Economics and other considerations: How much power will Breezy 5.5 produce for my use or to reduce my electric bill by generating back into the grid? How long will it take to recover my investment?
Lets begin by determining what “wind zone or class” we will be placing the turbine. We will use the site of our prototype as an example. The following Internet link will take us to a wind speed map.http://www.awea.org/faq/usresource.html
Looking at the map we see that in central Kansas we are at a class 3 wind power/speed. The chart shows that in a class 3 area the average wind speed is 6.4 to 7 m/s (meters per second) and the available wind power is from 300-400 watts per square meter. Here in the USA most of us like to use mph (miles per hour) so we can multiply by 2.24 to get a value of 14.33 to 15.68 mph.(mph x 0.447 = m/s……..m/s x 2.24 = mph). Notice also that on the wind speed chart the wind speed average from a class 1 to a class 5 is doubled and that the wind power (watts per square meter) has cubed (8 times the level). This means that a small change in average wind speed can have a much larger change in available power
Average wind speed includes all the time that the wind is blowing at very low speeds which the turbine would not be producing much if at all and winds above 23 mph which the turbine will not have increased it’s output. Typically the average monthly wind speed and power can vary greatly throughout the year. . Also, with regards to the map, you may very well have a location due to land formation, trees, etc. which exceeds or falls below the average in your area. So where to go from here? We could use statistical information or “Rayleigh Wind Distribution” information to figure out how many hours a year the wind blows at a particular speed apply that information to the Breezy 5.5 in a Class 3 zone and get a fair estimate of the power we can expect for other wind class/zones. A simplified method which we will use is based on actually measuring the power with a regular utility power meter (like the one on your house) over the course of a year or several years compare that power with the available wind power in our zone and project an estimate to other zones. We know from long term measurements using a KW meter to measure the power generated into our electric service and the grid that the turbine delivers an average of a little more than 1000 KW per month or 12,000 KW (12 mega watts) per year. Using a meter in this way accounts for turbine efficiency and subtracts out the small amount of power consumed to keep the turbine controls powered up when the wind isn’t blowing. (Other turbines specs. may state power generated and not power actually delivered for use. Many will loose as much as 20% of that power converting it to 60hz before it can be sent to the grid.)
To begin we see that the available power for a class 3 wind zone is 300-400 watts per square meter. We will use the available power of 350 w/m^ as our reference. When we see watts without any other reference we can assume that this is a measurement of watts per hour and we will need to multiply this out to get an annual average.
350 (w/m^) X 26 (m^ turbine area) X 24 (hours) X 365 (days) = 79,716KW
Now we know that there are approximately 79,000KW available in the 26 square meter area of our turbine in a zone 3 area. We know from measuring with a KW meter for a year, which is accounting for efficiency and losses, that we are harvesting an average of 12,000KW of this available wind power.
Note: 59% is the absolute maximum or limit (Betz Law: The Available Power in the Wind) that a turbine can capture so when compared to other turbines which use this limit as a reference Breezy 5.5 delivered 25.7% of the available wind power to the utility meter over the course of an average year.
Knowing the performance of the turbine in a zone 3 we can now project the figures to other zones and without actually placing a turbine in them to estimate the monthly power and the value of that power at different rates.
Note: These are projections based on the turbine on a 60’ tower in a zone 3 wind area. Significant increase of average power can be expected with an increase of tower height. We have made an effort to portray the performance of the turbine accurately and to keep projections conservative.
The cost of our electricity is definitely not going to go down. Looking at the chart above we can get an idea of the value of the turbine today. But what will the cost of power be in 20 or 30 years? A glance at the past should give us some insight to what may happen to electric rates in the future.
The cost of a turbine is one thing, maintaining it is another. At some point all turbines will require some sort of maintenance or repairs. If you think about the lifetime of the turbine what will the parts cost and will they even be available? Breezy 5.5 is designed around industrial components not being specific to “wind turbines”. When you have a choice in where you can purchase parts you have a definite completive edge as you build and maintain your turbine. Some tower designs require a crane rental to even perform minor maintenance on the turbine. With the tilt-up design used by Breezy 5.5 the turbine and tower can be tilted down in minutes with ordinary equipment. Additionally, we should think of the physical challenge that servicing the turbine might present 20 or 30 years down the road.
Many states are now coming onboard with tax incentives to promote the use of renewable energy. The cost of the turbine or a portion of it may be recovered through tax credits. This will vary state by state and should be checked into on an individual bases. Also at this time there is a federal tax credit of 1.8 cents for each KW produced and returned to the grid. This credit will be available for several years to come and we expect that it will again be renewed as part of the effort to curb the use of nonrenewable fuels to produce electricity.
Many of us are concerned with doing our part to protect the environment and limit our contribution to the effects of industrialization and modernization. It should be expected that we would want to enjoy the conveniences the modern world has to offer. Owning a turbine is one way that we can put something back. For each KW we send back to the grid that is one little piece of coal or measure of petroleum that didn’t have to get burned to provide a KW for someone else. For each KW we use ourselves that is just that much of those fuels that didn’t get burned on our behalf and we saved just that much on our utility bill.
For all you guys out there that like a good project, who like to get the guys together and create something special and worthwhile, need to get your sons and daughters out of the house and into the shop, Breezy 5.5 is for you.
Building this turbine is just plain fun.