Ak Nagpal Su Kam


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Conference on Rural Telecom Markets by Tele.net

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  • Dear Sir,
    Although now dated your study is very interesting. I was disappointed you did not look at using battery power in more detail/ Perhaps employing largere banks of batteries as opposed to Diesel?
    Are you sure you want to  Yes  No
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Ak Nagpal Su Kam

  1. 1. Energy Optimization & Alternative sources of Energy A.K. Nagpal 16th September 2009
  2. 2. Energy Requirement: Current Base Stations 1. Global: Number of mobile telephones currently is 4.1billion and is expected to reach 5 billion by 2015. In India currently (2009 Q1) the mobile subscriber base is 420 Million and is expected to reach 500 Million by 2010 2. More than 90% of the additions will come from emerging economies globally, with 60 to 80 % of them located in rural areas. 3. In India we expect that the number of new Base stations to be setup by 2011 will exceed 2,00,000. 4. Energy related expenditure accounts for nearly 70% of total operating cost per cell site in the rural areas.
  3. 3. Energy Requirement: Current Base Stations 1. The Power requirement of a BTS currently varies from 1300 – 2500 watts. 2. A large percentage of these deployments are still indoor type needing air conditioning. 3. Current SLAs (with operators) need shelter temperature to be maintained between 22 – 300 C range. 4. Powering systems are based on grid supply as primary source with diesel generators as stand by sources and Storage batteries as secondary sources
  4. 4. Energy Requirement: Current Base Stations 5. In case of indoor shelters where specified temperature needs to be maintained:- a. Rise in temperature is faster than decrease in battery voltage to its threshold b. DG set needs to be switched “on” to power the A/Cs and maintain the temperature c. Battery Capacity is not fully utilized.
  5. 5. Drawbacks of existing Powering Model for BTS 1. Base Stations are very power intensive 2. Diesel generators need regular maintenance 3. Diesel thefts are very prominent – they could be as much as 20 % diesel theft 4. Prices of petroleum products are continuously increasing 5. Grid supplies in rural areas are often erratic and unavailable requiring long runtime of DG sets.
  6. 6. TOTAL COST OF OWNERSHIP(TCO) OF A CELL SITE Model A Model C Ground Rent Ground Rent 5% Energy Cost 4% Cost of 9% Funds 31% Security Energy Cost Exp. 33% 9% Cost of O&M Funds 2% 48% Depreciation Security 21% O&M Exp. Depreciation 3% 8% 27% Normal site configuration Solar DG hybrid
  7. 7. TOTAL COST OF OWNERSHIP(TCO) OF A CELL SITE Ground Model B Rent Model D Energy Cost 5% Ground Rent 4% 5% Security Exp. Cost of 9% Funds Energy Cost 26% O&M 34% 2% Cost of c Funds 52% Security Exp. Depreciation Depreciation 9% 28% 24% O&M 2% Solar flow technology battery DG Flowtech by hybrid
  8. 8. Optimizing Energy Requirement of a Cell Site Realizing a OBTS (Optimized Energy Base Stations)
  9. 9. Cell site configuration Base Station Equipment Base Station Site-level Equipment RF parts Cooling and/or heating unit Power amplifier (PA) Rectifier Digital signal processing (DSP) Antenna line (feeder) Transmission Antenna Control Mast-head amplifier (MHA)
  10. 10. Cell site Energy Optimization Traditional Base Station Energy-Optimized Base Station WCDMA GSM WCDMA GSM Component Component % Energy %Energy %Energy % Energy (s) (s) Consumptio Consumption Consumption Consumption n RF + PA 50% 40% RF + PA 85% 75% DSP, DSP, transmission, 10% 20% transmission, 10% 20% MHA MHA Feeder, Feeder, 35% 35% N/A N/A Cooling Cooling Rectifier 5% 5% Rectifier 5% 5%
  11. 11. Key Strategies for Optimizing Power Requirement of a BTS 1. Deploy mainly outdoor BTS equipment which does not require Air Conditioning and intrinsically have low power consumption 2. BTS with Remote Radio Heads (RRH) placed next to the antennae mount thereby eliminating feeder loss. 3. The connectivity between RRH and Base Band can be Fiber based Ethernet eliminating the Coaxial Feeder 4. BTS with Standby Mode Systems that shut down TRX’s during off-peak periods dynamically.
  12. 12. Typical Industry Offerings for Energy Optimized BTS (OBTS) Sno. Equipment Type Configuration Power Consumption 1. LME 2111 (4-4-4) 450 watts 2. ZTE R 60 U (4-4-4) 400 watts 3. Vanu SDR (4-4-4) 650 watts
  13. 13. Adapting Alternative Sources of Energy for Powering BTS Sites
  14. 14. Adapting Alternative Sources of Energy for Powering BTS Sites • The first step towards adapting alternative sources of energy for powering cell sites is to realize OBTS. • The CAPEX for adopting alternative source of energy for powering such sites will become sustainable. • A number of technologies amongst alternative sources are in different stages of evolution • Often a combination of one or more sources of alternative energy needs to be deployed with / without DG sets.
  15. 15. Adapting Alternative Sources of Energy for Powering BTS Sites: The Rationale 1. These sources are CLEAN, GREEN & FREE (RUNNING COST) 2. The capex levels although high at present will come down as technologies mature and volumes attain critical mass. 3. The operating costs are almost nil as these sources are free. Maintenance and replacements are very low compared to diesel – driven sites. 4. Carbon credits can be a revenue stream on green sites (Estimated Rs. 20 K per annum per site)
  16. 16. Adapting Alternative Sources of Energy for Powering BTS Sites: Available technologies 1. SOLAR – DG HYBRID 2. WIND – DG HYBRID 3. SOLAR – WIND HYBRID 4. BIOFUELS 5. FUEL - CELLS
  17. 17. Adapting Alternative Sources of Energy for Powering BTS Sites: Solar Energy 1. MOST MATURED amongst all such technologies. 2. Power converted from light per m2 – efficiency* Polycrystalline Silicon: 12 – 15% Monocrystalline Silicon: 13 – 15% Saturn Monocrystalline Silicon: 15 – 18% *The percentage of sunlight falling on 1 Sq. Meter surface of a Solar Cell that is converted into Electrical power is defined as efficiency of solar cell. Thus a Solar cell with 15% efficiency delivers 150 Watt of Power converted from light falling on 1 Sq. Mtr. Surface at Noon.
  18. 18. Adapting Alternative Sources of Energy for Powering BTS Sites: Solar Energy 3. Main advantages Free, Clean, Green No Moving Parts – No Maintenance Cost 4. Suggested configuration a. Solar – DG Hybrid b. Solar – Wind Hybrid
  19. 19. Adapting Alternative Sources of Energy for Powering BTS Sites: WIND – BASED SYSTEMS FREE, CLEAN & GREEN 1. Advanced systems are widely available 2. Smaller systems can be mounted on existing radio-masts, reducing costs. 3. Horizontal wind turbines are more efficient 4. Systems available with low “cut – in” speeds of 2.4 m/sec CHALLENGES – Site – selection must be carefully done for deployment of wind – turbines, ISO – 820 wind maps must be studied before deploying wind turbines – Wind velocity is often erratic. Thus we need a very efficient charge controller and a sink for excess power – Sink for excess power can be a tube well for example
  20. 20. Adapting Alternative Sources of Energy for Powering BTS Sites: Bio-Fuel 1.Biodiesel is commonly produced by the transesterification of the vegetable oil or animal fat feedstock. There are several methods for carrying out this transesterification reaction including the common batch process, supercritical processes, ultrasonic methods, and even microwave methods. 2. Much of the world uses a system known as the "B" factor to state the amount of biodiesel in any fuel mix: fuel containing 20% biodiesel is labeled B20, while pure biodiesel is referred to as B100. It is common to see B99, since 1% petrodiesel is sufficiently toxic to retard mold. Blends of 20 percent biodiesel with 80 percent petroleum diesel (B20) can generally be used in unmodified diesel engines.
  21. 21. Adapting Alternative Sources of Energy for Powering BTS Sites: Technology Solutions Sample Solar-Wind Solution Application Power Required (Depending on Conditions) GSM base station (2/2/2) 600W-1800W 4kW solar array and 6kW turbine GSM base station (4/4/4) 900W-2300W 6kW solar array and 6kW turbine UMTS Node B macro/fiber 750W-1000W 3kW solar array and 2.5kW turbine (2/2/2) UMTS Node B macro/fiber 1300W-1700W 4kW solar array and 2.5kW turbine (4/4/4) Large WiMax base station 1.3kW (4-sector) 4kW solar array and 2.5 or 6kW turbine <30W,includes a Metro WiFi 100W solar array and small turbine backhaul solution 1kW solar array and 600W or 2.5kW P2P link (two heads) 110W for two units turbine
  22. 22. Case Study Solar Powering of SBI ATM Sites
  23. 23. Assumptions • Peak load of an ATM is 1600 watts. • Activity curve of an ATM site varies from locality to locality and area attributes such as rural, semi-urban and urban. • Grid availability varies considerably throughout the state. No authentic data can be given. However, in rural/remote sites, it varies from 0 hrs a day to 8 hrs a day. In semi-urban areas, it may be 8 hrs a day to 12 hrs a day and in urban areas it may be 12 hrs a day to 20 hrs a day. • Rural, semi-urban and urban areas have different activity curves and peak hit hours. • There are approximately 400 ATM hits/day. • Average transaction time is 30 sec. Power consumption during this time is peaky when mechanical movement is involved and low during data feeding and idle time. • For a rural ATM, main activity time would be 10 AM to 4 PM. • For a urban site, main activity time would be from 9 AM to 8 PM. • For a rural site, it is estimated that the average power consumption will be 1000 watt during main activity time and 100 watt during other time of the day. • For a urban site, it is estimated that the average power consumption will be 1000 watt during main activity time and 150 watt during other time of the day
  24. 24. Design parameters for Solar Powering Power output per panel (W) 100 Rated Voltage (V) 17.2 Output voltage per panel (V) 12 DOD 0.6 Inverter Efficiency 0.9 System Voltage (V) 50 Peak Load 1000 Duration for peak load 6 Off-peak load 100 Duration for off-peak load 18 Grid Availability (hrs) 4 Battery charging rate (Solar) (C/?) 15 Battery AH 274.0741 Battery charging current 18.2716 No. of panels in series 4.166667 No. of panels in series (actual) 4 No. of strings in parallel 6.582716 No. of strings in parallel (actual) 7 Total number of panels 28 Total power output 2800
  25. 25. Component Costs Price of Battery bank Price of Solar panel S.No AH Number Price S.No Cost per watt Panel Wattage Price 1 90 0 0 1 150 2800 420000 2 100 0 0 3 120 0 0 Price of Equalizer (12V) 4 135 0 0 S.No Unit Price Requirement Price 5 150 0 0 1 3000 1 3000 6 165 0 0 7 180 0 0 Price of Battery Coolant 8 200 0 0 S.No Unit Price Requirement Price 9 220 0 0 1 5000 4 20,000 10 250 0 0 11 300 4 108000 Price of PCU (2 KW, 50V) Total price of the battery bank 108000 S.No Unit Price Requirement Price 1 45700 1 45700 Installation & Commissioning charges 119,340 Total 716,040 (Note: All prices are in INR)
  26. 26. Return on Investment (ROI) Assumptions Diesel Price (Rs./liter) 35 Diesel usage by DG (Liters/hour) 2 Fuel pilferage/wastage (%) 5% DG service running hours 250 Life of DG (Years) 10 Price of DG (7.5 KVA) 200000 Scrap value of DG 20000 Cost of DG Service 1000 DG running hours per day 6
  27. 27. Return on Investment (ROI) 6 Hr 12 Hr 18 Hr OpEx Usage Usage Usage Running cost 153300 153300 306600 459900 Fuel pilferage/wastage cost 7665.0 7665 15330 22995 Fuel filling/transportation 12000 12000 12000 12000 charges/year No. of services required 9 9 18 26 Service cost 9000 9000 18000 26000 Maintenance+Consumable 10000 10000 16000 22000 spares Depreciation cost (Straight 18000 18000 18000 18000 line) Total per year cost (In Rs.) 209965 209965 385930 560895 Break-Even Time (Years) 3.41 3.41 1.86 1.28
  28. 28. Thanks Su-Kam – Morphing into a Green Company