Abstract
Microgrid works as a local energy provider for domestic buildings to reduce energy expenses and gas emissions by utilising distributed energy resources (DERs). The rapid advances in computing and communication capabilities enable the concept smart buildings become possible. Most energy-consuming household tasks do not need to be performed at specific times but rather within a preferred time. If these types of tasks can be coordinated among multiple homes so that they do not all occur at the same time yet still satisfy customers’ requirement, the energy cost and power peak demand could be reduced. In this paper, the optimal scheduling of smart homes’ energy consumption is studied using a mixed integer linear programming (MILP) approach. In order to minimise a 1-day forecasted energy consumption cost, DER operation and electricity-consumption household tasks are scheduled based on real-time electricity pricing, electricity task time window and forecasted renewable energy output. Peak demand charge scheme is also adopted to reduce the peak demand from grid. Two numerical examples on smart buildings of 30 homes and 90 homes with their own microgrid indicate the possibility of cost savings and electricity consumption scheduling peak reduction through the energy consumption and better management of DER operation.
1. Introduction
Due to the increase of energy demand and rising global emissions of greenhouse gases, the current centralised generation system is challenged. The future electricity distribution system will be integrated, intelligent and better known as smart grid, which includes advanced digital metres, distribution automation, communication systems and distributed energy resources. The desired smart grid functionalities include self-healing, optimising asset utilisation and minimising operations and maintenance expenses [1]. Microgrid is a relatively small-scale localised energy network, which includes loads, network control system and a set of distributed energy resources (DERs), such as generators and energy storage devices. A microgrid can operate in either grid connected or islanded mode1 when there are external faults and/or to gain economic advantage. A microgrid equipped with intelligent elements from smart grid has been adopted to enable the widespread of DERs and demand response programs in distribution systems [2], which is considered as future smart grid. Microgrid has an economic incentive due to avoiding energy purchases during peak periods and creation of carbon benefits through low-carbon/low-pollutant generation and co-production of heat and power, which has higher energy efficiency. It also provides secure and reliable energy supply during serious blackout period as a back-up energy supplying system.
6. Concluding remarks
An MILP model has been proposed for energy consumption and operation management in a smart building with multiple smart homes. Two examples of 30 homes with same living habit and 90 with different living habits for a winter day have been studied. Twelve domestic electrical tasks and equipment operations are scheduled based on given time windows, real-time half-hourly grid electricity prices and peak demand extra charge to obtain the minimum cost and energy demand. Significant cost savings and peak demand savings have been achieved in both examples.
