Energy Roi Spreadsheet by wwn12700


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									Average UK home energy consumption
Your annual electricity consumption (kWhrs)                            5500     The data below is the average for
Your annual heat consumption (kWhrs)                                  25000

Price of Electricity per kWhr                                         £0.10
Price of Gas per kWhr                                                 £0.03


Average UK home energy costs                                                    Bedrooms
Annual Cost of Electricity                                          £550.00                   1
Electricity standing charge (£s)                                    £142.35                   2
Annual electricity bill                                             £692.35                   3
Annual Cost of Heating                                              £750.00                   4

Heating (Gas?) standing charge                                       £32.49     5 or more
Annual Heating (boiler) service charge (£s)                         £100.00     Get an accurate quote from

Annual Heating Bill                                                 £882.49     Heating

Average daily electricity demand (kWhrs)                              15.07     Bedrooms
Total Annual Utility Energy Cost                                  £1,574.84                   1
Price per litre of Waste Vegetable Oil (£)                            £0.26                   3                                                 4

Capital cost of CHP including VAT                                 £5,692.50     5 or more
                                                                                Get an accurate quote from
kWhrs of energy available per litre of WVO                                9.3
kWhrs of electricity generated per litre of WVO                          2.05
Generator efficiency (fuel to electricity)                              22%
Ratio of heat to electricity generated by CHP                             1.9
Quantity of electricity generated to meet heating needs (kWhrs)       13158
Quantity of surplus electricity (kWhrs)                                 7658
ROC value per kWhr                                                     £0.09
Price of electricity sold to grid (kWhr)                               £0.06
Cost of WVO per kWhr of electricity generated                          £0.13
Cost of WVO per year                                              £1,672.07
Annual ROC revenue                                                £1,184.21
Annual electricity resale revenue                                   £459.47
Annual cost of electricity bought from grid when CHP is off         £250.00
Annual servicing costs of CHP                                       £150.00
Annual running cost of CHP                                          £428.38

Annual percentage increase in Utility costs                            0.0%
                          Return on Investment

                                                                            Year 1
£18,000                                                                     Year 2
£16,000                                                                     Year 3
                                                                            Year 4
£14,000                                                                     Year 5
£12,000                                               Cumulative Utility    Year 6
£10,000                                               Costs                 Year 7
                                                                            Year 8
 £8,000                                               Cumulative CHP        Year 9
 £6,000                                               Cost                 Year 10
          1   2   3   4   5   6    7   8    9    10
e data below is the average for the UK for the number of bedrooms specified. For accurate data, look at your past bills and convert them into


             Data from    
             Avg. electricity
             Add 250 kWh per
et an accurate quote from 

             Data from
             Avg. gas
             Add 2500kWh per
et an accurate quote from 
Cumulative Utility Cumulative     Annual utility
Cost               CHP Cost       cost
           £1,575          £6,121         1,575
           £3,150          £6,549         1,575
           £4,725          £6,978         1,575
           £6,299          £7,406         1,575
           £7,874          £7,834         1,575
           £9,449          £8,263         1,575
          £11,024          £8,691         1,575
          £12,599          £9,120         1,575
          £14,174          £9,548         1,575
          £15,748          £9,976         1,575
our past bills and convert them into kWhrs, and enter them into cells B2 and B3
Notes on using the spreadsheet
All the fields with a blue shaded background are input data fields. These may be altered as the user sees fit
without any of the spreadsheet formulae being changed. Hyperlinks to source data have been included.

There are many different ways that a CHP system could be used in a domestic environment (home). In this
analysis, were are assuming that the CHP is grid-linked (i.e. electricity can be drawn from the grid when the CHP
is not running, and electricity can be sold back to the grid when it is running. This scenario also assumes that the
CHP is used primarily for heating, and the resulting excess electricity is sold back to the grid.
Other scenarios may have the CHP being used primarily for electricity generation, and the shortfall in heat
generation being supplemented by a log-burning stove, heat pump, or boiler.
Other scenarios may include the use of a battery bank and inverter, or in conjunction with solar water heating.
Each different scenario will have its own analysis data and structure. This spreadsheet can be used as a staring
point for any other scenario.

Trends and events not included in the analysis
Utility fuel costs will continue to rise. This increase has not be included in the analysis, but will ultimately reduce
the time before the CHP will repay itself.
In 2011, Offgem will be introducing financial incentives for using the waste heat from microCHP systems.
Currently the incentives are based on electricity production using the ROC mechanism. New heat recovery
incentives (in addition to the existing ROCs) will be in place in less than 2 year time. This will reduce further the
time before the CHP system pays for itself.
The price you get for selling electricity to the grid will increase over time. There are companies that are already
offering better prices than 6p per kWhr. This trend is due to:- 1) it will need to increase in step with general utility
price increases, but more significantly 2) demand for electricity will soon exceed supply. This is because the UK
has to close all the old coal power stations as a part of an EU directive, and there is no possibility that new
stations can be built fast enough to replace the old ones.
The analysis compares the costs of running a CHP systems with grid electricity and natural gas for heating.
Natural Gas is currently the cheapest fossil fuel available. Any other fuel used for heating will be significantly more
expensive. Also, Natural Gas supplies are finite, and we have had political events affecting its availability in the
past, and this could happen again.
A new feed-in tariff specifically for microHP will be announced by the Government this autumn (2009), which will
significantly improve the return on investment for renewable domestic CHP systems.
Grants of £2500 will be available for domestc CHP systems when the certificatio process for products and
installers gets going. Volvox is working to get its CHP systems approved under the Microgeneration certification

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