Matching supply and demand

The challenge

Schoonschip aims for 100% renewable energy production on-site, in order to show that decentralised sustainable energy production on a local level is possible and viable. However, as long as the challenge of matching supply and demand on a local level is not addressed, the renewable energy production will never be truly local and self-sufficient, because you’ll still depend on the larger energy infrastructure to take up production surpluses and to fill up deficits. If renewable energy supply and demand can be matched at Schoonschip, it would be a huge achievement. The main disadvantage of renewable energy sources compared to traditional (fossil) sources is their variability. Solving this issue on a block level can lead the way to a more decentralized and resilient energy system.

In this overview, matching supply and demand will be addressed on two levels: the daily level and the seasonal level. For the daily match, the differences in energy supply and demand will be tracked over the course of a day. Resolving these differences will be done through demand side management and short-term energy storage. The largest challenge is presented by matching seasonal supply and demand. For this, the supply and demand will be tracked over the course of the year. Resolving these differences will be done through multi-sourcing and long-term energy storage.

Energy demand

Electricity

In an average Dutch household, the peak electricity demand is four times as high as the base electricity demand, which occurs at night. This difference may be even larger for Schoonschip, because unlike most Dutch households cooking is done with electrical cooking plates rather than gas stoves. The graph below was plotted by taking an average Dutch daily demand profile and multiplying it with the estimated total electricity demand of Schoonschip. If renewable electricity supply were constant and equally large as the demand, it would result in a surplus at night, a small deficit during daytime and a larger deficit during the evening.

Electricity demand isn’t very sensitive to seasonal changes. The main seasonal effect is caused by the increased need for lighting, and by people using their appliances slightly more in winter because they stay in more. All other demands are assumed to stay equal. In the calculation below, only the lighting demand was assumed to vary over the seasons. This provided a difference of 8.5% between the electricity demand in January and the demand in July.

Heat

The fluctuations in heat demand on a daily basis are caused by two things: the changes in inside heat demand and the changes in outdoor temperature. The required inside temperature is usually controlled by some sort of programmed thermostat, which provides a higher temperature when user activity is higher (in the mornings and in the evenings) and a lower temperature when activity is lower (during work hours and in the night). The outdoor temperature affects the heat demand as well: if outside temperatures are lower, more heat is needed to get the house to the desired temperature.

Heat demand is more sensitive to weather changes than electricity demand, and as a result will fluctuate more over the seasons. Heat demand will only be present on the coolest days in July, while in January demand is going to be high pretty much all the time.

TO DO: Ask Sam for heat supply and demand figures over the year. Also check the resolution of the heating figures: daily or hourly?

Solar electricity

Daily profile
Yearly profile

TO DO: discuss with Mathijs how important these short-term fluctuations are.

Solar heat

Solar collector production per sq. m
PV + air source/water source heat pump production per sq. m

Wind

Wind harvesting on location