Salient White Elephant

June 27, 2009

Cable Untwisting System for Small Wind Turbine

Cable Untwisting System for Small Wind Turbine

The diagram shows the turbine yawed to the position where its power cables are completely untwisted. In this case, the cable that untwists the yaw system attaches to its topmost pulley wheel in such a way that it is not wrapped around that topmost pulley wheel at all. (The topmost pulley wheel is the one with the axis of rotation that is coincident with the turbine’s yaw axis). Now as the turbine yaws, it doesn’t matter which direction the turbine yaws in. Whichever way the turbine yaws, it wraps the untwist cable around the topmost pulley wheel, and in so doing it draws the twist sensing component that is attached to the untwist cable (colored purple) up to a higher elevation. When this part of the sensor passes close by the topmost twist sensor component (colored red), the control system knows that the power cables are twisted up. To untwist the turbine, the controller simply turns on the small electric motor at the base of the tower until the cable mounted twist sensor component passes by the lowest red colored twist sensor component, then turns the motor back off. If the system fails for some reason, the result is that the small untwist motor will burn up or blow a fuse – a minor repair indeed. The controller might wait until the wind isn’t blowing before untwisting the power cables.

Sensorless Variation

In this variation, the controller merely untwists the turbine every time the wind speed drops to zero (rotor blades not turning). Some kind of slip clutch mechanism might be provided to keep the untwist motor from burning up if it runs too long. Alternatively, the motor could be turned off whenever the power it draws jumps up by a large value (indicating the turbine has been completely untwisted). Or a simple mechanical switch could be tripped whenever the turbine is completely untwisted.

Manual Variation

A manual version of this device might also work well. In this case, the controller might issue some kind of mechanical or telecommunications signal to let someone know that the turbine needs untwisting.

High Mechanical Efficiency Centrifugally Stable Darrieus Turbine

High Mechanical Efficiency Centrifugally Stable Darrieus Turbine

June 21, 2009

Business Savvy or Sexy Technology?

Filed under: Brash Environmental Commentary, Wind Energy, Wind Power, Wind Turbine — Tags: , , — Salient White Elephant @ 11:40 am

The earlier post, Why Renewables Aren’t Cost Effective, describes how a taking a different approach to the business of wind technology may produce even more attractive results than a dazzling new technology. Let’s look at other ways for using business ideas to improve the profitibility of small wind.

The Problems with Small Wind

There are two problems with small wind – maintenance and financing. Let’s start with maintenance.

Maintenance

Not many home owners want to climb an 80 foot tower to fix a 10 kilowatt wind turbine. To date, the designers and manufacturers of small wind machines have solved this problem by making their machines virtually indestructible. Many have only a few moving parts – the rotor, slip rings, and yaw bearings. But these machines still break. They could even be hit by lightning!

My answer to this problem is to first reduce the cost of the machine by making it more destructible. If the cost is reduced by a sufficient margin, then it will be deployed in larger numbers. If the number of machines in the field reaches a significant threshold, then a business can be developed for maintaining the machines. In other words, opt for a cheap clunky machine rather than an expensive high tech ultra-reliable machine. Now a customer either hires the maintenance company to repair the turbine or exercises warranty privileges. Technicians repairing the machine are experts, and they aren’t afraid of 80 foot towers. In other words, you can spend your money on two different options:

  1. super duper designs with super duper components, or
  2. mediocre designs with mediocre components and a solid company that provides highly qualified service technicians.

The later option makes more sense. Most home owners won’t even consider learning to repair and maintain a wind machine, but they’ll consider an option that’s backed by service contracts and warranties.

Financing

How long does a wind turbine take to pay for itself? Oh man… I don’t even want to know. If you’ve seen this kind of financial analysis, it’s complicated, and I doubt the average home owner can even understand it, much less believe it. But wait a second… if it’s true… if it really is true… that a 10 kilowatt wind turbine for your back yard is a good investment, then why aren’t there companies that bank roll the installation of such machines in exchange for dividing the wealth so created with the homeowner? Just as service technicians know more about repairing wind machines, financial companies know more about financing them.

What Does This Company Look Like?

The small wind machine manufacturer proposed here does not sell wind machines – it sells electricity. And it sells the electricity to the power company, not to the homeowner. In other words, the homeowner has exactly the same relationship with the small wind company that a farmer has with a utility scale wind farm owner/operator. Just as the utility scale wind farm owner/operator pays the farmer a monthly fee for the privilege of using a few hundred square feet of his farmland, the small wind company pays the homeowner a set monthly fee for the privilege of using her home to produce the electricity that is sold to the power company. The home owner sees a “reduction in her electricity bill” equal to the monthly fee she receives from the small wind company. Everything else, the construction, grid connection, maintenance, repair, and financing of the wind machine is the responsibility of the small wind company proposed here. All the homeowner has to do is avoid hitting the base of the tower with her lawnmower!

Negotiating Power Purchase Agreements

Another advantage of the company proposed here is that, provided its revenue is sufficiently large, it enjoys a strong negotiating position with the utility company. Consider this. When a company that owns a wind farm sells electricity to a power company, what happens to all the energy that is lost in transit as the electricity is carried 30 miles to the consumer over high voltage power transmission lines? Well… maybe it’s easier to look at the flip side of that coin. Suppose you install a wind machine in your back yard and run your meter backwards. The power company just saved a bunch of money because little of this energy is lost in transmission, since it is all used either in your own home or at least in your own neighborhood. The power company also saves money in reduced maintenance of high voltage transmission lines, and reduced need for transmission line capacity in the first place. How much of these savings do you think will be reflected in your electricity bill? You guessed it – zero. You just gave the power company a nice birthday present, and every day is their birthday!

The home owner is not in a position to challenge this state of affairs. But the company proposed here that operates tens of thousands of small wind turbines around the province is in a position to negotiate a reward for the benefits they provide… including the benefits of producing electricity at the point of consumption rather than 400 thousand miles away at the other end of a 10 billion dollar 900 thousand volt transmission line.

Conservation or Increased Exploration and Production?

In 1985 I bought a Toyota Starlet. A Starlet was a compact car that got 55 miles per gallon (mpg) on the interstate with a regular gasoline engine. (It was a regular car – not a hybrid). The average fuel efficiency of a car on the freeway today is easily half that value.

Think about it this way. It’s easy for us to drive cars that get 27 mpg instead of 55 mpg. All we have to do is to double our fuel production capacity. This is as easy as building a second Iraq.

Or you can think of it this way. If we double the fuel efficiency of cars, then we’ve just built a second Iraq – a virtual Iraq – an invisible Iraq – an Iraq that doesn’t actually exist. Everytime you drive 2 x 27 = 54 miles and burn only a single gallon instead of 2 gallons, then you just burned an invisible gallon of gas from an invisible country. You can’t go to war or even have policy differences with an invisible country. And the cost of the invisible gallon of gas is a whopping $0. Invisible oil fields are never depleted, and invisible OPEC’s are hard to disagree with. Invisible production facilities don’t catch on fire or need maintenance, and almost anyone can finance the exploration of an invisible oil reserve. Burning invisible gasoline produces, of course, invisible pollution. Even the increase in the earth’s temperature is not detectable, existing only in the parallel universe of “what might have been”.

Can you imagine what an incredibly huge task it would be to double the world’s oil production? The billions of dollars that would be required, the trade agreements, the transportation infrastructure that would have to be built to support it, the fear it would strike in the hearts of some governments if they felt they’d have less access to the new oil than other countries. Yet doubling the fuel efficiency of cars is easy. It’s already been done in 1985, and that was even before hybrid technology came along! Yet by doubling fuel efficiency, you’ve essentially accomplished all of the herculean tasks I just described for doubling the world’s oil production capacity, only instead of being a herculean task, it’s a piece of cake!

You can’t go to war with an invisible country. You can’t melt the polar ice caps with invisible heat. And you can’t stifle a government with invisible cronies.

Why Renewables Aren’t Cost Effective

The last electric bill I got charged me $65 for the luxury of being connected to the electricity grid, and $5.00 for the electricity I used. In other words, if I had conserved all of my electricity, using no electricity at all, then I would have saved only $5.oo! My bill would have been $65 instead of $70! Really makes you just want to go all out to conserve resources and reduce pollution, doesn’t it!?

The logic behind this rate structure is that the utility company must make electricity available to you whether you use it or not. They must guarantee that if you wake up at 3 o’clock in the morning and turn on every electrical gizmo in your house, then the electricity to power these devices will be available to you. That’s what I paid the $65 for. This $65 portion of my bill is appropriately called capacity charge. It varies based on how much capacity I require, as I will explain in a moment.

Two questions immediately come to mind:

  • Does this rate structure encourage waste. Answer: YES!
  • Does this rate structure reflect the utility company’s cost structure? In other words, are 65/70 = 93% of their costs really devoted to the provision of the service, with only 7% of their costs spent of making electricity? Well.. who knows… but does it sound believable to you?

How the Capacity Charge is Calculated

Now let me explain how the $65 is calculated. Basically, they keep a record of the amount of power you draw for 6 months. Then they look at the maximum amount of power you drew in any one minute for that 6 months, and your capacity charge is based on that amount. Let’s say for example that 3 1/2 months ago I turned everything in the house on at the same time and drew 10 kilowatts. And let’s say that this is the most power I drew at one time during the last 6 months. Then my capacity charge, $65, is based on that 10 kilowatts. Now suppose 2 1/2 months elapse, so that the moment when I drew 10 kilowatts is now more than 6 months ago. Now we look back over my history and find that the most power I drew at once during the last 6 months was only 5 kilowatts. Now my capacity payment drops to $65/2 = $32.50.

How to Beat the System

The manufacturers of small wind turbines designed for residential use are always complaining about this rate structure. Strange, huh? These small wind turbines go on dutifully pumping power backwards – into the grid rather than out of the gird – knowing that if there was so much wind as to make your net power consumption zero you would still only save $5!!! No wonder it takes so long for a small wind machine to pay for itself!

And yet the answer is obvious. Get a small wind machine, add a small battery, and use the wind turbine to keep the battery charged. Now design some electronics to detect peak power usage. Now if I wake up at 3 o’clock in the morning and turn everything on in the house, the wind turbine battery suddenly turns on to limit my peak consumption as much as possible. If the system is able to cut my peak consumption from 10 kilowatts to 5 kilowatts during the 5 minutes that I keep everything turned on at 3 am, then in that 5 minutes I just earned $35! Contrast this with the $5 I would have earned had my wind turbine worked hard every minute of the whole month, producing 100% of the electricity I used for that month!

Is a Wind Turbine Even Needed?

Obviously not. Just draw the electricity from an electrical outlet in your wall in order to charge the battery whenever you aren’t using much electricity for anything else. Now when you turn a lot of things on, the electronics that control the battery realize that you are approaching peak power consumption, and they kick the battery on so that it supplies part of the power you need, thereby limiting your peak consumption and its associated capacity charge.

If You’re an Environmentalist – Play It Smart

So if you don’t need a wind turbine, then what does all this have to do with wind energy? Well… if everybody had these battery systems in their homes to level out power consumption, we’d find out real quick whether $5 is really enough to cover the cost of electricity produced. My bet is that you’d see the rate structure change real quick. Once the rate depends more on the actual amount of energy the utility is required to produce, then it becomes more cost effective to install your own wind turbine and run the meter backwards.

Related Technologies

There’s a whole slew of technologies for conserving energy that become obvious when you look at the problem from the perspective of this post. For example, what about a clothes dryer that automatically shuts off anytime peak household consumption exceeds 5 kilowatts, and then turns back on anytime peak consumption dips back down below 5 kilowatts?

The Moral of the Story

The moral of the story is that environmentalism that is based on nothing but complaining is doomed to fail. What we need are jazzy inventors and entrepreneurs who are patient, calculating, and sufficiently intelligent to twist the arm of a greedy industrialist behind his back and inform him of changes to his job description. He needs to know that his duties no longer include destroying the planet and sending other people’s children overseas to die fighting over oil.

Remember – if twisted logic and pretzel laws work for those who oppose efficiency, then they will work for the proponents of sustainability as well.

A Product and Business Based on this Idea

You buy a product that includes electronics that monitor your electricity usage. A continuous record of electricity usage is kept. The system includes a battery that is just large enough to absorb the average amount of power you use in a day from the power grid. The electronics are designed so that the battery draws enough electricity for one day from the power grid between the hours of minimum demand. Let’s say the hours of minimum demand are from 11pm to 5 am. The battery draws enough power for one day’s worth of your electricity consumption, and it draws that power at a steady even rate from 11pm to 5am every evening. Anytime you use electricity in your house, it is drawn from the battery.

Now, to the power company, you are the ideal customer. You never draw anything but a small steady flow of power during the hours of minimum demand (when they’re trying to figure out how to get rid of their excess power anyway). If ever you use more than your average amount of power, the battery system is bypassed and you draw straight from the grid (increasing your electricity bill).

I think this is what they mean by the “smart grid”. (I keep seeing that term on the internet, but I haven’t had a chance to look it up in the dictionary yet.)

June 18, 2009

3 Spoked Wind Dam

3 Spoked Wind Dam

Pictures of Wind Dam

Found an old outdoor movie theater out in the countryside near Saskatoon, Saskatchewan, Canada. It looked very much like the way I imagined some of the wind dams I have described on this blog, so I stopped and took some pictures of it. I was very excited to see that the structure that supports the corrugated screen doesn’t seem to use very much metal! Keep in mind that this is in a high-wind area, and the screen has obviously been withstanding wind storms for many years. Also keep in mind that, unlike most of the designs described on this blog, the theater screen has no way to allow wind to pass through its surface unimpeded. So if the wind machine has a means for allowing high winds to pass through its flow manipulating surfaces unimpeded, it will require even less metal for its structural support!

The owner was working at the site when I drove up, and he told me the screen was 65 feet high. (I don’t remember how wide he said it was.)

 

 

outdoor theater near Saskatoon, Saskatchewan that looks like wind dam

 

 

outdoor theater near Saskatoon, Saskatchewan that looks like wind dam

 

 

outdoor theater near Saskatoon, Saskatchewan that looks like wind dam

 

 

outdoor theater near Saskatoon, Saskatchewan that looks like wind dam

 

 

outdoor theater near Saskatoon, Saskatchewan that looks like wind dam

 

 

outdoor theater near Saskatoon, Saskatchewan that looks like wind dam

 

 

outdoor theater near Saskatoon, Saskatchewan that looks like wind dam

June 17, 2009

Rooftop Wind Turbine

Posting from public library, so can’t put graphics into this post. Hope to add graphics later.

A residence has two roofs, one on top of the other. There’s a gap of what… 5 feet?… between the two roofs. The top roof has a hole cut into the vertex. A HAWT rotor that spins about a vertical axis is positioned in the hole.

The rotor is driven by two mechanisms – the ram air force that creates high pressure between the two roofs, and the suction created by wind that has to accelerate to go over the top of the roof. Imagine you are looking at the side of the house where you can see both halves of the roof sloping down at about 45 degree angles from the vertex. From this perspective, the vertex of the roof looks a little like the low pressure surface of the fattest part of an airfoil. The roof is smoothly curved to prevent turbulence and to maximize the low pressure that is created when wind flows from the right to the left, or from the left to the right. The top roof extends further from away from the outside walls of the house than does the bottom roof. This way, when the wind hits the side of the house, it will be diverted upward (on a nearly vertical path?), and the protruding lip of the upper roof will catch this “ram air” and direct it into the high pressure region between the two roofs. The lip is curved so that its edge is nearly vertical. This prevents the wind that goes over the top of the top roof from generating turbulence and vortices as it is forced to make a nearly 45 degree angle turn to conform to the top surface of the top roof.

As you probably already know, rooftop wind turbines usually don’t perform well because there’s too much turbulence over the roof for a typical wind turbine. I’m wondering if, properly designed, this idea could solve the rooftop turbulence problem. The worst turbulence is probably ulitmately generated by the wind that first “hits the side of the house”, but in contrast to a traditional turbine mounted on top of a house, the turbine described here actually makes use of this increased pressure, and controls the resulting flow so that it doesn’t result in a lot of turblence or vortices.

There are of course many details as well as possible variations not described here. Hope to fill in some more of this info later. In the meantime, note that a round house with a dome shaped roof might work best. Also, it seems like this idea might work for rooftops of retail buildings… like on the roof of a Walmart or something like that.

*****

Okay folks, here’s a simple pic:

Residential Rooftop Wind Turbine

Maybe a hinged diffusor could be added to increase the amount of suction produced by the wind that flows over the top of the top roof:

Residential Rooftop Wind Turbine with Hinged Flow Diffusor

Create a free website or blog at WordPress.com.