3 Zero carbon homes
19. Following the then Chancellor's announcement
of the zero carbon homes target in the 2006 Pre-Budget Report,
the Department for Communities and Local Government (CLG) outlined
further details in a consultation paper entitled Building a
Greener Future: Towards Zero Carbon Development.[33]
This set out a timetable for progressive mandatory improvements
in the energy efficiency of new buildings, with a 25% cut in carbon
emissions from 2006 standards by 2010, a 44% cut by 2013, leading
to the zero carbon standard by 2016. The Government projects that
meeting these targets would save at least 15 million tonnes of
CO2 per year by 2050.[34]
The UK Green Building Council's Zero Carbon Task Group hailed
the 2016 zero carbon target as "perhaps the most ambitious
environmental policy this Government has introduced."[35]
20. As numerous witnesses (including the UK-Green
Building Council and the Home Builders' Federation) pointed out,
the steps up from the 2010 standard, and even more from the 2013
standard to the zero carbon standard in 2016, will be very demanding.
The 2010 standard can be met by improving the energy efficiency
of the building fabric. While this may cost more money and be
logistically challenging to achieve at volume, it is essentially
a case of standardising designs and materials that are already
in use; it lies wholly within the competence and control of construction
firms. The 2013 standard will require new homes, not just to have
greater thermal efficiency, but to provide some of their own energy
from onsite renewable sources. Achieving the 2016 zero carbon
standard will require supplying all the energy used in the homei.e.,
heating, water, lighting, and all household appliancesfrom
renewable sources. This will add a great deal of extra complexity
to new housing developments, in terms of the skills and technologies
required for building electricity generating capacity. Neil Jefferson
of the National House-Building Council told us that the requirement
to provide all the energy for household appliances from renewable
electricity made the UK's zero carbon target the most exacting
and ambitious standard that he was aware of in the world.[36]
21. Even more important, individual sites for
development will vary widely in terms of their potential for generating
electricity. For example, urban sites will generally not be suitable
for wind turbines, blocks of flats may be too densely populated
relative to surface area to supply their own energy from solar
panels, and diseconomies of scale will mean that it may be very
expensive for small developments to generate their own energy.[37]
In August 2007 the Renewables Advisory Board estimated that at
least 11.6% of new homes built from 2016 would not be able to
generate all their own energy. A report in May 2008 by the UK-Green
Building Council's Zero Carbon Task Group reanalysed this finding,
and suggested it might apply to as many as 78.4% of new homes.[38]
22. In order to help make the zero carbon standard
practicably deliverable, CLG had originally announced that zero
carbon developments could, in certain circumstances, achieve the
required standard by funding the building of new renewable energy
capacity off-site.[39]
The Treasury then announced[40]
a more restricted definition of what could qualify as zero carbon,
stating that off-site renewables would only be acceptable if they
were connected to the new housing development by a private wire,
rather than connected to the grid; CLG then amended its definition
to match. This provoked considerable controversy, with both construction
and energy firms arguing it was too restrictive. For instance,
E.ON told us: "[
] the current definition of a zero-carbon
home shows a lack of understanding of how energy infrastructure,
particularly networks, actually works. A requirement for any 'offsite'
generation to be connected to the site by dedicated 'private wire'
is not a sensible approach."[41]
23. One argument E.ON made was that any decentralised
energy network would still need to be connected to the grid, partly
as a back-up when it was not generating enough power to be self-sufficient,
partly to export energy to the grid where it was generating more
than it needed. Another argument was the national grid is a natural
monopoly, and that it would be inefficient to allow housing developers
to begin to duplicate it through constructing dedicated private
transmissions networks. More fundamentally, E.ON argued that grid
electricity would be progressively decarbonised anyway, and that
zero carbon housing developments could contribute to this by effectively
buying offsets to help fund the growth of renewable energy generation
nationally.[42]
24. Responding to these concerns, and at the
invitation of Government, the UK-Green Building Council formed
a Zero Carbon Task Group which reported on its recommendation
for the definition of a zero carbon development in May 2008. This
recommended that, where meeting the energy demand of household
appliances from on- or near-site renewables is "not practicable
or [
] prohibitively expensive", developers could use
either of two options. In the first, off-site solutions would
be allowed (without requiring private wire networks), provided
that they are demonstrably additional and have been built specifically
to deliver the energy needs of the development. In the second,
the developer would pay into a 'Community Energy Fund', that would
ensure equal or greater net carbon savings are delivered through
new installations.[43]
Overall, the UK-GBC were clear about the need to ensure that in
building or funding off-site renewables, developers were not financing
something that would have been built anyway, given the existing
targets and incentives on power companies under the Renewables
Obligation.[44]
25. We asked the Housing and Environment Ministers
for their thoughts on the definition of "zero carbon".
They stated that they were still consulting on the definition,
but that their working ideas were along the lines of the UK-GBC's
proposals. Bob Ledsome, Deputy Director of Climate Change and
Sustainable Development at CLG, clarified the Government's thinking
as being that funding off-site installations would be acceptable,
and that: "We usually use 'off-site' in terms of the energy
being transmitted through the Grid as opposed to it being a local
system with connections but on a local distributing basis."[45]
In other words, where off-site renewables are allowed, there will
be no physical link between them and the development itself; their
contribution will be to add incrementally to the decarbonisation
of the grid electricity available to all households, rather than
to supply 100% carbon-free electricity to the development of new
"zero carbon" homes.
26. We accept the concerns raised about the
difficulties inand in some cases impossibility offully
meeting the target through on-site renewable energy sources. There
are certainly dangers in allowing this requirement to be watered
down: firstly, that it will become the default option; secondly,
that it will be added to the funding of large-scale renewables
that power companies are already incentivised and mandated to
build; thirdly, that if developers fund off-site renewables that
are connected to the grid, then the zero carbon status of the
new homes in question will be greatly complicated. In fact, these
homes will not themselves be using zero carbon energyany
more than any other household that draws its power from the grid.
27. Even in this case, however, we believe that
the zero carbon target could still make a significant environmental
contribution. First, while the new homes in question would still
be consuming grid electricity, they would be consuming less of
it than the average home, given both their energy efficient design
and the fact that they would still have to generate on-site all
the power they would need for heating, lighting, and hot water.
Second, by funding new renewable capacity they would be contributing
to the progressive decarbonisation of grid electricity, thus helping
to lower the carbon emissions of all households. Third, they would
be helping to develop a mass market for energy efficient materials
and microrenewable technologies and firms, thus reducing the costs
of such products, in turn encouraging their take up, not just
in the building of new housing but in the retrofitting of existing
buildings. Finally, by providing renewable heat and power to surrounding
properties, or by paying into the UK-GBC's proposed Community
Energy Fund, new developments could play a vital role in accelerating
the creation of community energy systems (otherwise referred to
as district energy or decentralised energy systems).
28. We recommend that, once
the zero carbon standard comes into effect, the initial priority
for developers must be to build on-site generating capacity and
planning policy should reflect this priority. Where off-site renewables
are used, these should not require the use of a private wire to
connect them to the housing development that is funding them,
but should simply be connected to the grid.
However, it is essential
that controls are established to ensure such off-site generation
is additional to what power companies would build anyway. Whether
new developments build on-site (or adjacent) generation, or pay
into some kind of proposed Community Energy Fund, we recommend
that the Government seizes the opportunity of the 2016 zero carbon
target to accelerate the development of district renewable energy
sources to supply existing neighbourhoods.
29. We received some evidence to warn of potential
problems in using the construction of new zero carbon homes as
a spur to increasing the provision of district energy systems
for existing neighbourhoods. One obvious potential problem is
that the energy requirements of new, ultra-efficient homes will
be very different to those of the existing housing stock. In some
ways this mismatch could be fruitful; where new zero carbon homes
use biomass combined heat and power (CHP) plants to generate electricity,
they will have less need for the surplus heat, which could be
usefully piped to older housing stock nearby. John Slaughter of
the Home Builders' Federation told us:
[
] there is enormous potential to develop systems
that work not just for new development but for the surrounding
existing housing stock and nearby commercial, industrial and public
service uses. That has a number of benefits: not only does it
potentially provide a more cost-effective way of decarbonising
everyone, it also means you have a more interesting investment
proposition on the commercial side from an energy supply perspectiveyou
will have balanced load, you will have a range of users and that
makes configuration of a local system more attractive and more
commercially interesting. I think therefore that if we look at
that somewhat bigger picture in terms of how the new build and
the existing stock can perhaps work together, then maybe we can
actually make that a win-win for everybody.[46]
30. In other ways, the difference between types
of housing stock could cause problems; several memos stressed
that the technologies required to build zero carbon homes may
differ substantially from that which could usefully be retrofitted
to existing housing.[47]
Most importantly, although biomass CHP might make sense in providing
for individual developments and districts, serious questions remain
about how extensively it could be rolled out. E.ON, for instance,
told us:
This may be a good option in certain circumstances,
but under the present policy the wider environmental impacts of
this technology will not be considered: impacts such as air quality
and fuel transportation will be critical in dense urban areas,
as well as issues such as the sustainability of the biomass fuel
sources.[48]
Similarly, the LGA told us:
London Councils' research, modelling the potential
cumulative impact of widespread small scale wood fuelled biomass
use across London, has shown a potential for an increase in air
pollutants such as nitrogen dioxide and particulates. Emissions
from different biomass appliances vary widely, and it is therefore
vital that councils are able to choose the best options for both
air quality and climate change for their local area.[49]
31. We recommend that the Department
for Energy and Climate Change (DECC) and the Department for Communities
and Local Government (CLG) urgently identify the practical difficulties
in establishing extensive district energy systems, and implement
a plan to address them. We further recommend that the Government
commissions and publishes an assessment of the potential of biomass
CHP, involving a detailed analysis of UK capacity to produce the
requisite biomass (bearing in mind other demands for land use,
and other demands for biomass), the sustainability of biomass
supplies, and the effects of biomass CHP on air quality in urban
areas and how to minimise them.
32. We raised the issue of whether the Government
was providing sufficient emphasis on the need for building design
also to adapt to the impacts of climate change, notably the potential
for increased incidences of flooding, drought, and heatwaves.
We received one very interesting piece of evidence on this, from
NGM Sustainable Developments, who drew our attention to the potential
for new buildings to be built with basement buoyancy tanks, enabling
them simply to float in the event of flooding.[50]
This might potentially make it more feasible to build new communities
on flood plains. We recommend
the Government places much greater emphasis on adapting housing
to the future impacts of climate change, both in terms of the
designs for new housing and elements that can be retrofitted to
existing housing stock. Critical to this will be the development
of the skills and supply chains needed to support and apply innovative
construction methods and design. The Government should ask
the UK Green Building Council to investigate what further action
is needed in this regard. In investigating these questions the
UK Green Building Council should take into account the views of
bodies such as the Environment Agency.
33 CLG, Building a Greener Future: Towards Zero
Carbon Development, December 2006 Back
34
Cm 7191, p 5, p 7 Back
35
UK Green Building Council (UK-GBC), The definition of zero
carbon, May 2008, p 4 Back
36
Q87 Back
37
Department for Business, Enterprise and Regulatory Reform (BERR),
UK Renewable Energy Strategy, June 2008, pp 139-40 Back
38
UK-GBC, The definition of zero carbon, p 27 Back
39
UK-GBC, The definition of zero carbon, p 4 Back
40
UK-GBC, The definition of zero carbon, p 4 Back
41
Ev 145 Back
42
Ev 145 Back
43
UK-GBC, The definition of zero carbon, p 5. The essential
difference between the two options proposed by the UK-GBC is that,
under the first, the developer would be responsible for finding
the land, gaining planning permission, and installing the renewable
generation themselves; whereas, under the second, they would pay
into a fund that would be managed centrally to finance the installation
of district energy generation. Back
44
UK-GBC, The definition of zero carbon, p 33 Back
45
Q189 Back
46
Q107 Back
47
For example, ev 145 Back
48
Ev 146 Back
49
Ev 72-3 Back
50
Ev 204-5 Back
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