The conference paper ‘Repowering: An option for refurbishment of old thermal power plants in Latin-American countries’ (in: Proceedings of ASME Turbo Expo 2010: Power for Land, Sea and Air GT2010 (June 14-18, 2010, Glasgow, UK). DOI: 10.1115/GT2010-23058) by Irrazabal Bohorquez et al. of the Universidade Federal de Itajubá (UNIFEI) in Brazil has several Sankey diagrams to visualize energy flows in repowered thermal power plants.

Flows are im MWe. The base situation (A) in the power plant built in the 1970ies is shown in this Sankey diagram:

And the situation in one of the six refurbishment scenarios (B to G) for the power plant:

In the refurbishment scenario gas turbines (GT) are being installed. Exhaust gas is recovered and used in a heat recovery steam generation (HRSG).

For each scenatio the cost for generated electricity is assessed as well as the CO2 emissions associated with energy generation.
Check out the paper @ Researchgate for more Sankey diagrams.

An English-language publication ‘A Practical Guide to Energy Efficiency in Production Processes’ published by the Ministry of Economics, Energy, Transport, Urban and Regional Development of the federal German state Hesse (PDF here) describes a structured approach and methodological toolbox to increase energy efficiency in large manufacturing companies. It also contains practical recommendations.

The below Sankey diagrams are based on data from a pilot implementation (“model project”) at a plastics manufacturer.

This is the Sankey diagram for the energy consumption (electricity and gas) in the existing (baseline) scenario

… and for one of the alternatives assessed in the project:

In this alternative scenario, heat is produced from natural gas rather than from electricity, thus reducing transformation losses. Heat recovery measures are also implemented. Flow values are in MWh per year for a given average production volume.

A second alternative scenario with trigeneration is also evaluated (see pp. 43-45 in the report) and potential cost savings and payback time are discussed.

From a design perspective the Sankey diagrams are quite okay, well structured. Some flaws can be noted in arrow segments that run diagonally, where the width of the arrow is not maintained. Overall energy supply and consumption are not shown in the diagram, but only individual values.

In a presentation on “Low CO2 production in European food and beverage industry” the author Christoph Brunner from AEE – Institute for Sustainable Technologies (AEE INTEC) suggests process flow sheets and Sankey diagrams as tools used for energy efficiency analysis.

This Sankey diagram is used as an example for the creation of mass and energy balances and the visualization of the production process.

The diagram is from Austria and thefore in German. From translating some words I understand this is probably for a food/dairy industry. Flows are in MWh, but without a time span. Two steam generators (one run with natural gas, the other with petroleum) supply heat to different processes. The cooking chambers (“Kochkammern”) require most, followed by “Selch” (?) and heating of a “KSPW Tank”. Some heat is recovered from condensate.

Sankey diagrams can help understanding the energy flows of process systems and detect hotspots for optimization.

Energy flows are visualized on a machine touch screen panel, giving realtime information of energy consumption. This is from the PROFOXY system offered by Kröhnert Infotecs, a German engineering firm.

Basically two pie charts, one for the red part on the left side, and one for the green part on the right, would suffice (… I can’t believe I’m actually advocating pie charts here :-( ), but this Sankey diagram additionally gives a notion of “flow” and allows a grouping of consumers (on the right).

Consulting firm Rytec analyzes energy and heat utilization level of Swiss waste incineration plants and visualizes the processes using Sankey diagrams.

This Sankey diagram from their website is a simplified view and offers no details as to the actual figures. More detail can be found in this project summary (PDF).

Diagram labeled in German, but thanks to my friend Google Translate, I can identify ‘heating’, ‘boiler’, ‘energy conversion’ and ‘flue gas losses’. Orange streams to the top are losses.

This Sankey diagram of energy flows in a “pusher type reheating furnace” illustrates an article on ‘Reheating Furnaces in Steel Plants’ by Satyendra on the ISPAT Guru blog.

Unit of flow is not clear, but the main stream arriving from the top represents the baseline 100% (508 units) of which a portion can be recuperated and fed back into the furnace as preheated air.

A web page of the federal german ministry for Environment, Climate and Energy in Baden-Wurttemberg informs companies about energy efficiency. Sankey diagrams are described as a useful instrument to detect hotspots for improvement and a tool in the framework of energy efficiency analysis.

Spanish company Prosener illustrates its energy efficiency analysis services and support for the introduction of energy management systems with the following Sankey diagram:

This is a simple breakdown of energy consumption in a company. Electricity in green, fuel in grey. Only percentages are shown, no absolute figures.