Management Tools to Optimize Energy Consumption 1

Transcription

1 Management Tools to Optimize Energy Consumption 1 Energy efficiency is usually defined as the relationship between the amount of energy consumed and the final products resulting from that consumption. 2 Energy consumption can be optimized in different ways, including savings and technological investments; improvements in basic resource management, such as water and electricity; and the efficient use of space. In addition, companies, people and households can adopt new consumption habits at work and within their communities. Almost 80% of today s energy production relies on non renewable fossil fuels, such as carbon, oil and natural gas. This presents several disadvantages, including high levels of environmental contamination and decreased efficiency in the relationship between energy investments and resulting products, among others. Several characteristics of this trend are relevant, including: Total global energy sales equal almost 3% of global GDP. Energy consumption for transportation represents approximately 20% of the total. Less than 10% of energy sources are renewable globally. Industry consumes approximately 37% of energy produced globally, or 15 TW (terawatts) per year. As a result, this is one of the sectors that most invests resources, time and money in seeking new ways to apply innovative technologies to generate energy savings. 1 This Technical Note, originally entitled Herramientas gerenciales para la optimización del consumo energético was supervised by INCAE Professor Dr. Juan Carlos Barahona and written by Gustavo André Jiménez. Distributed by INCAE to serve as the basis for classroom discussion and not to illustrate the correct or incorrect way to manage an administrative situation. Reviewed August 2009.INCAE Research Center. All rights reserved. Published September No part of this material may be copied, stored or transferred in any way (electronic, mechanical, photocopied, taped, recorded or other) without expressed authorization from INCAE. Translated from Spanish into English by Connie Gonzalez, December RESTRICTED DISTRIBUTION COPYING PROHIBITED 2 Taken from: d_1288.html.2009 and adapted by the author.

2 2 Figure No Energy Consumption, By Source Fossil fuels Nuclear Biofuels Traditional biomass Hydroelectric Geothermal Source: Adapted from Global Status Report 2007.Renewable Energy Policy Network for the 21st Centutry. In Latin America and the Caribbean in 2006, 68% of all energy came from oil and carbon. The following pie chart details demand by energy source. Figure No.2 Energy Demand in Latin America and the Caribbean 2006 Hydroelectric Biomass Nuclear Geothermal and others Biofuels Oil and derivatives Natural gas Carbon Source: OLADE 2006 Report. Due to this reality and global warming a phenomenon that becomes more apparent every day it is not likely that current consumption can be sustained over time, either economically or environmentally. Therefore, it is necessary to understand and adopt more efficient energy systems, by establishing sustainable management and energy savings plans.

3 3 Issues to establish a sustainable energy plan. Appropriate energy use and management are the first steps to true savings and to creating an effective energy savings plan. The methodology shown in Figure No. 3 can be used to establish this type of plan. This methodology seeks to create a virtuous cycle of constant improvement that helps establish minimum efficiency parameters within a company. The purpose of this methodology is to have a tool to elaborate a work plan that outlines a useful and applicable energy savings program. As with any framework methodology, certain measures must be available to monitor progress, including concepts and indicators that help guide the company and allow it to understand its health in terms of energy consumption. However, it is necessary to follow a sequential framework to establish an action plan. The following simple and structured methodology can be used as a model to build a concrete work plan. Agree on sustainable environmental policies Stage 1. AGREEMENTS ON COMPANY ENERGY SAVINGS At first, it isrecommendedto begin with short termgoals to provide incentives to personnel Figure No.3 Stage 4. Evaluation of proposed plan Regulatory Committee Stage 2. Study on company s energy use Phase 3: Implementplans Phase 2: Action plans for each company department Phase 1: Simple proposalto make improvements. Increase goals over time. Stage 3. Program to manage energy savings Phase 1: Collectinformationon general electricalgrid (Consumptionin kwh) Phase 2: Collect information on personnel s behaviors and attitudes Phase 3: Data analysis Source: Taken from Guía de Ahorro y eficiencia energética. and adapted by the author. The previous diagram tries to establish a baseline for an entire company; however, it is necessary to add standard measurements and concepts. There are factors and indicators that can be used as tools to measure certain important parameters in terms of energy use,

4 4 generation and consumption. Certain practical knowledge is needed to determine operational efficiency. Some basic indicators, such as demand factors, production factors and maximum demand, among others, offer a clear panorama of a company s energy health. In addition, they indicate which areas need improvement in order to reach certain energy savings. This is applicable to both offices and industries. Concepts and indicators Power factor 3 If the industry is large enough, it may be penalized by its power factor (pf). This factor is basically an indicator of electrical efficiency or the electricity that is used. For example, an electric stove or incandescent light bulb has a pf of 1. In any other appliance, the electrical charge s power is not completely used, since the current passes through and is not used 100% due to normal losses caused by the appliance. The power factor for an industry should equal approximately 0.9. Any number below that will be penalized on the monthly bill, at least in the case of Costa Rica. What does a power factor lower than 0.9 imply? Seen from the consumer s point of view, it means an increase in electricity consumption, strong drops in conductor tension, a reduction in the useful life of appliances and appliance imbalances. 4 On the other hand, from the perspective of the electricity distributor, a low power factor means greater investment in electrical generation equipment because KVA (kilovolt amperes) capacity is affected. 5 In addition, the distributor has to use lines and transformers with greater capacity, increasing energy loss and associated costs. Electric current 6 Electrical energy flow, or electric current, is measured in amperes (A). To generate an electric current through a cable, there must be a difference of tension or voltage between the two ends, which is expressed in volts (V). Water and electricity have very similar behaviors in terms of flows. As an analogy, if a person wants water to move through a tube, there must be different pressures between the two ends of the tube. This same principle applies to electricity. 3 Taken from Manuales de Energía Renovables/Biomas.UNDP,GEF,BUN CA 2002 and adapted by the author. 4 Taken from Castro, Jiménez. Artículo CO2 Neutro qué es? cómo funciona? INCAE Business School. September Power measurement equal to volt multiplied by the current. 6 Taken from Manuales de Energía Renovables/Biomas.UNDP,GEF,BUN CA 2002 and adapted by the author.

5 5 By creating a great difference in tension, large amounts of electricity or power can be transported per second using transmission lines or cables. Electric power is measured in watts (W), and equals the voltage multiplied by the amperage. Power = V x A. Two types of electric currents can be produced by electrical generators: Direct current (DC): energy travels or is transported in only one direction, from positive to negative. Direct current is used in low capacity systems, for example, batteries, cell phone batteries and low tension photovoltaic systems. Alternating current (AC): this current continuously alternates direction in a cyclical wave pattern, causing a sinusoidal voltage wave with both positive and negative peaks. The numbers of cycles per second is the frequency and is expressed in hertz (Hz). An electrical grid normally has a frequency of 50 Hz (Europe) or 60 Hz (Continental America). This type of current is used in large, high tension systems, such as electrical stations, and is sent through the electrical grid to houses and productive centers. One of the reasons why alternating currents are used is because it is cheaper to increase or decrease its voltage, and less energy is lost using high tension systems to transport energy over long distances. Generally, watts per hour are used to express the amount of electrical energy used (or Wh). One watt/hour is equivalent to the amount of converted energy during one hour for an appliance with 1 watt of power. Energy consumption is also regularly expressed in kilowatts per hour (kwh). Capacity factor (plant factor) 7 Wh= V*Ah ; where V is the general system tension or voltage. Plant factor is used as an indicator to measure the productivity of an electrical generation plant, for example, a hydroelectric, biomass, wind or solar system, among others. This indicator is the comparison of real production during a given amount of time with the amount of energy produced theoretically, if the plant had been producing at 100% capacity during that timeframe. See the following formula. Capacity factor = Real production x 100% Theoretical production 7 Taken from Manuales de Energía Renovables/Biomas.UNDP,GEF,BUN CA 2002 and adapted by the author.

6 6 Consider the following example: a system of 1 kw could theoretically generate 8,760 kwh in one year. This calculation was made using: Energy= power x time. Therefore, the energy generated would be 1kW x 24 hours/day x 365 days = 8,760 kwh It is important to note that an electrical generation plant cannot operate 100% of the time, due to maintenance and system and equipment technical failures, among other reasons. Continuing with the previous example, if this plant s real annual production was 5,000 kwh, then its capacity factor would be: Plant or capacity factor = 5,000 x 100 = 57% 8,760 This is a good plant factor. A good factor is usually one equaling 60 70%, even reaching more than 70% in exceptional cases, depending on the industry and business. Maximum demand 8 Maximum demand is representative of a period of time and has to do with electrical charges, from motors, compressors, lighting and refrigeration equipment, among others, that are in use during that timeframe. In other words, demand is the specific value in time for energy consumption of determined charges, measured in power units called kilowatts (kw). Peaks of maximum demand can be controlled. One way to do so is to avoid using electrical charges within an industry at the same time. Another way is to schedule sections of production when the cost per kw is lower, for example, at night. Companies can also scale the timing when equipment is turned on and off. This can be scheduled to incorporate preventive maintenance and offers two benefits. First, it avoids dead time and expenses in production due to maintenance issues. With good maintenance, the availability of equipment can increase by up to 90%. The second benefit comes from decreasing excessive energy use from unnecessary equipment in a factory. 9 8 Taken from Manuales de Energía Renovables/Biomas.UNDP,GEF,BUN CA 2002 and adapted by the author. 9 Source: Optimización del Plan de Mantenimiento. Diferencia entre OPM y RCM. OMCS Latin America.

7 7 Production schedules, an easy tool to use. There are several simple and low cost tools that we can implement to save energy without making a huge investment. One is knowing the different rates for kwh, depending on the schedule, region or country. Peak consumption hours are times when electrical energy demand is high. Scheduling scaled production based on consumption hours and changing the times that people start work during the year, can result in savings of up to 20% in each monthly electricity bill. Demand factors 10 This is the relationship between an industry or electrical system s maximum demand and the total charge connected at a specific time. This can be expressed using the following: Demand factor = Maximum demand Total potential charge This factor provides a panorama of the percentage of real demand at a factory or building. The following table shows demand factors for lighting, as an example; it was taken and adapted from the 1999 version of Electrical Installations from the National Electrical Code. This code is used in Costa Rica and most Latin American countries. 10 Taken from Manuales de Energía Renovables/Biomas.UNDP,GEF,BUN CA 2002 and adapted by the author.

8 8 Type of property Housing Table No.1 Demand factors for lighting Lighting charge that the demand factor applies to (VA) 11 For the first 3,000 or less From 3,001 to 120,000 Over 120,000 Demand factor (%) Hospitals First 50,000 or less Over 50,000 Hotels and motels, including First 20,000 or less apartment blocks without From 20,001 to 100,000 kitchens Over 100,000 Storage (warehouses) First 12,500 or less Over 100,000 All others Total volt amperes 100 Source: Taken and adapted from the National Electrical Code NEC Article 220, pages This table is an example of the information presented in the Electrical Code by country. This type of table offers a basic guide for an engineer to design an electrical system or a maintenance person to fix a system. Having this information on demand factors and related consumption, helps managers establish a factory s productive efficiency. In other words, they can determine how much energy per product unit is used for production. The less energy (kwh) that is used to produce one product unit with the same quality standards, the more efficient the system becomes. It is quite common to confuse the terms power and energy. This Note has tried to clarify these terms; however, the following examples will provide more clarity on the differences between these terms and their implications. 11 Volt amperes. This power unit does not include the power factor (pf). The following formula presents more information on the relationship between watts and volt amperes: Watt = VA x PF = Volt Ampere x Power Factor. Volt Amperes are volts multiplied by amperes (V x A.)

9 9 Table No.2 Differences between energy and power Energy Examples 1 KWh Energy demanded to increase the temperature of 1 liter of water by 1 degree Celsius. 1MWh Energy demanded to drive a vehicle 1,000 kilometers. 209 TWh Electricity consumed during a period of time. For example, Mexico consumed this amount of energy in Power Examples 1 kw Power resistance for an electric stove. 10 kw Power of a small truck. 1 MW Power of a small hydroelectric plan that meets the needs of approximately 20,000 people. Source: Adapted and modified from Biomass Renewable Energy, UNDP, This table helps clarify the differences between power and energy with simple examples. Efficiency The easiest way to determine the efficiency of a process, equipment or machine, in general terms, is to calculate the relationship between the energy used and energy taken. In other words, the following formula can be used: Efficiency = Energy used Energy received The general efficiency of an appliance or process depends on several factors, including design, materials used in manufacturing, the manufacturing quality, installations and the type of fuel or energy used for operations, among others. For example, an electric motor does not have the same efficiency as an internal combustion motor, such as one that runs using gasoline. The following table shows different efficiencies for internal combustion machines. Though the appliances operate using the same type of energy, the efficiencies are determined by size and fuel type and composition, among others. 12 Source: Disminuye consumo de energ%c3%ada el%c3%a9ctrica en M%C3%A9xico.2009

10 10 Table No.3 Combustion processes and ranges of efficiency PROCESS TYPICAL RANGE OF EFFICIENCY WOOD BURNING CHIMNEY % GAS WATER HEATER % COMMERCIAL BOILER USING GAS % RESIDENTIAL BOILER USING GAS WITH LOW EFFICIENCY ATMOSPHERIC BURNERS % COMMERCIAL OIL WATER HEATER % HIGH EFFICIENCY CONDENSER GAS OR OIL OVENS % Source: Taken from efficiency.html. July 20, 2009, Adapted by the author, 14 hrs. This tables lists equipment that is commonly found in industries and companies. Adaptation and change Once a company understands these basic parameters, it must start to make certain changes. Figure No. 3 can be used as a guide to determine which steps to follow. A company must begin by understanding that buildings have pre established energy efficiencies due to design and construction realities. Any changes to improve energy use will be based on limitations presented by the original designs. However, this does not mean that a company cannot adapt and renovate a property in order to optimize energy use. It is important to take energy consumption samples in different parts of the building during a period of least 6 months in order to understand general characteristics. This information helps the company determine the points of greatest consumption. These areas tend to include heating or air conditioning units. It is also important to understand the building s energy sources. Not all energy comes from the same source. For example, bunker or gas boilers can be used for heating or to produce energy, since they cost less than electricity; however, they also leave a greater carbon footprint in the environment. By understanding the building s energy matrix and points of consumption, the company can elaborate an action plan. This plan can be scaled and based on easy goals or include more elaborate programs related to the company s sustainability. The company s management must be committed to the plan so that it can be implemented efficiently and the company can experience permanent change. Without this support, any effort will face innumerous obstacles in the short term. In order to implement changes, the company must have dedicated personnel that identify with the goal, since they will be the program s main implementers. They must make the plan their own. Concrete actions for the plan should result from training, suggestions and recommendations promoted by the energy savings program. Recycling programs in many organizations have been fundamental to this type of initiative. A recycling campaign can be based on competition among different

11 11 departments, promoting participation within the company and involving family members externally. This not only generates a connection between the company and the community, but also builds credibility for the program. In sum, the issues and concepts that are presented in this document are basic guidelines that should be taken into consideration when designing programs to improve energy savings in companies. However, it is important that these issues are understood by operations and productions managers so that they can reach the proposed energy efficiency goals. Additional reading Technical note No INCAE Business School.: El papel de la energía en el desarrollo sostenible: Hechos y asuntos fundamentales. Manuales de Energía Renovables/Biomas. UNDP,GEF,BUN CA. San Jose, Costa Rica. September 2002.