2. Handout 1: Carbon emissions and environmental
energy sources
Carbon emissions
Within the United Kingdom, domestic and commercial/industrial
buildings possibly present the biggest opportunity for achieving the
20% reduction in carbon dioxide emissions targeted by the government
by 2016. However, due to the differing age range and overall condition
of the UKs housing stock that target is proving challenging to attain.
Carbon emissions from buildings
Although carbon emissions in the UK have remained fairly stable since
1990, buildings accounted for approximately 30% of all emissions in
2009 (40 million tonnes of carbon) which is an increase from 26.4% of
the UK’s overall production in 1990. Research undertaken by The
Select Committee on Environmental Audit calculated that this figure
could rise to over 55% in 2050.
3. Handout 1: Carbon emissions and environmental
energy sources
Zero carbon ambition
In the 2006 Pre-Budget Report the then government announced
their aspiration that all newly built homes would be zero carbon
by 2016. To encourage this, they offered an exemption from
stamp-duty.
Domestic energy usage
Buildings in the UK are amongst the least energy efficient in
Europe. During 2009 it was calculated that 30.2% of all energy
use was used for space heating, water heating, lighting and
cooking purposes, again up from 1990 which stood at 27.7%.
The figures for energy consumed during 2009
•Space heating - 60% (57% in 1990)
•Water heating - 23% (25% in 1990)
•Appliances and lighting - 13% (13% in 1990)
•Cooking - 2% (3% in 1990)
4. Handout 1: Carbon emissions and environmental
energy sources
The building services engineering industry is attempting to tackle
these problems by installing or upgrading buildings to meet the
government’s guidelines. This can be attained by the installation
of:
•energy efficient boilers
•solar installations to harness the free energy from the sun
•wind power
•grey water and rain water harvesting
•air source heat pumps
•ground source heat pumps
Solar power
There are two methods of using the free energy from the sun and
harnessing it to heat buildings or create useable electricity to
reduce the costs of heating or lighting buildings.
These are:
5. Handout 1: Carbon emissions and environmental
energy sources
Solar thermal
This is where an ‘evacuated tube’ solar panel is used to indirectly heat the water within
the hot water cylinder. There are two versions of this which are the drain-back system
and the sealed system.
The drain-back system, as its name explains is one that when the circulating pump is
switched off, the primary water is allowed to drain out of the tubes in the panel to an
internal reservoir to prevent the problem of freezing in the winter months.
The sealed system is a fully sealed installation that can only be filled by the use of a
‘filling loop’. It does not drain itself at pump shutdown and the problem of freezing in
winter months is overcome by the addition of Glycol
(antifreeze) to the primary water.
6. Handout 1: Carbon emissions and environmental
energy sources
Solar photovoltaic
This method of harnessing the
sun’s energy uses a different
type of panel that transforms the
energy from the sun into a
‘direct’ electrical current (dc
current). This dc current can be
used in this form or transformed
via an ‘inverter’ into an
‘alternating’ current (ac current)
that can be used around the
home for powering electrical
appliances or if not used, sold to
the electricity suppliers to be
used elsewhere.
7. Handout 1: Carbon emissions and environmental
energy sources
Wind power
The power of the wind can be harnessed to create energy for
use in buildings by using a wind turbine. These turbines come
in two forms,
Horizontal axis
This is where the blades are mounted like a windmill and are
rotated via the wind to produce reusable energy. These
blades themselves have to be rotated to face into the wind for
optimum generation.
Vertical axis
Vertical axis turbines do not need orientation to the wind and
are generally used for smaller energy generation use.
8. Types of wind turbine
Handout 1: Carbon emissions and environmental
energy sources
