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HomeMy WebLinkAboutCosmos Hills Hydroelectric Field Reconnaissance Report - Dec 2012 - REF Grant 2195413 If you disagree with any information contained herein, please advise immediately Rev. 0 Page 1 © Hatch 2012 All rights reserved, including all rights relating to the use of this document or its contents. H342690 Trip Report 12/3/2012 WHPacific Cosmos Hills Hydroelectric Project Distribution Daniel Hertrich, Hatch Steve Coleman, WHPacific Jay Hermanson, WHPacific Reconnaissance Trip Report Final Date: 9/26/2012 - 9/29/2012 Location: Wesley Creek and Kogoluktuk River Kobuk, AK and Bornite Mine, AK Present: Daniel Hertrich, Hatch Steve Coleman, WHPacific Tommy Jones, Kobuk resident, (907) 948- 2005 Purpose: Investigate Potential Hydroelectric Sites 1. Introduction This investigation relates to the overall feasibility effort for hydroelectric development in the Cosmos Hills area of Alaska, projects that would potentially serve the communities of Kobuk, Shungnak, and Ambler with consideration for serving current and future mining operations. The purpose of this investigation is to Review the existing reports and data collected Travel to the project sites for reconnaissance purposes provide a summary report with an initial analysis of the potential benefits of the projects based on the existing data and site visit. The existing studies and information collected for this report are listed in the Reference section at the end of this report. Rev. 0 Page 2 © Hatch 2012 All rights reserved, including all rights relating to the use of this document or its contents. 2. Logistics Dan and Steve departed Anchorage for Kotzebue on Alaska Airlines Wednesday 5:20 pm September 26th and stayed at the Nulla vik Hotel (907 442-3331). Departed Kotzebue for Kobuk on Era Aviation Thursday 8:50 am. NovaCopper Camp manager Johnny O transported (13 miles) to the NovaCopper's Bornite Mine camp before noon. The camp provided lodging and food for the remainder of the trip and was equipped with a kitchen and cook, showers, restrooms, laundry, medical, and other facilities. Dan and Steve utilized 2 four wheelers, owned by residents in Kobuk that were left at the camp, were accompanied by Tommy Jones on his own four wheeler and proceeded with reconnaissance of Wesley Creek and the cat trail from Dahl Creek airport to the Kogoluktuk River and arrived back at the camp around 8 pm. On Friday Steve and Dan departed the camp around 9 am to Kobuk and met Tommy who arranged the use of a skiff for transport up the Kogoluktuk river. After obtaining fuel the 3 set out and arrived at the lower end of the white water section of the Kogoluktuk around 11:30 which is about 1.5 river miles upstream of the end of the cat trail. Thence the reconnaissance proceeded to various river locations upstream to the upper end of the falls section (approximately 2.25 walking miles each way). Upon returning to Kobuk at 5 pm the boat was refuelled and Steve and Dan returned to the NovaCopper camp around 6:30 pm. Weather delays forced the cancelation of Era's morning flight but were able to travel back to Kotzebue on Bering Air and then back to Anchorage arriving at 10:30 pm. 3. Project Sites The table below lists the hydroelectric resources available in the Cosmos Hills vicinity and included in this analysis. The table also indicates the elevation configurations used where there is a lack of clear definition as to the best location for the powerhouse and/or features are outside the limits of the detailed elevation and imagery data. Table 1 - Project Configurations Parameter Wesley Kogoluktuk Dahl Cosmos Kogoluktuk Dam Basin Area (sq mi) 5.2 290 8.4 11.1 290 Avg Annual Flow (cfs) 13.3 780.3 19.2 24.7 780.3 Design Flow (cfs) 19 275 24 25 1300 Intake Elevation (ft) 656 225 523 700 360 Powerhouse Elevation (ft) 333 175 273 380 250 Static Head (ft) 323 50 250 320 110 Conduit Diameter (in) 22 96 26 26 N/A Conduit Length (ft) 8,000 3,900 9,370 11,000 N/A Net Efficiency 80% 80% 80% 80% 80% Capacity (kW) 354 886 345 460 9,696 Annual Energy Output (kWh) 1,430,000 5,570,000 1,550,000 1,950,000 32,480,000 3.1 Wesley Creek The Wesley Creek project is a run of river configuration with numerous possible configurations primarily varying in powerhouse location and length of pipeline. Further Rev. 0 Page 3 © Hatch 2012 All rights reserved, including all rights relating to the use of this document or its contents. feasibility is required to determine the most appropriate project configuration. Initial estimates indicate that total head can vary from about 320' to over 400' with pipeline lengths from about 8,800' to almost 14,000'. Future analysis should consider, in addition to the variety of powerhouse locations, the option of moving the intake upstream slightly, and the possible diversion of tributaries located just outside the Wesley Creek basin near the headwater boundary (potentially increase basin area by ~60%). Photo 1 - Possible Intake Site, Wesley Creek Small tributary visible at the right of the photo. 3.2 Lower Kogoluktuk The Kogoluktuk project, also referred to as the Lower Kogoluktuk site, is a potential run of river project with very low head and large flows. The suggested intake site has bedrock features along the banks and is located where the river cross section is relatively narrow (100' wide at 12' above river surface) which is an important consideration with regard to glaciation and capturing low flows during the winter. The suggested powerhouse site is located at the end of the falls section where the river opens up to a broad, flat section width. The static head listed in the configuration table is estimated based on visual observations and the elevations from the Digital Elevation Model. Elevation distance between the Aerometric ground points at the point of intake and the edge of coverage limit is 36'. Future feasibility analysis must consider the actual head based on additional survey data, location of features, diversion structure heights, draft tube locations and efficiencies, and ice considerations. Rev. 0 Page 4 © Hatch 2012 All rights reserved, including all rights relating to the use of this document or its contents. Photo 2 - Possible intake site on Kogoluktuk River The intake site could support a typical concrete diversion structure, an obermeyer type structure, or possibly an intake excavated out of the bedrock. The last option would sacrifice the additional head gained by a raised dam and should only be considered in order to keep concrete use to an absolute minimum and offer the possibility for the project to use the natural water feature FERC licensing exemption. The pipeline route for the Kogoluktuk project is expected to generally follow the right bank of the river when looking downstream although a buried route that short circuits the river bend may be feasible (see Figure 1) in conjunction with a higher diversion structure. Consideration should be given to utilizing different sizes of pipe so that smaller diameters can be shipped inside the larger diameters to maximize the bulk versus weight considerations of air transport. The powerhouse location along the Kogoluktuk is at the end of the exposed bedrock section and some additional site investigation is required to select the best location once the Digital Elevation Model and Orthoimagery is extended to cover this area. The powerhouse will need to be situated high enough to avoid glaciation related flooding. A split level powerhouse with a vertical turbine potentially below submergence levels and a generator situated above may allow for lower turbine elevations if draft tube designs are not able to maximize head while avoiding potential flooding. Turbine and generator options must also be investigated to determine the optimal project configuration. A Kaplan type turbine is expected although an enclosed Archimedes screw may be feasible as well. The Kogoluktuk project utilizes heavy and bulky components that will require feasibility investigation of shipping by air freight to the Dahl Creek runway. Rev. 0 Page 5 © Hatch 2012 All rights reserved, including all rights relating to the use of this document or its contents. Photo 3 - Kogoluktuk Powerhouse area (right bank) looking downstream from Bluff Photo 4 - Kogoluktuk lower falls area not included in Digital Elevation Model and Orthoimagery (looking upstream from same Bluff as photo above). Rev. 0 Page 6 © Hatch 2012 All rights reserved, including all rights relating to the use of this document or its contents. Figure 1 Map of Kogoluktuk Project with 10' Contours 3.3 Upper Kogoluktuk - Dam The Kogoluktuk river flows through a narrow canyon area upstream from the run of river project location discussed above. Two projects were considered at this location, a run of river project and a storage project. This upper canyon area is also referred to as the Upper Kogoluktuk site. Rev. 0 Page 7 © Hatch 2012 All rights reserved, including all rights relating to the use of this document or its contents. The run of river option at this site is generally discarded because of issues associated the inclination of faults in the bedrock, poor intake site options, lower head (~32'), and the longer distance from roads and transmission. The storage option along the upper Kogoluktuk would be suitable for loads about 10 times larger than the communities current needs (including heat and electricity). The capacity of the project is suggested to be about 10 MW (utilizing 1300 cfs). Further analysis including modeling of reservoir volumes would be required to more accurately establish capacity and energy. The storage project may be desirable for a moderate sized future industrial load but is oversized at this time. Lacking demand for this much energy it is not considered further. Photo 5 - Bedrock Gorge of Kogoluktuk Canyon (Upper site) 3.4 Dahl Creek Heads for projects on Dahl Creek vary from about 250' to over 300' with corresponding pipeline lengths of 9,400' to 12,000'. A site visit to this project was not done. The suggested configuration is based on review of the Digital Elevation Model and Orthoimagery. Rev. 0 Page 8 © Hatch 2012 All rights reserved, including all rights relating to the use of this document or its contents. 3.5 Cosmos Creek Consistent with other sites in area, configurations for this project have static heads ranging from 300' to over 370' with pipeline lengths ranging from 14,000' to 18,000' although there is some estimation based on USGS topographic mapping1. A site visit to this project was not done. The suggested configuration is based on review of the Digital Elevation Model and Orthoimagery and USGS 1:63360 topographic maps. 4. Project Energy and Benefit Analysis This trip report also presents a preliminary analysis of the benefits of the projects to aid in defining future feasibility efforts. 4.1 Methods The resource analysis pairs the hydrology data collected for the water year 2010/2011 with load data for the same period. A basic operational model is used wherein diesel fuelled energy is displaced by the available hydroelectric energy. Hydroelectric energy is determined using a fixed efficiency value and the headloss occurring at full flow. Design flow (and capacity) for the Kogoluktuk project is based on limiting capacity with a total head loss of about 5%. Design flow for the remaining creek projects is based on limiting head loss to 15% of the static head. The hydrology and electric demand data sets were reduced to daily averages with daily peak loadings retained and used to simulate diesel generated electricity when the hydroelectric output was at or below this peak value. The model utilizes a minimum diesel loading of 30 kW over a 12 hour period whenever the hydro potential is below the daily peak demand. Diesel usage in the model is determined using a fixed efficiency of 13 kWh/gallon for electricity and 133,000 BTU/gal with an 80% conversion efficiency for heating. The determination of the economic value of the displaced diesel is based on present day prices for electrical generation of $6 per gallon and a retail fuel price of $10 per gallon for heating. The net present dollar value is calculated based on a 30 year term and 3% rate. 4.2 Analysis The hydrology data used in the analysis has been compared with the USGS historical data for the Kobuk River and Dahl Creek. Table 2 - Hydrology Comparison Sites Site Name 15744500 KOBUK R NR KIANA AK 15743850 DAHL C NR KOBUK AK Latitude 66°58'25" 66°56'46" Longitude 160°07'51" 156°54'32" Drainage Area (mi^2) 9,520 11 Discharge Begin Date 9/1/1976 7/17/1986 Discharge End Date 10/10/2012 10/10/2012 Record Count 11728 7425 1 USGS 1:63360 scale Alaska Topographic Quad maps Rev. 0 Page 9 © Hatch 2012 All rights reserved, including all rights relating to the use of this document or its contents. The historical data has been reduced to average daily values and is compared with 2010/2011 data used in this report using the following chart. Figure 2 - Chart of Hydrology Data Basic comparison of the hydrology data sets shows that the data used in this analysis appears generally consistent with the historical data and this may be typical for the climate associated with this region. Additional analysis should examine annual and seasonal variability in the historical data along with the more recent collected 2011/2012 data when it is available. The electrical load information provided by AVEC was summarized into daily averages and is shown in the chart below. AVEC has a generating plant in Shungnak that is connected to Kobuk by a transmission line. AVEC also operates a generation plant in Ambler and is planning another transmission line to connect to Shungnak and Kobuk. Review of the three years of load data does not show any significant change in patterns or trends in electrical demand for both Shungnak/Kobuk and Ambler. AVEC reports that the drop in load that occurred around December 2010 is an anomaly (likely a transmission line failure serving Kobuk). Therefore, that event has been removed from the comparison data by using the 2011 data for the same period. The ongoing data collection and reporting ability by AVEC is adequate for future feasibility analysis. 0.1 1 10 100 9/1 9/29 10/27 11/24 12/22 1/19 2/16 3/16 4/13 5/11 6/8 7/6 8/3 8/31 Day of Year (2010data) UnitHydrograph (cfs/sq mi) Kobuk USGS Dahl USGS Wesley Kogoluktuk Dahl Cosmos Rev. 0 Page 10 © Hatch 2012 All rights reserved, including all rights relating to the use of this document or its contents. During the site visit the NovaCopper exploration camp utilized a 175 kW generator for their operations. It was reported by the camp manager that the generator was slightly undersized for their needs and that exploration activity was expected to increase over the next several years. Camp operations begin around mid May and end after September. A 200 kW flat load scenario occurring from 5/15 through 9/30 annually has been added as an optional demand in the benefit analysis. Figure 3 - Chart of Demand Data The analysis of displaced heat energy utilizes the daily average heating degree days from the Bettles Airport to allocate total annual community heating requirements to daily values. The Bettles meteorological data has been collected since 1951 and is situated fairly close to the Cosmos Hills area making it suitable for this purpose. The annual heating requirements were obtained from the Alaska Energy Pathway 2010 data that was reported in mmBTU for Kobuk, Shungnak, and Ambler with about 80% of that demand being met by diesel and 20% by wood. For this report displaced heat demand was assumed to be entirely diesel fuelled. Future work should refine the annual heating requirements, the fuels used, their costs, and the timing of their use if displacing heat is to factor into the feasibility. 5. Results The modeling of the hydroelectric benefits indicates that the run of river project on the lower Kogoluktuk will displace the most diesel fuel. Without cost or constructability considerations, this project would be the clear choice for hydroelectric development. The benefits of this project are more pronounced when heating loads and the Ambler intertie is modelled. 50 100 150 200 250 300 Date Ambler Shungnak/Kobuk Rev. 0 Page 11 © Hatch 2012 All rights reserved, including all rights relating to the use of this document or its contents. The modeling also shows that the gain in benefits reduces as projects are combined. Thus, if the Wesley and Dahl creek projects are constructed there is generally little additional gain in fuel savings by adding the Kogoluktuk project. Another result of the modeling is the need for sizing projects to maximize economics based on the projected energy needs. For the Kogoluktuk, the capacity should be larger when considering incorporating the Ambler demand and heating loads. For the remaining projects, reduced capacities would be appropriate when combining multiple projects because the availability of water does not generally coincide with the need for energy. The modeling results for each load scenario and project development scheme are presented as the annual displaced fuel and net present value (NPV) in the following table. Table 3 - Annual Fuel Savings and Present Value Benefits for Each Project Option Demand/Hydro Scenario Electrical Heat Combined Hydro Size (kW) Annual Fuel Savings (gal) NPV Savings (millions of $) Annual Fuel Savings (gal) NPV Savings (millions of $) Annual Fuel Savings (gal) NPV Savings (millions of $) Shungnak-Kobuk (SK) Wesley Creek 350 64,000 $7.5 13,000 $2.6 77,000 $10.1 Wesley + Dahl Creek 700 87,000 $10.2 21,000 $4.2 108,000 $14.4 Wesley + Dahl + Cosmos Creek 1160 103,000 $12.2 30,000 $5.8 133,000 $18.0 Kogoluktuk 890 116,000 $13.6 59,000 $11.6 175,000 $25.2 Wesley + Kogolutuk 1240 117,000 $13.8 65,000 $12.8 183,000 $26.6 Wesley + Dahl Creek Kogoluktuk 1580 119,000 $14.0 71,000 $14.0 191,000 $28.0 Ambler-Shungnak-Kobuk (ASK) Wesley Creek 350 88,000 $10.4 9,000 $1.7 97,000 $12.1 Wesley + Dahl Creek 700 125,000 $14.7 28,000 $5.5 153,000 $20.2 Wesley + Dahl + Cosmos Creek 1160 152,000 $17.9 38,000 $7.4 190,000 $25.3 Kogoluktuk 890 188,000 $22.1 62,000 $12.0 249,000 $34.1 Wesley + Kogolutuk 1240 196,000 $23.1 70,000 $13.8 267,000 $36.9 Wesley + Dahl Creek Kogoluktuk 1580 203,000 $23.9 80,000 $15.7 283,000 $39.6 SK + Mine Camp Wesley Creek 350 102,000 $12.0 3,000 $0.6 105,000 $12.6 Wesley + Dahl Creek 700 137,000 $16.1 21,000 $4.1 158,000 $20.2 Wesley + Dahl + Cosmos Creek 1160 154,000 $18.1 30,000 $5.8 184,000 $23.9 Kogoluktuk 890 166,000 $19.6 59,000 $11.5 225,000 $31.1 Wesley + Kogolutuk 1240 168,000 $19.7 65,000 $12.9 233,000 $32.6 Wesley + Dahl Creek Kogoluktuk 1580 170,000 $20.0 71,000 $14.0 241,000 $34.0 ASK + Mine Camp Wesley Creek 350 110,000 $12.9 0 $0.0 110,000 $12.9 Wesley + Dahl Creek 700 173,000 $20.4 21,000 $4.0 194,000 $24.4 Wesley + Dahl + Cosmos Creek 1160 202,000 $23.8 37,000 $7.3 239,000 $31.1 Kogoluktuk 890 238,000 $28.0 59,000 $11.6 298,000 $39.6 Wesley + Kogolutuk 1240 247,000 $29.0 70,000 $13.8 317,000 $42.8 Wesley + Dahl Creek Kogoluktuk 1580 254,000 $29.9 80,000 $15.6 334,000 $45.5 The following charts show the daily modeling results for selected projects. Rev. 0 Page 12 © Hatch 2012 All rights reserved, including all rights relating to the use of this document or its contents. Figure 4 - Power Profile of Wesley + Dahl Creek with Shungnak/Kobuk Demand Figure 5 - Power Profile of Wesley + Dahl Creek with Ambler + Shungnak/Kobuk Demand 0 200 400 600 800 1000 1200 9/1 10/1 11/1 12/1 1/1 2/1 3/1 4/1 5/1 6/1 7/1 8/1 Day of Year (2010) Diesel forHeat Diesel forElectricity Hydropowerfor Heat, kW Hydropowerfor Electricity HydropowerOutput AvgElectrical Demand Heat + Electrical Demand 0 500 1000 1500 2000 2500 9/1 10/1 11/1 12/1 1/1 2/1 3/1 4/1 5/1 6/1 7/1 8/1 Day of Year (2010) Diesel forHeat Diesel forElectricity Hydropowerfor Heat, kW Hydropowerfor Electricity HydropowerOutput AvgElectrical Demand Heat + Electrical Demand Rev. 0 Page 13 © Hatch 2012 All rights reserved, including all rights relating to the use of this document or its contents. Figure 6 - Power Profile of Kogoluktuk with Shungnak/Kobuk Demand Figure 7 - Power Profile of Kogoluktuk with Shungnak/Kobuk + Ambler Demand 0 200 400 600 800 1000 1200 9/1 10/1 11/1 12/1 1/1 2/1 3/1 4/1 5/1 6/1 7/1 8/1 Day of Year (2010) Diesel forHeat Diesel forElectricity Hydropowerfor Heat, kW Hydropowerfor Electricity HydropowerOutput AvgElectrical Demand Heat + Electrical Demand 0 500 1000 1500 2000 2500 9/1 10/1 11/1 12/1 1/1 2/1 3/1 4/1 5/1 6/1 7/1 8/1 Day of Year (2010) Diesel forHeat Diesel forElectricity Hydropowerfor Heat, kW Hydropowerfor Electricity HydropowerOutput AvgElectrical Demand Heat + Electrical Demand Rev. 0 Page 14 © Hatch 2012 All rights reserved, including all rights relating to the use of this document or its contents. 6. Conclusions and Recommendations This site visit and preliminary analysis indicates that there are definite hydro resources in Cosmos Hills area that could serve local energy needs. However, there is a need for further feasibility work including data gathering and cost estimating before a development recommendation can be made. A preliminary opinion regarding project selection is that the lower Kogoluktuk is preferable if it can be constructed for a reasonable cost and is properly designed and constructed to ensure low maintenance operation. Additional feasibility investigations with a focus on the option of displacing energy for Ambler and heating needs, construction methods and costs, capacity configurations, and general risk assessments should result in a clearer understanding of the best solution for hydroelectric development. The following general recommendations are made for future work: Extend collection of LIDAR data and orthoimagery, or obtain elevations from land surveying, for the lower Kogoluktuk powerhouse and the Cosmos Creek intake. Perform additional hydrology review and analysis. The capacity and/or static head for each project should be further evaluated especially where multiple projects are considered. Evaluate access road and transmission route at the hillside next to the Kogoluktuk. Perform additional reconnaissance, particularly for the Kogoluktuk features including the pipeline, and develop preliminary conceptual project design(s). Perform additional feasibility analysis including cost estimates and investigations of construction and other development issues to conclude the recommended development scenario. 7. Disclaimer This report was prepared by Hatch, together with WHPacific, for the sole and exclusive benefit of Alaska Village Electric Cooperative (the “Owner”) for the purpose of assisting the Owner to determine the feasibility of hydroelectric development near Cosmos Hills (the “Project”) ], and may not be provided to, relied upon or used by any third party. Any use of this report by the Owner is subject to the terms and conditions of the Services Agreement between Hatch, WHPacific, and the Owner, including the limitations on liability set out therein. This report is meant to be read as a whole, and sections should not be read or relied upon out of context. The report includes information provided by the Owner, WHPacific, and by certain other parties on behalf of the Owner and WHPacific. Unless specifically stated otherwise, Hatch has not verified such information and disclaims any responsibility or liability in connection with such information. This report contains the expression of the professional opinion of Hatch, based upon information available at the time of preparation. The quality of the information, conclusions and estimates contained herein is consistent with the intended level of accuracy as set out in this report, as well as the circumstances and constraints under which this report was prepared. However, this report is a scoping study and, accordingly, all estimates and projections contained herein are based on limited and incomplete data. Therefore, while the work, results, estimates and projections herein may be considered to be generally indicative of the nature and quality of the Project, they are not definitive. No representations or predictions are intended as to the results of future work, nor can there be any promises that the estimates and projections in this report will be sustained in future work. Rev. 0 Page 15 © Hatch 2012 All rights reserved, including all rights relating to the use of this document or its contents. 8. References Cosmos Hills Hydrologic Network Installation and Operation, August 2010 - December 2011, Lilly, Brailey, and others, May 2012. Cosmos Hills Hydroelectric Feasibility Project, Preliminary Assessment & Technical Memorandum, WHPacific, 17 pages. Geotechnical Investigation Kogoluktuk River Hydropower Site, Cosmos Hills Hydroelectric Feasibility Study, WHPacific, December 14, 2011 Draft Geotechnical Reconnaissance Report, AVEC Cosmos Hills Hydroelectric Feasibility Study, Golder Associates Inc., December 1, 2010. Digital Elevation Model obtained from WHPacific, LIDAR data acquired by Aerometric on August 2010. Acquired at 1200 meters above mean terrain (AMT) and have a horizontal accuracy of 0.38 meters, vertical accuracy of 0.15 meters or better, and with a nominal point spacing of 0.75 meters, for production of 1' contours. Orthoimagery obtained from WHPacific, Digital Orthomosaic based on 24 August 2010 aerial photography with a pixel ground resolution of 0.5 ft originating from Aerometric. Climate data resource: National Climate Data Center, http://www.ncdc.noaa.gov/, average daily heating degree days for station "Bettles Airport, AK", station id "GHCND:USW00026533", located on page http://www.ncdc.noaa.gov/cdo- web/datasets/NORMAL_DLY/stations/GHCND:USW00026533/detail. Hydrology resource: http://cosmos.gwscientific.com/Main/HomePage, password "hydropower", hydrology data files containing data collected from each of the resources considered in this report for the 2010/2011 water year. Files are located on the page http://cosmos.gwscientific.com/Main/2011SQ. Files used include the following excel files: Upper_Cosmos_Creek_Corrected_Stage_Mean_Daily_Flow.xlsx, Upper_Dahl_Creek_Corrected_Stage_Mean_Daily_Flow.xlsx, Upper_Kogoluktuk_River_Corrected_Stage_Mean_Daily_Flow.xlsx, and Upper_Wesley_Creek_Corrected_Stage_Mean_Daily_Flow.xlsx Community electrical demand provided by Alaska Village Electric Cooperative consisting of 15 minute interval energy usage for Shungnak/Kobuk and Ambler for 2009 through mid 2012. Annual heating fuel use obtained from Alaska Energy Authority, Alaska Energy Pathway 2010. ftp://ftp.aidea.org/2010AlaskaEnergyPlan/2010AlaskaEnergyReport.html Daniel Hertrich