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HomeMy WebLinkAboutWEATS AVEC Wind Generation 08-2007AVEC and Wind GenerationPresented by Brent PetrieWEATSAugust 2007Selawik, Alaska AVEC has considered wind generation options in the past, but there were obstacles:•Lack of appropriately sized machines•Reliability concerns of equipment•Lack of sufficient machines to support service providers•Difficulty in integrating intermittent wind with small diesel systems Over the past eight years, several changes have occurred.•Robust equipment in the 66 kW range has been successfully demonstrated by Kotzebue Electric AssociationƒAtlantic Orient 66 KW machine with a 15-meter rotorƒKEA installed 12 of them at Kotzebue and 2 at Wales•A new 100 kW machine built for cold weather by Northern Power Systems entered the marketƒAVEC ordered thirteen for delivery in 2005-2007ƒRefurbished machines modified for cold weather have potential Tower #2Toksook Bay Northwind 100 Lessons Learned•AVEC and KEA have learned lessons from the high-penetration demonstration project at WalesƒIntegration with small diesels (avoid retrofits where possible)ƒManagement of secondary loads for use of excess wind energy (electric heaters)ƒLogistics (try to combine wind work with other work to reduce cost)ƒOperations and maintenance (make sure personnel or contractors can readily get to the site) How can wind generation be of value to AVEC?•Let’s take a look at the location of AVEC villages Now let’s take a look at the high-class wind regimes that overlay the AVEC villages. Background Information•27 of AVEC’s 52 villages are in wind regimes of class 4 or better.•Given the characteristics of an NW/100, this means that one machine should be able to produce about 250,000 kWh per year.•Given a diesel efficiency of 14 kWh/gallon generated by our new diesel sets, this means that one 100-kW wind turbine might displace about 17,800 gallons per year of diesel fuel use for power generation. A mini-wind farm of three units would displace about 53,400 gallons per year. Consider that in 2006 AVEC:•Purchased 5.1 million gallons of diesel fuel•Actively used nearly 550 fuel tanks for storage•Took on fuel in 160 separate deliveries (including 41 by air)•Has only one village – Minto – that can be supplied by a fuel truck•Continued to experience electric load growth driven by new water and sewer systems, airports, schools and housing in the villagesƒThis load growth increases fuel use and fuel storage needs Therefore, successful integration of wind generation could mean the following to AVEC:•A hedge against increasing fuel costs•A hedge against the increasing costs of marine deliveries•Extension of on-hand fuel supplies which may translate to favorable delivery scheduling by marine transporters•A reduction of the need to build expensive, additional storage on hard-to-acquire or difficult-to-construct sites. To do such efforts cost effectively, we need to do good planning and coordinate efforts with other construction projects underway in the village.•The recent bulk fuel tank farm and power plant priorities of the Denali Commission provide some opportunity to coordinate logistics and use specialty equipment such as pile drivers or cranes that may be on-site. As a further means to reduce costs, AVEC is working to:•Develop alliances with competent parties•Work with vendors to develop a steady and reliable supply of parts and equipment.•Encourage development of in-state expertise in tower foundation and erection. •Encourage development of in-state expertise in resource assessment.•Foster positive relationships with regulatory agencies dealing with environmental and siting issues.•Provide feedback to critical financing entities such as USDA-RUS and the Denali Commission.•Participate with specialty industry associations:ƒNRECA – Cooperative Research NetworkƒUWIG – Utility Wind Interest GroupAs a further means to reduce costs, AVEC is working to: AVEC is also cost-sharing preparation of a high-resolution wind map in partnership with the Alaska Energy Authority and the National Renewable Energy Lab that will provide much more detailed resolution of wind resources for a portion of western Alaska.•This effort is funded with money from:ƒNRELƒAEAƒAVEC The following slide is an example of such before and after mapping in North and South Dakota. The map will be useful in determining where additional wind resource monitoring may or may not be useful. Comparison of Digital Wind Map from 1987 U.S. Wind Atlasand New (2000) High-Resolution (1-km2) Wind Map North and South Dakota AVEC is also participating with the Alaska Energy Authority on placing wind monitoring equipment in several western Alaska villages. Wind Resource Assessment and Analysis is:•Critical to determining the estimated output of a project•Time consuming, but is a small cost compared to cost of a misplaced project. In addition to the wind resource, we also have to consider:•Land ownership and land use in the area•Geotechnical considerations for foundations•Possible historical and cultural resources on the site•Bird issues•Equipment access for construction•Access to power lines. •They must not settle, tilt or be uplifted•Pile foundations (six to eight piles) may extend 1/3 to 2/3 the height of the tower into the groundFoundations in permafrost are a challenge Access for specialty equipment required to place foundations and erect turbines is a challenge. Poor roads, water and sewer lines, boardwalks and existing overhead power and phone lines present obstacles and challenges. Selawik, AlaskaNew modular power plant, bulk fuel tank farm, four wind turbines, and waste heat recovery system Aerial view of new power plant, tank farm, and wind turbines at Selawik, Alaska. Wind siteOverview – Toksook Bay •Holes pre-drilled•Piles driven to refusal•Piles later cut •Drilling out center of piles 20’ below end of pile Six piles for a single tower foundation Steel Foundation Star (Typical of 3) Rebar cage Foundation Design Criteria- Design Wind Speed = 130 mph (50 year)- Overturning moment = 1,830,000 ft lb- Total tower/turbine weight = 42,000 lbFrequency Analysis-Tower only natural frequency (supported on infinitely rigid base) = 1.15 Hz-Minimum natural frequency for tower and foundation = 1.07 HzBased upon 5% over maximum rotor frequency plus 5% factor of safety-Operating frequency of rotor – 0.97 Hz (58 rpm) Wind Turbine Controller Tower/Turbine Specifications- 108 feet from ground level tocenter of rotor- Rotor diameter (3 blades) = 61 feet Nacelle at NPS production facility at Barre, Vermont Second tower section being put in place Note wiring along ladder and mid point landing. Three wind turbines. Ice on turbineblades. Any questions?Presented byBrent PetrieAlaska VillageElectricCooperativeToksook Bay.