RET_2015-01-02-03-04_Flipbook
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Flexibility and demand: a distribution systems operator’s perspective - Joost Gottmer, EU affairs, EDSO for<br />
Smart Grids<br />
INTRODUCTION<br />
The expansion of decentralised and variable renewable generation, together with new<br />
consumption patterns is prompting Europe’s electricity grids to take an active role in<br />
managing their systems. They will also need to do so in a cost-effective way that will<br />
help them to minimise or postpone grid reinforcements. The use of flexibility will be<br />
one of the solutions available.<br />
As electricity could not be stored on a large-scale and cost-efficient basis, the electricity<br />
industry has been expected to invest in increased generation, transmission and<br />
distribution capacity to making sure that generation meets demand at all times. Our<br />
existing electricity infrastructure has thus been designed to transport power almost<br />
exclusively supplied by large, centralised generation plants through high-voltage lines<br />
and down to low-voltage cables in a fairly predictable way.<br />
Distributed energy resources (DERs) challenge the conventional way. The most<br />
common forms of renewable energy sources (RES) i.e. solar or wind are variable: they<br />
generate electricity only when the wind blows or the sun shines. Variable RES are likely<br />
to cause system imbalances or deviations from voltage and thermal line limits. In areas<br />
with low demand, where RES generation may easily exceed consumption, distribution<br />
systems may have to be reinforced and extended to transport the excess to other<br />
places as they reach their technical limits more quickly.<br />
Alongside a generational shift in our electricity supply, demand is also likely to change<br />
as new parts of our economy start to electrify i.e. heat and transport. Although in terms<br />
of total energy demand (kWh) the development of electro-mobility may not be very<br />
high, it can have a measurable impact on capacity (kW). Depending on their charging<br />
time and location, electric vehicles could create potentially extreme local demand. In<br />
the Netherlands, the market is currently at over 94.000 electric vehicles 1 purchased, but<br />
the next decade will see a lot of new cars with battery capacities of over 60 kWh 2 and<br />
ranges of over 300 km.<br />
As most of distributed energy resources will be connected to distribution grids of lowvoltage<br />
and medium-voltage levels, this has profound implications for the DSOs.<br />
Distribution grids have not been designed for taking up large amounts of electricity, but<br />
rather for distributing it to final customers. DSO grids need to be ready for the change<br />
where loads follow variable generation, instead of having generation following loads as<br />
is the situation today.<br />
In the traditional way, DSOs would have to cope with the variable energy flows and<br />
surges in demand by either reinforcing or extending their grids capacity and assets.<br />
Nevertheless, conventional grid expansion may not always be the most cost-efficient. A<br />
better alternative is to heighten the use of flexibility in power grids. This solution is also<br />
1<br />
BEVs (battery electric vehicles) 11,121; PHEVs (plug-in hybrids) 82,886. Source: Rijksdienst voor<br />
Ondernemend Nederland<br />
2 Today’s average battery capacity for electric vehicles is about 24 kWh.<br />
Revue E Tijdschrift – 131 ste jaargang/131 e année – n° 1-2-3-4-<strong>2<strong>01</strong>5</strong> (publication mars/publicatie maart 2<strong>01</strong>7)<br />
3