Wednesday, September 12, 2012

Getting significant power from wind

Ever since I lived in North Dakota in the mid 1960s, I have fervently believed we could power our world with wind—there is something about the winds out there that makes you believe the winds are infinite.  Of course, they are not—any more than the fish in the sea are infinite.

The wind boosters in ND claimed that they could generate more than enough electricity to power the whole nation.  "We are the Saudi Arabia of wind" they would say.  Of course, these were projections done with back-of-the-envelope calculations.  What else could they do?  At the time, no one was building commercial-quality wind turbines so there was a lack of real-world expertise.  But even now with plenty of real-world expertise, the idea still resounds—yes we can do this.

So now we have an academic making much better back-of-the-envelope calculations that say, yes we can power ourselves with wind.  He crunches some interesting numbers.  4,000,000 five megawatt wind turbines is a BIG number.  But his study does get at the biggest unanswered question to date which is, "What happens to winds when you extract multi-terawatts of energy from the atmosphere?"  It obviously changes something.  In northern Minnesota, we have the forested NE where the winds barely blow and the wide-open Red River Valley in the NW where serious winds blow all the time.  This is a question worth asking, "If we actually can harvest so much energy from the atmosphere, will this slow down the progression of weather patterns so a gentle 1" rain becomes an 8" flash-flood causing downpour?"  AND "If there is a limit to how much energy we can extract from the winds, what is that limit?

Wind could meet many times world's total power demand by 2030, researchers say

Using the most sophisticated climate model available, researchers show there's plenty of wind for clean-energy economy

Andrew Myers
Stanford School of Engineering

In 2030, if all energy is converted to clean energy, humans will consume about eleven-and-a-half terawatts of power every year, all sources combined. If there is to be a clean-energy economy based on renewable energy, wind power will no doubt have to help meet much of that demand.

In a new study, researchers at Stanford University's School of Engineering and the University of Delaware developed the most sophisticated weather model available to show that not only is there plenty of wind over land and near to shore to provide half the world's power, but there is enough to exceed total demand by several times if need be, even after accounting for reductions in wind speed caused by turbines.

The findings were published in the Proceedings of the National Academy of Sciences (PNAS) by Mark Z. Jacobson, a professor of civil and environmental engineering at Stanford and Cristina Archer, an associate professor of geography and physical ocean science and engineering at the University of Delaware.

In their study, Jacobson and Archer adapted the three-dimensional, atmosphere-ocean-land computer model known as GATOR-GCMOM to calculate the theoretical maximum wind power potential on the planet taking into account wind reduction by turbines. Their model assumed wind turbines could be installed anywhere and everywhere, without regard to societal, environmental, climatic, or economic considerations.

The new paper contradicts two earlier studies that said wind potential falls far short of the aggressive goal because each turbine steals too much wind energy from other turbines, and that turbines introduce harmful climate consequences that would negate some of the positive aspects of renewable wind energy.

The new model provides a more sophisticated look than previously possible by separating winds in the atmosphere into hypothetical boxes stacked atop and beside one another. Each box has its own wind speed and weather. In their model, Jacobson and Archer exposed individual turbines to winds from several boxes at once, a degree of resolution earlier global models did not match.

"Modeling the climate consequences of wind turbines is complex science," said Jacobson. "This software allows that level of detail for the first time."

With a single model, the researchers were able to calculate the exposure of each wind turbine in the model to winds that vary in space and time. Additionally, the model extracts the correct amount of energy from the wind that gets claimed by the turbines, reducing the wind speed accordingly while conserving energy. It then calculates the effect of these wind speed changes on global temperatures, moisture, clouds and climate.

Among the most promising things the researchers learned is that there is a lot of potential in the wind — hundreds of terawatts. At some point, however, the return on building new turbines plateaus, reaching a level in which no additional energy can be extracted even with the installation of more turbines.

"Each turbine reduces the amount of energy available for others," Archer said. The reduction, however, becomes significant only when large numbers of turbines are installed, many more than would ever be needed.

"And that's the point that was very important for us to find," Archer said.

The researchers have dubbed this point the saturation wind power potential. The saturation potential, they say, is more than 250 terawatts if we could place an army of 100-meter-tall wind turbines across the entire land and water of planet Earth. Alternatively, if we place them only on land (minus Antarctica) and along the coastal ocean there is still some 80 terawatts available — about seven times the total power demand of all civilization. Hypothetical turbines operating in the jet streams six miles up in the atmosphere could extract as much as an additional 380 terawatts.

"We're not saying, 'Put turbines everywhere,' but we have shown that there is no fundamental barrier to obtaining half or even several times the world's all-purpose power from wind by 2030. The potential is there, if we can build enough turbines," said Jacobson.

How many?

Knowing that the potential exists, the researchers turned their attention to how many turbines would be needed to meet half the world's power demand — about 5.75 terawatts — in a 2030 clean-energy economy. To get there, they explored various scenarios of what they call the fixed wind power potential — the maximum power that can be extracted using a specific number of wind turbines.

Archer and Jacobson showed that four million, five-megawatt turbines operating at a height of 100 meters could supply as much 7.5 terawatts of power — well more than half the world's all-purpose power demand — without significant negative affect on the climate.

"We have a long way to go. Today, we have installed a little over one percent of the wind power needed," said Jacobson. more
One of the HUGE advantages of wind generation is that it is scalable.  The local colleges here in town have demonstrated that even one or two wind turbines will save them significant money.  In the following article, we have an example of a small town in Germany that thinks they can be experts in the sound operation of a wind farm.  This is a nice size too.

Town turns wind power into community business


Germany’s shift toward alternative energy has seen wind parks pop up around the country. Not everyone wants a power plant in their own backyard. But in Schlalach, the wind park has become a part of town life.

In Schlalach-Mühlenfließ, a small town in the German region of Brandenburg, 16 gigantic wind turbines stretch into the air. Every tower has huge, rotating blades and a height of close to 180 meters. Elsewhere in Germany, locals have complained that new wind parks are ruining the scenery. In Germany, critics often compare wind turbines to asparagus rising into the sky. There have been massive protests as local communities have tried stop turbine construction projects from going ahead.

But that’s not the case in Schlalach-Mühlenfließ. Here, locals are proud of their wind park, which produces 60 times more electricity than the town of 1,000 inhabitants needs for its own purposes. "We are fine, there is hardly any tension here," says Peter Hahn, who lives in the town and co-founded a local group called ‘Wind Power in Schlalach’. He says that getting everyone to agree on the wind park took a lot of hard work.

Right at the beginning of the project, recalls Peter Hahn, they encountered their biggest challenge. "In 2002, this area here was declared suitable for wind energy projects," he says, pointing at vast fields that lie between the village and a motorway.

"About ten operating companies suddenly arrived. They wanted contracts with the people who owned the patches of land." But they realized that the best land for wind turbines wasn’t owned by large-scale farmers. The best plots belong to about 100 small farms in this region. "We had to find some sort of agreement," explains Hahn.

That’s how the ‘Wind Power in Schlalach’ working group came to life. Anyone who wanted to discuss the pros and cons of building a wind park in Schlalach could join. "We asked all the owners not to sign any contracts. We went for a proper call for tenders instead," says Hahn.

Hartmut Höpfner, another member of the working group, approached wind park development companies. He received 20 replies and the group set to work looking for the most suitable candidate. "Half the developers wouldn’t have been able to go through with their plans if you look at the difficulties of such a project, such as electricity transfer from the turbines and the long years of getting clearance for it,” he explains. more
Offshore wind generation is so hideously difficult, I can barely comprehend it.  Yet folks are trying to make it work.  Not surprisingly, they are behind schedule and over budget.  They are trying to build in the North Sea, for goodness sakes.

My absolute favorite line in this story, however, is this "The entire financial world views with concern Germany's hastily announced energy revolution."  To which I would ask, "what possible evidence has there been in the entire financial world that gives them the right to even ask such a question?"  Pirates are NOT qualified to evaluate engineering.
Germany's Offshore Fiasco

North Sea Wind Offensive Plagued by Problems

By Matthias Schulz

Germany wants to pepper its northern seas with offshore wind turbines as part of its ambitious energy revolution. But strict laws, technology problems and multiple delays are turning the massive enterprise into an expensive fiasco. Investors and the public are losing patience.

In his 1957 work "Book of Imaginary Beings," Argentine writer Jorge Luis Borges describes Zaratan, an ocean turtle that was so large that she served as an artificial island. Forests grew on her shell.

The managers of the British offshore firm Seajacks have developed such an affinity for the monster that they named their latest creation after the mythical being. Their Zaratan looks like a giant barge. It has a huge crane and four hydraulic legs, each of them 85 meters (280 feet) long. The legs allow it to lift itself out of the water like an insect.

The vehicle is an "installation vessel," a tool of the offshore wind-power industry that does only one thing: It installs offshore wind turbines that that are sometimes taller than 150 meters.

On a recent Saturday, the ship was waiting at the wharf in the northern German port town of Cuxhaven to take four "monopiles," each weighing 750 metric tons (1.64 million pounds), on board. Monopiles are 70-meter steel masts that serve as foundations for the offshore wind turbines.

The vessel, operated by the firm WindMW, was set to drive the first of these monumental poles 40 meters into the seabed at a site 23 kilometers (14 miles) north of the North Sea island of Helgoland, heralding the beginning of a sea change in German power generation.

The hammers on the installation vessel will generate noise at levels of 160 decibels.  Zaratan will hammer 80 monopiles into the sand in the next few months. After that, the Zaratan and its sister ship, the Leviathan, will install the giant rotors on the turbines.

Since harbor porpoises are sensitive to noise while raising their young in the summer, all of this has to happen in the fall and winter, under overcast skies and in heavy seas.

It will also cost a lot of money: at least €1.2 billion ($1.5 billion).

Jens Assheuer, 37, heads the pioneering project. He is wearing a pink tie as he sits in a leather armchair in his office in the northern German port city of Bremerhaven, gazing out at the Weser River through a large, panoramic window. He hasn't slept much.

For weeks, the CEO of WindMW has been commuting back and forth between government offices in Berlin and his financial backers in Frankfurt. During teleconferences with his offshore planners in Denmark and England, he discusses things like the "Infrastructure Planning Acceleration Law" or the tiresome high-voltage, direct current (HVDC) transmission outlets.

Assheuer, an engineer by training, effortlessly rattles off this industry jargon. In general, he is a fast talker and likes to tear down the Autobahn at 200 kilometers per hour in his Audi A7. He is visibly tense. The entire financial world views with concern Germany's hastily announced energy revolution, which aims to boost renewable energy to 35 percent of total power consumption in Germany by 2020 and 80 percent by 2050 while phasing out all of Germany's nuclear power reactors by 2022. Billions are at stake, and many aspects of the energy transition are in sorry shape. more

No comments:

Post a Comment