Conducting an Energy Design Review [Chemical Engineering Progress]
(Chemical Engineering Progress Via Acquire Media NewsEdge) Formal energy design reviews help to ensure that energy is treated as a key factor in decision-making throughout the various stages of a design project. This approach can significantly improve a site's energy performance.
An energy design review (EDR) is a structured, interdisciplinary analysis of the design of an industrial project to determine the most-efficient energy solutions that also allow the project to operate safely and reliably. Companies carry out these reviews to help maximize the energy efficiency and competitive advantage of their facilities, thereby reducing lifetime operating costs and improving the return on their investment.
Contrary to what might be expected, opportunities to improve energy efficiency exist at all stages of an engineering design project. In particular, the front-end loading phases (Figure 1 ) - conceptual, pre-feasibility, and feasibility - are often overlooked. Experience has shown that conducting formal EDRs throughout the design process significantly improves a site's energy performance. Through this process, in which key stakeholders communicate about energy use throughout the project development stages, energy is treated as one of the key factors in project decision-making.
At the early planning/conceptual stage, when all possible project alternatives are examined, EDR identifies high-level energy solutions that could have significant impacts on the project and recommends those that warrant additional study. This allows the designers to consider a variety of energy options rather than automatically replicating traditional approaches.
In the pre-feasibility stage, when the possible alternatives are evaluated and the best option is selected, EDR investigates the energy consumption of each option and recommends the most-energy-efficient design solution for the particular process. Applying EDR at this stage enables the designers to factor these options into the project planning, rather than forcing them later to select an alternative without adequate study and industry benchmarking.
During the feasibility stage, when the selected option is developed further, EDR can support the project with an evaluation of the selected process options and identification of additional energy improvement opportunities. The advantage of applying EDR at this stage is that with this detailed evaluation of energy solutions, the engineers can incorporate the preferred options into the final design. Including appropriate energy metering in the facility design will also enable operators to better monitor and control energy once the plant begins operating. This recognizes that there would likely not be the time or budget flexibility at a later stage to influence the design in a substantial way.
At the implementation stage, when the design is ready for construction and the operating procedures are prepared, EDR can integrate energy efficiency best practices into the facility's energy management system. This enables continuous energy monitoring and integration of the energy management information systems.
This article presents the overall methodology for conducting an EDR, and outlines the roles of the EDR team, which is typically composed of a certified energy manager (CEM), supporting engineers with specialized energy management experience, and the project design staff.
Planning and data collection
The first step of an EDR is a kick-off meeting at which the EDR team meets the key project design staff, and they discuss the overall project objectives, scope, milestones, schedule, next steps, etc. The EDR team explains the project data that it will need, and addresses any questions or concerns that may arise in the early stages of the EDR.
The design team then provides the engineering design documentation, such as a list of large energy users, project design criteria, process flow diagrams, etc., to the EDR team. The EDR team, with support from technical experts for the particular type of facility, reviews this information and brainstorms to create a list of preliminary energy-saving opportunities.
Next, the EDR team and the project design staff convene again to discuss the project in more depth. It is important that all who will participate in the opportunity evaluation workshop (the next activity) participate in this alignment discussion. It is often done in a face-to-face meeting, but also can be done virtually.
The EDR team summarizes the data it has received to date and requests any additional information that may be required for the evaluation workshop. The project designers make note of any status or scope changes that have occurred since the kick-off meeting, and outline their overall expectations of the upcoming workshop.
Based on this exchange, the EDR team prepares a list of potential opportunities to be studied.
The opportunity evaluation workshop
The heart of the EDR process is the opportunity evaluation workshop. It is critical that a cross-section of all disciplines on the project design team - including process engineers, mechanical and electrical designers, operations staff, etc. - as well as the EDR team members participate in the workshop.
Review the current design. The design team member most familiar with the project design discusses the project's block flow diagram and provides an overview of the process, outlining key areas of energy consumption and areas where energy could be used more efficiently.
Identify key energy-consumption areas. The team then reviews the project's design documentation (e.g., process flow diagrams, mass and energy balances, etc.) to identify the key energy-consumption areas. Process flow diagrams can be used to prepare summary charts that identify which large equipment within each area should be targeted based on usage volume and the type of energy used.
Identify and evaluate potential opportunities. The EDR team steps through each major process area, presenting the energy-saving opportunities it identified earlier and soliciting feedback from the project design staff. Additional potential opportunities often emerge during this discussion as well.
The EDR team assesses each opportunity within each major process area in terms of its ability to effectively minimize energy waste, maximize energy efficiency, and optimize energy supply. Only options that are considered to be safe and technically feasible, that will not negatively impact production in a significant way, and that are economically attractive are looked at in detail. Throughout this process, the EDR team considers predefined energy design criteria and lessons learned from previous EDRs.
Table 1 provides an example of design criteria used in carrying out an EDR. These criteria relate to heat transfer and heat recovery, and are grouped according to the project phase in which they can be best applied (conceptual, preliminary, or detailed design).
The following procedure can be used to identify potential energy- and cost-saving opportunities within the project design.
1. Review energy use and seek to reduce energy consumption. Minimize energy wasted within large energyconsuming areas; wasted energy can manifest itself as excess time, excess temperature, excess quality, excess work, and excess material movement. Implement better controls (e.g., temperature controls, moisture controls, pressure controls) on equipment that consumes large amounts of energy. Ensure that regular maintenance is performed on equipment that consumes large amounts of energy; include maintenance considerations in equipment specifications.
2. Review energy efficiency. Investigate heat-recovery opportunities in areas that release large volumes of highquality heat. Identify potential heat sinks to most efficiently recover waste heat; ideally, heat sinks are in close proximity to the heat sources. Use the energy cascade approach, which pairs high-grade sources of energy with end uses that require high-grade energy, and pairs low-grade sources with lowgrade end uses.
Ensure that equipment is sized correctly for the application. Use variable-frequency drives on large motors with loads that vary substantially during normal operation. Install insulation on piping and equipment to minimize heat losses.
3. Review energy technologies. Consider renewable energy generation (e.g., wind, solar photovoltaic, solar thermal, geothermal, etc.) for a greener energy supply. Consider cogeneration to supply electricity and thermal energy. Investigate fuel switching, as well as new, more-energyefficient technologies for equipment that consumes large amounts of energy.
Rank and prioritize the opportunities. The teams document each idea in an opportunity matrix, including comments on any major benefits and/or drawbacks. Then they create a prioritization chart that ranks all of the promising opportunities according to overall energy savings, capital cost, and ease of implementation. These rankings are generally based on high-level, order-of-magnitude savings and cost estimates developed by the technical experts.
Cost/ benefit analysis
The EDR team evaluates the top opportunities in more detail, quantifying the energy savings and performing a cost/benefit analysis. This typically involves about five opportunities, although the number may be higher or lower depending on the project budget and scope. The other opportunities discussed in the workshop are captured as additional ideas for future consideration.
Based on the results of the cost/benefit analysis, the EDR team prepares the business case for implementation of the top energy saving opportunities derived from the EDR workshop.
Putting EDR into practice
One-off, independent energy design reviews can yield large energy savings. The most effective approach, however, is to integrate formal energy-management and EDR activities into the project design workflow as follows:
1 . Assign a member of the design team to serve as an energy manager. Ideally, this person has knowledge of leading energy-efficiency technologies that other project team members do not. The energy manager assists project personnel in considering energy consumption factors in their design work, and ensures that the designers focus on the project's energy consumption and seek to meet or achieve energy targets. He or she also conducts high-level economic analyses to determine whether the energy conservation opportunities are economically feasible.
The energy manager is an important role, because factors such as schedule, capital cost, and throughput objectives can be strong project drivers, and energy needs to have a champion within the project management structure. The energy manager is in a position to challenge the status quo.
2. At the start of the design work, establish an overall framework for considering energy consumption as one of the criteria in the design of each component of the project. Establish a consistent set of parameters that all project personnel should use in making tradeoffs among size, capital cost, source of energy, and energy consumption of components. Set an aggressive target for the overall energy-consumption level of the project by benchmarking against the energy consumption of facilities processing similar materials under similar circumstances.
3. Periodically during the project, carry out independent energy design reviews using an approach similar to the one described in this article. It is most effective to conduct these when the project passes from one stage to another (e.g., from the pre-feasibility to the feasibility stage), as the completion of a suitable EDR can be one of the requirements for corporate approval to move the project to the next stage.
4. Take steps to operate the project under an energymanagement system in compliance with the international energy management standard ISO 50001.
This article is based on a paper presented at the Carbon Management Technology Conference, Orlando, FL, Feb. 7-9, 2012. © 2012 CMTC. Adapted with permission of the copyright owner. Further reproduction prohibited without permission of CMTC.
SIGNIFICANT SAVINGS ARE POSSIBLE
A recent project employed this approach. The client was building a large new mineral-extraction plant, and a team of energy management specialists and technical experts for this type of process plant was hired to carry out an independent energy design review of the preliminary design.
The EDR identified numerous cost-effective energyefficiency improvement opportunities. The analysis indicated that if all the opportunities meeting the client's capital investment criteria were implemented, annual energy savings and greenhouse gas emissions reductions in the range of 3&-40% were possible.
ROBERT GRI ESBACH, P.ENG.
EMILY THORN CORTHAY, P.ENG.
ROBERT STOREY, P.ENG.
MEGAN DOVER, P.ENG.
ROBERT GRIESBACH, P.Eng., CMC, is Director of Energy Consulting for Hatch, Ltd. (Mississauga, ON; Phone: (905) 403-4102; Email: rgriesbach® hatch.ca), where he is responsible for Hatch's energy management practice and its supply-side energy consulting work. He has led the execution of energy-efficiency improvement, integrated power-supply planning, economic and financial analysis of energy projects, due diligence, tariff, and energy market assessment projects for clients that include large energy users, major electric utilities, independent power producers, private investors, investment funds, government agencies, and international financing agencies such as the World Bank and the Inter-American Development Bank. He also held senior corporate positions in a large engineering company and was involved in information systems, corporate planning, budgeting, financial analysis, and procurement. He has worked in Canada, the U.S., and more than 20 other countries. He holds a bachelor's degree in chemical engineering and an MBA from McGill Univ., and is a Professional Engineer licensed in the province of Ontario and a Certified Management Consultant.
EMILY THORN CORTHAY, P.Eng., CEM, CMVP, is a senior consultant in energy management with Hatch, Ltd. (Phone: (905) 403-3989; Email: ethomcorthay® hatch.ca), where she is the project manager for an energy design review pilot project with Ontario industrial facilities and the energy lead for the implementation of an energy management information system. She has over 10 years of engineering, project management, and business development experience, primarily in the energy field within North America and internationally. She has acted as project manager, technical reviewer, or energy engineer for over 25 industrial energy assessments and numerous energy design reviews and energy engineering studies, mainly in the mining and metals industries. She was also a team member for Canada's first pilot program aimed at helping companies achieve the new ISO 50001 energy management standard. She holds a bachelor's degree in systems design engineering from Univ. of Waterloo and a master's degree in mechanical engineering from the Swiss Federal Institute of Technology, and she is a Professional Engineer licensed in the province of Ontario, a Certified Energy Manager, and a Certified Measurement and Verification Professional.
ROBERT STOREY, P.Eng., CMC, is a senior consultant in energy management with Hatch, Ltd. (Phone: (905) 403-3660; Email: firstname.lastname@example.org). He has more than 25 years of operations and energy management experience, primarily in Canada, but also in the U.S., Australia, Russia, and South Africa. His most recent assignments have included ISO 50001 projects, energy design reviews, and engineering studies of major energy savings retrofits at a number of industrial sites in Ontario. He holds a bachelor's degree in mechanical engineering from the Univ. of Alberta, and is a Professional Engineer licensed in the province of Ontario and a Certified Management Consultant. He is a member of the Canadian Institute of Mining and Metallurgy, the Association of Energy Engineers, and the Association for Iron and Steel Technology.
MEGAN DOVER, P.Eng., CEM, is a management consultant with Hatch, Ltd. (Phone: (905) 403-3896; Email: email@example.com) with more than six years of experience in energy assessment, market research, due diligence, risk assessment, and valuation for the mining, metals, and energy sectors and other industries. She has worked closely with multidisciplinary teams of technical experts and clients in detailed project risk assessment and modeling reviews to help identify key project risks and build those into schedule and capital cost probability forecasts for investment and acquisition assessments. She has developed financial models, reports, and presentations to demonstrate project viability showing the sensitivity to key variables such as commodity prices, metallurgical and logistical constraints, project schedules, and capital and operating costs. She holds a bachelor's degree in chemical engineering from Queen's Univ., and is working toward a master's in business at the Rotman School of Management in Toronto. She is a Professional Engineer licensed in the province of Ontario and a Certified Energy Manager.
(c) 2013 American Institute of Chemical Engineers
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