Energy Auditing and Demand Side Management10EE842 SOLUTION TO QUESTION BANK UNIT-1 1.Write short notes with respect of electrical equipment’s July, Dec 2015 If you manufacture electrical equipment, you must comply with the Electrical Equipment (Safety) Regulations 1994. These implement into UK law the European Council Directive 2006/95/EEC - commonly referred to as the Low Voltage Directive (LVD). The aim of these regulations is to ensure that electrical equipment designed for use within certain voltage limits is safe to use. This guide covers all the main points of the regulations - including which electrical equipment is affected, definition of electrical equipment, safety requirements and how to comply. The Electrical Equipment (Safety) Regulations 1994 apply to your business if you manufacture electrical equipment designed or adapted for use between 50 and 1,000 volts (in the case of alternating current) or 75 and 1,500 volts (in the case of direct current). The regulations cover domestic electrical equipment and equipment that is intended for use in the workplace, except electrical equipment described in Schedule 2 of these regulations. Coponents The regulations apply to electrical equipment. In general, components are not covered by the regulations. Only components which are in themselves electrical equipment need to satisfy the requirements of the regulations and, in particular, bear European Conformity (CE) marking. The term electrical equipment is not defined in the regulations and should therefore be given the ordinary dictionary meaning. Electrical is defined as ―operated by means of electricity‖ or ―of pertaining to electricity‖. Equipment is defined as ―apparatus‖ which is in turn defined as ―the things collectively necessary for the performance of some activity or function‖. An item is only subject to the requirements of the regulations if it is electrical equipment so defined. Department of EEE, SJBIT Page 1 Energy Auditing and Demand Side Management 10EE842 Electrical components Certain components of electrical equipment may in themselves be considered to be electrical equipment. In such cases, steps should be taken to ensure that they satisfy the requirements of the regulations - if they are to be supplied as separate items. This includes supply for retail sales and to other manufacturers for incorporation into other electrical equipment. 2.Explain the broad features of Indian electricity rule 1956. July, Dec 2014 The Government of India has enacted the Energy Conservation Act in 2001 to provide legal framework and institutional arrangements for enhancing energy efficiency. This Act led to the creation of Bureau of Energy Efficiency (BEE) as the nodal agency at the center and State Designated Agencies (SDAs) at the State level to implement the provisions of the Act. Under the Act, Central Government, State Government and Bureau of Energy Efficiency have major roles to play in implementation of the Act. The Mission of BEE is to develop policy and strategies based on self-regulation and market principles with the goal of reducing energy intensity of the Indian economy. This will be achieved with active participation of all stakeholders, resulting in rapid and sustained adoption of energy efficiency in all sectors. Electricity Act, 2003 The government has enacted Electricity Act, 2003 which seeks to transform and develop the electricity sector by distancing Government from the task of regulation. Before enactment of this act, electricity supply in India was governed by Indian Electricity Act, 1910, the Electricity (Supply) Act, 1948 and the Electricity Regulatory Commissions Act, 1998. There was a need to consolidate the provisions of above act and consequently, Electricity Act, 2003 was introduced. 3.What is energy conservation? Explain July 2014 Energy Conservation and Energy Efficiency are separate, but related concepts. Energy conservation is achieved when growth of energy consumption is reduced in physical terms. Energy Conservation, therefore, is the result of several processes or developments, such as productivity increase or technological progress. On the other hand Energy efficiency is achieved when energy intensity in a specific product, process or area of production or consumption is reduced without affecting output, consumption or comfort levels. Promotion of energy efficiency Department of EEE, SJBIT Page 2 Energy Auditing and Demand Side Management 10EE842 will contribute to energy conservation and is therefore an integral part of energy conservation promotional policies. Energy efficiency is often viewed as a resource option like coal, oil or natural gas. It provides additional economic value by preserving the resource base and reducing pollution. For example, replacing traditional light bulbs with Compact Fluorescent Lamps (CFLs) means you will use only 114th of the energy to light a room. Pollution levels also reduce by the same amount (refer Figure 1.11) Nature sets some basic limits on how efficiently energy can be used, but in most cases our products and manufacturing processes are still a long way from operating at this theoretical limit. Very simply, energy efficiency means using less energy to perform the same function. Although, energy efficiency has been in practice ever since the first oil crisis in 1973, it has today assumed even more importance because of being the most cost-effective and reliable means of mitigating the global climatic change. Recognition of that potential has led to high expectations for the reduction of future CO2 emissions through more energy efficiency improvements than that achieved in the past. The industrial sector accounts for about 41 per cent of global primary energy demand and approximately the same share of CO2 emissions. Department of EEE, SJBIT Page 3 110 in one year is a future value equivalent to the Rs. SJBIT Page 4 . Once the payback period has ended. all these present and future cash flows must be equated to a common basis. For example. The shorter the payback period. The length of the maximum permissible payback period generally varies with the company concerned. then a Rs. and a series of annual costs and/or cost savings (i. Department of EEE. etc. Mention its advantages and Disadvantages Dec 2015 Payback Period: The simplest technique which can be used to appraise a proposal is payback analysis.e. considering only the Annual Net Saving (Yearly benefitsYearly costs). The method by which these various cash flows are related is called discounting. The payback period can be defined as the time (number of years) required to recover the initial investment (capital cost). called the capital cost. or the present value concept. To assess project feasibility.110 in one year's time.Energy Auditing and Demand Side Management 10EE842 UNIT-2 1.Explain payback analysis. maintenance. operating. Thus the Rs. The problem with equating cash flows which occur at different times is that the value of money changes with time. if money can be deposited in the bank at 10% interest. all the project capital costs will have been recovered and any additional cost savings achieved can be seen as clear 'profit'. 100 present value.) throughout the life of the project. Time Value of Money A project usually entails an investment for the initial cost of installation. the more attractive the project becomes. energy. 100 deposit will be worth Rs. e. SJBIT Page 5 . (ii) and (iii) above.g. mean system power drawn per pumpset = 9000 / 49 i.56*10 5 and its estimated that after 25 years it will have to be replaced by a new one.90.90.e.91 plus 10% interest equals Rs. Rs.34 kW and 183. iii) From (i) and (ii) above.91 represents the present value of Rs.100 cash flow occurring one year in the future.Energy Auditing and Demand Side Management 10EE842 In the same manner. calculate cumulative system kW for minimum and maximum number of pumps simultaneously operated.100).90.000 kWh. 3(700).100 received one year from now is only worth Rs. 183.91 in today's money (i. total consumption 5. v) Depending on efficiency of transformer at load factors corresponding to differentcumulative kW.67 x 3 = 551. cumulative system kW drawn for 2 numbers of pumps and 3 numbers of pumps operating shall be 183. b) Reducing balance method c) Sinking fluid deprecation method at 8% annual compound interest July 2015 i) Examine few electric bills in immediate past and calculate total number of days. iv) From (i). calculate totalpump hours of individual pump sets. calculate mean system kW drawn per pumpset [In the example.A plant cost Rs 7. Rs. calculate output of transformer for loads of different Department of EEE.01 kW respectively]. then the equivalent present value would also change.49.67 kW]. If the interest rate were something different than 10%. daily pump hours shall be 2989 ÷ 61 = 49 pump hours. ii) Examine log books of pumping operation for the subject period. pump hours of individualpumpsets are : 1(839). then average daily consumption shall be 9000 kWh].total kWh consumed and average daily kWh [e. [In the example. 2. Thus Rs.67 x 2 = 367. 2(800). Averagedaily operations are: 2 numbers opumps working for 11 hours and 3 numbersof pumps working for 9 hours].56* 105 calculate i) annual deposit to be made in order to replace the plant after 25 years ii) the value of the plant after 10 years in the following basis a) Straight line depreciation method. total pump hours over the period andaverage daily pump hours [Thus in the above example. 4(350) and 5(300) then as total hours are2989 pump-hours. in an installation with 3 numbers working and 2 numbers standby if bill period is 61 days. at that instant its salvage value will be Rs 1. 537. Here are the key reasons why a cash flow forecast is so important: Department of EEE. Cash flow forecasting is important because if a business runs out of cash and is not able to obtain new finance. [In the example. 3. If the business is struggling.97 and 0.22 kW and 179. 154.34 x 0.975i.09 kW each for 3 pumps working simultaneously.e. being negligible. for all practical purpose can be considered as cumulative inputs to motors for the combinations of different number of pumps working simultaneously. How often management should forecast cash flow is dependent on the financial security of the business. it is essential that management forecast (predict) what is going to happen to cash flow to make sure the business has enough to survive.32 kW and 551.e. the business owner should be forecasting and revising his or her cash flow on a daily basis.01 kW respectively.23 kW respectively.e. average input tomotor shall be 356. if motor efficiency is 0.975 for load factor corresponding to 367. or is keeping a watchful eye on its finances. if transformer efficiencies are 0.e.23÷ 3 i.86 i. The clearance need to be physically checked by dismantling the pump and measuring diametral clearances in wearing rings and replacing the wearing ring. it will become insolvent. Cash flow is the life-blood of all businesses—particularly start-ups and small enterprises.Energy Auditing and Demand Side Management 10EE842 combinationsof pumps.6% of rated discharge. viii) Depending on efficiency of motor at the load factor.[In the example.16 x 0. However. If actual discharge is within 4% . the results are deemed as satisfactory. 179.e. then forecasting and revising cash flow weekly or monthly is enough. 356.07 x 0.86. 153. 178. As a result. vii) Cumulative input to motors divided by number of pumpsets operating in the combination shall give average input to motor (In the example. if the finances of the business are more stable and 'safe'. average input to pump shal be178. it indicates that wearing rings are probably worn out.01 x 0. SJBIT Page 6 .0 kW].86 i.32 ÷ 2 i.e.16 kW each for 2 pumps working and 537. planning its future cash requirements to avoid a crisis of liquidity.34 kW and 551. then outputs of transformer for the loads shall be 367.Explain cash flow model July 2015. vi) The outputs of transformer. If discharge varies beyond limit.July 2014 Cash flow forecasting or cash flow management is a key aspect of financial management of a business.97 i. can be ignored. Cable losses. calculate average input to pump. similar to preparing business budgets. Spot problems with customer payments—preparing the forecast encourages the business to look at how quickly customers are paying their debts. Cash flow is the change in cash or treasury position from one period to the next period. but often what is forecast is treasury position which is cash plus shortterm investments minus short-term debt. cash flow forecasting is the modeling of a company or entity's future financial liquidity over a specific timeframe. dividendsand interest on debt. Suppliers who don't get paid will soon stop supplying the business. Receipts are primarily the collection of accounts receivable from recent sales. etc.Energy Auditing and Demand Side Management 10EE842 Identify potential shortfalls in cash balances in advance—think of the cash flow forecast as an "early warning system". Certainly. SJBIT Page 7 . Cash usually refers to the company's total bank balances. data is available. External stakeholders such as banks may require a regular forecast. Definition In the context of corporate finance. as opposed to projected. This direct R&D method is best suited to the short-term forecasting horizon of 30 days or so because this is the period for which actual. it is even worse if employees are not paid on time. This is. payment of accounts payable from recent purchases. As an important discipline of financial planning—the cash flow forecast is an important management process. Disbursements include payroll. the most important reason for a cash flow forecast. if the business has a bank loan. Make sure that the business can afford to pay suppliers and employees. The three indirect methods are based on the company's projected income statements and balance sheets. by far. the bank will want to look at the cash flow forecast at regular intervals. Note—this is not really a problem for businesses (like retailers) that take most of their sales in cash/credit cards at the point of sale. Methods The direct method of cash flow forecasting schedules the company's cash receipts and disbursements (R&D). proceeds of financing. but also include sales of other assets. Department of EEE. large accruals are reversed and cash effects are calculated based upon statistical distributions and algorithms. therefore. it is more complicated than the ANI or PBS indirect methods. and need to be adjusted for the difference between accrual-accounting book cash and the often-significantly-different bank balances. Definition In the context of entrepreneurs or managers of small and medium enterprises. if all the other balance sheet accounts have been correctly forecast. The pro-forma balance sheet (PBS) method looks straight at the projected book cash account. But instead of using projected balance sheet accounts. which is similar to the ANI method. planning what cash will come into the business or business unit in order to ensure that outgoing can be managed so as to avoid them exceeding cashflow coming in. Both are limited to the monthly or quarterly intervals of the financial plan. But because the ARM allocates both accrual reversals and cash effects to weeks or days. Both the ANI and PBS methods are best suited to the medium-term (up to one year) and longterm (multiple years) forecasting horizons. The ARM is best suited to the medium-term forecasting horizon. The third indirect approach is the accrual reversal method (ARM). It also eliminates the cumulative errors inherent in the direct. R&D method when it is extended beyond the shortterm horizon.Energy Auditing and Demand Side Management 10EE842 The adjusted net income (ANI) method starts with operating income (EBIT or EBITDA) and adds or subtracts changes in balance sheet accounts such as receivables. cash will be correct. Department of EEE. This allows the forecasting period to be weekly or even daily. payables and inventories to project cash flow. too. SJBIT Page 8 . Uses A cash flow projection is an important input into valuation of assets. they must become good at cashflow forecasting. Entrepreneurs need to learn fast that "Cash is king" and. budgeting and determining appropriate capital structures in LBOs and leveraged recapitalizations. cash flow forecasting may be somewhat simpler. Parameters of importance other than electrical such as temperature & heat flow.. A danger of using too much corporate finance theoretical methods in cash flow forecasting for managing a business is that there can be non cash items in the cashflow as reported under financial accounting standard. Reactive power (kVAr). Write short note on energy audit instruments July 2015. liquid flow. pH. noise and vibration. Frequency (Hz). Key instruments for energy audit are listed below. The parameters generally monitored during energy audit may include the following: Basic Electrical Parameters in AC &DC systems .CO2. which in turn requires judgement honed by experience of the industry concerned. apparent power (demand) (kVA). This requires that the quantity and timings of receipts of cash from sales are reasonably accurate. air velocity. 02. revolutions per minute (RPM). July 2014 The requirement for an energy audit such as identification and quantification of energy necessitates measurements. combustion efficiency etc. CO. etc. NO. easy to operate and relatively inexpensive. The operating instructions for all instruments must be understood and staff should familiarize themselves with the instruments and their operation prior to actual audit use. relative humidity. dust concentration. Department of EEE. and it is also rare for customers all to pay on time. Active power (kW). these measurements require the use of instruments. Harmonics. Current (I). SO. radiation. Total Dissolved Solids (TDS). These instruments must be portable. Energy consumption (kWh).Energy Auditing and Demand Side Management 10EE842 Methods The simplest method is to have a spreadsheet that shows cash coming in from all sources out to at least 90 days.Voltage (V). and all cash going out for the same period. air and gas flow. Power factor. SJBIT Page 9 . moisture content. UNIT-3 1. flue gas analysis . These principles remain constant whether the cash flow forecasting is done on a spreadsheet or on paper or on some other IT system. because it is rare for cash receipts to match sales forecasts exactly. durable. This goes to the heart of the difference between financial accounting and management accounting. SJBIT 10EE842 Page 10 .Energy Auditing and Demand Side Management Department of EEE. SJBIT 10EE842 Page 11 .Energy Auditing and Demand Side Management Department of EEE. SJBIT 10EE842 Page 12 .Energy Auditing and Demand Side Management Department of EEE. SJBIT 10EE842 Page 13 .Energy Auditing and Demand Side Management Department of EEE. • Discuss economic guidelines associated with the recommendations of the audit. July 2014 Phase I -Pre Audit Phase Activities A structured methodology to carry out an energy audit is necessary for efficient working. as the planning of the procedures necessary for an audit is most important. kWh. steam. oil or gas meters. During the initial site visit the Energy Auditor/Engineer should carry out the following actions: • Discuss with the site's senior management the aims of the energy audit. Initial Site Visit and Preparation Required for Detailed Auditing An initial site visit may take one day and gives the Energy Auditor/Engineer an opportunity to meet the personnel concerned. • Analyze the major energy consumption data with the relevant personnel. electricity distribution etc. • To identify the instrumentation required for carrying out the audit. • To decide whether any meters will have to be installed prior to the audit eg. • To plan with time frame Department of EEE. Explain detailed energy audit.building layout. compressed air distribution. • Obtain site drawings where available . 10EE842 Dec 2015. • Tour the site accompanied by engineering/production The main aims of this visit are: • To finalize Energy Audit team • To identify the main energy consuming areas/plant items to be surveyed during the audit. • To identify any existing instrumentation/ additional metering required. An initial study of the site should always be carried out. steam distribution.Energy Auditing and Demand Side Management 2. SJBIT Page 14 . to familiarize him with the site and to assess the procedures necessary to carry out the energy audit. major energy consuming centers • To create awareness through meetings/ programme Phase II. 6.Detailed Energy Audit Activities Depending on the nature and complexity of the site. steam). Whenever possible. compressed air.) 3. production of by-products for re-use in other industries. a comprehensive audit can take from several weeks to several months to complete.Energy Auditing and Demand Side Management 10EE842 • To collect macro data on plant energy resources. by end-use 2. energy and material balances for specific plant departments or items of process equipment are carried out. which must then be per-formed to justify the implementation of those conservation measures that require investments. and at least a preliminary assessment of the cost of the improvements will be made to indicate the expected pay-back on any capital investment needed. Generation and distribution of site services (eg. to ensure that nothing is overlooked. by major items of process equipment. at nights and at weekends as well as during normal daytime working hours. intermediate and final products. Detailed studies to establish. The information to be collected during the detailed audit includes: 1. use of scrap or waste products. and investigate. Material balance data (raw materials. Means of improving these efficiencies will be listed. electricity from the grid or self-generation) Department of EEE. Energy consumption by type of energy. The audit report will include a description of energy inputs and product outputs by major department or by major processing function. by department.g. Sources of energy supply (e. The audit report should conclude with specific recommendations for detailed engineering studies and feasibility analyses. Process and material flow diagrams 5. etc. SJBIT Page 15 . and will evaluate the efficiency of each step of the manufacturing process. recycled materials. checks of plant operations are carried out over extended periods of lime. Energy cost and tariff data 4. Department of EEE. high voltage transmission lines that transport electricity over long distances.Energy Auditing and Demand Side Management 10EE842 7. With a vector diagram. A high power factor can help in utilizing the full capacity of your electrical system. and energy control centers to coordinate the operation of the components. and the use of co-generation systems (combined heat and power generation). explain various components of power triangle July 2015. Potential for fuel substitution. The Figure shows a simple electric supply system with transmission and distribution network and linkages from electricity sources to end-user. c) Voltage level at the load end is increased. SJBIT Page 16 . UNIT-4 1. Explain plant energy performance (PEP) and power flow concept. substations that connect the pieces to each other. distribution lines that deliver the electricity to consumers. d) KVA loading on the source generators as also on the transformers and lines up to the capacitors reduces giving capacity relief. process modifications. July 2014 Electric power supply system in a country comprises of generating units that produce electricity.July 2014 The Power Triangle The advantages of PF improvement by capacitor addition a) Reactive component of the network is reduced and so also the total current in the system from the source end. 2. b) I2R power losses are reduced in the system because of reduction in current. lines and distribution transformers. Distribution at 11 kV / 6. power over long distances at voltages like. the 3-phase voltage is stepped up to a higher voltage for transmission on cables strung on cross-country towers. containing step-down transformers. Sub-stations.3 kV constitutes the last link to the consumer. 66 kV or 33 kV constitutes the next link towards the end user. Electricity must be generated. Where transmission is over 1000 km.C. SJBIT Page 17 . high voltage direct current transmission is also favored to minimize the losses. as and when it is needed since electricity cannot be stored virtually in the system. reduce the voltage for distribution to industrial users.Energy Auditing and Demand Side Management 10EE842 The power plants typically produce 50 cycle/second Hertz). High voltage transmission is used so that smaller. Subtransmission network at 132 kV. 220 kV & 400 kV. who is connected directly or through transformers depending upon the drawl level of service. 110 kV. Department of EEE. At the power plant site. High voltage (HV) and extra high voltage (EHV) transmission is the next stage from power plant to transport A. more economical wire sizes can be employed to carry the lower current and to reduce losses. alternating-current (AC) electricity with voltages between 11kV and 33kV. The voltage is further reduced for commercial facilities.6 kV / 3. The transmission and distribution network include sub-stations. Distributors. 4. Over head primary distribution feeders are supported by mainly supporting iron pole (preferably rail pole). Distribution networks consist of following main parts 1. Department of EEE. SJBIT Page 18 . 5. Now these stepped down electric power is fed to the distribution transformer through primary distribution feeders. Write short notes on primary and secondary distribution. Primary distribution feeder. Distribution substation. Some times in congested places.Energy Auditing and Demand Side Management 3. Distribution of electric power is done by distribution networks. Service mains. for primary distribution purpose. 2. The conductors are strand aluminum conductors and they are mounted on the arms of the pole by means of pin insulators. Distribution Transformer. underground cables may also be used for primary distribution purposes. The transmitted electric power is stepped down is substations. 10EE842 July 2014 The main function of an electrical power distribution system is to provide power to individual consumer premises. Distribution of electric power to different consumers is done with much low voltage level. 3. the current at sending end is equal to that of receiving end of the conductor. Feeder feeds power from one point to another without being tapped from any intermediate point. Service main of the consumers may be either connected to distributors or sub distributors depending upon the position and agreement of consumers. we have already mentioned about both feeders and distributors. but they have one basic difference. Both feeder and distributor carry the electrical load. and hence the current varies along their entire length. Distributors are directly connected to the secondary of distribution transformers whereas sub distributors are tapped from distributors. Different consumers are fed electric power by means of the service main. The distributors can also be re-categorized by distributors and sub distributors. In this discussion of electrical power distribution system. Radial Electrical Power Distribution System In early days of electrical power distribution system. SJBIT Page 19 . As because there is no tapping point in between. the associated consumers would not get any power as Department of EEE. The secondary of the transformer is connected to distributors.Energy Auditing and Demand Side Management 10EE842 Distribution transformers are mainly 3 phase pole mounted type. These service mains are tapped from different points of distributors. The distributors are tapped at different points for feeding different consumers. different feeders were radially come out from the substation and connected to the primary of distribution transformer directly. Radial Distribution SystemBut radial electrical power distribution system has one major drawback that in case of any feeder failure. the supplying agencies should take into account all the costs involved from the point of generation to the point of the consumption. time at which load is required. small scale industries. SJBIT Page 20 . of the ring. Ring Main Electrical Power Distribution System The drawback of radial electrical power distribution system can be overcome by introducing a ring main electrical power distribution system. iii) While framing the tariff. this section can easily be isolated by opening the associated section isolators on both sides of the faulty zone. Department of EEE. List the characteristics of tariff Jan 2015. Here one ring network of distributors is fed by more than one feeder. If any fault occurs on any section. Derive tariff. commercial or industrial). There are different methods of charging different types of consumers depending on the type of load (domestic. In case of transformer failure also. Aims and objectives of tariff The aims and objectives of tariff are: i) The rates charged by the supplying agency must conform with the energy received by the consumers. In other words the consumer in the radial electrical distribution system would be in darkness until the feeder or transformer was rectified. In this case if one feeder is under fault or maintenance. except in some cases where special concession have to be given to special type of consumers such as farmers. maximum demand. UNIT-5 & 6 1. In addition to that the ring main system is also provided with different section isolates at different suitable points. ii) The recovery from the different types of consumers should be equitably distributed among them. In addition to generation.July 2014 Tariff is the rate of payment of schedule of rates on the energy bill of the consumer is prepared. the power supply is interrupted. In this way the supply to the consumers is not affected even when any feeder becomes out of service. cottage industries etc.Energy Auditing and Demand Side Management 10EE842 there was no alternative path to feed the transformer. the ring distributor is still energized by other feeders connected to it. power factor of the load and the amount of energy consumed. meter reading. July 2014 Power factor is the percentage of electricity that is being used to do useful work It is defined as the ratio of 'active or actual power' used in the maul measured in watts or kilowatts ( or KW to the 'apparent power expressed in volt-amperes or kilo Va-amperes (VA or KVA) Active Power W Power factor = or Apparent Power VA The apparent power also referred to as total power delivered by utility company has.Energy Auditing and Demand Side Management 10EE842 transmission and distribution costs. ° Components 1) Productive Power' that powers the equipment and performs the useful work It is measured in Kw (kilowatts) 2) 'Reactive Power' that generates magnetic fields to produce field necessary for the operation of induction devices (AC motors. inductive furnaces. billing.).What are the limitations of low power factor? Explain in brief July 2015. together make up apparent power which is measured in kilovoltamperes (KVA) Graphically it can be represented as Understanding Power Factor Department of EEE. ovens etc ) It is measured in KV. same no output work is being accomplished until a load is applied The current associated with no-load motor readings is almost entirely "Reactive" Power As a load is applied to shaft of the motor. the 'Reactive" Power requirement will change only a small amount The 'Productive Power' is the power that is transferred from electrical energy to some other form of energy (such as heat energy or mechanical energy) The apparent power is always in always in excess of the productive power for inductive loads and is dependent on the type of machine in use The working power (KM a. 2. (Kilovolt-Ampere-Reactance) Reactive power produces no productive work An inductive motor with power applied and no load on rms shaft should draw almost nil productive power. reactive power (KV. of metering. SJBIT Page 21 . transformer. bill collection and annual charges on capital investment should also be considered. cables. If steps are not taken to improve the power factor of the load. For instance known information taken from billing about electrical system: KVA = 1000. (Unity). and transformers in the same manner as the useful current.) introduces inefficiencies into the electricity supply network by drawing additional currents. SJBIT Page 22 . Perfect power factor is 1. conveyors.Energy Auditing and Demand Side Management 10EE842 The cosine of the phase angle 0 between the KVA and the 1.8. For inherently low power factor equipment. Although these currents produce no useful power they increase the load on the supplier's switchgear & distribution network and on the consumer's switchgear & cabling. Typical uncorrected industrial power factor is 0. To put it the other way.80 Department of EEE. refrigeration plant etc. Any industrial process using electric motors (to drive pumps. To discourage these inefficiencies the electricity companies charge for this wasted power. KVAR = 600. PF = . The Relationship between KVA KW and KVAR is non-linear and is expressed KVA2= KW2 + KVAR2 A power factor of 0. The inefficiency is expressed as the ratio of useful power to total power (KW/KVA) known as Power Factor. KVAR represents the non-productive reactive power and 0 is lagging phase angle. KW = 800. This results in increased capital expenditure and higher transmission and distribution losses throughout the whole network. called "inductive reactive currents". a 3-phase 100KW load would draw 172A per phase instead of the 139A expected. These charges appear on electricity bills as "reactive power charges". the utility company has to generate much more current than is theoretically required.72 would mean that only 72% of your power is being used to do useful work. all the equipment from the power station to the installation sub-circuit wiring. fans. This means that a 1MVA transformer can only supply 800KW or that a consumer can only draw 80 useful Amps from a 100Amp supply. has to be larger than necessary. This excess current flows through generators.0. meaning 100% of the power is being used for useful work. "KVA maximum demand" or "KVA availability charges".KW components represents the power factor of the load. Direct costs of low power factor Power factor may be billed as one of or combination of. which requires both generators and beneficiaries to commit to day-ahead schedules. and only when stated as such. Included in this charge is a charge for KVAR since KVAR increase the amount of KVA. Department of EEE. They view it only as a direct charge on their electrical bill. the amount of useful power available inside the installation at the distribution transformers is considerably reduced due to the amount of reactive energy that the transformers have to carry. 4) KVA demand: A straight charge is made for the maximum value of KVA used during the month. 2) An increasing penalty for decreasing power factor.Energy Auditing and Demand Side Management 10EE842 Disadvantages of low power factor Many engineers are oblivious to the effects of low power factor. It is a system of rewards and penalties seeking to enforce day ahead pre-committed schedules. SJBIT Page 23 . What is ABT? Write the broad features of ABT design. Indirect costs of low power factor Loss in efficiency of the equipment: When an installation operates with a low power factor. The figure below indicates the available actual power of distribution equipment designed to supply 1000KW 3. though variations are permitted if notified One and one half hours in advance. July 2014 It is a performance-based tariff for the supply of electricity by generators owned and controlled by the central government It is also a new system of scheduling and despatch. 3) A charge on monthly KVAR Hours. the following: 1) A penalty for power factor below and a credit for power factor above a predetermined value. Low power factor is a direct cost to the utility company and must be paid for. How is ABT different from normal proceedings to determine generation tariff? 1. composition of the Rate Base.A charge for Unscheduled Interchange (UI charge) for the supply and consumption of energy in variation from the pre-committed daily schedule. Proceedings to redefine these norms are being held separately.A fixed charge (FC) payable every month by each beneficiary to the generator for making capacity available for use. The ABT proceeding has not attempted to consider most of the cost drivers like ROE. Income Tax and Interest on working capital.In the case of hydro stations it will be the residual cost after deducting the variable cost calculated as being 90% of the lowest variable cost of thermal stations in a region. Hence it reflects the marginal value of energy at the time of supply. Operational Costs. . . 2. This charge varies inversely with the system frequency prevailing at the time of supply/consumption. O&M expenses. Hence the ABT proceedings have been concerned more with tariff design rather than definition of tariff norms or determination of tariff levels. Disciplined beneficiaries and generators stand to gain. it will comprise interest on loan. The FC. Non-payment of prescribed charges will be liable for appropriate action under sections 44 and 45 of the ERC Act. depreciation. It has three parts: . will also vary with the level of availability achieved by a generator. Undisciplined beneficiaries and generators stand to lose. depreciation rate. It's incidence is a function not only of the behaviour of a generator but also of the behaviour of a beneficiary. Department of EEE. . where the fixed charge has not already been defined separately by GOI notification. The FC is not the same for each beneficiary. ROE. payable by each beneficiary. SJBIT Page 24 .An energy charge (defined as per the prevailing operational cost norms) per kwh of energy supplied as per a pre-committed schedule of supply drawn upon a daily basis. capital structure etc.In the case of thermal stations like those of NLC. . It varies with the share of a beneficiary in a generators capacity.Energy Auditing and Demand Side Management 10EE842 The order emphasises prompt payment of dues. 1. 85% for Hydro in the first year and 77% (82% after one year) for NLC. 2. 5. It implements the long held view that electricity tariffs should be two-part comprising of a fixed charge and a separate energy charge. It introduces severe financial penalties for grid indiscipline along with significant rewards for behaviour. It delinks the earning of incentive from availability and links it instead to the actual achievement of generation. This order disallows such payments. The draft notification provided for recovery of (annual fixed costs minus ROE) at 30% availability and recovery of ROE on pro-rata basis between 30% and 70% availability. 3. 6. It increases the target availability level at which generators will be able to recover their fixed costs and ROE from 62. Hence incentives will be earned by generators only where there is a genuine demand for additional energy generation unlike the prevailing situation. It increases the minimum performance criterion for the earning of an incentive from 68.79% deemed PLF at present to 80% (85% after one year) for all thermal stations. which enforces grid discipline for both generators as well as beneficiaries. Draft notification linked incentives to equity. 4. Misdeclaration of availability entails severe penalties. under which it is earned purely because the generator is available. 9.Energy Auditing and Demand Side Management 10EE842 Broad features of ABT design. 8. It rationalises the relationship between availability level and recovery of fixed cost. 85% for Hydro and 77% (82% after one year) for NLC. This order preserves the status quo of one paise per kwh per each 1% increase in PLF above target availability. or the proposed draft received from the GOI. This order provides for payment of capacity charges between 0% and target availability (as indicated in item 2 above) on pro-rata basis. SJBIT Page 25 . 4. The draft notification had provided for payment of capacity charges for prolonged outages. Department of EEE. 7.5% deemed PLF at present to 80% (85% after one year) for all thermal stations. 8lagging. which raises the P.95= 253 Annual bill = Rs 50X 253 + Rs 0.40 paise=40 paise When power factor is increased to 0.the maximum demand in KVA = 240/0.8 =240/0.An Industrial load takes 1.1 X 50000 =Rs 15000+ Rs 5000= Rs 20000 =flat rate /unit= Rs20000/50000=Rs 0. The order permits market pricing for the trading of surplus energy by beneficiaries and generators.f.50/KVAR. GOI to decide applicability of the order. the record maximum demand is 500 KVA . The tariff is Rs.8=300 Annual bill = Demand charges+ energy charges =Rs 50X 300 + Rs 0. 11. from 0.8 to 0.5 paise /KWh calculate the Annual cost of supply and find out the annual saving in cost by installing phase advancing plant costing Rs. the average power factor being 0.Energy Auditing and Demand Side Management 10EE842 10. The order urges the GOI to allocate the unallocated capacity a month in advance so that beneficiaries know their exact share in capacity in advance and can take steps to trade surplus power.120 KVA of maximum demand plus 2. 12.000 units in a year .95 percent . Allow 10 % per year on the cost of phase advancing plant to cover all additional costs. 4.95 lagging.2000 starting from the South. July2013 Maximum demand in KVA at a pf of 0. SJBIT Page 26 .00.1 X 50000 =17650 Department of EEE. The new norm for incentive will however be applicable from this date for all central stations. It will be implemented in stages from April 1. In the case of NPC. Changes in load curves must decrease electric systems running costs . as consumers would also benefit from cheaper energy services. as overall efficiency would increase. SJBIT Page 27 .The monthly reading’s of a consumers meter are as follows: maximum demand: 50 Kwh. DSM has been driven by strict economic reasons. in societal terms.6 X 8760 KWh =262800 Max demand in Kva =50/pf = 50/0. Energy efficiency was a privileged instrument for DSM implementation.Briefly explain DSM planning and implementation July 2015. and also allow for deferring or even avoiding some investments in supply-side capacity expansion. as will be seen.F X Hours in a year = 50 X 0. It has been originally defined as the planning.energy consumed =36000 Kwh. this was a typical win-win situation. Thus.Energy Auditing and Demand Side Management 10EE842 Annual saving =Rs 20000-17650 = Rs 2350 5.both production and delivery costs -. If the tariff is Rs 100/KW of maximum demand plus 6 paise/unit plus 0. reactive energy 23.5 paise/unit for each 1% of power factor below 86% . Department of EEE. July2014 units consumed/year = Max demand X L. implementation and monitoring of a set of programmes and actions carried out by electric utilities to influence energy demand in order to modify electric load curves in a way which is advantageous to the utilities. Hence.400 KVAR. more specifically in the electricity industry. in the mid-eighties. July 2014 The concept of demand-side management (DSM) has been introduced in the USA.calculate the monthly bill of consumer.86= 58.13 Annual bill = maximum demand charges + energy charges = 262800+ 18000= Rs 280800 Monthly charges + 280800/12 = RS 23400 UNIT-7 & 8 1. Cost-benefit analysis will dictate which options to adopt.the amount of energy used by unit of time. brought by DSM to the portfolio of utility management options. In general. Department of EEE. namely those tools related to remote load control. alternative pricing. Different techniques of DSM – time of day pricing Cost of supply is not constant for any type of energy delivery. flexible load curve. in general. load shifting. and also to huge environmental benefits. gas or heated water. all other options require that the utility's system is under pressure and requires either capacity expansion or load relief. Yet. valley filling. In many cases utilities have opted for DSM in order to avoid or postpone important financial stresses. The same does not apply with the same extension to other utilities. direct incentives. Tariff systems with multi rate structure are. Energy efficiency was actually a newcomer to the business. trade ally co-operation.Energy Auditing and Demand Side Management 10EE842 DSM has been a major breakthrough that led to a great deal of innovation. a great number of DSM tools already existed previously to the concept. The alternative is the so-called flat rate. SJBIT Page 28 . known as load management (LM). DSM implementation options may be classified into several different broad categories: customer education. strategic conservation and strategic load growth. Variations of demand per unit time within a given period of time cause variable operating conditions that correspond to variable system running cost. meaning a constant price. an adequate response to variable costs of supply. Some measures pin-pointed in the text below are examples of some of them. be it electricity.they are usually based on long term previsions of marginal cost of delivery. But LM aims predominantly at influencing power use . In the electricity business multi rate tariffs are already traditional. and had been in use by many utilities. The causes for variations are different among energy forms but variations always exist. There are six main objectives defined in the context of DSM. known as: peak clipping. as they correspond to pass on to consumers an approximate image of supply cost variations -. direct customer contact. Apart from strategic load growth (SLG). mainly because of technical and management difficulties. advertising and promotion. independent of cost of supply variations. both at business management and at technological development. at specific times. at least to certain customer classes. Hence. Energy efficiency was a privileged instrument for DSM implementation. Usually. the goal of demand side management is to encourage the consumer to use less energy during peak hours. known as load management Department of EEE.both production and delivery costs -. 2. DSM has been driven by strict economic reasons. and also allow for deferring or even avoiding some investments in supply-side capacity expansion.Energy Auditing and Demand Side Management 10EE842 Multi rate tariffs potentially lead to a reaction of demand that depends on its actual elasticity with price.supplier and consumers. Changes in load curves must decrease electric systems running costs .Explain energy efficient technology in electrical system. DSM has been a major breakthrough that led to a great deal of innovation. as will be seen. Thus. a great number of DSM tools already existed previously to the concept. which is in principle beneficial to both sides -. These tend to see positively the possibility of controlling more effectively their bills. also known as demand side management (DSM).[1] Peak demand management does not necessarily decrease total energy consumption. depending on elasticity. this was a typical win-win situation. which corresponds in general to an efficient use of supply resources. and also to huge environmental benefits. It has been originally defined as the planning. more specifically in the electricity industry. as consumers would also benefit from cheaper energy services. Yet. implementation and monitoring of a set of programmes and actions carried out by electric utilities to influence energy demand in order to modify electric load curves in a way which is advantageous to the utilities. Theoretically there is a reciprocal influence between prices and demand level. in the mid-eighties. July2014 Energy demand management. demand reaction will induce variations on the level of emissions. Indirectly. namely those tools related to remote load control. or to move the time of energy use to off-peak times such as nighttime and weekends. SJBIT Page 29 . as overall efficiency would increase. is the modification of consumer demand for energy through various methods such as financial incentives and education. and had been in use by many utilities. but could be expected to reduce the need for investments in networks and/or power plants. in societal terms. The concept of demand-side management (DSM) has been introduced in the USA. both at business management and at technological development. In many cases utilities have opted for DSM in order to avoid or postpone important financial stresses. strategic conservation and strategic load growth. Apart from strategic load growth (SLG).Energy Auditing and Demand Side Management 10EE842 (LM). at specific times. and the president Enhanced Energy Awareness Aggressive Energy Conservation Policies which address: Heating and cooling season temperature settings Building HVAC and fan operating schedules Computer operations and "green computing" Ban on all incandescent bulbs and halogen torchiere lamps (the latter is also a safety issue) Energy purchasing (including buying green power) Energy efficiency purchasing standards for various types of equipment -. known as: peak clipping. load shifting. brought by DSM to the portfolio of utility management options. Energy efficiency was actually a newcomer to the business.the amount of energy used by unit of time. Cost-benefit analysis will dictate which options to adopt. There are six main objectives defined in the context of DSM. all other options require that the utility's system is under pressure and requires either capacity expansion or load relief. SJBIT Page 30 . But LM aims predominantly at influencing power use . the chief business officer.hopefully going beyond Energy Star compliance Improved space utilization to avoid new construction or heating/cooling of underused space Energy efficiency standards for new construction Department of EEE.Explain energy conservation opportunities in illumination and industrial sector Dec 2014 Here are key components of an effective campus energy conservation program to reduce energy use and GHG emissions from campus operations: Strong Program Leadership An energy officer to develop energy conservation measures and projects and catalyze the entire effort.Full support from facilities leadership. 3. valley filling. flexible load curve. risk complaints Adequate facilities staffing levels – especially HVAC controls technicians. SJBIT Page 31 .g. -. ban refrigerators. load limits per room.) Curtailment periods when campus use is minimal and energy shutdowns can be implemented Engaged Facilities Operations An active facilities energy conservation committee which meets regularly and is encouraged and empowered by the physical plant director (and campus leadership) to push the envelope and aggressively pursue all conservation opportunities Comprehensive implementation of no cost/low cost operational measures – e. etc.e. i. mechanics.to operate the campus efficiently and readily implement energy conservation measures and projects in-house Periodic re-commissioning of all existing buildings to optimize energy efficiency Facilities staff performance appraisals that evaluate staff on commitment to energy conservation Empowerment of highly motivated staff who are anxious to implement energy conservation measures Rewarding of staff who identify conservation opportunities and implement conservation measures Reconsideration of the timing of the academic calendar to better align it with periods of least energy cost operation. microwaves. TVs. etc. equipment run-times and building occupancy hours. heating and power plant operators. e. in cold regions this might involve shifting academic activity and campus occupancy away from the coldest months and implementing a partial campus shutdown during that period Department of EEE.g.that push the envelope. temperature set-points.Energy Auditing and Demand Side Management 10EE842 Restrictions on the use of portable space heaters Energy practices in on-campus residence halls and student apartments Residential appliance policies (e. and electricians -.g. for example. Load management generally falls into one of three categories: load clipping. At the same time. economic complexities strongly influence the overall picture. 10EE842 July2013 Electric load management. however. not necessarily to elucidate their business strategies. with modern predictions typically within 1% Electric load management is a complex subject for several reasons: the technology is not trivial. load shifting. and the interplay between supply and demand. so they are motivated to shift large electrical loads from high-demand peak times to low-demand off-peak times. and on hot afternoons when the air conditioners are on.Write short notes on i) Peak clipping ii) Load shifting iii) valley falling. However.Energy Auditing and Demand Side Management 4. A power company must be able to supply power at all times. Practically speaking. and valley filling. Raising rates during peak hours is possible because peak usage is quite predictable. and much of the data comes from sources (power companies) that are out to make money. A steady supply of power is generally quite straightforward to produce with a typical coal. this usually means raising energy prices during peak usage times and on high-volume users. one cannot understand the power generation and distribution system without considering fluctuations in demand. refers to the systems in place that match electricity supplies with demand. gas or nuclear plant .simply fire up the generator and make sure you have a steady supply of fuel. which is often called simply load management. The means by which they do this are collectively called load management. which are shown in Figure Most of the strategies described here are load clipping or load shifting strategies. SJBIT Page 32 . Department of EEE. the demand is not steady: there is more demand during dinnertime.
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