The amount comes from the agreed energy assessment and the council's applicable pricing method. It is not a universal flat fee for every home project. [1][2]
Establish whether the policy applies
London's planning framework includes carbon and energy requirements distinct from the statutory planning application fee. Westminster's current supporting-document guidance requires an energy statement for major development, addressing its City Plan and London Plan policies including SI2: Minimising greenhouse gas emissions. That does not establish that every householder extension has the same assessment or payment requirement. [3]
Before including an offset allowance in a budget, identify the development category, the current local policy and the energy-assessment method the council expects. For mixed or partly retained buildings, ask the energy consultant to distinguish the new and refurbished elements rather than applying one unexplained assumption across the site. Westminster's checklist specifically asks for that distinction. [1]
Reduce emissions before calculating the residual
The energy statement should show the reductions achieved on site and the remaining shortfall. Westminster's checklist asks applicants to demonstrate that on-site reductions have been maximised before stating the proposed offset payment. A payment is therefore not a substitute for preparing an energy strategy or demonstrating the required on-site performance. [1]
At design stage, keep the energy calculations aligned with the actual building fabric, heating system and proposed renewable installations. Ask the consultant to explain which approved design features underpin the claimed savings and what needs updating if those features change.
How a contribution is calculated
A council may calculate an offset using the residual annual emissions, a price per tonne and a specified assessment period. In its Cabinet report dated 22 April 2025, Haringey described using £95 per tonne over 30 years and noted that a higher locally evidenced price could be set. This is a historical example; confirm the current rate with the relevant council. [2]
Using that 2025 method purely as an illustration, one tonne of annual residual emissions over 30 years gives 1 × £95 × 30 = £2,850. The annual shortfall and the lifetime total must not be confused. The actual contribution still depends on the accepted assessment, the applicable local price and the agreement. [2]
Ask the council to confirm the price basis and any indexation before fixing the budget. Do not take a carbon price from an old report and describe the resulting calculation as the current demand for a different authority.
The agreement and the payment trigger
Carbon contributions can be secured through Section 106 obligations. Haringey's report describes using them for local carbon-saving projects, subject to the relevant agreement. The deed should identify the obligation and when it must be fulfilled; the date cannot be assumed from an unrelated project's payment schedule. [2][4]
Keep this contribution separate from CIL and from the building-control application fee. They have different purposes and calculation procedures, even where the same development encounters more than one. [5][6]
Upcoming standards and policies
The published Future Homes and Buildings Standards regulations generally take effect on 24 March 2027, with transitional arrangements and a separate 24 September 2027 date for specified higher-risk-building provisions. For an affected project, re-check the energy baseline and the council's updated planning guidance rather than assuming an existing offset calculation remains valid. [7]
The draft new London Plan may also alter future policy if adopted. A consultation draft is not an automatic cancellation of an existing planning obligation. [8][4]