How much power do you lose going from 5% to 1%?

A one-sided test uses $H_0: \mu = 0$ against $H_1: \mu > 0$ with a known $\sigma = 10$, a sample of $n = 25$. The true mean is $\mu = 6$. At $\alpha = 0.05$ the power is 0.91.

Recompute the power if the significance level is tightened to $\alpha = 0.01$, and comment on the trade-off.