Cologne Public Works Facility Wind Power Proposal

Transcription

1 Cologne Public Works Facility Wind Power Proposal Prepared by Lauren Katalinich, Kevin Jiang, Jessica Kartohandojo, Yu Lian, and Karissa Horbal Students in BBE 5733: Renewable Energy Technologies College of Science and Engineering University of Minnesota Instructor: Min Addy Prepared on Behalf of Carver County

2 This project was supported by the Resilient Communities Project (RCP), a program at the University of Minnesota that convenes the wide-ranging expertise of U of M faculty and students to address strategic local projects that advance community resilience and sustainability. RCP is a program of the Center for Urban and Regional Affairs (CURA) and the Institute on the Environment. This work is licensed under the Creative Commons Attribution-NonCommercial 3.0 Unported License. To view a copy of this license, visit or send a letter to Creative Commons, 444 Castro Street, Suite 900, Mountain View, California, 94041, USA. Any reproduction, distribution, or derivative use of this work under this license must be accompanied by the following attribution: Produced by the Resilient Communities Project at the University of Minnesota, Reproduced under a Creative Commons Attribution-NonCommercial 3.0 Unported License. This publication may be available in alternate formats upon request. Resilient Communities Project University of Minnesota 330 HHHSPA th Avenue South Minneapolis, Minnesota Phone: (612) rcp@umn.edu Web site: The University of Minnesota is committed to the policy that all persons shall have equal access to its programs, facilities, and employment without regard to race, color, creed, religion, national origin, sex, age, marital status, disability, public assistance status, veteran status, or sexual orientation.

3 Project Description Over the last several years Carver County has made strategic energy improvements that reduce energy consumption and fossil fuel use, and that also have a short payback. Projects that have or will take place at Carver County which support the reduction in energy consumption include: working with Energy Management Solutions (EMS), the Judicial Center converting to LED lights, Public Works converting to LED lights, and the purchase of an energy efficient convection oven. The County is considering additional renewable energy improvements that are fiscally responsible and reduce reliance on fossil fuels. Carver County s public works facility is located in Cologne. The County has looked into the feasibility of adding wind power to the site. The initial data that was explored several years ago did not support this addition. However, with changes to technology and potentially new data, the County would like to explore this option again. To help the County weigh the costs and benefits of wind power at the facility, a team of students in BBE 4733: 1. Investigated various types of commercially-available small- to moderate-sized wind energy systems, and identify the pros and cons of each type of system (including, but not limited to, cost, maintenance requirements, tie-in efficiency to the grid, and energy generation potential). 2. Assessed the suitability for wind energy at this site. What is the feasibility of wind generation on various sites at this location? 3

4 3. Provided a recommendation to the County regarding a wind energy system: Is there a good alternative for this site that would work and that is cost-beneficial in terms of the return on investment? Project Assignment Lauren Katalinich is assigned to discuss environmental impacts, Kevin Jiang will look into the design aspect of wind turbines, Jessica Kartohandojo is in charge of investigating energy input/output, Yu Lian is going to talk about social/economic impact, and Karissa Horbal will explore the advantages and disadvantages of adding wind power. We made contact and communicated with the director of the Resilient Communities Project (RCP) and two employees from the Carver Public Works facility. One of our team members, Kevin, was able to travel to Cologne to discuss the project further with them. There is a website that was set up by RCP that the Carver Public Works facility used to share information with us. The Carver Public Works facility has shared all of their past assessment data with our team, including: 2007/2008 energy management consultant wind assessment Site plan for public works facility Energy data usage for the facility Future land use plans for neighboring communities We used this data to proceed to the assessment and design phases of our project. 4

5 Design of Wind Turbines Many factors are considered when designing a wind turbine. The turbine needs to efficiently capture wind energy and convert mechanical energy to electrical energy. It also requires mechanisms to start, stop, and point the turbine. In addition, integration of wind turbines into electrical grids needs to be considered. Wind turbines can be categorized into horizontal axis wind turbines (HAWT) and vertical axis wind turbines (VAWT). The majority of wind turbines today are of the horizontal axis type. In comparison to a HAWT, a VAWT does not generate as much energy but is more versatile, since it can be operated with winds going in all directions. For the Carver County design, HAWT will likely be used. Wind turbine sizes vary from several kilowatts (utility-scale turbines), to several megawatts (industrial turbines used for electricity generation of entire cities). Depending on whether wind energy will be a supplemental source or the main source of electricity for Carver County, several smaller wind turbines generating several hundred kilowatts or a larger turbine which can generate several megawatts can be considered. Another important aspect of wind turbine designing is the controller. Controllers are responsible for operating the turbine under various conditions. They can shut down the turbine when the wind speed is too low to conserve energy and when the wind speed is too high to prevent damage to the turbine. 5

6 Turbine control can be categorized into pitch control and stall control. Pitch control is an active form of control, while stall control is passive and relies on the aerodynamic design of the turbine for control. Stall control is simpler than pitch control but has limited practicality, especially in larger turbines which can generate over 1 MW of power. Therefore, it is recommended to use pitch control. The blades of the turbines usually have two forces acting on them. These forces, lift and drag, should be taken into consideration in the design of the blades. Blades that utilize drag forces can generate higher torques, which are ideal for lifting objects, but have limited rotational velocities. Blades that utilize lift forces, however, can achieve much higher rotational velocities, which are suitable for electricity generation. Once the wind turns the blades and generates mechanical energy, the mechanical energy needs to be converted to electrical energy and sent to the power grid. This is usually done by a generator. The spinning of the blades moves the motor inside the generator, which generates electricity. Maintenance on small wind turbines is recommended every six months to ensure optimal performance. The items which are usually inspected are the blades, the braking system, and wires and bolts. It is recommended that parts are properly lubricated and bearings and shock absorbers are in good condition. Routine maintenance of wind turbines can greatly extend their lifetimes. 6

7 Energy Input/Output The levelized cost of energy (LCOE) is a metric used to evaluate the economic value of an energy-generating system. The LCOE is defined as the ratio of the life-cycle cost of generation, which includes all of the costs (initial investment cost, operation and maintenance costs, capital cost, etc.), to the energy generated over its lifetime. Unfortunately, the LCOE for wind energy is large and therefore, a longer investment payback period for wind generation is inevitable. In other words, the reduction of the LCOE of wind energy is essential in order to enhance the economic value of wind energy. There are many ways to reduce the LCOE of wind energy, i.e., to reduce the total cost and/or to increase the generated energy. However, it is very difficult to evaluate the LCOE, because all of the costs depend on the installation site. Therefore, we only focused on increasing the energy generated by a wind generator in this paper. Wind Power The power obtained from the wind can be represented by the following formula: P = C! P!"# P!"# = 1 2 ρ π R! v! (1) (2) P = C! ( 1 2 ρ π R! v! ) (3) where P is the wind power (W), C! is the power coefficient of the wind turbine, ρ is the air density (at 15 and 1 atm, ρ = 1.225!"!), R is the blade length (m), and v is the wind speed! normal to the cross-sectional area through which wind passes (! ). Additionally, air density is a! function of temperature and altitude. The wind speed, on the other hand, is significantly 7

8 affected by the friction that the air experiences as it moves across the earth s surface. Therefore, the power transformed by the wind turbine is influenced by blade length, wind speed, power coefficient, temperature, and altitude. For instance, a wind turbine with a large blade installed at a high wind speed site will generate a greater energy output than this with a small blade. Capacity Factor A capacity factor (CF), which is defined as the ratio of the actual generated energy to the potential generated energy, is directly related to the generated energy. In other words, a wind turbine with a higher CF will generate more energy. In order to calculate the CF, the power curve of a wind turbine and the probability density function of the wind resources at the installation site are needed. (i). Power Curve Due to design limitations, a sufficient amount of kinetic energy obtained from the wind speed is essential for the turbine to generate power. The minimum wind speed at which the turbine begins to rotate and generate power is called the cut-in wind speed. In addition, the maximum power a turbine can generate depends on the size of the generator. The maximum power output of a turbine is called the rated power and the rated wind speed is the wind speed at which the turbine generates its rated power output. The maximum wind speed at which the turbine is halted to avoid damage from high winds is called the cut-out wind speed. Due to the above specifications, equation (3) cannot accurately represent the power generated by the 8

9 turbine for a measured wind speed and therefore, manufacturers normally provide a power curve which describes the power generated by the turbine at the measured wind speed. (ii). Wind Probability Density Function To estimate the power generated by a wind turbine, it is crucial to take into account the fact that air does not blow consistently over the year. In other words, it is necessary to document the frequency of a measured wind speed to calculate the probability of the corresponding wind speed in a year and therefore, is able to generate a wind speed probability distribution. There are various wind speed distribution models used to fit the wind speed distribution. The 2- parameter Weibull probability density function is acknowledged as the best model because the parameters can be adjusted to fit a period of time. f(v! ) =!! (!!! )!!! exp[(!!! )! ] where f(v! ) is the probability of the corresponding wind speed described by Weibull (4) probability density function, k is the shape parameter, c is the scale parameter (!! ), and v! is the wind speed (! ). There are several ways to calculate the parameters k and c; one of the! ways is using the standard deviation and the mean wind speed to obtain k and using the mean wind speed and the gamma function of k to obtain c. However, these calculations require an extensive data which is not available for the purpose of this project; therefore, Rayleigh probability density function derived from Weibull probability density function with the assumptions that k = 2 and c =! v = 1.128v is used instead.! f(v! ) = π v! 2 v! exp[ π 4 (v! v )! ] (5) 9

10 where f(v! ) is the probability of the corresponding wind speed described by Rayleigh distribution and v is the average wind speed in a year (!! ). (iii). Capacity Factor The capacity factor is defined as: CF =!"#$%&!"#$%"&"' =!"#!"#$%&!"!"##!"#$%!,!"#!!"#$% (6) where CF is the capacity factor and P!"#$% is the rated power of the wind turbine (W). AEP = 8,760!!!!! f(v! ) P(v! ) where AEP is the annual energy production (W), N! is the number of wind speed values, (7) f(v! ) is the probability of the corresponding wind speed, P(v! ) is the power generated by the wind turbine at the corresponding wind speed (W). In other words, a turbine with a higher CF will generate more energy and therefore, CF is often used to compare different types of wind turbines to evaluate its economic value. For instance, a wind turbine with a smaller rated wind speed can achieve a larger CF at a low wind speed site with the same rated power. Another method to estimate the capacity factor for a wind energy system when very little is known about the site or wind turbine is to use the following formula which is obtained by fitting a linear curve to a plot of the capacity factor for a NEG Micon 1000/60 wind turbine as a function of wind speeds (assuming Rayleigh statistics): CF = 0.087v P! D! where CF is the capacity factor, v is the annual average wind speed (!! ), P! is the rated power (kw), and D is the rotor diameter (m). It turns out this equation works quite well as a means of 10

11 (8) estimating the capacity factor for many wind turbines within a range of average wind speed from 4 m/s to 8 m/s. The following table consists of different types of small wind turbines with the associated capacity factor calculated using the above formula with an annual average wind speed at 80m height of 6.5 m/s. Discussion The highlighted columns on Table 1 (See Analytical Supplement Section) represent the top four small wind turbines with higher CF and reasonable price among the other turbines. Table 2 (See Analytical Supplement Section), on the other hand, consists of different types of large wind turbines with the corresponding capacity factor. The highlighted columns represent wind turbines with greater capacity factor than the recommended wind turbine which is Siemens_NGPS Since the pricelist for large wind turbines is not available, further discussion and calculations will only focus on small wind turbines. Table 3 (See Analytical Supplement Section) describes the energy delivered per year calculated using equation (9) and (7) (Rayleigh probability density function). In conclusion, Table 3 indicates that Bornay (Inclin 1500) seems to be the most suitable wind turbine to be installed at the facility since it generates the most energy, requires the least space, and costs the least compared to the other wind turbines. 11

12 Economic Analysis Economists looked at wind capacity installed from 2000 to 2008 in 12 states: Iowa, Kansas, Minnesota, Nebraska, North Dakota, South Dakota, New Mexico, Oklahoma, Texas, Colorado, Montana, and Wyoming. In all, the study area included 1,009 counties. Researchers found that for every megawatt of wind power capacity installed, total county personal income increased by $11,150 over the 2000 to 2008 period. And, for every megawatt of wind energy installed in a county, one half of a job was created. The most powerful wind turbine is rated at 7 megawatts. One of the world s largest wind turbine farms is in Roscoe, Texas, where there are 627 wind turbines and a total installed capacity of megawatts. By the end of 2011, roughly 47,000 megawatts of wind turbines had been installed in the U.S., accounting for about 2.5 percent of the nation s electricity supply. From 2007 to 2010, wind contributed 36 percent of all new electric generation built in the U.S. Environmental Impacts Noise Wind turbines do produce noise when they operate, but more often than not the noise is contained within the wind farm. Noise from wind turbines is the most cited concern in a community. The noise is covered by other, natural environmental noises usually the wind masks the noise of the turbine. In response to growing concerns about noise, there have been many changes to wind turbines to eliminate noise. Turbines can be insulated to further reduce 12

13 noise and choosing the best location for the turbines is important to reduce noise pollution. It is recommended that the wind farm be located at least 300 m away from any neighborhoods. Visual Impacts The site of turbine is more of a nuisance than an environmental concern. The location of a wind turbine needs to have optimal wind patterns and it is possible that those locations can be visually impairing. Avian and bat mortality Wind turbine collisions with birds and bats are an emerging issue that many conservation groups are worried about. Some wind farms have more issues with birds and bats than others, depending on avian patterns in the area. In response, there have been efforts to further research the nature of collisions, bird and bat migration patterns, and re-designing turbines to minimize impacts. When a new wind farm is in its development stages, companies are required to monitor bat and bird activity in the area. Choosing a location with minimal avian activity can greatly reduce the amount of collision possibilities. If the only land available are areas with avian and bat activity, white or red lights can be installed on turbines to shoo away animals. Waste Wind energy does not produce any waste products. The only consistent waste from wind turbines is from lubrication oils and hydraulic fluids. Therefore there is little concern for 13

14 environmental contamination. If blades need to be replaced or an entire turbine needs to be replaced, there are proper disposal protocol to follow. Safety There is concern for public and wildlife safety. Wind turbines should be located in fenced-off areas to project the public from electrical dangers. The fencing should not allow animals to enter the wind farm area. Aircraft safety is also very important. The turbines cannot be in the way of any airport runways or any approach or takeoff paths. Land Use The land use required by a wind farm varies based on location. Hilly locations generally occupy less land than flat locations. On a wind farm, the turbines themselves occupy a small portion of the land required. In general, per megawatt of power generated from a wind farm, anywhere from 30 to 141 acres are required. Unused industrial locations are ideal locations for wind farms because they do not require destruction of the environment. As with any development with land, there is a risk for destruction of habitats for wildlife and plants. The wind farm location needs to be assessed for wildlife impact. If necessary, wildlife and plants may need to be moved to another location. Visual Impacts of Wind Power Visual impacts have been leading socio-environmental constraint to installing wind farms and their transmission line in Europe and North America. In developing countries there is less 14

15 concern because turbines are viewed as novelty or sign of economic progress. Shadow flicker is special case of visual impacts. Shadow flicker is a flickering effect that is generated when the blades of a turbine inconsistently cast a shadow into homes or neighborhoods. This is a nuisance for the surrounding community. Advantages and Disadvantages of Wind Power An obvious advantage of installing wind turbines at the Carver County public works facility is that they won t be producing emissions that cause harmful environmental effects. Wind power is a clean energy source and that is something Carver County should feel very happy about if they are to install wind turbines. Another advantage of wind power is that the turbines are available in a range of sizes. The public works facility shouldn t have a problem finding a turbine that fits their needs. Installing wind turbines at the public works facility will have a positive impact on the image of the county as well. People from all over the area will see that Carver County cares about renewable energy and the environment. Also, the installation of wind turbines will create short-term jobs. Jobs are created during the construction of wind farms and long-term jobs are created for maintenance and operation. If the wind farm is built on rural land that is privately owned, the wind farms generates income for the landowner. Lastly, wind power is cost effective. Ignoring the initial installation cost, wind power is one of the cheapest renewable energy technologies available today. Some disadvantages to installing wind turbines are that wind turbines produce noise, have a high initial cost, have moving blades that may harm local wildlife, and may appear ugly to some 15

16 people. Because the turbines are dependent on the wind to make energy, there may be periods of time where the turbines are hardly producing energy at all. However, this isn t a large disadvantage because there are ways to determine what the average wind speed will be for a certain area and so the lack or abundance of wind wouldn t come as a surprise. Another disadvantage is that the project could interfere with cultures. Certain cultures may find wind power unwelcome or undesirable. To avoid this, consultants that specialize in culturally sensitive projects should be involved in the project. Another disadvantage is that there could be impacts on the area s physical culture resources. This includes fossils, historical artifacts, and archaeological resources. If any of these exist in the area, they need protection. Conclusion After our analysis of energy input and output, economics, advantages and disadvantages, and wind turbine design, we recommend that the Carver County Public Works Facility look into adding the Bornay Inclin 1500 turbine to their site. It is the cheapest option that supplies the most energy. Most individuals view wind power as a positive addition to their communities, but they are not fans of wind farms or transmission lines in their backyards. Finding an effective stakeholder engagement is key. It is also important to share prior information. When defining who is a stakeholder, it is important to look at a number of factors, including: the types of lease/rent or royalty payment arrangements, local employment opportunities, and community-based wind power schemes. 16

17 Analytical Supplement Table 1: Small Wind Turbines Specifications, Capacity Factor, and Costs Product Rated Turbine and 25m Rotor Power CF Tower Price Diameter (m) (kw) (2008)* Siemens_NGPS N/A Southwest (Air X) $1, Southwest (Whisper 100) $2, Southwest (Whisper 200) $3, Southwest (Whisper 500) $8, Southwest (Skystream 3.7) $6, Aeromax Engineering (Lakota S, SC) $2, Bergey (BWC 1500) $6, Bergey (BWC XL.1) $4, Bergey (BWC Excel-R) $25, Bornay (Inclin 250) $3, Bornay (Inclin 600) $3, Bornay (Inclin 1500) $5, Bornay (Inclin 3000) $7, Bornay (Inclin 6000) $12, Abundant Renewable Energy (ARE110) $13, Abundant Renewable Energy (ARE442) $38, Kestrel Wind (600) $2, Kestrel Wind (800) $2, Kestrel Wind (1000) $4, Kestrel Wind (3000) $10, Solacity (Eoltec) $27, * Generator, installation, and transportation fees are not included 17

18 Table 2: Large Wind Turbines Specifications and Capacity Factor Product Rotor Diameter (m) Rated Power (kw) CF NorthWind A xle xl sl A27/ E E E E E E V52-850KW V MW V80-1.8MW V & V80-2.0MW V90-3.0MW FL FL G58-850KW G90-2.0MW N S77/1500 KW N90/ N100/2500 KW Serie S S MW S

19 Table 3: Energy Delivered per Year with Rayleigh Assumptions Gantt Chart Table 4: Economic Analysis on Southwest (Wisper 200) Payment method Payment at Payment of Payoff of loan Profit of Total profit beginning each period each year Pay all the money at beginning $3205 $ years $ $ Loan 100% profit $0 $ years $0 $ $0 $ years $0 $ years $ $ $ $

20 Table 5: Economic Analysis on Aeromax Engineering (Lakota S, SC) Payment method Payment at beginning Payment of each period Payoff of loan Profit of each year Total profit Pay all the money at beginning $2395 $ years $ $ Loan 100% profit $0 $ years $0 $ $0 $ years $0 $ years $78.26 $ $ $ Table 6: Economic Analysis on Bornay (Inclin 1500) Payment method Payment at Payment of Payoff of Profit of Total profit beginning each period loan each year Pay all the money at beginning $5130 $ years $ $ Loan 100% profit $0 $ years $0 $ $0 $ years $0 $ years $ $ $ $

21 Table 7: Economic Analysis on Kestrel Wind (800) Payment method Payment at Payment of Payoff of Profit of Total beginning each period loan each year profit Pay all the money at beginning $2799 $ years $ $ Loan 100% profit $0 $ years $0 $ $0 $ years $0 $ years $58.78 $ $ $

22 Figure 1: Gantt Chart 22

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24 11. Wind Energy Development Environmental Concerns. (n.d.). Retrieved October 23, 2015, from Yoon, G., Lee, H., Lee, S., Hur, D., & Cheol, Y. (2014). Power Curve of a Wind Generator Suitable for a Low Wind Speed Site to Achieve a High Capacity Factor. Journal of Electrical Engineering and Technology, 9, doi: