top of page

LETI 2019 Workstreams

This page summaries our 2019 workstreams. Click here for our 2021 Workstreams.

Since we put forward our joint comments to the draft London Plan in March 2018, the London Energy Transformation Initiative (LETI) has been busy working on: Leading by Example; developing a zero carbon framework with the UKGBC; and firming up the LETI Legacy - ensuring we can keep implementing the positive impact of LETI over the long term. To build on our achievements and in the collaborative spirit of LETI we held a workshop on the 18th of October to set the direction for the next year.

The workshop discussion ‘pit-stops’ were based on the suggested workstreams chosen by everyone in the LETI network that signed up for the workshop. There were six workshop pit-stop sessions, and participants were welcome to choose which sessions to attend.

Below is a summary of the pit-stop sessions, outcomes and likely future direction – leading to the LETI workstreams for 2019. Participants at the workshop were then given the opportunities to sign up to express an interest in 'being involved in the workstream' or to 'help organise the workstream'.


Be Seen

The groups discussing the Be Seen addition to the energy hierarchy were excited to see the move towards reporting of actual performance (although there was still a hope that this could one day extend to existing buildings as well!).  It was recognised that currently the GLA proposed wording contains little information on the details of what should be reported in practice. Careful design of the reporting process and approach to data management, as well as consideration of incentives for this reporting, would be key to the validity of the data and the overall success of the policy.  A wide range of risks, issues and opportunities were identified, but encouragingly there were also good examples of where other places or sectors have successfully implemented similar initiatives. 

Participants felt that there was a key role for LETI in helping make this policy a real spur to transforming the energy debate in London.  Opportunities to be developed by the 2019 'Be Seen' workstream included recommendations on the energy and contextual data that should be reported, providing advice on the practicalities of setting up metering, monitoring and reporting systems and demonstrating some of the uses of the data and the opportunities it brings.


Net Zero Carbon

Net Zero Carbon buildings are highly energy efficient and use renewable energy sources and to offset in-use energy. In spite of significant work that has focused on these topics, there are still only a handful of buildings in the UK that currently operate at net zero carbon. The discussions at this pit-stop expressed an enthusiasm for collaboration (particularly with the UKGBC and the GLA) in order to find solutions. Participants seem to be very keen to make net zero carbon more tangible, coherent and achievable for the industry, whilst confronting issues such as cost and business case.

Based on discussions, voting and current opportunities, the emerging priorities for the 2019 workstream to focus on appear to be (in their current order of preference):

  • Setting out what net zero carbon buildings could look like by working up examples for typical London archetypes, e.g. a 5,000 sqm office, a Primary School, a medium density apartment block of 60-100 units

  • Collaborating with the GLA on a policy roadmap to achieve net zero carbon new buildings by 2030 and existing buildings by 2050. This would include discussions on planning requirements and infrastructure.

  • Feeding into the UKGBC-led work on a definition for net zero carbon. LETI will have a representative on the industry Task Group and could organise a LETI workshop to produce written recommendations.

  • Developing a technical tool for designing and delivering net zero carbon buildings, using the LETI declaration as a starting point.


Embodied Carbon and Whole Life Carbon

Most attention on low carbon buildings, in London and elsewhere, has focused on the operational energy use of the building. However, the ambitious 1.5 degree climate goal set out in the UNFCCC Paris agreement requires buildings to be near net zero carbon over their full lifecycle by 2050 at the latest. This includes the emissions resulting from manufacture, transport and assembly of the materials used to construct and maintain the building, as well as emissions associated with building operation and end of life. There is therefore increasing interest in reducing emissions embodied in building materials such as concrete and steel.


LETI Declaration

Over the last year LETI has supported the London Plan in taking some big steps in the right direction by introducing energy use disclosure, zero emission plans, enhanced fabric efficiency, minimising peak demand and approaches for decarbonising heating. However, policy only represents a minimum standard. In order to meet our goals, it is crucial that industry leads by example and builds upon the changes in the draft London Plan to be able to deliver operational net zero carbon buildings. LETI developed the LETI Declaration tools to help us achieve this, with a strong focus on nudging design teams to think about how their design proposals would perform in operation.  


The embodied carbon LETI 2019 workstream looks to work with UK and international actors such as UK/WGBC, WBCSD, Climate KIC and CIFF to provide guidance relevant to planners and built environment professionals in London. In particular, stakeholders have told us that better guidance on conducting embodied carbon assessments is needed, especially where to source data on carbon embodied in certain materials and building services and where to draw the boundaries of an embodied or lifecycle carbon assessment. We also need to raise awareness of embodied carbon among politicians and the GLA, building professionals and building occupiers and owners.


At the workshop LETI participants said they would be keen to see the Declaration adopted by the GLA to enforce its use, as well as see it linked to the new ‘Be Seen’ step in the energy hierarchy.


In the 2019 workstream there is an opportunity to help refine, develop and test the LETI Declaration. We are also currently working with the GLA to understand how their new Carbon Emission Reporting Spreadsheet aligns with the LETI Declaration. In order to create real change we need your help to develop and trial its use, so it can be improved in the light of experience.


Demand Response and Energy Storage

The Demand Response and Energy Storage (DRES) workstream will support the work of LETI in establishing how being flexible about ‘when’ we use energy in our lives can positively impact our Carbon emissions. This workstream will endeavor to provide guidance on the following issues:

1.     How can DRES reduce the Carbon Footprint of Buildings in and of themselves?

2.     How can Government bodies assess whether a building has been designed to maximise flexibility and use DRES well?

3.     How can DRES reduce or delay the need for Grid Upgrades (which have a carbon cost) by improving grid resilience?

4.     How can using DRES in a development impact the wider national electrical infrastructure so more renewables can be included on the network reducing our reliance on fossil fuels?


The Future of Heating

There are dramatic changes afoot for heating system choice to meet carbon targets, given the imminent halving of Grid electrical carbon factors. This means that certain solutions running on grid electricity can achieve better carbon savings than district heating and CHP. This is expected to accelerate as more wind power feeds into the grid. It is also likely to become more complicated because of markedly different grid carbon factors between high and low demand periods. In addition, how is the electrical grid capacity going to cope with a doubling or more increase in peak demand, when recent winter spare capacity dropped below 10%? And what of consumer increasing energy bills if carbon drives a change to electrical heating?

Drawing on these discussions and its multiple related facets, LETI intends to make sense of this rapid change, exploring issues in the LETI 2019 workstream such as:

  • Is carbon the correct metric for driving building energy design and refurbishment?

  • Should there be a refocus on reducing heat demand instead of supply efficiency?

  • How close are we to good enough building fabric for individual or clusters of buildings to run on their internally generated heat gains?      

  • Can the planning policy Heating Hierarchy be rewritten to be more technology agnostic?


​This sets the scene for the LETI Future Heating workstream to develop clear guidance for industry facing this rapid change.


Calculation Methodologies - Building Regulations - Part L

While LETI focuses on London and planning policy, we recognise actions by the Mayor of London are at least to some extent framed by Building Regulations Part L. We therefore held a workshop in collaboration with CIBSE to gather feedback on the current Part L, and ideas for changes that would help it better drive real reductions in energy consumption and carbon emissions. The ideas gathered follow on from previous LETI work streams; they included:

  • Part L should retain carbon metrics, but it should also include energy metrics to better reduce carbon, and make a more efficient use of resources. The preferred approach is probably to use metered energy consumption, as consumers could easily relate to it.

  • How effective is an approach based on the notional building?   Should we replace it with simpler targets per building type (as in Passivhaus), or a more comprehensive set of elemental limits for fabric and systems? or have several routes available to project teams, depending on the scale and complexity of the project? Simple methods are required for small projects.

  • There should be more emphasis to operational outcomes, but work is needed to know how this could be imposed – for example, how to account of occupants (and their privacy) in residences? How to account for speculative development? As a first step there should be a requirement for disclosure, which links well with the LETI “Be Seen” workstream.

  • There needs to be more attention to peak demand, but not necessarily with regulatory limits; Part L should at least encourage and enable demand management.

The focus for the 2019 workstream will be to put together detailed recommendations for the energy assessment methodology for Part L of the Building Regulations as well as developing recommendations on the role of performance modelling.


Mission and Governance

Over the last year and a half LETI has focused on actionable outcomes and has developed naturally led by the LETI taskforce.  However in order to maintain our momentum, develop our priorities, increase in impact and keep focused we need to agree a LETI mission statement and develop a governance strategy.

A draft LETI mission statement was developed for comment on at the workshop:

The London Energy Transformation Initiative has been established to support the transition of London’s buildings to net zero carbon in order to tackle climate change and reduce energy costs. We do this by:

  • working with stakeholders including regulatory bodies, developers, occupiers and investors to catalyse rapid and deep market transformation and cost effective solutions to the energy trilemma;

  • making the regulatory system fit for purpose by advising on practicable policy alterations, for example in planning and building codes, to deliver desirable and low carbon buildings, placing verified performance at their core;

  • encouraging collaboration between built environment professionals, ensuring that professionals in London are working together to achieve these goals.


The participants at the workshop thought LETI should be a 'Quality Guardian', a group with no political allegiance / underlying drivers, acting as technical support driving the industry towards zero carbon and helping to reduce the performance gap. There were discussions on if the focus should be energy or carbon, that although LETI has London in it's name it should be available for the entire UK and on whether the focus should be buildings or infrastructure. If you have any comments on the draft mission statement please email

bottom of page