IEEE Power & Energy Magazine - May/June 2018 - 81
and Market Pricing
Power Output (MW)
Deviation Power (MW)
the state underproduces or overdraws, there is a penalty. Secondary Applications
Conversely, when the frequency is below 50.05 Hz and the secondary use cases of the Bess include 1) ramp manif the state overproduces or underdraws, there is an in- agement of the integrated wind-solar plant, 2) fast frequency
centive. Figure 3 shows how a Bess can be discharged response, 3) primary frequency response, and 4) ramp manduring periods when the frequency is below 50.5 Hz agement for the system during morning and afternoon ramps.
and the state is withdrawing more than the scheduled
energy, as well as how it can be charged during other Sizing of the BESS
periods to reduce the dsM penalty.
the generic Bess design process is depicted in Figures 4-6.
✔ Shifting renewable energy to peak demand hours: Figure 4 illustrates the first step in the evaluation, during which
another primary application of energy storage is application-specific battery power command is developed. as
shifting renewable energy to peak demand hours. an example, from a native wind generation profile and forecast,
this application was identified as key for the state application-specific controls would generate the storage power
of andhra Pradesh, which has a high target (8,100 Mw needed to bring the total (wind and storage) generation closer
of wind and 4,081 Mw of solar) for renewable energy. to the forecast. By combining these profiles with local market
during off-peak load hours (8:00 a.m.-2:00 p.m.), rules and prices, revenue streams (or avoided penalties) can be
the Bess charges and stores energy, which it dis- calculated for the specific application and market.
next, as shown in Figure 5, energy storage technolocharges during peak load hours (6:00-10:00 p.m.).
thus, the integrated plant supplies a consistent gies are selected and sized by processing the battery power
amount of energy to customers during peak hours command into a use-intensity map. relying on a database
th rough a combination of wind, sola r, a nd en- of physics-based performance models, the installed cost
to meet the application requirements is calculated for each
✔ Forecast deviation reduction for wind and solar plants: technology, including storage and BoP.
another of the primary applications energy storage can
provide is forecast deviation
Phase 1-a Example: DSM Charge Reduction
reduction for wind and solar
from 24 January 2015 AP State Data
plants. the concept is that enZero Rate
ergy storage can be dispatched
to reduce a renewable energy
plant's forecast errors and thus
prevent lost revenues. in india,
there is a tiered penalty strucStorage
ture for deviations in wind and
solar generation. For example,
if the wind generation is below
t he scheduled va lue i n a
15-min block by 25%, then a
deviation charge applies: 110%
of the fixed rate for balance
Time of Day (h)
energy beyond 15% and up to
25% (i.e., there is no deviation
charge for the first 15%).
figure 3. The DSM charge management using a BESS.
figure 4. The first phase of the energy storage value analytics methodology: applications and revenues.
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