This paper presents an insight into end-users' perception of smart grid products for households. The analysed products included three types of home energy management products (HEMPs) namely: smart thermostats, smart plugs and smart wall sockets. The analysis involved existing commercial HEMPs, as well as newly designed HEMPs from a students' project executed at University of Twente (Netherlands) in 2013 and 2014. Various industrial design methods were applied, and an online survey was utilised for data collection. The smart thermostat was considered the product with the greatest potential to stimulate energy-efficient behaviour. Features most preferred by end-users are: 1) visual display of energy information; 2) monitoring of energy use of appliances; 3) remote control, and expected ease of use. Appearance also appeared to have influenced the preferences of end-users regarding specific HEMPs. This study highlights the main features that household end-users desire in products that could stimulate energy-efficient behaviour.@en

Two residential Smart Grid pilots, PowerMatching City, Groningen (NL) and Pecan Street, Austin Texas (USA) have been compared regarding their energy performance and the experiences of users in these pilots. The objective of the comparison was to gain new insights that could support the successful deployment of future residential Smart Grids. Measured data on electricity generation and electricity consumption of households in 2013 and 2014 were evaluated. Existing reports with results of surveys of users were also analyzed. The energy performance revealed that the average domestic electricity consumption of households in PowerMatching City was lower compared to Pecan Street (2.6 GW h versus 10.1 GW h). At the same time, households in Pecan Street generated a higher amount of electricity compared to PowerMatching City (6.8 GW h versus 1.14 GW h). Households in Pecan Street consumed on average, 8% less electricity with respect to the USA average household domestic electricity consumption of 10.9 GW h; while households in PowerMatching City consumed 19% less electricity compared to the Dutch average household domestic electricity consumption of 3.1 GW h. Households in PowerMatching City appeared to have a higher potential to contribute to electricity demand and supply balancing, because their electricity consumption from the grid was largely reduced with increased self-generation. User experiences revealed that end-users in both pilots preferred technologies that automatically shift their energy use, since this requires minimal effort from them. We conclude that the pattern of households’ electricity generation and consumption in Smart Grid pilot projects, and their contribution to peak load balancing in the electricity network is largely influenced by existing Smart Grid set-ups, local climate and related needs for heating and cooling, the average capacity of installed energy generating technologies and the prevailing energy behavior.

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This article presents a simple comparative model which has been developed for the estimation of the performance of photovoltaic (PV) products' cells in indoor environments. The model predicts the performance of PV solar cells, as a function of the distance from a spectrum of artificial (fluorescent light, halogen light, and light-emitting diodes) and natural light. It intends to support designers, while creating PV-integrated products for indoor use. For the model's validation, PV cells of 12 commercially available PV-powered products with power ranging from 0.8 to 4 mWp were tested indoors under artificial illumination and natural light. The model is based on the physical measurements of natural and artificial irradiance indoors, along with literature data of PV technologies under low irradiance conditions. The input data of the model are the surface of the solar cell (in m2), the wavelength-dependent spectral response (SR) of the PV cell, the spectral irradiance indoors, and solar cell's distance from light sources. The model calculates solar cells' efficiency and power produced under the specific indoor conditions. If using the measured SR of a PV cell and the irradiance as measured indoors, the model can predict the performance of a PV product under mixed indoor light with a typical inaccuracy of around 25%, which is sufficient for a design process. Measurements revealed that under mixed indoor lighting of around 20 W/m2, the efficiency of solar cells in 12 commercially available PV products ranges between 5% and 6% for amorphous silicon (a-Si) cells, 4–6% for multicrystalline silicon (mc-Si) cells, and 5–7% for the monocrystalline silicon (c-Si) cells.@en

In order to better understand how ‘lead-users’ interact with PV-powered products, the behaviour of 100 people interacting with six different PV-powered products in their daily life was analysed. The sample of respondents to be observed consisted of 20 groups, each one formed by five students of Industrial Design Engineering at Technical University of Delft (TU Delft). The tested PV products are: the IKEA Sunnan lamp, the Waka Waka light, the Waka Waka power (charger and light), the Little Sun light, the Logitech solar keyboard and the Beurer kitchen weight scale. In this study the design of the six tested PV products was analysed, lead-users’ expectations were outlined, as well as their opinion of the products’ performance during and after use was addressed. Results show that respondents need reliable PV products with appealing design and improved performance.@en

The transition of the electricity system to smart grids requires residential end-users to be more involved in managing energy demand and supply. New innovative products and services could help to support end-users to play a more active role in the management of the future electric power system. This paper evaluates the role of Industrial Design Methods (IDMs) in the development of new innovative smart grid related product concepts at the household level. Based on students' design projects, carried out within a master study programme, various IDMs were systematically utilized to develop new innovative products for smart grid households. Our study shows that five IDMs, namely: platform-driven product development, delft innovation model, theory of inventive problem solving, technology roadmapping, and innovative design and styling were mainly applied in the development of the conceptual products. This study shows that a thorough and careful application of various IDMs helped to develop inspiring potential smart grids product concepts that could support end-users at the household level to gain more insight into their energy use, and contribute to balancing energy demand and supply. These concepts include various in-home displays, smart plugs, and smart wall sockets. The resulting product concepts are presented in this paper. We conclude that the systematic use of various IDMs helped to identify and incorporate various technological, societal, market, and end-user aspects necessary for creating innovative smart grid related products that meet end-user and future market expectations.@en