An analysis of a demand charge electricity grid tariff in the residential sector

This paper analyzes the demand response from residential electricity consumers to a demand charge grid tariff. The tariff charges the maximum hourly peak consumption in each of the winter months Dec, Jan, and Feb, thus giving incentives to reduce peak consumption. We use hourly electricity consumption data from 443 households, as well as data on their grid and power prices, the local temperature, wind speed, and hours of daylight. The panel data set is analyzed with a fixed effects regression model. The estimates indicate average demand reductions up to 0.37 kWh/h per household in response to the tariff. This is on average a 5% reduction, with a maximum reduction of 12% in hour 8 in Dec. The consumers did not receive any information on their continuous consumption or any reminders when the tariff was in effect. It is likely that the consumption reductions would have been even higher with more information to the consumers.     

The optimization of demand response programs in smart grids

The potential to schedule portion of the electricity demand in smart energy systems is clear as a significant opportunity to enhance the efficiency of the grids. Demand response is one of the new developments in the field of electricity which is meant to engage consumers in improving the energy consumption pattern. We used Teaching & Learning based Optimization (TLBO) and Shuffled Frog Leaping (SFL) algorithms to propose an optimization model for consumption scheduling in smart grid when payment costs of different periods are reduced. This study conducted on four types residential consumers obtained in the summer for some residential houses located in the centre of Tehran city in Iran: first with time of use pricing, second with real-time pricing, third one with critical peak pricing, and the last consumer had no tariff for pricing. The results demonstrate that the adoption of demand response programs can reduce total payment costs and determine a more efficient use of optimization techniques.     

Peak-load management in steel plants

Mini steel-plants in India, using electric-arc furnaces for steel manufacturing, are highly energy intensive. In the context of increasing electricity prices and the introduction of time varying electricity rates by utilities, mini steel-plants can reschedule their operations to reduce their electricity bills. This paper presents a load model, which incorporates the characteristics of batch-type loads common to any type of process industry. The model is coupled with an optimisation formulation utilising integer programming for minimising the total electricity-cost satisfying production, process flow and storage constraints for different tariff structures. The methodology proposed can be used for determining the optimal response for any industry under time varying tariffs. The case study of a steel plant shows that significant reductions in peak-period demand (about 50%) and electricity cost (about 5.7%) are possible with optimal-load schedules. The utility can also get significant reduction in the peak coincident demand if large industries optimally reschedule their productions in response to time-of-use (TOU) tariff.     

Estimating the option value of a non-firm electricity tariff

We estimate the option value of a non-firm electricity tariff commonly used by a local distribution company (LDC) in its electricity demand response program. This option value captures the benefit that a LDC enjoys from not serving an end-use load during high-price hours in a wholesale electricity market. It is conservative in that it does not include the cost savings in meeting the LDC's resource adequacy requirement or deferring transmission and distribution (T&D) investments necessary for delivering reliable service. Illustrated by a Northern California example, our two-pronged approach entails (a) a set of summer monthly market price regressions to forecast daily spot price distributions that incorporate uncertainty in natural gas price and weather; and (b) a simulation exercise to quantify the tariff's value under a specific design. The results indicate that a non-firm service tariff can have varying option value estimates that are highly sensitive to the tariff's design, and that an incentive payment based on the option value alone is likely insufficient to attract customer participation in a non-firm service program.     

Development of a three-part time-of-day electrical energy tariff

This paper presents an analytical technique for determining peak, offpeak and midpeak hours tariffs for various durations of these three periods. The technique considers the existing flat rate tariff, an hourly generation scenario of a utility on an average yearly demand day, the weighted average life time, annutised capital cost and fuel cost of base and peak load plants, and a break even point condition in the utility's revenue. The developed tariff has been applied to 30 representative industrial consumers served by the Bangladesh Power Development Board (BPDB) to estimate the minimum possible shift in consumption pattern and hence corresponding reduction in peak generation capacity requirement as well as peak time load shedding by BPDB. © 1998 John Wiley & Sons, Ltd.     

The chilled water storage analysis for a university building cooling system

In this paper, a methodology is presented to determine the optimal chilled water storage (CWS) capacity and corresponding operating strategy for the air conditioning loads for different electricity tariff. Several scenarios were studied for the KMUTNB air conditioning system. It was concluded that the CWS with a chiller of 450 RT (2 units) running continuously, thermal-energy storage of 9413 RT-h and 5175 m³ volume was most suitable. The mechanical chiller (MAC) capacity and peak demand could be decreased by over 2 times and 31.2% respectively. It can move the energy consumption from the on peak to the off peak periods by 35.7%. The economics result showed PB, IRR and NPV are 10 y, 21% and 0.834 MUS$ compared with the existing system.     

Impact of electricity prices and volumetric water allocation on energy and groundwater demand management:: analysis from Western India

In recent years, power tariff policy has been increasingly advocated as a mean to influence groundwater use and withdrawal decisions of farmers in view of the failure of existing direct and indirect regulations on groundwater withdrawal in India. Many researchers argue that pro rata electricity tariff, with built in positive marginal cost of pumping could bring about efficient use of the resource, though some argue that the levels of tariff in which demand becomes elastic to pricing are too high to be viable from political and socio-economic points of view.The paper presents a theoretical model to analyze farmers’ response to changes in power tariff and water allocation regimes vis à vis energy and groundwater use. It validates the model by analyzing water productivity in groundwater irrigation under different electricity pricing structures and water allocation regimes. Water productivity was estimated using primary data of gross crop inputs, cost of all inputs, and volumetric water inputs. The analysis shows that unit pricing of electricity influences groundwater use efficiency and productivity positively. It also shows that the levels of pricing at which demand for electricity and groundwater becomes elastic to tariff are socio-economically viable. Further, water productivity impacts of pricing would be highest when water is volumetrically allocated with rationing. Therefore, an effective power tariff policy followed by enforcement of volumetric water allocation could address the issue of efficiency, sustainability and equity in groundwater use in India.     

Power-use profile analysis of non-domestic consumers for electricity tariff switching

For both domestic and non-domestic consumers, dynamic electricity tariffs have been proposed as a way to reduce their energy costs and to facilitate demand-side response. It is difficult for businesses which are tenants to adopt energy efficiency measures; thus, tariff switching is the easier option. Therefore, understanding the limits of the cost saving offered by tariff switching is an important step. This raises two questions: by how much could bills be reduced, and would all consumers benefit equally? Using a dataset of half-hourly electricity readings from more than 7500 British businesses, we performed an empirical analysis to discover which types of businesses might have lower or higher costs when changing between static and real-time tariffs. We identified differences in demand profiles that demonstrate that the decision whether to switch tariff types is a subtle one which may have a significant cost impact. The dataset was aggregated into five categories: Entertainment, Industry, Retail, Social, and Other. Our analytical methods can be used to distinguish the differences between typical electricity demand profiles for small- to medium-sized businesses and sectors in different market options. Our analyses of switching to a real-time tariff suggest that most of those small- to medium-sized businesses that would reduce their annual electricity bill would gain by no more than 10 %. Most of these businesses would gain by less than 5 %. This, we suggest, sets a realistic upper limit of the likely cash savings before energy efficiency, or other measures must be taken to further reduce bills.     

Support schemes and vertical integration—Who skims the cream?

This paper examines how the effectiveness of feed-in tariffs for distributed generators, producing renewable electricity, depends on industry structure, i.e., vertical integration vs. unbundling. A stylized analytical model with a monopolist and a competitive fringe (distributed generators) will be developed to analyze the impact of feed-in tariffs on renewable power production. The vertically integrated monopolist maximizes profits by setting the electricity price for residual demand and a network access charge incurred by the fringe. The fringe receives a fixed feed-in tariff per unit of electricity produced. Under vertical integration, a rise in the feed-in tariff induces the monopolist to raise access charges for fringe firms and skim part of their additional income. This partially offsets the supply increase of the fringe firms stimulated by the feed-in tariff. However, in the case of effective unbundling with an externally set access charge, there is no possibility for the monopolist to extract part of the fringe's profit. Then, the feed-in tariff fully accrues to the competitive fringe, and its supply will further increase. This setting will be extended to horizontal expansion when the monopolist also enters the renewable production segment. The effects on prices and output will be derived and compared.     

The role of hydrogen in achieving the decarbonization targets for the UK domestic sector

To meet the UK's decarbonization targets the introduction of novel integrated renewable energy generation, storage and demand management systems is required. In this paper the current role of fuel cells in the British domestic sector is discussed using simulation results of a solid oxide fuel cell (SOFC) system in a typical British single dwelling. 17% of carbon dioxide emissions are saved and 69% of the electricity generated by the SOFC system is exported to the grid for this single dwelling according to simulation results. Additionally, the same SOFC system is integrated with photovoltaic technology in a 7 home zero carbon community. The community approach adds a significant benefit given it increases the amount of electricity generated by the SOFC system which is used onsite by 128%, being the price of imported electricity 3 times higher than the export tariff. Then, a combination of short-term and long-term energy storage strategies is suggested by means of a lithium-ion battery and polymer electrolyte membrane (PEM) electrolyser which increased the self-consumption by 118%. According to simulation results, a 6 kW PEM electrolyser with an annual efficiency of 66% only generates 19% of the hydrogen which is consumed by the SOFC system which was used to meet the peak demand using PV generation.     

Reduction of electricity use in Swedish industry and its impact on national power supply and European CO2 emissions

Decreased energy use is crucial for achieving sustainable energy solutions. This paper presents current and possible future electricity use in Swedish industry. Non-heavy lines of business (e.g. food, vehicles) that use one-third of the electricity in Swedish industry are analysed in detail. Most electricity is used in the support processes pumping and ventilation, and manufacturing by decomposition. Energy conservation can take place through e.g. more efficient light fittings and switching off ventilation during night and weekends. By energy-carrier switching, electricity used for heat production is replaced by e.g. fuel. Taking technically possible demand-side measures in the whole lines of business, according to energy audits in a set of factories, means a 35% demand reduction. A systems analysis of power production, trade, demand and conservation was made using the MODEST energy system optimisation model, which uses linear programming and considers the time-dependent impact on demand for days, weeks and seasons. Electricity that is replaced by district heating from a combined heat and power (CHP) plant has a dual impact on the electricity system through reduced demand and increased electricity generation. Reduced electricity consumption and enhanced cogeneration in Sweden enables increased electricity export, which displaces coal-fired condensing plants in the European electricity market and helps to reduce European CO₂ emissions. Within the European emission trading system, those electricity conservation measures should be taken that are more cost-efficient than other ways of reducing CO₂ emissions. The demand-side measures turn net electricity imports into net export and reduce annual operation costs and net CO₂ emissions due to covering Swedish electricity demand by 200 million euros and 6 Mtonne, respectively. With estimated electricity conservation in the whole of Swedish industry, net electricity exports would be larger and net CO₂ emissions would be even smaller.     

Seasonal relationship of peak demand and energy impacts of energy efficiency measures—a review of evidence in the electric energy efficiency programmes

While energy efficiency programmes traditionally focus on energy savings, there is also a policy interest in their impact on system peak demand. Examples include demand-side management, integrated resource planning and recent developments to integrate energy efficiency into forward capacity markets. However, there is only limited research on the relationship between peak demand impacts and overall energy savings from efficiency measures, although this relationship can have important bearings on efficiency programmes. This paper reviews utility efficiency programmes in nine jurisdictions in North America and analyses how the seasonal peak-energy relationship differs between commercial and industrial (C&I) and residential sectors, among efficiency measures. In terms of the seasonal difference in peak demand impacts, these programmes show that residential lighting and residential water heating can deliver greater peak savings in weekday early evening winter peak periods. By contrast, C&I lighting and residential appliances make higher peak savings in weekday afternoon summer peak periods. A seasonal difference is more significant in lighting, especially residential lighting, than other measures. The evidence from North America also suggests that space cooling in both sectors and C&I lighting may well make greater peak savings relative to non-peak impacts than other measures during summer peak periods, while in winter peak periods, residential lighting can achieve greater peak savings relative to non-peak impacts. This review highlights the significance of regional electricity use patterns along with climatic and regulatory conditions and indicates how further research may contribute to appropriate electricity demand reduction programme design and monitoring regimes in particular regions.     

Shadow prices for heat generation in time-dependent and dynamic energy systems

Shadow prices for heat generation are used to study the impact of changes in heat demand on the total system cost of an existing district-heating system in Sweden. The energy system may be considered to be both dynamic, because there is energy storage, and time-dependent since the electricity tariff is time-differentiated and the heat demand varies over the year and day. The energy system has been analysed with and without energy storage. The analysis shows that despite a reduction in system cost, the use of energy storage can result in higher shadow prices for heat generation in some time periods.     

Can poor consumers pay for energy and water? An affordability analysis for transition countries

Low-income households spend a substantial share of their income on utility services such as electricity, heating and water. The difficulty of these socially vulnerable consumers to absorb further price increases is often used as an argument against tariff reform. However, detailed quantitative information on the affordability of tariff adjustments for low-income consumers is actually quite scarce. Much of the available information is based on households. This paper takes a more detailed look at the affordability of electricity, district heating and water for low-income consumers in transition countries. While the available data are incomplete, the paper finds that affordability is a problem for low-income consumers in most countries, in particular in the water sector and in the Commonwealth of Independent States (CIS). The affordability consequences of tariff reform ultimately depend on the speed of tariff adjustments relative to the growth in household income, the level of tariffs needed for cost recovery, the level of effective tariffs at the outset (tariffs adjusted for non-payment) and the demand response to the tariff increase. The paper finds that delaying tariff reform by a few years makes little difference to affordability constraints, and may therefore not be an effective way to mitigate the social impact of utility reform.     

Extreme daily increases in peak electricity demand: Tail-quantile estimation

A Generalized Pareto Distribution (GPD) is used to model extreme daily increases in peak electricity demand. The model is fitted to years 2000–2011 recorded data for South Africa to make a comparative analysis with the Generalized Pareto-type (GP-type) distribution. Peak electricity demand is influenced by the tails of probability distributions as well as by means or averages. At times there is a need to depart from the average thinking and exploit information provided by the extremes (tails). Empirical results show that both the GP-type and the GPD are a good fit to the data. One of the main advantages of the GP-type is the estimation of only one parameter. Modelling of extreme daily increases in peak electricity demand helps in quantifying the amount of electricity which can be shifted from the grid to off peak periods. One of the policy implications derived from this study is the need for day-time use of electricity billing system similar to the one used in the cellular telephone/and fixed line-billing technology. This will result in the shifting of electricity demand on the grid to off peak time slots as users try to avoid high peak hour charges.     

Short- and long-run time-of-use price elasticities in Swiss residential electricity demand

This paper presents an empirical analysis on the residential demand for electricity by time-of-day. This analysis has been performed using aggregate data at the city level for 22 Swiss cities for the period 2000−2006. For this purpose, we estimated two log–log demand equations for peak and off-peak electricity consumption using static and dynamic partial adjustment approaches. These demand functions were estimated using several econometric approaches for panel data, for example LSDV and RE for static models, and LSDV and corrected LSDV estimators for dynamic models. The attempt of this empirical analysis has been to highlight some of the characteristics of the Swiss residential electricity demand. The estimated short-run own price elasticities are lower than 1, whereas in the long-run these values are higher than 1. The estimated short-run and long-run cross-price elasticities are positive. This result shows that peak and off-peak electricity are substitutes. In this context, time differentiated prices should provide an economic incentive to customers so that they can modify consumption patterns by reducing peak demand and shifting electricity consumption from peak to off-peak periods.     

Air-conditioning Australian households: The impact of dynamic peak pricing

International mandates for smart metering are enabling variable and real-time pricing regimes such as dynamic peak pricing (DPP), which charges 10–40 times the off-peak rate for electricity during short periods. This regime aims to reduce peak electricity demand (predominantly due to increase in residential air-conditioning usage) and curb greenhouse gas emissions. Although trials indicate that DPP can achieve significant demand reductions, particularly in summer, little is known about how or why households change their cooling practices in response to this strategy. This paper discusses the outcomes of a small qualitative study assessing the impact of a DPP trial on household cooling practices in the Australian state of New South Wales. The study challenges common assumptions about the necessity of air-conditioning and impact of price signals. It finds that DPP engages households as co-managers of their cooling practices through a series of notification signals (SMS, phone, in-home display, email, etc.). Further, by linking the price signal to air-conditioning, some householders consider this practice discretionary for short periods of time. The paper concludes by warning that policy makers and utilities may serve to legitimise air-conditioning usage and/or negate demand reductions by failing to acknowledge the non-rational dynamics of DPP and household cooling practices.     

Price,environment and security: Exploring multi-modal motivation in voluntary residential peak demand response

Peak demand on electricity grids is a growing problem that increases costs and risks to supply security. Residential sector loads often contribute significantly to seasonal and daily peak demand. Demand response projects aim to manage peak demand by applying price signals and automated load shedding technologies. This research investigates voluntary load shedding in response to information about the security of supply, the emission profile and the cost of meeting critical peak demand in the customers’ network. Customer willingness to change behaviour in response to this information was explored through mail-back survey. The diversified demand modelling method was used along with energy audit data to estimate the potential peak load reduction resulting from the voluntary demand response. A case study was conducted in a suburb of Christchurch, New Zealand, where electricity is the main source for water and space heating. On this network, all water heating cylinders have ripple-control technology and about 50% of the households subscribe to differential day/night pricing plan. The survey results show that the sensitivity to supply security is on par with price, with the emission sensitivity being slightly weaker. The modelling results show potential 10% reduction in critical peak load for aggregate voluntary demand response.     

A review on cool thermal storage technologies and operating strategies

The thermal energy storage (TES) system for building cooling applications is a promising technology that is continuously improving. The TES system can balance the energy demand between the peak (daytimes) and off-peak hours (nights). The cool-energy is usually stored in the form of ice, phase change materials, chilled water or eutectic solution during the nighttimes and used in the daytime. A well-designed TES system would effectively decrease the electricity demand with a reasonable cost. This paper summarizes the findings, investigations and analysis of the TES systems for the space cooling applications. In this regards, different types of storage technologies, as well as various operating strategies, are discussed and some of the outstanding case studies are presented. Since the TES system can provide any portion of the required cooling load, the designer must focus on the best practical and economical solution, which is mainly influenced by localized parameters. It is evident that to improve the available designing standard, a sustainable investigation on localized parameters such as the electricity demand trend, the peak and off-peak hours, the climate change profiles, the electricity tariff rate and the system setup costs are still required.     

The pricing of off-peak power

Benefit-cost analysis is used to show that even with only one electricity production technique, marginal cost pricing of electricity in a firm off-peak period might reduce social welfare rather than improve it. This may occur when there are more periods with dissimilar demands for power than feasible prices for electricity. Thus the conclusion is reinforced that it may be more important to charge a higher price for electricity during periods of peak demand than a price equal to marginal running costs during the most off-peak hours.