gi and pg, the total would go up $35 per year for 6 years, so $35 higher year 1, $70 higher year 2, $105 higher year 3, finishing with $210 higher in year 6.
Seattle City Light was very poorly managed in the early 2000s, and had a longtime head who made sure to ingratiate himself with the mayors. That head was forced out over Mayor Nickel's objections and we got Carrasco, the current head, who seems to be quite capable and competent. However, he is hamstrung to some degree by Seattle City Light's moderate featherbedding labor contracts, and to a smaller degree by the mayor and City Council's tendency to use City Light as a piggy bank to fund their pet projects/initiatives when they can't do it in the City budget itself (ever notice the ugly little lighted tower "sculptures" lining the Ballard Bridge's overpass at Leary Way -- that's one way your ratepayer dollars were thrown away). That's one big reason they need to raise prices.
Reason 2 is that in the drought/mismanagement of the early 2000s, the City had City Light borrow a lot of money instead of raising rates. That borrowing now has to be paid for, so prices would have to be raised significantly just for that.
Reason 3 is the stupidly-worded state initiative we passed a few years back that forces electricity companies to use "renewable" energy, but doesn't count hydro power as renewable! Thus, City Light has to pay tens of millions of dollars to buy "renewable" rights every year, even though its power is already almost all hydro. Rates need to be raised to pay for that.
ds - congrats on the new house!