22 May 2008

ANALYSING THE ECONOMIC AND CARBON DIOXIDE REDUCTION VIABILITY OF GSHPS IN THE UK INTO THE FUTURE


This paper seeks to consider the application of GSHPs in the UK context by
considering the future electricity generation mix and changing energy prices. This is against
a backdrop of increased national legislative pressure to implement low carbon technologies
from recent building regulations triggered by the European Performance in Buildings
Directive. From an economic standpoint increasing gas prices versus electricity have made
this technology more competitive against the historically dominant techniques of space
heating and cooling in the UK.
A number of scenarios are used to present both the economic and environmental variation
throughout the assumed lifetime of the GSHP. In economic terms, electricity and gas prices
are projected by considering recent trends whilst the carbon dioxide intensity is reviewed
using current government guidelines and projections.
The case study is used to demonstrate the effect of dynamic carbon dioxide factors and
compares the results against static carbon dioxide factors commonly used by building
services engineers. Consideration is further given to changing energy prices to highlight the
effect on the economic payback which is frequently a constraint to the application of GSHPs
in the UK.
In conclusion, it can be argued that although the application of GSHPs in the UK remains
promising a more accurate dynamic model would be useful to consider the range of future
carbon dioxide and operational savings. This would also aid comparison against other low or
zero carbon dioxide approaches. Furthermore, post occupancy evaluation of buildings and
GSHPs in the UK is needed to understand the sensitivity of design decisions on the actual
performance.