The increase will affect one third of homes supplied by the company. : Scottish Power has announced its second bill increase in 2018, and said its standard variable domestic gas and electricity prices will go up from 8 October. The increase will affect one third of homes supplied by the company, about 900,000 households. The other homes supplied by Scottish Power will not be affected, the firm said. In June, a price change announced earlier in the year took effect, with Scottish Power customers on the standard tariff seeing bills rise by £63 to £1,211 for the year.