Page 20 - CARILEC CE Journal CENOV 2021

Spinning reserves are on standby at all times, ready to start and reach full power inside two minutes,
to provide extra power for a surge in demand or quickly taking over the load initially supplied by the
in the event that a generation asset unexpectedly ESS.
goes offline. Using power generation assets for this
purpose is costly, because idling engines burn fuel. The energy storage system is also an asset that
Instead, the ESS will provide this service, freeing up provides voltage and frequency regulation. With
the engines to run in their most efficient mode when an energy storage system on the grid, excess or
producing electricity. The addition of energy storage insufficient power is absorbed or supplied to provide
will reduce fuel and maintenance costs for the utility. a ‘smoother’ electricity supply and preserve grid
infrastructure.
The ESS also serves as spare capacity in the case All these features will effectively increase the service
of an undesired event on the grid – for example, if quality experienced by the customers of the utility.
a hurricane strikes and takes out transmission or
distribution infrastructure, or an engine generating OPTIMAL DISPATCHING
set becomes unavailable for short periods of time. It Impressive as these individual components are,
is not designed to replace generation assets, but to the real star of the show is the GEMS Power
provide the vital two-hour window for the utility to Plant Controller, a product of the Wärtsilä GEMS
bring other generators online. Platform Suite. GEMS is an intelligent energy asset

The ESS also offers grid forming and ‘black-start’ management system that will not only provide a
capabilities, which are critical for vulnerable regions single interface to control the operation of the new
like the island of St.Thomas, where aging generators multi-fuel engines and the energy storage system,
used to restart a plant may become unavailable over but will also integrate and synchronise all the other
time. To prevent blackouts across the island, GEMS power generation assets on the St. Thomas island
can provide a response as fast as in 50 milliseconds. grid and ‘optimise’ dispatching – in other words, the
If a contingency event becomes unavoidable and system will carry out full grid management.
causes a loss of connection between generators
and the loads, the ESS black-start function allows the Wärtsilä’s GEMS conducts this synchronisation in
inverter to generate a sine wave for itself allowing, the most efficient way possible, by matching the
for instance, Wärtsilä’s 32LG engine generating sets electricity load with generation, so that supply equals

20