Carbon Dioxide Pollution
figures for various fuels (updated 2010)
(SAP 2009 version 9.90)
See assumptions below.
Running
cost for various heating methods
Updated June 2008.
Notes and
assumptions.
It is now quite difficult to compare fuel prices
due to 2-tier pricing. Furthermore, prices are
presently changing. Please check your local
supplier.
Oil cost 55p/ litre.( 2008), LPG, 39p/ lit.
Electricity 12.5p/unit
Gas condensing boiler efficiency 90%
Oil boiler efficiency 85%
LPG condensing boiler efficiency 88%
Electricity 100% efficient at point of use.
Off-peak storage heaters often 85%, but electricity
pollution figures are often better at night,
so these two factors tend to cancel each other
out.
The COP (coefficient of performance) of a
heat pump is the ratio of input to output.
Variation
in efficiency with heated water temperature.
You MUST understand this
graph, please have a good look.
The above graph shows how important
it is to keep the heated water temperature as
low as possible. To attain a COP of 4, it is
necessary to keep the heated water down to 35°C.
This is only possible with a good underfloor
heating system. If radiators are used, then
they must be oversized to keep the temperature
down as far as possible.
The red line shows how much the efficiency improves
if spring water is used. Unfortunately, this
is not commonly available.
The difference between the two lines demonstrated
how important it is to have a large ground collector
area that will keep the source water as warm
as possible.
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The Graph below might
be useful when assessing the benefit of running
a heat pump.
The vertical scale on the left shows CO2
pollution per kWh of heat delivered. The two
horizontal lines show figures for mains gas
and oil heating. The curves are for heat pumps
with COP's up to 5. Direct electric heating
has a COP of 1, and this is shown on the left.
The UK government figure for CO2 pollution caused
by electricity generation has been 0.422 (kg
co2/kWh). However the SAP 2009 version 9.90
figure is 0.591 (kg co2/kWh). The actial present
figure is around 0.5, and will tend to be high
in mid winter when coal power station are brought
on-line to meet increased electricity demand.
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The graph below gives an indication
of the possible harm caused by a refrigerant
leak compared to the saving of CO2
released during a 10 year period of a heating
system. Like the domestic fridge, refrigerant
leaks are very rare.
Graph taken from expected consumption
for a year 2002 regs. house.
10,500kWh space heating, 3,600kWh. hot water.
See ECOLOGY
page for more details
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