The method of calculating what would have been the total cost to each public electricity supplier P of purchasing the electricity mentioned in paragraph 1 if that electricity had been generated by a fossil fuel generating station (which, when combined with the like total cost attributable to every other public electricity supplier, is expressed as By in paragraph 2 of Schedule 2) is given by the formula–

${\mathrm{B}}_{\mathrm{y}\mathrm{P}}=\underset{\mathrm{n}}{\mathrm{\Sigma }}\underset{\mathrm{j}}{\mathrm{\Sigma }}(\underset{\mathrm{nj}}{\mathrm{Y}}\times \underset{\mathrm{nj}}{\mathrm{Z}})+\underset{\mathrm{n}}{\mathrm{\Sigma }}[(\underset{\mathrm{n}}{\mathrm{V}}-\underset{\mathrm{j}}{\mathrm{\Sigma }}\underset{\mathrm{nj}}{\mathrm{Y}})\times (\genfrac{}{}{0.1ex}{}{\underset{\mathrm{j}}{\mathrm{\Sigma }}\underset{\mathrm{nj}}{\mathrm{Z}}}{\underset{\mathrm{n}}{\mathrm{W}}}\left)\right]$