The Secret to Improved Return on Investment –
Why an Increase in Capital Can Lead to a Increased ROI
© Viessmann Limited
17/10/2012
Page 1
Viessmann Group
The Viessmann Group is one of the leading international manufacturers of heating
technology systems.
© Viessmann Limited
Comprehensive Range
1.5 kW – 116,000 kW
Broad Distribution
Systems Engineering
System solutions for all energy sources and application areas in the field of heating,
air conditioning and CHP
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The Renewable Heat Incentive (RHI) – The Key to Biomass
© Viessmann Limited
17.10.2012
Page 4
The Key to the Renewable Heat Incentive?
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The RHI has many rules and regulations as to
metering, heat meter, eligible and Ineligible
heat.
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The application process can be lengthy and
the correct information must be supplied
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The most important factor is – You only get
paid for the usable heat that passes through
the heat meters
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The Key to ROI on the Renewable Heat
Incentive is efficiency!
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Spot the buried heating main!
© Viessmann Limited
17.10.2012
Page 5
Boiler and System Efficiency
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The Engine of the system
The Viessmann Pyrot boiler operates a
combustion efficiency between 90-92% efficient
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Comparable boiler may have 5 % lower efficiency
This would mean a requirement for 5% more fuel
to achieve the same heat output to the system
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The biomass boiler must be the lead boiler and run
times optimised
The highest levels of insulation should be used on
pipework
Controls also play a major part in the operation of
the biomass boiler, associated plant and any
backup boilers
Variable speed pumps as opposed to constant
speed pumps should be used.
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© Viessmann Limited
17.10.2012
Page 6
Fuel Quality
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EN Plus Wood Pellets and ÖNORM M7133
wood chips are the benchmark.
There are lower priced fuels available but
generally these tend to be lower quality
EN Plus pellets give nearly 5 kWhr/kg
Poor quality pellets can be as low as 4 kWhr/kg
calorific value. This would mean up to 20% more
fuel would be required to get the required heat
from the boiler.
Higher moisture content fuels will also provide
lower calorific values
Lower quality fuels will provide :
 Lower calorific values
 More ash build up
 Quicker ‘clinker’ build up
 Increased maintenance
 Ultimately reduced boiler efficiency
© Viessmann Limited
17.10.2012
Page 7
Thermal Stores
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Thermal stores are an essential part of any
biomass boiler installation.
They should be sized to suit the individual
application but there should be
 a minimum of 20 ltr/kW of boiler load
 through the summer on a DHW load,
50 ltr/kW of boiler load should be allowed
Small thermal stores or none at all will lead to
cycling of the biomass plant.
This is akin to driving your car using the
accelerator with the brake as an on/off pedal
Boiler cycling leads to;
 Incomplete combustion
 Increased ‘clinker’ build up
 Increased servicing
 Increased emissions
 Reduced boiler efficiencies e.g. average -20%
© Viessmann Limited
17.10.2012
Page 8
Service and Maintenance
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Biomass boilers are not like standard fossil
fuel boilers, they require more regular
maintenance and servicing
Qualified and experience personnel are a
must, to carry this out
Build up of residue in the boiler tubes will
lead to efficiency reductions, possibly 20%
plus –pneumatic cleaning is a must
Poor servicing leads to
 Increased ash and ‘clinker’ build up
 Increased incomplete combustion of the
fuel exacerbating the clinker build up
 Residue build up in the boiler tubes
 Drastically reduced boiler efficiency
 Potential failure of the boiler
 Increased costs to reinstate the boiler
back to being operational
© Viessmann Limited
17.10.2012
Page 9
Correct Sizing
The RHI only pays on what goes through the meter
Careful thought needs to be put into boiler sizing, what is your base load?
Sizing the boiler to 100% of the heat load, leads to disproportionately high costs
Can solar thermal support the load in the summer, with resulting RHI payments?
50% of the Boiler load equates
to 85% of the heat load
coverage.
70% equates to 98% load
coverage.
Outside
Temperature (oC)
Relative Boiler Output
(%)
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© Viessmann Limited
17.10.2012
Heating Days
Page 10
Overall Annual System Ownership Costs
100 kW Biomass, pneumatic
cleaning, correct size thermal
store
100 kW Biomass, no pneumatic
cleaning, no/small thermal
store
£90,000
£78,000
92%
87%
-5%
4.8 kWh/kg
4.0 kWh/kg
-20%
Matched to boiler load
Continuous cycling
-20%
Pneumatic cleaning and regular
maintenance
Annual service no maintenance
-20%
85%
60%
Heat input required
Heat Input / system efficiency
= 131,400 / 85%
= 131,400 / 60%
Amount of pellets need to
generate 131,400 kWh (tier1)
154,588 kWh input
32,205 kg
32.2 T
219,000 kWh input
54,750 kg
54.75 T
£220 per tonne
= £7,084
£200 per tonne
£10,950
Capital Installation costs
Boiler efficiency
Fuel calorific value
Thermal store
Servicing
Estimate accumulated boiler
efficiency factor %
Cost of fuel per year only
operating on tier one
© Viessmann Limited
17.10.2012
Page 11
Overall Annual System Ownership Costs – Correct Sizing
100 kW Boiler, no pneumatic
cleaning, no/small thermal
store
70 kW Biomass, pneumatic
cleaning, correct size thermal
store
Peak load 100 kW
Peak load 100 kW
£78,000
£78,000
220,000 kWh
220,000 kWh
Load coverage
100%
98%
RHI tier 1 hours
RHI tier 2 hours
Total
131,400
88,600
220,000
91,980
123,620
215,600
220,000 / 60% = 366,667 kWh
215,600 / 85% = 253,647 kWh
Fuel required
@ 4.0 kWh/kg
91.7 T
@ 4.8 kWh/kg
52.8 T + £337 oil
RHI payment
£12,767
£10,230
£18,340 (£200/tonne)
£5,573
£11,953 (£220/tonne)
£1723
£189,460
Potential early boiler failure
£112,460
(£77,000 saving)
Installation information
Capital cost + installation costs
Heat load
Heat input required
Heat Input / system efficiency
Fuel costs per annum £
Nett Fuel costs /annum
20 year cost , not index linked :
capital + fuel
© Viessmann Limited
17.10.2012
Page 12
Live Example: 150 kW Heat load, Client selected 199 kW boiler
199 kW Boiler, no pneumatic
cleaning, no/small thermal store
100 kW Biomass, pneumatic
cleaning, correctly sized thermal
store
Peak load 150 kW
Peak load 150 kW
£100,000
£90,000
300,000 kWh
300,000 kWh
Load coverage
100%
96%
RHI tier 1 hours
RHI tier 2 hours
Total
261,486
38,514
300,000
131,400
156,600
288,000
51% system efficiency
588,235 kWh
85% system efficiency
338,824 kWh
Fuel required
@ 4.0 kWh/kg
147.1 T
@ 4.8 kWh/kg
70.6 T+ £870 Oil
RHI payment
£22,512
£14,195
Fuel costs per annum £
Nett fuel costs /annum
£29,420 (£200/tonne)
£6,908
£16,410 (£220/tonne)
£2,215
20 year cost , not index
linked:
Capital + Fuel
£238,160
Highly probable early boiler failure
£134,300
(£103,860 saving)
Installation Information
Capital cost + installation
costs
Heat load
Heat input required
© Viessmann Limited
17.10.2012
Page 13
RHI What It Means
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Efficiency is essential
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You only get paid for what goes through the
meter
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Fuel quality, thermal stores, servicing and
maintenance are key factors in RHI delivery
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Look at other options for low load periods
 e.g. summer, with solar. 8.9 p/kWhr via RHI
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Increased Capital investment offers a better
system efficiency
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Correct sizing leads to substantial cost savings
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Your system must last 20 years
© Viessmann Limited
17.10.2012
Page 14
Existing Viessmann Installations Still in Operation
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1985
1987
1989
1993
1993
1994
1995
1995
1998
2001
2005
Pyromat ECO 50
Pyrotec 125kW
Pyrotec 450kW
Pyrotec 800kW
Pyrotec 800kW
Pyrotec 1000kW
Pyrotec 1350kW
Pyrotec 2000kW
Pyrot 220kW
Pyrot 480kW
Pyrot 1250kW
Log boiler
Woodchip
Woodchip
Log boiler
Woodchip
Woodchip
Woodwaste
Woodchip
Pellet boiler
Pellet boiler
Pellet boiler
Over 7500 working installations in Europe
Quality
is the key!
© Viessmann Limited
17.10.2012
Page 15
Thank you for your attention
© Viessmann Limited