Chapter 6 Conclusions and Future Research Plan
6.1 Major Conclusions
As a consequence of the fast development of the smart grid in recent years, an
increasing number of DERs, smart meters and other ICT based devices have been
installed in the grid, especially in the distribution network. This vast deployment leads
to significant reduction of carbon emission, but the inherent intermittence of DERs also
brings new challenges such as demand and supply unbalance to the grid. The smart
home and building solutions provide not only the living comforts improvements and
energy optimisation to the end users but also the interaction service to the power grid
operators. The EMS, which bears the energy management work in smart homes &
buildings, contributes great power in solving the new challenges caused by the
increasing DERs and loads.
EMS helps delivering a necessary coordinating platform for the controllable loads,
DERs and the advanced tariffs to schedule their operations. This thesis has proposed a
range of solutions for individual device, individual home all the way to residential
buildings.
1. As a large energy consuming devices in residential house and commercial buildings,
the space heating & cooling system is one of most valuable loads to be controlled
and optimised by EMS. However, the current system in the market only provides
the basic control features such as timer and constant temperature control, which is
not compatible with the smart tariffs such as RTP. A GA based EMS for space
heating system has been proposed in chapter 3, fully considering the house thermal
models, residents’ living comforts and the float tariffs. With the pre-configuration
of the proposed EMS, the space heaters can operate in-advance according to the
price signals; the residents’ house will acts as a temporary thermal storage media,
which store the low-price electricity for a short-period before people come back
home, so that people can enjoy the warm environment once they get home but
spend less. The results within different prices scenarios indicate that the proposed
solution can cut the energy bills up to 36.8% for the customers without sacrificing
living comforts compared to the heaters equipped with basic control features. A
hardware based test bed has been established in the lab and the performance of the
proposed GA based EMS has been validated on the test bed.
2. For a complete EMS solution of a residential house, all the controllable loads such
as clothes dryer and water boiler, and the DERs should be taken into account.
Regarding the quick change of the loads and the DERs’ states, the optimisation
speed and accuracy of the EMS are the critical factors to be considered. In order to
been proposed in chapter 5, which combined both RTCS and RO, so that the load
scheduling will rely on not only the predicted data but also the real-time
information collected by the sensor network. In addition, the DR programs are
promoted by the energy suppliers in the distribution network, giving incentives for
an increasing number of residential houses to join the programs to earn extra
benefits. Therefore, the DR automatic response and control mechanism were
embedded in the proposed EMS control approach in order to fulfill the
requirements of the customers to join DR programs. It should be mentioned that the
BESS and PV systems, considered as the DERs installed in the home, are taken into
the optimisation as well. The numerical results presented in chapter 5 indicated that
the proposed control approach can schedule the loads such as WB and EVs to
operate during the relatively low price period and fulfill the DR events at the same
time. The BESS performs excellently in assisting the optimisation of energy
consumption, through storing spare energy of PV generation and purchasing cheap
energy from the gird in off-peak time based on FLC.
3. Compared with the EMS for a single residential house, the management of the loads
and DERs in building by aggregator tends to be more intricate. The complexity lies
in heavy scheduling work of load and DERs as well as the variety of user
requirements and conditions. Especially for the residential apartment building, the
distribution network. In order to solve the problem, an aggregator service for the
residential building was proposed in chapter 5, which coordinates and optimises the
DERs in the building. According to the predicted information of renewable energy
generation, EVs’ using pattern, electricity price and the load consumption in the
building, the aggregator generated the control plan for the EV and BESS. This
mechanism minimized the cost of electricity imported from the grid and brought
profits to the stakeholders of the DERs and residents in the building. Considering
the cheap energy exporting price of the Feed-in tariff, the inside trading of PV
generation and BESS energy proposed in chapter 5 no doubts provided much
better financial benefits to the stakeholders. The case studies in chapter 5 have
given the performance of the proposed aggregator service for the residential
building with three different kinds of tariffs. The results in all three cases validated
the effectiveness of the proposed aggregator service in shortening the pay-back
periods of the DER investments and provide cheap energy to residents.