CHP Scoping Model v0.2

See the introductory post for this model here.  

This is v0.2 of the CHP scoping model I am developing.  The model is setup with some dummy data.

If you want to get it working for your project all you need to do is change:

  • heat & power demands (Model : Column F-H)
  • prices (Model : Column BF-BH)
  • CHP engine (Input : Engine Library).

You can also optimize the operation of the CHP using a parametric optimization VBA script (Model : Column BW).

You can download the latest version of the CHP scoping model here.

Thanks for reading!

3 thoughts on “CHP Scoping Model v0.2

  1. Duncan Campbell

    I see you use a CO2 emissions calculation methedology of using NG (does this account for catalytic conversion of CO to CO2, and is that even significant?), import power, and export power carbon intensities.

    What are your thoughts on considering self-generation’s effect on the remaining import power’s carbon intensity? In theory, merit order tells us that low marginal cost resources like wind and solar will not be displaced by reducing system load (until a point of course). Therefor, the CHP system is likely displacing centralized dispatchable generation of load-following and peaking form, and thus using the “grid average” carbon intensity might be selling the CHP system’s CO2 offset short.

    The EPA attempts to address this in their CHP CO2 Savings Calculation Methodology document (linked below, relevant section on the last several pages). Their approach (fossil fuel and non-baseload grid carbon intensities) is obviously imperfect (and optimizing would be quite difficult), but it may be more accurate than the grid average method.

    BTW, awesome model! If it would be useful, I’d love to help build out the engine library.

    https://www.epa.gov/chp/fuel-and-carbon-dioxide-emissions-savings-calculation-methodology-combined-heat-and-power

    Reply
    1. Duncan Campbell

      After reading through other posts here I see you’ve already written marginal emissions. Don’t mind me!

      Reply
    2. Adam Green Post author

      I agree totally with you – the carbon benefit of CHP is likely underestimated using an annual average intensity for import power.

      This is for two reasons – as you highlight CHP generation is likely to displace the marginal (and carbon intense) plant – but also if a CHP follows an optimal dispatch stragety then it will not be operating when the grid carbon intensity is low.

      The way to deal with it is to use a variable grid intensity – I think you can use operational data to estimate this (ie data from Elexon).

      Duncan – would be great for you to help! I think the engine library could be formatted better – it is hard to structure the tables as there is the additional dimension of load.

      Please feel free to work on it as you like – get in touch with me at adam.green@adgefficiency.com and we can merge them together.

      Reply

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