The London Plan Energy Hierarchy: Be Lean, Clean, Green, Seen

The London Plan Energy Hierarchy: Be Lean, Clean, Green, Seen

Every major scheme in London has to show planners how it cuts carbon, one step at a time. The London Plan calls this the energy hierarchy: Be Lean, Be Clean, Be Green, Be Seen. The order matters. Each step has to do as much as it can before you move on to the next, and planners check the figures at every stage.

Who has to follow it

Policy SI 2 of the London Plan 2021 says major development should be net zero-carbon. In planning terms, major usually means 10 or more homes, or 1,000 m² or more of new floor space. Larger schemes referred to the Mayor, such as 150 or more homes or most buildings over 30 metres, are checked by the GLA as well as the borough.

The strategy goes in an energy statement submitted with the planning application.

Be Lean: use less energy

Be Lean is about the building itself: fabric, air tightness, glazing, ventilation and efficient services, before any low-carbon heat or renewables. The London Plan asks for at least a 10% carbon saving over Part L from energy efficiency alone on homes, and 15% on non-residential space.

Better U-values, less thermal bridging and a sensible amount of glazing are cheap to fix at planning and expensive to fix at as-built. Overheating is checked alongside it. The GLA asks for TM59 modelling on homes and TM52 on non-residential space, and its cooling hierarchy puts shading, orientation and ventilation ahead of air conditioning.

Be Clean: supply energy efficiently

Be Clean looks at where the heat comes from. In Heat Network Priority Areas, the GLA expects a communal low-temperature heating system and sets an order for the heat source:

• connect to an existing or planned heat network
• zero-emission or local secondary heat, with a heat pump if needed
• low-emission CHP, only where it makes an area-wide network possible
• ultra-low NOx gas boilers, only once the other options are ruled out

Direct electric heating is not accepted in most cases. If there is no network to join, the statement has to say so and explain the heating choice.

Be Green: generate renewable energy on site

The GLA asks applicants to investigate and commit to the most renewable energy the site can take, including storage where it makes sense. On most London schemes that means heat pumps and solar PV. Roof space is usually the limit, so plan PV, plant and green roofs together. We size the PV in the SAP or SBEM, so the figures in the statement match what goes to building control.

Be Seen: report how it performs

Be Seen means monitoring and reporting real energy use once the building is occupied. Major schemes report to the Mayor through the GLA's online monitoring platform for at least five years. Plan the meters at design stage.

The 35% target and the offset payment

Across all the steps, major schemes need at least a 35% on-site carbon reduction beyond Part L 2021. The GLA's 2022 guidance adds a benchmark: residential schemes should aim for 50% or more. Homes are modelled in SAP 10.2 and non-residential space in SBEM or approved dynamic software.

The carbon left over between the on-site saving and net zero is paid to the borough's carbon offset fund. The GLA's recommended price is £95 per tonne of CO₂, multiplied by an assumed life, typically 30 years. Boroughs can set their own price. The guidance is clear: an offset payment is only accepted once the on-site savings have gone as far as they can.

The new Part L comes into force on 24 March 2027. The GLA's current guidance still measures the 35% against Part L 2021.

The draft new London Plan

The Mayor published a draft new London Plan on 16 July 2026, and the consultation closed on 15 October 2026. Its energy policies sit in Chapter 5, "a greener, resilient and healthy city": GHR1 Energy-efficiency, GHR2 Low-cost low-carbon heat, GHR3 Whole life-cycle carbon and GHR4 Heat risk. The draft still has to go through an Examination in Public, and the GLA expects to adopt it in early 2028.

Until then, the London Plan 2021 and the GLA's 2022 Energy Assessment Guidance apply. Planners can already take the draft into account, so we check it on every London scheme and tell you if it changes anything.

What we need from you

Planning drawings, the schedule of accommodation, the site plan, any pre-app comments and the heating strategy if you have one. Energy statements start from £600+VAT, including the SAP or SBEM calculations behind them, with a 5 working day turnaround once we have everything. One team does the statement and the calculations, so the planning figures match the ones building control sees later.

Questions we get asked

Does a scheme under 10 homes have to follow the hierarchy? Not under the London Plan itself. Many boroughs still ask for a carbon cut or a short energy statement on minor schemes. Send us the validation checklist and we'll tell you.

Can we skip Be Clean if there is no heat network? No. You still have to show the heating choice follows the GLA's order. Without a network, that usually means heat pumps.

Can we just pay the offset instead of reaching 35%? No. The 35% has to be met on site. The offset only covers the gap between the on-site saving and net zero.

Is the energy statement the same as a SAP calculation? No. SAP shows building control that a home meets Part L. The energy statement uses SAP and SBEM results to show planners the scheme meets the London Plan. We do both, so the numbers agree.

More: Energy statements, Energy assessments in London, SAP calculations, SBEM and BRUKL, TM59 dynamic overheating, Solar PV in SAP and SBEM and the latest industry updates.

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