The expressions of fuel cost of two thermal generating units as a function of the respective power generation $P_{G1$ and $P_{G2}$ are given as}
\[
F_{1}(P_{G1}) = 0.1aP_{G1}^2 + 40P_{G1} + 120 \; \text{Rs/hour}, 0 \leq P_{G1} \leq 350 \, MW
\]
\[
F_{2}(P_{G2}) = 0.2P_{G2}^2 + 30P_{G2} + 100 \; \text{Rs/hour}, 0 \leq P_{G2} \leq 300 \, MW
\]
where $a$ is a constant. For a given value of $a$, optimal dispatch requires the total load of $290 \, MW$ to be shared as $P_{G1} = 175 \, MW$ and $P_{G2} = 115 \, MW$. With the load remaining unchanged, the value of $a$ is increased by $10%$ and optimal dispatch is carried out. The changes in $P_{G1}$ and in the total cost of generation, $F = F_{1} + F_{2}$, will be as follows: