SCCER-FURIES - Determination of the flexibilisation potential of the electricity demand. ReEL D114b

The mismatch between household electricity consumption and solar energy production is a key issue for the fast deployment of this technology in a low-voltage grid. Namely, as high photovoltaic generation occurs during the day while the load remains low, the power flow can be reversed from the low-voltage grid to the medium voltage grid. This is a key parameter in the limitation of the photovoltaic hosting capacity. \ In order to increase the penetration of solar energy in a low-voltage network, demand-side management is a promising solution. The principle is to encourage customers to shift their load toward high photovoltaic generation periods in exchange for a financial reward. Namely, time-of-use tariffs can be used as an incentive. \ This report presents a field experiment, in which the flexibility potential of household electricity consumption is assessed. Additionally, the impact of this behavioural flexibility is evaluated on the extension of a low-voltage grid photovoltaic hosting capacity. The electricity consumption of about 600 households was analyzed over a period of more than 3 years. The load curves are coming from smart meter data at a 15 min resolution allowing to study the intraday consumption patterns.\ The theoretical potential for flexible consumption is evaluated through a dedicated methodology based on non-intrusive load monitoring. It is estimated to be as high as 24% of the total energy consumption. The practical flexibility is evaluated by studying the households reaction to two different financial incentives. A first treatment group was facing a reduction of the electricity price of 15 cts/kWh between 11 am and 3 pm compared to the normal price, while the price was increased by 4 cts/kWh during the remaining of the day. A second treatment group was facing alternative pricing in a form of time-of-use pricing. Every night households received a short-text message (SMS) informing them of the time of the low rate period for the next day, that could potentially range from 10 am to 7 pm. Both treatment groups reaction are compared to a reference control group which receive no information about the experiment. The results showed a moderated reaction of the households. The increase in consumption during low rate period is marginal and doesn't necessarily involve a reduction in consumption during the rest of the day. Additionally, there are significant differences in reaction between the households. Although the financial incentive is significant, the potential gain is rather small and there was no possibility for loss as the households were guaranteed to pay at most the monthly bill calculated with their reference electricity price. \ The gain in photovoltaic hosting capacity and penetration rate thanks to the theoretical demand flexibility was assessed to reach 20% while keeping the same total cost of energy with respect to the reference case without flexibility. In this case, it means that the flexibility does not bring any additional revenue. However, as the levelized cost of electricity decreases with respect to the feed-in tariff, the potential revenue generated by the flexibility increases. As an alternative solution, curtailing the exceeding photovoltaic generation always comes with a cost and thus cannot compete with the flexibility to increase the solar energy penetration rate.