Abstract: With the acceleration of my country' s power spot market construction process，in order to solve the

problem of heat-electricity mismatch in the northern region，two different day-ahead scheduling strategies of a

flexible co-generation plant based on the participation of cogeneration units in the day-ahead market bidding were

discussed. The combination of the power plant included multiple combined heat and power units，a heat storage

device，a gas boiler and an electric boiler. The first strategy relied on a two-stage stochastic optimization，which used a scheme of electricity price and heat load as input. The second "parity" strategy used deterministic forecasts of

electricity prices and heat load. The four-month data of the two strategies in a northern city in 2019 was evaluated by continuously simulating the participation in the bidding before the day and the operation of the subsequent power plants. Both strategies were based on standard parameter optimization. Compared with the average bidding scheme，stochastic optimization reduces the cost，but it requires much more calculation time.

      Key words: probability prediction；bidding strategy；combined heat and power（CHP）；uncertain model；

stochastic optimization