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Review Group 176. Possible Alternative to use of SND in Demand Estimation. Use of SND in the Formula. Demand t = AQ/365 x ALP t x (1 + (DAF x WCF) ) x SF WCF (Weather Correction Factor – at LDZ level) = (Actual LDZ NDM Demand – Seasonal Normal NDM Demand t ) Seasonal Normal NDM Demand t
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Review Group 176 Possible Alternative to use of SND in Demand Estimation
Use of SND in the Formula • Demandt = AQ/365 x ALPt x (1 + (DAF x WCF) ) x SF • WCF (Weather Correction Factor – at LDZ level) = (Actual LDZ NDM Demand – Seasonal Normal NDM Demandt) Seasonal Normal NDM Demandt • DAF (Daily Adjustment Factor – at EUC level) = WSENSt/SNDt (for EUC) WSENSt/SNDt(for LDZ)
Suggested approach - WCF • Use WCF = (Actual LDZ NDM Demand – Σ(AQEUC/365 x ALPt)LDZ) Σ(AQEUC/365 x ALPt)LDZ • i.e. Derive an approximation of Seasonal Normal Demand for the LDZ by applying the ALP for the day to total AQ/365 for each EUC • Options for frequency of calculation: Annual off-line calculation in September for new Gas Year Infrequent, easy Frequent, complex Monthly off-line calculation throughout Gas Year, reflect evolution of AQs Daily calculation, part of on-line Demand Attribution
Suggested approach - DAF • DAF currently published in August for next Gas Year • DAF less sensitive to SND than WCF • Use DAF = WSENSt/ AQEUC/365 x ALPt WSENSt/ Σ(AQEUC/365 x ALPt)LDZ • Options for frequency of calculation: • During Spring analysis using prior year AQs • In September when AQ amendment window closes • Monthly to reflect evolution of AQs • Daily calculation – not necessary/desirable? • Suggest calculation in advance in Spring – greater accuracy not required
Advantages Removes reliance on DN Forecasts AQs already visible to Shippers – more “neutral” No UKLink impact for annual/ monthly calculation Should reduce WCF values if SND is generally overstated Would complement a rolling AQ regime Disadvantages AQs based on historic data – out-of-date? Can’t reflect current trends Impact on UKLink for daily calculations Annual/monthly calculations may not evolve quickly in line with actual AQs Use of AQ and ALP – Summary