Economics
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the big picture
By Jeremy Harrison

Is micro CHP worth the money?

Many people interested in micro CHP are unsure whether it is economically worthwhile to install such a system.  This simple calculator is intended as a tool for you to calculate your potential energy savings, based on your current fuel bills.  From this you can work out how long it will take to pay back the investment in micro CHP.

Please note that this spreadsheet is provided only for you to undertake an estimate and that each home and household is different.  You should satisfy yourself that the result is reasonable.  You will not be asked for your personal details, but if you want more information on the product you have selected, please contact the manufacturer (or other supplier) via the links on the products page.

Download the MS Excel spreadsheet and then enter your details to work out how much you can save.

Clicking on the "calculator" button will take you to a Microsoft Excel spreadsheet.  You need to have MS Excel installed to run this calculation.

CALCULATOR

This calculation assumes that you are considering replacing your boiler (which has reached the end of its useful life) with either a micro CHP unit or a new 88% efficient condensing gas boiler.  It is based on replacing the boiler with a WhisperGen micro CHP unit.  You will need to know your gas and electricity costs for a complete year, which you can see from your annual energy bills.

Simplified Example

An example of a simplified calculation is shown below for illustration only.  It assumes that the system is installed in parallel with the existing power supply and that surplus generation is exported to the grid and any shortfall in requirements is imported from the grid.  It is based on the WhisperGen (1.0kWe/7kWt) micro CHP unit in a family home with annual heat demand of 28,000 kWh.
Annual heat demand 28,000 kWh
Running hours 4,000 hours
Electricity generated 4,000 kWh
Own use of generation 67 %
Unit cost of avoided import 12 p/kWh
Value of avoided import 322 £
Unit value of export 3 p/kWh
Value of export 40  £
Value of FIT 400 £
Total value of generation 762 £
Additional gas consumed (compared with new condensing boiler) 4,000 kWh
Cost of additional gas consumed @3.5p/kWh 140 £
Net saving = £762-140 622 £
Marginal cost of unit 4000 £
Simple payback 6.4 years
Page updated January 2012      

 

the big picture
By Jeremy Harrison

This public site provides information on micro CHP free of charge.  If you have found it useful, please consider making a donation to support maintenance and development so that others may also benefit.

Thank You!
Contact : info@microchap.info

Disclaimer:  Information is provided for general information only and no endorsement or recommendation of any company or product should be inferred.  None of the companies mentioned in the main text are direct sponsors of the site; inclusion of sponsored links does not imply endorsement or relevance.  Please note that the views expressed on this site are  entirely my own and do not represent the official position of my current or previous employers. 

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This site was last updated on 9th January 2012  © Jeremy Harrison