Different domains of knowledge — namely, telecommunications, electrotechnics, mechanics, automation, informatics, sociology, architecture — were necessary for planning and building the PREMIO platform. The project partners brought their own languages and unique understanding of the project specifications along with their own priorities. The use cases developed during the project were useful in defining the scope of the project, harmonizing specifications and common understanding between partners, as well as defining a common language for effective collaboration.
Feedback from the DER installation period shows host customers must be kept informed as much as possible during the installation phase and be associated with the project during the operational phase. Even though the performance of most of the technologies is supposed to be imperceptible by the host customers (load shedding, Optilesteur and Pulssi, for example), they are the closest to the devices and want information about the different steps of the project and the operation of their DER. They also want to understand the purpose of the intervention and be aware when installed devices are operating. This basic information can improve customer acceptance of these new technologies.
The installation phase highlighted the importance of subcontractors and subcontractor training to the PREMIO project. For the most part, the devices used in PREMIO were new to the subcontractors tasked with the installation, and a lengthy learning curve can bring misunderstanding and delay. For example, temperature measurements inside residential homes are needed to guarantee host customer comfort and evaluate the acceptability of the devices.
It is important for temperature sensors to be placed in an area with a representative of the host-customer comfort; however, in some cases, because of ease of installation or a host-customer suggestion, the subcontractor installed the temperature sensor in an unsuitable location. Moreover, subcontractors are the point of contact with the host-customer and bring their field experience to the project partners. From the perspective of a smart grid deployment rollout, subcontractor training should be a priority.
PREMIO Rollout Program
PREMIO began its operation during the winter of 2010-2011. This period was mostly dedicated to testing, establishing improved devices, learning how the new DER technologies behave and identifying potential problems. It is important to note the PREMIO project enabled a qualitative more than a quantitative assessment of the results, mainly because of the low number of DER units installed.
DERs responded to requests sent by the control unit, and load reductions issued from direct control were effective. Control unit optimization and request dispatch processes were validated. The variation between power requested and effective load reduction (often less than requested) was, in most cases, because of underestimation or overestimation of load reduction capacity. Load-reduction accuracy varies depending on the DER considered.
Because of the high level of uncertainty in the residential sector’s electrical demand, accurate forecasting for individual capacity seems to be difficult. Research in this field is ongoing and a certain level of aggregation to estimate capacity for this type of DER should be considered.
Microscope technology — 4.8-kWh batteries and photovoltaic panels to store and provide electricity to the grid — was the first DER to be connected in the PREMIO platform and be fully operational. This demonstrated microscope technology’s ease of integration into a smart grid, compared to other DERs. This technology can charge and discharge electric power — on average, 700 W per system, but many systems are installed per site — according to the needs of the electrical power system, such as increased generation or voltage regulation.
For example, initial feedback from the field showed the impact of several factors, including battery damage from deep discharge, thermal losses from overloads and variations in the system efficiency of different types of batteries. The use of open lead batteries entails frequent maintenance operations (every two to three months), but replacing them with sealed lead batteries reduced maintenance costs but introduced challenges in regulation, such as taking into account battery temperature. In addition, microscope technology’s range of power and energy could be increased by using 10-kWh batteries able to deliver 2 kW to 3 kW. These batteries are the subject of future development of this technology.