having the right attitude. Last year, in a display of the power of positive thinking, Dr Archer and a colleague from California calculated that wind turbines could deliver half the world’s energy demands by 2030 with minimal environmental impact. This would require four million turbines at 100 metres above ground level in all the windiest places. Not everybody agrees: others argue that wind energy in particular cannot match coal, oil or nuclear, because the ratio of power to unit area is so much lower. A few days ago, commentators warned in Nature Geoscience that a world driven by renewable energy would create an enormous demand for metals and minerals – and energy to extract them. But Dr Archer isn’t the only researcher at the University of Delaware to take a distinctly optimistic view of renewable resources. In January a different team from the same institution reported that a combination of wind power and solar energy could keep the US grid supplied around 99.9% of the time. – Climate News Network

FOR IMMEDIATE RELEASE Wind farms, along with solar energy,  could soon provide enough energy to provide for half the world’s needs, researchers say. The only problem is working out how best to build them. LONDON, November 6 – US scientists have worked out how to get 33% more power from an offshore wind farm – stagger the turbines rather than line them up in neat, orderly rows. Cristina Archer of the University of Delaware and colleagues report in Geophysical Research Letters that they started with a real, working offshore wind farm – Lillgrund in Sweden – and then, using computer simulations and real weather data, hypothetically arranged the turbines to achieve the optimum results. The problem is a real one. In April two US scientists calculated that spacing set practical limits to wind power: the impact of air on turbine blades set them turning but also set up eddies that took the wind out of the sails of the turbine downstream. Land costs are huge, so there is a limit to the possibilities of spacing for onshore wind farmers. But offshore farms can spread themselves a little more comfortably. Dr Archer and her colleagues tried six simulated configurations, sometimes keeping the turbines at the same distance, sometimes further apart, and sometimes staggering them according to the prevailing wind, in the way theatre seats are staggered to give everyone a better view of the stage.

Hopes of huge potential

It was a combination of the two approaches – more generous spacing, and a staggered alignment – that gave the best results. In general, they argue, the right placement and arrangement could improve energy yields by 13% to 33%. It all boils down to having the right attitude. Last year, in a display of the power of positive thinking, Dr Archer and a colleague from California calculated that wind turbines could deliver half the world’s energy demands by 2030 with minimal environmental impact. This would require four million turbines at 100 metres above ground level in all the windiest places. Not everybody agrees: others argue that wind energy in particular cannot match coal, oil or nuclear, because the ratio of power to unit area is so much lower. A few days ago, commentators warned in Nature Geoscience that a world driven by renewable energy would create an enormous demand for metals and minerals – and energy to extract them. But Dr Archer isn’t the only researcher at the University of Delaware to take a distinctly optimistic view of renewable resources. In January a different team from the same institution reported that a combination of wind power and solar energy could keep the US grid supplied around 99.9% of the time. – Climate News Network

Smarter energy 'can save billions'

FOR IMMEDIATE RELEASE
New ways of producing and using energy offer significant financial savings and mean technologies like wind power can perform much better than at present.

London, 5 July – US energy researchers have devised a new way to save billions: tailor the air-conditioning to the needs of the people in the room.

Scientists at Pacific Northwest National Laboratory in the state of Washington have calculated that they could boost energy efficiency by 18% simply by customising air movement according to whether the room is empty or full.

A sensitive detector that could “count” the people in a room could turn down – or turn up – fan speed to the right levels automatically. Occupancy sensors already turn off needless lighting in offices: the next step would be ventilation, says the new report.

“This is the reason you often feel cold when you’re in a big space like a conference room or cafeteria without a lot of people. Technology today doesn’t detect how many people are in a room, and so air flow is at maximum capacity nearly constantly”, said Guopeng Liu, lead author.

He and colleagues focused on a typical office block 12 stories high and with a basement, covering an area almost as big as a football field. Such buildings in the US cover 4.4 billion square feet, at least 40,000 hectares, of urban space.

Avoiding waste

They calculated that advanced ventilation controls could save $40,000 a year in costs in such a building in 13 of the nation’s 15 climate regions.

In two cities in very different climates, Baltimore, Maryland and Fairbanks, Alaska, savings could be more than $100,000 a year per building. The only catch so far is that the technology has yet to be perfected – and of course must then be installed.

The same laboratory has just delivered a new report on ways to make the most of wind power by “storing” energy for use later.

In the region, the wind often drives turbines at times when demand is low. But it should be possible when demand is low to use the surplus power to compress air and tuck it away in an underground geological storage structure: as the wind dies away and the power demand rises, the stored air could be released to the surface, where it would warm up, expand and drive the turbines.

Compressed air storage plants – one already exists in an old salt mine in Alabama, another in Germany – could return as much as 80% of the energy they take in: energy that would otherwise be wasted.

Aiming for the heights

But, of course, subterranean technology offers yet another solution to the energy challenge, according to a recent paper in Science. Two scientists from the University of Utah point out that geysers in California already deliver 850 megawatts to the grid; steam from an Italian volcano at Lardarello turns out nearly 600 megawatts and 90% of homes in Reykjavik in Iceland are heated by geothermal water piped from the rocks.

The hard bit is getting at the subterranean heat. Just two per cent of the thermal energy trapped at depths of 3.5 to 10 kilometres would, the researchers calculate, yield 2,000 times the current annual energy use of the United States.

Meanwhile, in Switzerland, energy research is looking up: at an experimental power plant  flown like a kite, at heights of 300 metres. Wind turbines right now reach no more than 100 metres.

Researchers from Empa, the Swiss Federal laboratories for materials science, and other institutes, reason that the most reliable and powerful wind currents are at higher altitudes. So they have begun to develop Twingtec – a high technology kite fastened to a reel at a ground station.

As the kite soars, the line tenses and the reel unwinds: the movement gets converted to current by electromagnetic induction. Once the kite gets to its maximum height, the reel tugs it in so it can rise again. The prototype has already been tested in the Jura mountains, not far from Bern. – Climate News Nnetwork

FOR IMMEDIATE RELEASE
New ways of producing and using energy offer significant financial savings and mean technologies like wind power can perform much better than at present.

London, 5 July – US energy researchers have devised a new way to save billions: tailor the air-conditioning to the needs of the people in the room.

Scientists at Pacific Northwest National Laboratory in the state of Washington have calculated that they could boost energy efficiency by 18% simply by customising air movement according to whether the room is empty or full.

A sensitive detector that could “count” the people in a room could turn down – or turn up – fan speed to the right levels automatically. Occupancy sensors already turn off needless lighting in offices: the next step would be ventilation, says the new report.

“This is the reason you often feel cold when you’re in a big space like a conference room or cafeteria without a lot of people. Technology today doesn’t detect how many people are in a room, and so air flow is at maximum capacity nearly constantly”, said Guopeng Liu, lead author.

He and colleagues focused on a typical office block 12 stories high and with a basement, covering an area almost as big as a football field. Such buildings in the US cover 4.4 billion square feet, at least 40,000 hectares, of urban space.

Avoiding waste

They calculated that advanced ventilation controls could save $40,000 a year in costs in such a building in 13 of the nation’s 15 climate regions.

In two cities in very different climates, Baltimore, Maryland and Fairbanks, Alaska, savings could be more than $100,000 a year per building. The only catch so far is that the technology has yet to be perfected – and of course must then be installed.

The same laboratory has just delivered a new report on ways to make the most of wind power by “storing” energy for use later.

In the region, the wind often drives turbines at times when demand is low. But it should be possible when demand is low to use the surplus power to compress air and tuck it away in an underground geological storage structure: as the wind dies away and the power demand rises, the stored air could be released to the surface, where it would warm up, expand and drive the turbines.

Compressed air storage plants – one already exists in an old salt mine in Alabama, another in Germany – could return as much as 80% of the energy they take in: energy that would otherwise be wasted.

Aiming for the heights

But, of course, subterranean technology offers yet another solution to the energy challenge, according to a recent paper in Science. Two scientists from the University of Utah point out that geysers in California already deliver 850 megawatts to the grid; steam from an Italian volcano at Lardarello turns out nearly 600 megawatts and 90% of homes in Reykjavik in Iceland are heated by geothermal water piped from the rocks.

The hard bit is getting at the subterranean heat. Just two per cent of the thermal energy trapped at depths of 3.5 to 10 kilometres would, the researchers calculate, yield 2,000 times the current annual energy use of the United States.

Meanwhile, in Switzerland, energy research is looking up: at an experimental power plant  flown like a kite, at heights of 300 metres. Wind turbines right now reach no more than 100 metres.

Researchers from Empa, the Swiss Federal laboratories for materials science, and other institutes, reason that the most reliable and powerful wind currents are at higher altitudes. So they have begun to develop Twingtec – a high technology kite fastened to a reel at a ground station.

As the kite soars, the line tenses and the reel unwinds: the movement gets converted to current by electromagnetic induction. Once the kite gets to its maximum height, the reel tugs it in so it can rise again. The prototype has already been tested in the Jura mountains, not far from Bern. – Climate News Nnetwork

Brazil's indigenous harness the wind

While Brazil’s Government tends to favour a one-size-fits-all approach to energy provision, an indigenous group in the far north has come up with its own more sustainable solution, as our São Paulo correspondent reports

SAO PAULO, 9 May – A few years ago I lay in a hammock in a mud and wattle hut in a Makuxi village, shining my torch on the walls to look for spiders, listening to the BBC World Service on my radio (I learnt that Labour leader John Smith had died). There was no light – the noisy diesel generator which provided a few hours energy each day was turned off at night.

The Makuxi, one of Brazil’s largest indigenous communities, with about 19,000 people and 140 villages, inhabit an area of savannah and sierras in the far northern state of Roraima, sharing  borders with Venezuela and Guyana.

Their land, which was offically recognised by a Supreme Court ruling only in 2009, after years of conflict with invading goldminers, cattle ranchers and rice farmers, stretches to the foothills of the imposing Mount Roraima, a table top mountain with sheer cliffs rising 9,000 feet (2,750 m) high.

This was the mountain that inspired Arthur Conan Doyle to write The Lost World, published one hundred years ago. In the book, prehistoric creatures still roamed the plateau of a remote table mountain. The Makuxi, however,  are more concerned with today’s problems than yesterday’s myths.

After the illegal occupiers had been expelled, they began the task of  restoring land and rivers contaminated by years of  pesticides. And they are now looking for ways to replace the old diesel-powered generators with renewable sources of energy. The nearest power grid is 185 miles (300 kms) away.

Planning for sustainability

 

The Brazilian Government has a programme to bring electricity to rural communities which is called Light For All, and it is considering building a number of dams inside the Makuxi reserve.

But the Makuxi have come up with another idea. The Brazilian Atlas of Wind Potential shows that the northern region of their reserve, Raposa-Serra do Sol, enjoys some of the strongest winds in the country, with speeds of up to 11 metres per second being registered, and an average of six to nine metres.

So in February three towers were installed to measure the winds over the period of  a year, in order to calculate the potential  for generating  energy. The project is the result of a three-way partnership between the Indigenous Council of Roraima (CIR),  the Socioenvironmental  Institute (ISA), one of Brazil’s largest NGOs, and the Federal University of  Maranhão (UFMA).

The towers were installed by the Makuxi themselves. They also plan to map the energy needs of each family in their communities. A team of 14 indigenous researchers is travelling round the villages with GPS equipment and questionnaires.

They hope the energy to be generated will be enough, not only for domestic consumption, but also for the agricultural activities they are also preparing, as part of their plan to develop their reserve sustainably.

Too many helpers

 

The Makuxi do not want to repeat the experience of the other large indigenous community in Roraima, the Yanomami. Several years ago the German Government’s development agency donated solar panels for a health post and other buildings in their area. But none of the Yanomami were trained to maintain them.

Carlo Zaquini, an Italian missionary who has worked with the Yanomami for decades, told me what happened: “Over the years the panels developed problems, but because none of the Yanomami knew how to repair them, every visiting outsider, whatever his speciality, has had a go at tinkering with them, so now they don’t work at all.”

Once they have the results of the wind speed study the Makuxi hope to persuade the Government that harnessing the region’s powerful winds will be a more sustainable solution than hydropower, which researchers now conclude also produces carbon emissions.

The Makuxi’s extraordinary wind power potential, favoured by their terrain of savannah and mountains, is probably unique among Amazonian indigenous populations.

Solar energy – with local people trained to maintain the equipment – seems a much more feasible solution for rainforest communities. So far the Brazilian Government, committed to a gigantic programme of  dam building, has shown little interest in these more modest solutions. Backing from NGOs is probably the only way to make them happen. – Climate News Network

While Brazil’s Government tends to favour a one-size-fits-all approach to energy provision, an indigenous group in the far north has come up with its own more sustainable solution, as our São Paulo correspondent reports

SAO PAULO, 9 May – A few years ago I lay in a hammock in a mud and wattle hut in a Makuxi village, shining my torch on the walls to look for spiders, listening to the BBC World Service on my radio (I learnt that Labour leader John Smith had died). There was no light – the noisy diesel generator which provided a few hours energy each day was turned off at night.

The Makuxi, one of Brazil’s largest indigenous communities, with about 19,000 people and 140 villages, inhabit an area of savannah and sierras in the far northern state of Roraima, sharing  borders with Venezuela and Guyana.

Their land, which was offically recognised by a Supreme Court ruling only in 2009, after years of conflict with invading goldminers, cattle ranchers and rice farmers, stretches to the foothills of the imposing Mount Roraima, a table top mountain with sheer cliffs rising 9,000 feet (2,750 m) high.

This was the mountain that inspired Arthur Conan Doyle to write The Lost World, published one hundred years ago. In the book, prehistoric creatures still roamed the plateau of a remote table mountain. The Makuxi, however,  are more concerned with today’s problems than yesterday’s myths.

After the illegal occupiers had been expelled, they began the task of  restoring land and rivers contaminated by years of  pesticides. And they are now looking for ways to replace the old diesel-powered generators with renewable sources of energy. The nearest power grid is 185 miles (300 kms) away.

Planning for sustainability

 

The Brazilian Government has a programme to bring electricity to rural communities which is called Light For All, and it is considering building a number of dams inside the Makuxi reserve.

But the Makuxi have come up with another idea. The Brazilian Atlas of Wind Potential shows that the northern region of their reserve, Raposa-Serra do Sol, enjoys some of the strongest winds in the country, with speeds of up to 11 metres per second being registered, and an average of six to nine metres.

So in February three towers were installed to measure the winds over the period of  a year, in order to calculate the potential  for generating  energy. The project is the result of a three-way partnership between the Indigenous Council of Roraima (CIR),  the Socioenvironmental  Institute (ISA), one of Brazil’s largest NGOs, and the Federal University of  Maranhão (UFMA).

The towers were installed by the Makuxi themselves. They also plan to map the energy needs of each family in their communities. A team of 14 indigenous researchers is travelling round the villages with GPS equipment and questionnaires.

They hope the energy to be generated will be enough, not only for domestic consumption, but also for the agricultural activities they are also preparing, as part of their plan to develop their reserve sustainably.

Too many helpers

 

The Makuxi do not want to repeat the experience of the other large indigenous community in Roraima, the Yanomami. Several years ago the German Government’s development agency donated solar panels for a health post and other buildings in their area. But none of the Yanomami were trained to maintain them.

Carlo Zaquini, an Italian missionary who has worked with the Yanomami for decades, told me what happened: “Over the years the panels developed problems, but because none of the Yanomami knew how to repair them, every visiting outsider, whatever his speciality, has had a go at tinkering with them, so now they don’t work at all.”

Once they have the results of the wind speed study the Makuxi hope to persuade the Government that harnessing the region’s powerful winds will be a more sustainable solution than hydropower, which researchers now conclude also produces carbon emissions.

The Makuxi’s extraordinary wind power potential, favoured by their terrain of savannah and mountains, is probably unique among Amazonian indigenous populations.

Solar energy – with local people trained to maintain the equipment – seems a much more feasible solution for rainforest communities. So far the Brazilian Government, committed to a gigantic programme of  dam building, has shown little interest in these more modest solutions. Backing from NGOs is probably the only way to make them happen. – Climate News Network

Wind power 'has inescapable limits'

EMBARGOED until 2301 GMT on Tuesday 9 April
Wind power is undoubtedly valuable for generating electricity, but researchers say they have found evidence that the more you use the resource, the less of it there is.

LONDON, 9 April – The wind blows almost everywhere, but its power to turn turbines may have been overestimated, according to US scientists.

Amanda Adams from the University of North Carolina and David Keith of Harvard suggest that large-scale wind farms may create conditions that would ultimately limit their capacity to fulfil demand.

The problem, they warn in Environmental Research Letters, is not one of economics, or engineering: it is one of atmospheric physics. When a steady wind slams into a blade and keeps it turning, it transfers energy to the blade, and thence to the turbine. That slows down the wind.

Because each turbine carries a “wind shadow” beyond it, wind farm entrepreneurs have to compromise: they need to space their turbines as far apart as possible, given that it makes sense to erect as many turbines as possible on the limited land available.

That is, output is going to depend on calculations involving both capacity and density. The usual rule of thumb is that a wind farm could sustain production rates of 2 to 4 watts per square metre. Over a square kilometre, that is 2-4 megawatts.

Adams and Keith calculate that, in wind farms bigger than 100 square kilometres, generating capacity is more likely to be limited to one watt per square metre, because of the local drag on winds. In effect, harvesting the resource also reduces the resource.

There are other problems. Wind farms change the natural wind shear and produce turbulence; they also – consistent with the logic of thermodynamics – affect local temperatures.

“It is easy to mistake the term renewable with the term unlimited when discussing energy”

She and Keith based their findings on a series of simulations involving modest, medium-sized and very large notional wind farms studded with hypothetical turbines at varying intervals, in various regions of the US, and using global forecasting system final analysis data over specific 10-day periods in winter and summer to provide the wind levels.

The results showed that, for large wind farms, it would be difficult to sustain wind power production with a power density of much more than 1.2 watts per square metre.

“It is easy to mistake the term renewable with the term unlimited when discussing energy,” said Adams. “Just because you can keep generating new energy from a source does not mean you can generate energy in an unlimited amount.”

These cautious conclusions run counter to a much more hopeful scenario reported by Climate News Network in January – that, in theory at least, renewable sources could provide more than 99% of American needs.

They are also countered by some positive findings from Germany in the last few days. And the Earth Policy Institute recently reported that Iowa and South Dakota in 2012 got almost 25% of their electricity needs from wind power. Wind provided at least 10% of electricity generation in seven other states.

The US, says the institute, now has 60,000 megawatts online, enough to meet the needs of 14 million homes, and developers scrambled to complete wind farm construction before the end of 2012, to qualify for federal wind production tax credits that were scheduled to expire in December. – Climate News Network

EMBARGOED until 2301 GMT on Tuesday 9 April
Wind power is undoubtedly valuable for generating electricity, but researchers say they have found evidence that the more you use the resource, the less of it there is.

LONDON, 9 April – The wind blows almost everywhere, but its power to turn turbines may have been overestimated, according to US scientists.

Amanda Adams from the University of North Carolina and David Keith of Harvard suggest that large-scale wind farms may create conditions that would ultimately limit their capacity to fulfil demand.

The problem, they warn in Environmental Research Letters, is not one of economics, or engineering: it is one of atmospheric physics. When a steady wind slams into a blade and keeps it turning, it transfers energy to the blade, and thence to the turbine. That slows down the wind.

Because each turbine carries a “wind shadow” beyond it, wind farm entrepreneurs have to compromise: they need to space their turbines as far apart as possible, given that it makes sense to erect as many turbines as possible on the limited land available.

That is, output is going to depend on calculations involving both capacity and density. The usual rule of thumb is that a wind farm could sustain production rates of 2 to 4 watts per square metre. Over a square kilometre, that is 2-4 megawatts.

Adams and Keith calculate that, in wind farms bigger than 100 square kilometres, generating capacity is more likely to be limited to one watt per square metre, because of the local drag on winds. In effect, harvesting the resource also reduces the resource.

There are other problems. Wind farms change the natural wind shear and produce turbulence; they also – consistent with the logic of thermodynamics – affect local temperatures.

“It is easy to mistake the term renewable with the term unlimited when discussing energy”

She and Keith based their findings on a series of simulations involving modest, medium-sized and very large notional wind farms studded with hypothetical turbines at varying intervals, in various regions of the US, and using global forecasting system final analysis data over specific 10-day periods in winter and summer to provide the wind levels.

The results showed that, for large wind farms, it would be difficult to sustain wind power production with a power density of much more than 1.2 watts per square metre.

“It is easy to mistake the term renewable with the term unlimited when discussing energy,” said Adams. “Just because you can keep generating new energy from a source does not mean you can generate energy in an unlimited amount.”

These cautious conclusions run counter to a much more hopeful scenario reported by Climate News Network in January – that, in theory at least, renewable sources could provide more than 99% of American needs.

They are also countered by some positive findings from Germany in the last few days. And the Earth Policy Institute recently reported that Iowa and South Dakota in 2012 got almost 25% of their electricity needs from wind power. Wind provided at least 10% of electricity generation in seven other states.

The US, says the institute, now has 60,000 megawatts online, enough to meet the needs of 14 million homes, and developers scrambled to complete wind farm construction before the end of 2012, to qualify for federal wind production tax credits that were scheduled to expire in December. – Climate News Network

Wind power 'may be less than thought'

EMBARGOED until 0001 GMT on Wednesday 27 February
The world may have to revise downwards its expectations of the contribution wind energy can make to to a less carbon-reliant world, a study says.

LONDON, 27 February – Wind power may in some conditions manage to produce less energy than its supporters believe it can, two US researchers suggest.

In the latest contribution to the debate over wind’s potential,  they say they have found evidence that some of the largest wind farms may cause effects which substantially reduce their generating capacity.

The research, published in the journal Environmental Research Letters, suggests that the generating capacity of large-scale wind farms has been overestimated.

Each wind turbine creates behind it a “wind shadow” in which the air has been slowed down by drag on the turbine’s blades. The ideal wind farm strikes a balance, packing as many turbines onto the land as possible, while also spacing them far enough apart to reduce the impact of these shadows.

But as wind farms grow larger, the researchers say, they start to interact, and the regional-scale wind patterns matter more. This means we may not manage to obtain as much wind power as scientists had thought.

The authors are David Keith, professor of applied physics at the Harvard school of engineering and applied sciences and Amanda S. Adams, assistant professor of geography and earth sciences at the University of North Carolina at Charlotte.

Professor Keith’s research has shown that the generating capacity of very large wind power installations (larger than 100 square kilometers) may peak at between 0.5 and 1 watts per square meter. Previous estimates, which ignored the turbines’ slowing effect on the wind, had put that figure at between 2 and 7 watts per square meter.

“One of the inherent challenges of wind energy is that as soon as you start to develop wind farms and harvest the resource, you change the resource, making it difficult to assess what’s really available”, says Professor Adams.

Recognising limits

 

“If wind power’s going to make a contribution to global energy requirements that’s serious, 10 or 20% or more, then it really has to contribute on the scale of terawatts in the next half-century or less”, Keith adds. A terawatt (TW) is one trillion watts. In 2006 energy use worldwide amounted to about 16 TW.

Keith says: “Our findings don’t mean that we shouldn’t pursue wind power – wind is much better for the environment than conventional coal – but these geophysical limits may be meaningful if we really want to scale wind power up to supply a third, let’s say, of our primary energy.”

“The real punch line is that if you can’t get much more than half a watt out, and you accept that you can’t put them everywhere, then you may start to reach a limit that matters.”

To stabilize the climate, he estimates, the world will need to find sources for several tens of terawatts of carbon-free power within a human lifetime. In the meantime, policymakers must also decide how to allocate resources to develop new technologies to harness that energy.

Keeping their distance

 

In doing so, Keith says: “It’s worth asking about the scalability of each potential energy source – whether it can supply, say, three terawatts, which would be 10% of our global energy need, or whether it’s more like 0.3 terawatts and 1%.

“Wind power is in a middle ground. It is still one of the most scalable renewables, but our research suggests that we will need to pay attention to its limits and climatic impacts if we try to scale it beyond a few terawatts.”

Apart from debate over wind’s fitfulness and inconstancy and claims that it is environmentally more damaging than acknowledged (to birds and landscapes, for example), scientists differ on the contribution it can make to a low-carbon economy.

But this latest study, funded by the Natural Sciences and Engineering Research Council of Canada, chimes with the conclusion recently reached by other US researchers (see our story of 20 January, Renewables: The 99.9% solution.

Consistent wind power can be obtained, they said, if the turbine fields are dispersed at distances greater than 1,000 kilometres. – Climate News Network

EMBARGOED until 0001 GMT on Wednesday 27 February
The world may have to revise downwards its expectations of the contribution wind energy can make to to a less carbon-reliant world, a study says.

LONDON, 27 February – Wind power may in some conditions manage to produce less energy than its supporters believe it can, two US researchers suggest.

In the latest contribution to the debate over wind’s potential,  they say they have found evidence that some of the largest wind farms may cause effects which substantially reduce their generating capacity.

The research, published in the journal Environmental Research Letters, suggests that the generating capacity of large-scale wind farms has been overestimated.

Each wind turbine creates behind it a “wind shadow” in which the air has been slowed down by drag on the turbine’s blades. The ideal wind farm strikes a balance, packing as many turbines onto the land as possible, while also spacing them far enough apart to reduce the impact of these shadows.

But as wind farms grow larger, the researchers say, they start to interact, and the regional-scale wind patterns matter more. This means we may not manage to obtain as much wind power as scientists had thought.

The authors are David Keith, professor of applied physics at the Harvard school of engineering and applied sciences and Amanda S. Adams, assistant professor of geography and earth sciences at the University of North Carolina at Charlotte.

Professor Keith’s research has shown that the generating capacity of very large wind power installations (larger than 100 square kilometers) may peak at between 0.5 and 1 watts per square meter. Previous estimates, which ignored the turbines’ slowing effect on the wind, had put that figure at between 2 and 7 watts per square meter.

“One of the inherent challenges of wind energy is that as soon as you start to develop wind farms and harvest the resource, you change the resource, making it difficult to assess what’s really available”, says Professor Adams.

Recognising limits

 

“If wind power’s going to make a contribution to global energy requirements that’s serious, 10 or 20% or more, then it really has to contribute on the scale of terawatts in the next half-century or less”, Keith adds. A terawatt (TW) is one trillion watts. In 2006 energy use worldwide amounted to about 16 TW.

Keith says: “Our findings don’t mean that we shouldn’t pursue wind power – wind is much better for the environment than conventional coal – but these geophysical limits may be meaningful if we really want to scale wind power up to supply a third, let’s say, of our primary energy.”

“The real punch line is that if you can’t get much more than half a watt out, and you accept that you can’t put them everywhere, then you may start to reach a limit that matters.”

To stabilize the climate, he estimates, the world will need to find sources for several tens of terawatts of carbon-free power within a human lifetime. In the meantime, policymakers must also decide how to allocate resources to develop new technologies to harness that energy.

Keeping their distance

 

In doing so, Keith says: “It’s worth asking about the scalability of each potential energy source – whether it can supply, say, three terawatts, which would be 10% of our global energy need, or whether it’s more like 0.3 terawatts and 1%.

“Wind power is in a middle ground. It is still one of the most scalable renewables, but our research suggests that we will need to pay attention to its limits and climatic impacts if we try to scale it beyond a few terawatts.”

Apart from debate over wind’s fitfulness and inconstancy and claims that it is environmentally more damaging than acknowledged (to birds and landscapes, for example), scientists differ on the contribution it can make to a low-carbon economy.

But this latest study, funded by the Natural Sciences and Engineering Research Council of Canada, chimes with the conclusion recently reached by other US researchers (see our story of 20 January, Renewables: The 99.9% solution.

Consistent wind power can be obtained, they said, if the turbine fields are dispersed at distances greater than 1,000 kilometres. – Climate News Network