The Smart Solar Plant is a conventional solar thermal cycle, backed by long-term thermal storage and electronic power conversion systems, integrating PV generation and electrochemical storage.

1. Innovative technology solutions for
sustainability
ABENGOA
RESEARCH
Smart Solar Power Plant – Concept Paper

2. SSP - Smart Solar Power Plant
Need for energy storage in electrical systems
For a long time, electrical companies have been interested in energy storage
technologies due to their great potential for achieving optimal, reliable electrical system
operations.
Historically, one of the most important contributions of energy storage, generally
hydraulic, to the electrical system is “load leveling”, which consists of energy storage
during periods of low demand (valley) in order to liberate it later during periods of high
electricity demand (peak), thereby avoiding overcharge generation during said periods.
In recent years, these functions have expanded to include support for wind and
photovoltaic power plants, which have a markedly variable generation profile.
More recently, electrical companies have also begun to consider energy storage as a
partial solution for sustainable growth of the electrical system, optimizing the use of
existing infrastructure and preventing, or at least postponing, the construction of new
power lines and plants.

3. SSP - Smart Solar Power Plant
Functions of the SSP based on EES and power processors
The SSP is a conventional solar thermal cycle, backed by long-term thermal storage and
electronic power conversion systems, integrating PV generation and electrochemical
storage.
This permits the creation of a high-performance solar generation system, both in terms
of reliability and efficiency, as well as interaction with the electrical system.
The thermal cycle with various hours of energy storage provides constant generation.
The PV section, complemented by a short-term electrochemical storage system
(approximately 30 minutes), has a very fast dynamic, covering response ranges of up to
milliseconds.
This feature, complemented by a dynamic fast-response steam turbine, allows the plant
to act quickly in the case of sudden imbalances in electricity generation and demand,
improving the capacity for interacting with high demand loads (for example, mining
mills) or intermittent renewable energy generation systems.

4. SSP - Smart Solar Power Plant
Functions of the SSP based on EES and power processors
In addition, the plant’s rapid response allows it to offer other ancillary services, such as
damped power oscillation, participating in the improvement of the system’s dynamic
stability, and power quality, mitigating the effect of harmonic components and
distortions.
The SSP offers electrical system performance highly superior to conventional systems, as
it features a very quick, damped response, which, in addition to participating in the
system’s energy balance flows, also mitigates power oscillations in the connection area.
The integration, through the smart control system, of photovoltaic generation and
electrochemical energy storage in a conventional solar thermal plant improves its
regulation capacity considerably, making it possible, for example, to regulate an
electrical “island” when the plant is operating while disconnected from the main system,
or the smooth recovery of the electrical system in the case of a collapse.

5. SSP - Smart Solar Power Plant
Smart Solar Power Plant
•Ancillary services
•Advanced grid
support
•Grid-forming services
•Precise performance models
•Demand and generation
forecasting
•Market and grid constraints
•Base-load, peaking and
load-following generation
•Firming intermittent output
•High efficiency at the lowest
LCOE
•Accurate forecasting
•Energy storage
•Virtual power plant
3) Presenting
deterministic
performance
1) Offering
operational
flexibility
2) Interacting
harmoniously
with power
systems
4) Having optimal
participation in
electricity markets

6. SSP - Smart Solar Power Plant
 Base-load, peaking and load-following generation: Energy storage
systems make smart solar plants manageable. Therefore, cheap solar
power can be supplied to the grid whenever it is more needed. The smart
solar plant can operate in different modes:
 Base-load,, generating constant power throughout the day,
independently of the availability of the solar resource.
 Peaking, producing clean energy when demand and prices are
higher.
 Load-following, adapting its generation not only to variations in the
demand, but also to fluctuations of other renewable sources.
 Firming intermittent output: The coordinated control of fluctuating
renewable resources and energy storage enables filtering any oscillation
in the input power and injecting a constant amount of power in the grid,
following a schedule. This makes the plant more reliable and suitable to
participate in hourly energy markets.
 High efficiency at the lowest LCOE: The hierarchical control structure of
the smart solar plant allows optimally sharing the duty of generating
power among the units forming the plant. Each objective of the power
plant (producing a constant amount of power, following a load ramp,
etc.) is achieved employing the proper technology and the best suited
stations in order to minimize the total cost of producing energy.
1) Offering operational flexibility

7. SSP - Smart Solar Power Plant
 Ancillary services: Unlike many power plants using renewable sources,
the smart solar plant is able to provide ancillary services.
 Manageability of active power (due to energy storage systems and
power curtailment) providing frequency regulation.
 Advanced control systems for converters and reactive power
modulation providing voltage support within scheduled limits
(better stability and efficiency).
 Advanced grid support: Power electronics converters using the
synchronous power controller (SPC) technique act as synchronous
generators with emulating inertia.
 This inertia limits frequency deviation and it decisively contributes
to stability.
 Grid-forming services: Opposite to grid-feeding converters SPC ones
provides a voltage source behavior:
 Adverse grid conditions can be tolerated
 Black-start capability: to energize a system after a blackout,
generating a stable voltage so loads and other generators can be
reconnected.
2) Interacting harmoniously with power systems

8. SSP - Smart Solar Power Plant
 Accurate forecasting tools: An accurate resource forecast is needed to
precisely assess the power availability in the plant in different time
horizons. This provides valuable inputs to:
 Market and System Operators to achieve the proposed economic
dispatch with minimum available backup reserves.
 Plant Operators to perform the optimum dispatching control of the
entire generation asset of the plant (solar + stored energy).
 Energy storage system (EES): The use of energy storage systems makes the
behavior of the plant more predictable, as in the case of any sudden lack
of resource when the ESS can respond and provide the agreed power
output (real-time control of ESS performance plays a crucial role here).
 Virtual power plant (VPP): A coordinated control of several generation
plants with complementary production dynamics (thermal and PV), or with
complementary resource characteristics (PV and wind) reduces variability
while providing advanced grid response dynamics.
3) Presenting a deterministic performance

9. SSP - Smart Solar Power Plant
 Precise performance models: These models are used to predict the
production capacity with a given resource (forecast). They are a key
element to participate in electricity markets: generation and bidding
strategies are set as to maximize the overall profit.
 Demand and generation forecasting: Other agents participating in the
market influence the final prize and amount of energy to be sold. This
information is integrated into a tool to optimally manage energy
(generating/storing when it is most beneficial).
 Market and grid constraints: Technical constraints in the market are also
integrated as they can limit the output of certain power plants (avoiding
congestion or voltage issues). These information also allows to
participating in ancillary services markets.
4) Having an optimal participation in electricity markets

10. SSP - Smart Solar Power Plant
Key elements - Hierarchical control of a distributed power plant
10
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Resource Station Cluster Plant Island Area
PMU1
To area
controller
From
SO/ area
controller
$CSP
$BESS
$PV
The hierarchical control architecture should consider all the possible logical control levels,
from generation/consumption devices to commercialization of energy and services in the
market.