Transcript 11/3/2008 Initial presentation seeking what was needed

Sustainable Energy Use &
Generation-High-Rise Dwellings
• John Currell - Housing Asset & Sustainability
Manager at Thornsdale 11th March 2008
What does Sustainable
Development mean?
• Brundlandt Report ‘Our Common Future’
(1987) came up with a definition:
• ‘development that meets the needs of the
present without compromising the ability of
future generations to meet their own
needs’
Some reasons for behaving more
sustainably
• Can reduce human
impact on the
environment
• Helps conserve
scarce resources for
future generations
• May help limit the
impact of climate
change
• Potential to help
reduce our own costs
(e.g of heating our
homes)
• Potential to reduce
our increasing
dependency on
imported resources
(e.g natural gas)
Current Policies
• Current R & M
Sustainability Policy set
out in Housings’
Sustainable Building
Guidance
• Approved by council
committee September
2006 & supported by
Energy Saving Trust
• Aims to support corporate
sustainability policies
Energy Performance
Certificates(EPCs)
• Will need to be issued
on all new tenancies
from Oct 2008
• Includes information
on estimated energy
use and associated
carbon emissions
• Also recommends
measures that could
improve energy rating
Energy Use Reductions -What has
been achieved so far ?
• NHER approved Energy
database set up for council
managed housing stock in
2003
• In April 2004 the estimated
annual carbon emissions from
tenanted dwellings was 57,493
tonnes
CO2 Emissions
60000
50000
40000
30000
20000
• By January 2008 this has been
lowered to 48,456 tonnes, a
reduction of 15%
10000
0
CO2 Emissions
Energy Use Reduction Benefits
and energy price movements
• This energy requirement reduction has improved
underlying affordability of energy for tenants, for example
by reducing the amounts of energy required for
adequate heating
• But - improvement undermined by price increases made
by utility companies
• Most forecasts predict further rises in world energy
prices in the medium term due to increased worldwide
energy demand and likely limits on supply due to
declining known reserves of oil and natural gas
Nationally recognised High-Rise
construction characteristics
• Energy Saving Trust
states that existing High
Rise construction may
exhibit any of the
following characteristics:
• Poor thermal
performance
• Out of date and inefficient
community heating
networks with inadequate
controls in dwellings
• Poor extract ventilation
and condensation/mould
growth
• Flat Roofs that are poorly
insulated and temporarily
patch repaired
• Concrete or brick spalling
• Single glazed windows
that leak or are draughty
• Excessive heat loss
through very large
windows giving onto
balconies
• Thermal bridging from
outside to inside due to
continuous floor/wall
slabs
Opportunities for improving energy
performance
• Best opportunity occurs when
refurbishment works take place
• Example: if extensive repairs
required to the exterior in any
case, it may make external
insulation, or cavity wall
insulation, where appropriate,
much more cost effective
• Combining measures &
programmes will often result in
reduced costs and more
efficient installation procedures
• Primary Objective should be to
maximise insulation of the
building fabric wherever
possible
• Thereafter - most effective
reductions derived by
improvements to heating
systems & controls such as
programmable room
thermostats
• Other considerations controlled ventilation to
minimise the causes of
condensation
• Consider scope for introducing
low or zero carbon energy
sources
Low or Zero Carbon (LZC) energy
options
• Low or Zero carbon energy is term given
to renewable energy sources and also to
those which emit significantly less carbon
in providing heating or power
• Often grants can be obtained for partfunding of the installation
Energy Efficiency Measures
Options
•
•
•
•
WALL INSULATION
External insulation
Internal lining
Cavity fill
• Roof Insulation
Improvements
• Improvements to
Windows and doors
• Space Heating & Hot
Water System
Improvements
• All above reduce
condensation risk but
effective ventilation
also required
Opportunities to implement energy
efficiency measures
General Works Required
Potential for energy
upgrading
Rewiring
Internal Wall Insulation, energy
efficient lighting, improved communal
controls introduce ‘smart’ metering
Refitting kitchens & bathrooms
Internal Wall Insulation. Ventilation
External brickwork/concrete repairs
External Insulation or Cavity Insulation
Replacing Windows/Doors
High efficiency windows & doors
Replacing heating Systems
Higher efficiency system & improved
controls. Installation of ‘smart’
metering systems. If communal
system, CHP considered.
Repairing/replacing flat roof
Improved insulation & consider
renewable energy options for roof
Low or Zero Carbon (LZC)
Energy Types - Overview
Technology
Carbon
Dioxide
Savings
Cost
Effectiveness
Local Impact
Photovoltaic
(Solar PV)
Low
Low
Low
Combined Heat
& Power (CHP)Gas
Medium
Medium
Low-Medium
CHP-Biomass
Medium-High
Medium
Low-Medium
Ground Source
Heat Pumps
Medium
Medium
Low
Wind Power
Low-Medium
Medium
Medium-High
Photovoltaic (PV) power
• Generates electricity from
sunlight
• 3 types of solar cells:
monocrystalline,
polycrystalline & thin film
• Can be roof mounted on
frame or integrated into
building fabric (e.g thin
film on canopies)
• Electricity generated can
be used in the building or
sold to the grid
• Low maintenance, longlife, no noise issues
Combined Heat & Power (CHP)
• CHP is the local simultaneous generation of electricity
and heat
• CHP most appropriate on sites that have a year-round
demand for heat or community heating networks
• Most common fuel is natural gas, however Biomass can
be used
• Can be installed in community heating schemes to run
as the ‘lead’ boiler. Sizing correctly is important.
• Possible to ‘sell’ electricity generated to dwellings, but
regulatory obstacles to this (i.e utility company/billing etc)
• Alternative is to sell excess electricity back to the grid.
CHP - Biomass
• CHP system with all potentials of the above, but
is ‘carbon neutral’
• Typically wood chips or pellets
• Boiler house size - larger than for natural gas
due to fuel storage need & access for deliveries
• Can produce particles that need filtering by the
flue
• Can also have gas fired boilers on same site for
peak demand or as back up
Ground Source Heat Pumps
• Utilise the solar heat absorbed by the ground
• Refrigerant pumped round a ground loop or borehole(s).
Suitable for properties with undeveloped land around them
• Input energy is electricity, but up to 4 times energy input is
returned as heat. Can utilise locally generated electricity as
input fuel
• Initial capital costs relatively high due to groundworks but
boreholes have very long-life 50 yrs + and little maintenance
required generally on the system
• Amount of energy available depends on borehole depth and
undeveloped land area available. Low output temperature
means need boosting for hot water needs.
• One of the most cost effective ways of reducing carbon
emissions : £119 per tonne according to DTI Low Carbon
Building Programme Guidance
Wind Power
• Wind power can be used to
generate electricity for use in
buildings, including heating
water
• Average wind speeds min of
6m/s typically required
• On high rise would need to be
roof mounted - potential
structural , vibration & noise
implications (PP required)
• Glastonbury House in
Westminster gained
Permission for a vertical axis
wind rotor (VAWT), which have
low noise output and start up
at low wind speeds
General things we can all do
•
•
•
•
Avoid leaving appliances on ‘standby’
Install low-energy, long-life lightbulbs
Buy ‘A+’ Rated appliances
Avoid paying for gas/electricity on ‘prepayment’ meters wherever possible
• Consider paying for gas & electricity
together and by direct debit
• Compare tariffs online e.g
theenergyshop.com