Estimated Transmission Loss Adjustments
Glossary
Estimated Transmission Loss Adjustments (ETLM/ETLMOs) are small adjustments made to account for electricity lost as it travels through the grid. These are estimated values used for reporting purposes to give an idea of transmission losses.
This parameter is the estimated value of two types of adjustment:
- Delivering Transmission Losses Adjustment (TLMOᵢ⁺) – applied to generators
- Off taking Transmission Losses Adjustment (TLMOᵢ)– applied to suppliers
The Imbalance Settlement Group (ISG) reviews the ETLM values annually on behalf of the BSC Panel.
ETLM data
The table below displays the ETLM values between the given dates.
| Effective From Date | Effective To Date | ETLMOj+ | ETLMOj- |
|---|---|---|---|
| 01 Mar 2026 | 31 Mar 2026 | -0.01703 | 0.00691 |
| 01 Dec 2025 | 28 Feb 2026 | -0.01726 | -0.00333 |
| 01 Sep 2025 | 30 Nov 2025 | -0.01637 | 0.00397 |
| 01 Jun 2025 | 31 Aug 2025 | -0.01877 | 0.01244 |
| 01 Apr 2025 | 31 May 2025 | -0.01703 | 0.00691 |
| 01 Mar 2025 | 31 Mar 2025 | -0.01577 | 0.01080 |
| 01 Dec 2024 | 28 Feb 2025 | -0.01753 | 0.00825 |
| 01 Sep 2024 | 30 Nov 2024 | -0.01630 | 0.01330 |
| 01 Jun 2024 | 31 Aug 2024 | -0.01692 | 0.01485 |
| 01 Apr 2024 | 31 May 2024 | -0.01577 | 0.01080 |
| 01 Mar 2024 | 31 Mar 2024 | -0.01260 | 0.00954 |
| 01 Dec 2023 | 29 Feb 2024 | -0.01446 | 0.00791 |
| 01 Sep 2023 | 30 Nov 2023 | -0.01309 | 0.01018 |
| 01 Jun 2023 | 31 Aug 2023 | -0.01378 | 0.01200 |
| 01 Apr 2023 | 31 May 2023 | -0.01260 | 0.00954 |
| 01 Mar 2023 | 31 Mar 2023 | -0.01231 | 0.00852 |
| 01 Dec 2022 | 28 Feb 2023 | -0.01444 | 0.00608 |
| 01 Sep 2022 | 30 Nov 2022 | -0.01473 | 0.00925 |
| 01 Jun 2022 | 31 Aug 2022 | -0.01265 | 0.00999 |
| 01 Apr 2022 | 31 May 2022 | -0.01231 | 0.00852 |
| 01 Mar 2022 | 31 Mar 2022 | -0.01442 | 0.00782 |
| 01 Dec 2021 | 28 Feb 2022 | -0.01569 | 0.00436 |
| 01 Sep 2021 | 30 Nov 2021 | -0.01395 | 0.00872 |
| 01 Jun 2021 | 31 Aug 2021 | -0.01415 | 0.00977 |
| 01 Apr 2021 | 31 May 2021 | -0.01442 | 0.00782 |
| 01 Mar 2021 | 31 Mar 2021 | -0.01166 | 0.00674 |
| 01 Dec 2020 | 28 Feb 2021 | -0.01120 | 0.00621 |
| 01 Sep 2020 | 30 Nov 2020 | -0.01173 | 0.00672 |
| 01 Jun 2020 | 31 Aug 2020 | -0.01340 | 0.00999 |
| 01 Apr 2020 | 31 May 2020 | -0.01166 | 0.00674 |
| 01 Mar 2020 | 31 Mar 2020 | -0.01085 | 0.00864 |
| 01 Dec 2019 | 29 Feb 2020 | -0.01093 | 0.00681 |
| 01 Sep 2019 | 30 Nov 2019 | -0.01082 | 0.00713 |
| 01 Jun 2019 | 31 Aug 2019 | -0.01055 | 0.00877 |
| 01 Apr 2019 | 31 May 2019 | -0.01085 | 0.00864 |
| 01 Mar 2019 | 31 Mar 2019 | -0.00938 | 0.00720 |
| 01 Dec 2018 | 28 Feb 2019 | -0.00899 | 0.00555 |
| 01 Sep 2018 | 30 Nov 2018 | -0.00834 | 0.00705 |
| 01 Jun 2018 | 31 Aug 2018 | -0.00977 | 0.00706 |
| 01 Apr 2018 | 31 May 2018 | -0.00938 | 0.00720 |
| 01 Apr 2017 | 31 Mar 2018 | -0.00899 | 0.01040 |
| 01 Apr 2016 | 31 Mar 2017 | -0.01053 | 0.01210 |
| 01 Apr 2015 | 31 Mar 2016 | -0.00932 | 0.01076 |
| 01 Apr 2014 | 31 Mar 2015 | -0.00836 | 0.00992 |
| 01 Apr 2013 | 31 Mar 2014 | -0.00913 | 0.01098 |
| 29 Nov 2012 | 31 Mar 2013 | -0.01039 | 0.01264 |
| 01 Apr 2012 | 28 Nov 2012 | -0.00842 | 0.01050 |
| 01 Apr 2011 | 31 Mar 2012 | -0.00757 | 0.00941 |
| 01 Apr 2010 | 31 Mar 2011 | -0.00881 | 0.01099 |
| 01 Apr 2009 | 31 Mar 2010 | -0.00782 | 0.00973 |
| 01 Oct 2008 | 31 Mar 2009 | -0.00805 | 0.01002 |
| 01 Apr 2008 | 30 Sep 2008 | -0.00863 | 0.01075 |
| 01 Apr 2007 | 31 Mar 2008 | -0.00785 | 0.00977 |
| 01 Apr 2006 | 31 Mar 2007 | -0.00718 | 0.00892 |
| 01 Oct 2005 | 31 Mar 2006 | -0.00695 | 0.00863 |
| 01 Apr 2005 | 30 Sep 2005 | -0.00695 | 0.00863 |
| 01 Apr 2004 | 31 Mar 2005 | -0.00645 | 0.00800 |
| 01 Apr 2003 | 31 Mar 2004 | -0.00645 | 0.00800 |
| 01 Apr 2002 | 31 Mar 2003 | -0.00792 | 0.00985 |