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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EPRI Proprietary Licensed Material<br />
Prospects <strong>f<strong>or</strong></strong> Success<br />
The key issue <strong>f<strong>or</strong></strong> the VRB will be system reliability. The VRB can be packaged and<br />
controlled <strong>f<strong>or</strong></strong> this application, and could be a very effective load management tool.<br />
However, in <strong>or</strong>der <strong>f<strong>or</strong></strong> the VRB to be successful, it must demonstrate a level <strong>of</strong> reliability<br />
that is <strong>com</strong>parable to substation trans<strong>f<strong>or</strong></strong>mers and other T&D equipment. Given that the<br />
VRB inc<strong>or</strong>p<strong>or</strong>ates equipment (e.g., pumps, power electronics) <strong>f<strong>or</strong></strong> which there is little <strong>or</strong><br />
no experience with failure modes and effects in the substation environment, this may be<br />
difficult to verify in the near term. Extended field experience will be required to validate<br />
this level <strong>of</strong> reliability.<br />
3.3. Spinning Reserve<br />
Description<br />
Grid operat<strong>or</strong>s increasingly procure ancillary services in open <strong>com</strong>petitive markets, either<br />
in long-term contracts <strong>or</strong> in daily auctions. These services provide stability to the grid in<br />
the event <strong>of</strong> loss <strong>of</strong> generation units. F<strong>or</strong> example, the Cali<strong>f<strong>or</strong></strong>nia Independent System<br />
Operat<strong>or</strong> (CAISO) auctions four services as shown in Table 4:<br />
Table 4<br />
CAISO Reserve Power Definitions<br />
Regulation Reserves<br />
Generation that is on-line and synchronized with the<br />
ISO control grid so that the power can be increased <strong>or</strong><br />
decreased instantly by the energy management system<br />
(EMS) through automatic generation control (AGC).<br />
Regulation is used to maintain continuous balance <strong>of</strong><br />
resources and load to maintain frequency during n<strong>or</strong>mal<br />
operating conditions.<br />
Spinning Reserves<br />
Generation that is already on-line and "spinning" with<br />
additional capacity, capable <strong>of</strong> ramping over a specified<br />
range within 10 minutes and running <strong>f<strong>or</strong></strong> at least two<br />
hours.<br />
Non-spinning Reserves<br />
Generation that is available but not on-line. This<br />
generation must be capable <strong>of</strong> starting, synchronizing<br />
with the grid, and ramping to a specified level within 10<br />
minutes, and it must be capable <strong>of</strong> running <strong>f<strong>or</strong></strong> at least<br />
two hours. Effectively, non-spinning reserves provide<br />
the same benefit to the ISO as spinning reserves, but<br />
differ only in that non-spinning reserves are not kept online<br />
continuously.<br />
Replacement Reserves<br />
Generation that is capable <strong>of</strong> starting up (if not already<br />
operating), synchronizing with the grid, ramping to a<br />
specified load within one hour, and running <strong>f<strong>or</strong></strong> at least<br />
two hours.<br />
Source: “Ancillary Services Overview”, Settlements Guide (Draft), CAISO, May 8, 2002.<br />
The VRB is capable <strong>of</strong> serving any <strong>of</strong> these four applications. However, due to the<br />
continuous system losses (battery losses, PCS losses, and pumping loads) that would be<br />
Vanadium Redox Battery 24
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