Optimal Dispatch of Microgrid with Combined Heat and Power System Considering Environmental Cost

Abstract

With the rapid development of wind power generation and photovoltaic power generation, the phenomenon of wind and solar abandoning becomes more and more serious in the operation of power systems, and the microgrid is a new operating mode of power systems which provides a new consumption mode for wind power generation. With the increasingly close connection among energy resources and people's increasing awareness of environmental protection, this paper establishes a microgrid optimal scheduling model with a combined heat and power system, in consideration of environmental costs. This model aims at the lowest comprehensive cost, at the same time taking into account the emission reductions of SO 2 and NO x , considering the cost of power generated by the micro-generator, environmental cost, the related cost of battery, operation and maintenance cost of wind power, and photovoltaic power generation. The related constraints of thermal balance and power balance are also considered during microgrid system operation. The established model is solved with an improved particle swarm algorithm. At last, taking a microgrid system as an example, the validity and reliability of the proposed model are verified.Energies 2018, 11, 2493 2 of 23 microgrid system with wind and light storage [11,12], to achieve the goal of reducing the total operating costs and SO 2 and NO x emissions, has become an urgent problem to be solved.In recent years, the related research on microgrids has achieved certain results. In [13], Mao et al. comprehensively considered the operating cost, pollutant discharge, and operational risk, and established a multi-objective optimization model based on microgrids. It considered the impact of distributed power output volatility on microgrid operation, which can effectively improve the operation and management level of microgrids. In [14], Wu et al., based on the model of each power source in the microgrid, established the scheduling model when grid-connected, and proposed the mixed integer programming method applied to the optimal scheduling of the microgrid, which proves that this method has strong advantages in both computation time and calculation accuracy, and can provide fast and accurate scheduling information for short-term and ultra-short-term energy management of microgrids. In [15], Fubara et al. comprehensively considered the power balance and heat balance in a microgrid, and took the lowest operation cost as target, while considering the energy utilization rate, and two different operational strategies were proposed, which were applied to three different models. Through calculation, the operating costs under each power generation strategy were compared and verified. This contributed to the improvement of the energy efficiency of the microgrid. However, in [14,15], the investment of renewable energy, such as wind power and photovoltaics, is not taken into account, which can reduce the emission of pollutants to a certain degree. In [16], Thompson et al. established a multi-objective economic scheduling...

Generation Units Maintenance in Combined Heat and Power Integrated Systems Using the Mixed Integer Quadratic Programming Approach

“…where shows the ceiling function. Constraints regarding the power and heat balances are calculated using Equations (23) and 24, respectively. Based on Equation 20, the power-only and CHP units participate in power generation to supply the power demand.…”

“…Furthermore, in Merkert et al [21], a unit commitment model is presented for optimal operation of CHP units considering the thermal inertia of connected district heating grid. Researchers in references Li and Wang et al [22,23] have investigated an environmental cost-based model for economic dispatch of CHP units. In another attempt Dinh et al [24], a modified bat algorithm is employed for economic dispatch of CHP units.…”

Optimal Economic Dispatch in Microgrids with Renewable Energy Sources

“…A new dimension is presented in [11] with respect to the temporal correlation of intermittent renewable energy sources in hybrid systems and considers the daily variations of energy consumption in the different seasons of the year for a dispatch strategy with conventional machines; however; in this approach, the costs of regeneration of pollutants produced by conventional generation systems are not considered, nor is the concept of restriction of demand. In paper [12] is presents a distributed method to solve the problem of economic dispatch of combined heat and energy, which formulates a distributed coupled optimization problem that establishes two consensus protocols with feedback parts that satisfies the balance between electrical demand and heat demand, through an iterative method, in this approach are not considered additional aspects such as the regeneration of polluting, nor demand constraints [13][14][15]. In [16] an approach based on the generation of wind energy and photovoltaic generation is presented, here it is considered a new way of operating energy systems in a micro grid, suggesting a new mode of consumption, derived from the growing connection between energy resources and awareness of environmental protection, taking into account the reductions in SO 2 and NOx emissions, however the aspect of demand restriction nor is considered in the proposal.…”

Control Strategy of the Pumped Storage Unit to Deal with the Fluctuation of Wind and Photovoltaic Power in Microgrid

“…Its valuable academic achievements had greatly inspired the follow-up research of wind power and other clean energy for the majority of scholars. Most of the above literature use the optimized PSO algorithm [24][25][26] to solve the model. In summary, adopting appropriate strategy to operation and control in joint dispatching can effectively guarantee the stability and reliability of joint output's power.…”