. Suppose we are planning power system operations for 4 hours. Demand in the four hours is 350, 480, 460, and 380 MW, respectively. We have a collection of zero-cost variable resources with output of 0, 80, 40, and 0 MW in the four hours. We also have a collection of thermal assets with a cost function f(x) = .05x 2 (e.g., it costs $500 to produce 100 MW for an hour and $2000 to produce 200 MW for an hour). As in Problem 2, we can also curtail load at a cost of $10,000/MWh. Construct a model in Excel describing this system and solve to determine an optimal production schedule for the three resources (variable, thermal, and demand). Since the problem is nonlinear, you will need to choose the GRG Nonlinear solving method rather than Simplex LP.