Hello miraStud. To step back a little and ask what your game plan is? And to add some thoughts.
There is a tradition of using exergy analysis to audit and optimize single site energy facilities and to price co-production (for instance, Keenan 1932). But relative little work in relation to energy system optimization models. I worked on a project called deeco from 1995 thru 2005 (Bruckner et al 2003). deeco tracked the intensive state of the system and used heuristic methods to match flows based on their intensive state (defined here). An underlying assumption was intensive/extensive state orthogonality, meaning that one could first determine the intensive state and then second optimize the extensive state of the network without disrupting the prior intensive state. For example, that DC power flows (extensive) could be solved without disturbing the nominal voltage (intensive). The general justification was the presence of sophisticated control systems to ensure just this situation prevailed (maintain voltage, regulate temperatures and pressures, and so on).
A key paper (Groscurth et al 1995) describes the abstract NEMESS model, which underpinned deeco. The use of exergy (as opposed to energy) as a commodity currency was developed further in my MSc (Morrison 2000), as was the concept of exergetic quality (the report contains generalized exergetic quality equations that I have not seen written down elsewhere).
There is a lot of literature on the thermoeconomics (an unnecessarily grandiose term) of single site facilities, but the problem of cost allocation between streams and across multiple products (including cogenerated steam and power) persists with these methods (this same issue arises in economic input/output modeling and joint production pricing, although mathematical work-arounds have been proposed, such as Patterson et al 2006). Incidentally, thermoeconomic analysis is being “replaced” by user-guided brute-force simulation, as tools (such as Aspen Plus and Ebsilon) improve in terms of their user interface and speed.
At the end of the day, the solver knows nothing of commodities, currencies, or efficiencies, howsoever conceived. It cares not whether you account for and define your transformation and transport processes using the first or second law. But of course you need to be consistent with your underlying formulation, that goes without saying.
Exergy is clearly more pedagogical that energy. But my feeling is that it is better for models to account using the first law and optionally overlay a second law analysis on the results if that provides additional insights. That then does not burden all model users with the need to understand exergy analysis. Hope this helps, Robbie.
Bruckner, Thomas, Robbie Morrison, Chris Handley, and Murray Patterson (2003). “High-resolution modeling of energy-services supply systems using ‘deeco’ : overview and application to policy development”. Annals of Operations Research. 121 (1–4): 151–180. doi:10.1023/A:1023359303704.
Groscurth, Helmuth-M, Thomas Bruckner, and Reiner Kümmel (1995). “Modeling of energy-services supply systems”. Energy – The International Journal. 20 (9): 941–958.
Keenan, JH (1932). “A steam-chart for second-law analysis: a study of thermodynamic availability in the steam power plant”. Mechanical Engineering. 54: 95.
Morrison, Robbie. (2000) Optimizing exergy-services supply networks for sustainability — MSc thesis. Otago University, Dunedin, New Zealand: Physics Department.
Patterson, Murray G, Graeme C Wake, Robert McKibbin, and Anthony O Cole (15 March 2006). “Ecological pricing and transformity: a solution method for systems rarely at general equilibrium”. Ecological Economics. 56 (3): 412–423. ISSN 0921-8009. doi:10.1016/j.ecolecon.2005.09.018.