Nul op de Trafo Analysis, Houtlaan, Assen

The neighborhood of Houtlaan in Assen, the Netherlands, has ambitious targets for reducing the neighborhood’s
carbon emissions and increasing their production of their own, sustainable energy. Specifically, they wish to
increase the percentage of houses with a heat pump, electric vehicle (EV) and solar panels (PV) to 60%, 70%
and 80%, respectively, by the year 2030. However, it was unclear what the impacts of this transition would be on
the electricity grid, and what limitations or problems might be encountered along the way.
Therefore, a study was carried out to model the future energy load and production patterns in Houtlaan. The
purpose of the model was to identify and quantify the problems which could be encountered if no steps are taken
to prevent these problems. In addition, the model was used to simulate the effectiveness of various proposed
solutions to reduce or eliminate the problems which were identified

Based on the model outcomes, Houtlaan’s energy transition will likely result in congestion and curtailment
problems on the local electricity grid within the next 5-7 years, possibly sooner if load imbalance between phases
is not properly addressed.
During simulations, the issue of curtailment was observed in significant quantities on one cable, resulting in a
loss of 8.292 kWh of PV production per year in 2030. This issue could be addressed by moving some of the
houses on the affects cable to a neighboring under-utilized cable, or by installing a battery system near the end of
the affected cable. Due to the layout of the grid, moving the last 7 houses on the affected cable to the neighboring
cable should be relatively simple and cost-effective, and help to alleviate issues of curtailment.
During simulations, the issue of grid overloading occurred largely as a result of EV charging. This issue can best
be addressed by regulating EV charging. Based on current statistics, the bulk of EV charging is expected to occur
in the early evening. By prolonging these charge cycles into the night and early morning, grid overloading can
likely be prevented for the coming decade. However, such a control system will require some sort of infrastructure
to coordinate the different EV charge cycles or will require smart EV chargers which will charge preferentially
when the grid voltage is above a certain threshold (i.e., has more capacity available).
A community battery system can be used to increase the local consumption of produced electricity within the
neighborhood. Such a system can also be complemented by charging EV during surplus production hours.
However, due to the relatively high cost of batteries at present, and losses due to inefficiencies, such a system
will not be financially feasible without some form of subsidy and/or unless it can provide an energy service which
the grid operator is willing to pay for (e.g. regulating power quality or line voltage, prolonging the lifetime of grid
infrastructure, etc.).
A community battery may be most useful as a temporary solution when problems on the grid begin to occur, until
a more cost-effective solution can be implemented (e.g. reinforcing the grid, implementing an EV charge control
system). Once a more permanent solution is implemented, the battery could then be re-used elsewhere.