Handbook of Energy Storage for Transmission or ... - W2agz.com
Handbook of Energy Storage for Transmission or ... - W2agz.com
Handbook of Energy Storage for Transmission or ... - W2agz.com
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Regenesys Electricity <strong>St<strong>or</strong>age</strong> Technology<br />
Area/Frequency Regulation<br />
EPRI Proprietary Licensed Material<br />
Interconnected utilities not only strive to regulate the frequency <strong>of</strong> their power output but also<br />
have ties with other utilities on the grid that add <strong>com</strong>plexity to the task <strong>of</strong> regulating power. In<br />
addition to experiencing fluctuations in load demand from their own customers, interconnected<br />
utilities can experience unscheduled power transfers to and from utilities in the neighb<strong>or</strong>ing area.<br />
“Area regulation” refers to the activity undertaken by utility system dispatchers to reduce the net<br />
unscheduled exchange <strong>of</strong> power between neighb<strong>or</strong>s to zero over a specified interval <strong>of</strong> time,<br />
typically 15 minutes.<br />
To achieve such area regulation, Regenesys energy st<strong>or</strong>age plants installed in the transmission<br />
system close to the load could respond to changing load conditions Instead <strong>of</strong> system operat<strong>or</strong>s<br />
dispatching “cycling” thermal power plants to adjust power flows (at significant operating<br />
expense), operat<strong>or</strong>s would dispatch the Regenesys energy st<strong>or</strong>age plant to prevent the unplanned<br />
<strong>or</strong> unscheduled transfer <strong>of</strong> power between utilities on the grid.<br />
In an isolated utility such as that on an island, large changes in electrical load (i.e., large relative<br />
to the total system capacity) affect the operating speed <strong>of</strong> generat<strong>or</strong>s at power plants.<br />
Additionally, loss <strong>of</strong> a generating plant <strong>or</strong> key transmission line would have a similar effect.<br />
Operating speeds that differ too much from 60Hz can damage the generat<strong>or</strong>s and lead to<br />
electricity that does not match the 60Hz requirements <strong>of</strong> electrical devices in the US. To<br />
regulate the frequency, a transmission <strong>com</strong>pany could install a Regenesys energy st<strong>or</strong>age system<br />
that would discharge to meet rising load (<strong>or</strong> loss <strong>of</strong> supply), and charge when loads fall-<strong>of</strong>f. In<br />
this way, the energy st<strong>or</strong>age plant would protect the generat<strong>or</strong> from fluctuations in load and<br />
prevents subsequent variations.<br />
Both frequency regulation and area regulation would require Regenesys energy st<strong>or</strong>age plants in<br />
the 10s <strong>of</strong> MWs. Both applications require about one hour <strong>of</strong> st<strong>or</strong>age to ensure that the energy<br />
st<strong>or</strong>age plant can deliver and accept power during the frequent, shallow charging and discharging<br />
that would occur during the 250 weekdays that the energy st<strong>or</strong>age plant would operate. During<br />
low demand periods (e.g., weekends <strong>or</strong> nighttime hours), when other power sources can<br />
economically provide frequency and area control, and the energy st<strong>or</strong>age plant would be<br />
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