Ted Spooner

Coordinated Scheduling of Residential Distributed Energy Resources to Optimize Smart Home Energy Services

We describe algorithmic enhancements to a decision-support tool that residential consumers can utilize to optimize their acquisition of electrical energy services. The decision-support tool optimizes energy services provision by enabling end users to first assign values to desired energy services, and then scheduling their available distributed energy resources (DER) to maximize net benefits. We chose particle swarm optimization (PSO) to solve the corresponding optimization problem because of its straightforward implementation and demonstrated ability to generate near-optimal schedules within manageable computation times. We improve the basic formulation of cooperative PSO by introducing stochastic repulsion among the particles. The improved DER schedules are then used to investigate the potential consumer value added by coordinated DER scheduling. This is computed by comparing the end-user costs obtained with the enhanced algorithm simultaneously scheduling all DER, against the costs when each DER schedule is solved separately. This comparison enables the end users to determine whether their mix of energy service needs, available DER and electricity tariff arrangements might warrant solving the more complex coordinated scheduling problem, or instead, decomposing the problem into multiple simpler optimizations.

Inverters for single-phase grid connected photovoltaic systems-an overview

An overview on developments and a summary of the state-of-the-art of inverter technology in Europe for single-phase grid-connected photovoltaic (PV) systems for power levels up to 5 kW is provided in this paper. The information includes details not only on the topologies commercially available but also on the switching devices employed and the associated switching frequencies, efficiency, price trends and market share. Finally, the paper outlines issues associated with the development of relevant international industry standards affecting PV inverter technology.

Scheduling of Demand Side Resources Using Binary Particle Swarm Optimization

Interruptible loads represent highly valuable demand side resources within the electricity industry. However, maximizing their potential value in terms of system security and scheduling is a considerable challenge because of their widely varying and potentially complex operational characteristics. This paper investigates the use of binary particle swarm optimization (BPSO) to schedule a significant number of varied interruptible loads over 16 h. The scheduling objective is to achieve a system requirement of total hourly curtailments while satisfying the operational constraints of the available interruptible loads, minimizing the total payment to them and minimizing the frequency of interruptions imposed upon them. This multiobjective optimization problem was simplified by using a single aggregate objective function. The BPSO algorithm proved capable of achieving near-optimal solutions in manageable computational time-frames for this relatively complex, nonlinear and noncontinuous problem. The effectiveness of the approach was further improved by dividing the swarm into several subswarms. The proposed scheduling technique demonstrated useful performance for a relatively challenging scheduling task, and would seem to offer some potential advantages in scheduling significant numbers of widely varied and technically complex interruptible loads.

The value of accurate forecasts and a probabilistic method for robust scheduling of residential distributed energy resources

We describe a decision-support tool that optimizes the energy services of residential end-users by scheduling the operation of available distributed energy resources. We discuss the application of the tool to a ‘smart’ home case study and the solution to the resulting highly-dimensional scheduling problem. We then use the optimal schedules formulated by the tool to determine the value of the forecasted information used when the schedules are created. This is achieved by computing the additional costs avoided by the end-users due to the accuracy of the forecasts. We also demonstrate how to use the tool to derive robust schedules when the end-users are not certain on the magnitude of solar insolation, magnitude of energy service demands, availability of a plug-in hybrid vehicle as storage, and status of Critical Peak Pricing. The robust schedule is derived by maximizing the expected net benefit when the schedule is applied to all likely scenario outcomes.

Ensuring the reliability of PV systems through the selection of international standards for the IECRE conformity assessment system

One of the key issues facing the PV industry, and renewable energy in general, is the need to assure investors of the value of their system. As one means of accomplishing this goal, the International Electrotechnical Commission (IEC) has decided to establish a new system for conformity assessments of renewable energy projects (IECRE). An important requirement for the new IECRE system is to establish which international or national standards should be used as the basis for conformity assessments. This paper presents a technical analysis of the available standards, and identification of gaps where new standards are needed.

Coordination of international standards with implementation of the IECRE conformity assessment system to provide multiple certification offerings for PV power plants

To help address the industrys needs for assuring the value and reducing the risk of investments in PV power plants; the International Electrotechnical Commission (IEC) has established a new conformity assessment system for renewable energy (IECRE). There are presently important efforts underway to define the requirements for various types of PV system certificates, and publication of the international standards upon which these certifications will be based. This paper presents a detailed analysis of the interrelationship of these activities and the timing for initiation of IECRE PV system certifications.

Ensuring the reliability of PV systems through the formation of the IECRE Conformity Assessment System and the development of new International Standards

One of the key issues facing the PV industry, and renewable energy in general, is the need to assure investors of the value of their system. As one means of accomplishing this goal, the International Electrotechnical Commission (IEC) has established a new system for conformity assessments of renewable energy projects (IECRE). An important activity supporting the new IECRE system is the development of new international or national standards to be used as the basis for conformity assessments. This paper presents a summary of IECRE activities to date, a review of gaps where new standards are needed, and the latest status of efforts to fill these gaps.

Investigating the value of making hourly operational decisions for residential distributed energy resources

We investigate the value of making hourly operational decisions for residential distributed energy resources such as interruptible and shiftable appliances and energy storage. The value is determined by computing the savings achieved when making hourly decisions and comparing it to the savings achieved when making day-ahead decisions. These decisions, or schedules, are formulated considering the uncertainties in energy service demand and status of dynamic peak pricing. The robust schedules are generated using an energy service decision support tool we have presented in an earlier paper. We used the tool to formulate day-ahead schedules by maximizing the expected net benefit of the consumer over an optimal set of scenarios that represents the range of uncertainty, and the results were presented in another paper. In this paper, we used the tool to implement hour-by-hour decision-making by applying the rolling horizon model to the optimal scenario set approach. Based on the scenarios we simulated, the average savings is not significant enough to favor it over day-ahead scheduling. The day-ahead schedules, therefore, are already robust and improving it by making hourly decisions savings may not be enough to recover the expenses for the effort and equipment required to support real-time decision-making.

Whole System Design of an Energy Efficient Residential Pool System

The impact of low-speed filtration on the performance of salt water chlorinators, pool cleaners, and the pool water quality, based on experimental and modelled data, is investigated. Results show that a typical salt water chlorinator and pressure pool cleaner do not work well for flow rates of less than 1 litre s and 1.3 litre s respectively. With the implementation of a robotic pool cleaner, energy savings of more than 70% can be obtained by operating the filtration system at around 1 litre s with a correctly adjusted chlorinator setting. This does not compromise the system performance and achieves a largely improved water quality. Furthermore, it is shown that a small photovoltaic system can provide nearly all the energy required by such energy efficient pool system. This PV powered pool filtration system achieves a discounted payback period (DPP) of 5.4 years in comparison to the grid supplied pool filtration system (the Business as Usual (BAU) scenario).