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| 1 |
ID:
090076
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2009.
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| Summary/Abstract |
In Norway there is a growing concern that electricity production and transmission may not meet the demand in peak-load situations. It is therefore important to evaluate the potential of different demand-side measures that may contribute to reduce peak load. This paper analyses data from an experiment where residential water heaters were automatically disconnected during peak periods of the day. A model of hourly electricity consumption is used to evaluate the effects on the load of the disconnections. The results indicate an average consumption reduction per household of approximately 0.5 kWh/h during disconnection, and an additional average increase in consumption the following hour, due to the payback effect, that may reach up to 0.28 kWh/h per household.
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| 2 |
ID:
117309
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2013.
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| Summary/Abstract |
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.
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| 3 |
ID:
121276
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2013.
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Many pre-existing air conditioner load control programs can provide valuable operational flexibility but have not been incorporated into electricity ancillary service markets or grid operations. Multiple demonstrations have shown that residential air conditioner (AC) response can deliver resources quickly and can provide contingency reserves. A key policy hurdle to be overcome before AC load control can be fully incorporated into markets is how to balance the accuracy, cost, and complexity of methods available for the settlement of load curtailment. Overcoming this hurdle requires a means for assessing the accuracy of shorter-term AC load control demand reduction estimation approaches in an unbiased manner. This paper applies such a method to compare the accuracy of approaches varying in cost and complexity - including regression analysis, load matching and control group approaches - using feeder data, household data and AC end-use data. We recommend a practical approach for settlement, relying on an annually updated set of tables, with pre-calculated reduction estimates. These tables allow users to look up the demand reduction per device based on daily maximum temperature, geographic region and hour of day, simplifying settlement and providing a solution to the policy problem presented in this paper.
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| 4 |
ID:
098564
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2010.
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| Summary/Abstract |
This study investigates consequences of integrating plug-in hybrid electric vehicles (PHEVs) in a wind-thermal power system supplied by one quarter of wind power and three quarters of thermal generation. Four different PHEV integration strategies, with different impacts on the total electric load profile, have been investigated. The study shows that PHEVs can reduce the CO2-emissions from the power system if actively integrated, whereas a passive approach to PHEV integration (i.e. letting people charge the car at will) is likely to result in an increase in emissions compared to a power system without PHEV load. The reduction in emissions under active PHEV integration strategies is due to a reduction in emissions related to thermal plant start-ups and part load operation. Emissions of the power sector are reduced with up to 4.7% compared to a system without PHEVs, according to the simulations. Allocating this emission reduction to the PHEV electricity consumption only, and assuming that the vehicles in electric mode is about 3 times as energy efficient as standard gasoline operation, total emissions from PHEVs would be less than half the emissions of a standard car, when running in electric mode.
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| 5 |
ID:
109448
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2011.
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| Summary/Abstract |
As a strategy to deal with the increasing intermittent input of renewable energy sources in Germany, the adaptation of power consumption is complementary to power-plant regulation, grid expansion and physical energy storage. One demand sector that promises strong returns for load management efforts is cooling and refrigeration. In these processes, thermal inertia provides a temporal buffer for shifting and adjusting the power consumption of cooling systems. We have conducted an empirical investigation to obtain a detailed and time-resolved bottom-up analysis of load management for refrigeration systems in the city of Mannheim, Germany. We have extrapolated our results to general conditions in Germany. Several barriers inhibit the rapid adoption of load management strategies for cooling systems, including informational barriers, strict compliance with legal cooling requirements, liability issues, lack of technical experience, an inadequate rate of return and organizational barriers. Small commercial applications of refrigeration in the food-retailing and cold storage in hotels and restaurants are particularly promising starting points for intelligent load management. When our results are applied to Germany, suitable sectors for load management have theoretical and achievable potential values of 4.2 and 2.8 GW, respectively, amounting to about 4-6% of the maximum power demand in Germany.
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| 6 |
ID:
121281
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2013.
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| Summary/Abstract |
New developments towards a more sustainable energy delivery system require electricity distribution grids that support distributed generation and a potential increase in electricity demand. In this article, the impact of changes in future residential use on the electricity distribution grids is assessed by using a scenario-based methodology to model residential loads. It illustrates that scenarios resulting from varied economic and demographic developments, but also driven by the focus of energy policies, can have considerable consequences on the loading and the resulting required network capacities of electricity distribution grids. A strategy for network operators to cope with these changes and optimise the utilisation of their grids is to use the possibilities to control flexible loads to reduce peak loads and shift demands. This article shows that if these loads can be managed in such way, the electricity profiles can be flattened significantly. For the case of the Netherlands, the peak demands in residential areas can be reduced with 35-67% in various scenarios. Load-flow analyses of medium voltage networks show that a load management strategy to reduce peak demands can realise a reduction of 21-40% for required capacity of cables and transformers. This makes a reduction 45-72% in investment costs possible.
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| 7 |
ID:
088988
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| Publication |
2009.
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| Summary/Abstract |
Shifting domestic load to off-peak time periods could potentially reduce electrical distribution losses and associated carbon emissions. This paper provides the first quantitative estimate of the possible reduction in losses, for a situation where domestic energy demand is shifted in time but not reduced. At a likely 0.02% of energy distributed by the network, the reduction is small relative to overall losses and to their variability, giving little rationale for distribution network operators in Great Britain to encourage such load-shifting for that reason. The paper also considers the limited regulatory incentives for the reduction, and the fragmentation of costs and benefits across different parties. The societal value is considerably higher than the current regulatory incentive, but nonetheless may still not warrant the cost of action. Reducing rather than shifting load is likely to give greater environmental benefits.
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