RET_2015-01-02-03-04_Flipbook

Flexibility and demand: a distribution systems operator’s perspective - Joost Gottmer, EU affairs, EDSO for
Smart Grids
INTRODUCTION
The expansion of decentralised and variable renewable generation, together with new
consumption patterns is prompting Europe’s electricity grids to take an active role in
managing their systems. They will also need to do so in a cost-effective way that will
help them to minimise or postpone grid reinforcements. The use of flexibility will be
one of the solutions available.
As electricity could not be stored on a large-scale and cost-efficient basis, the electricity
industry has been expected to invest in increased generation, transmission and
distribution capacity to making sure that generation meets demand at all times. Our
existing electricity infrastructure has thus been designed to transport power almost
exclusively supplied by large, centralised generation plants through high-voltage lines
and down to low-voltage cables in a fairly predictable way.
Distributed energy resources (DERs) challenge the conventional way. The most
common forms of renewable energy sources (RES) i.e. solar or wind are variable: they
generate electricity only when the wind blows or the sun shines. Variable RES are likely
to cause system imbalances or deviations from voltage and thermal line limits. In areas
with low demand, where RES generation may easily exceed consumption, distribution
systems may have to be reinforced and extended to transport the excess to other
places as they reach their technical limits more quickly.
Alongside a generational shift in our electricity supply, demand is also likely to change
as new parts of our economy start to electrify i.e. heat and transport. Although in terms
of total energy demand (kWh) the development of electro-mobility may not be very
high, it can have a measurable impact on capacity (kW). Depending on their charging
time and location, electric vehicles could create potentially extreme local demand. In
the Netherlands, the market is currently at over 94.000 electric vehicles 1 purchased, but
the next decade will see a lot of new cars with battery capacities of over 60 kWh 2 and
ranges of over 300 km.
As most of distributed energy resources will be connected to distribution grids of lowvoltage
and medium-voltage levels, this has profound implications for the DSOs.
Distribution grids have not been designed for taking up large amounts of electricity, but
rather for distributing it to final customers. DSO grids need to be ready for the change
where loads follow variable generation, instead of having generation following loads as
is the situation today.
In the traditional way, DSOs would have to cope with the variable energy flows and
surges in demand by either reinforcing or extending their grids capacity and assets.
Nevertheless, conventional grid expansion may not always be the most cost-efficient. A
better alternative is to heighten the use of flexibility in power grids. This solution is also
1
BEVs (battery electric vehicles) 11,121; PHEVs (plug-in hybrids) 82,886. Source: Rijksdienst voor
Ondernemend Nederland
2 Today’s average battery capacity for electric vehicles is about 24 kWh.
Revue E Tijdschrift – 131 ste jaargang/131 e année – n° 1-2-3-4-2015 (publication mars/publicatie maart 2017)
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