Abstract: A method of operating a solar energy collection system comprising an array of pivotable PV modules and a group of plants arranged to produce a crop, includes performing a optimization of a value function based on a current state, responsively to predicted insolation, by dynamically determining one or more orientations for the array of PV modules, and controlling, based on the optimization of the value function, at least one of the PV modules to switch orientation to increase or decrease instantaneous photovoltaic conversion of incident solar radiation by the array of PV modules and/or increase or decrease instantaneous photosynthetic conversion of the incident solar radiation by the group of plants.

Abstract: A solar energy system comprising a photovoltaic array, an inverter, and an energy storage device is operated according to the following steps: (a) accessing irradiance data for a past time period; (b) acquiring an irradiance forecast for a future time period having a length of not more than 15 minutes and having a cumulative irradiance forecast of between 20% and 80% of clear-sky irradiance; (c) calculating a smoothed energy target-value for an imminent time step within the future time period, using the irradiance data for the past time period and the forecasted irradiance for the future time period; and (d) during the time step, delivering a quantity of energy to the inverter based on the calculated smoothed energy target-value. The energy storage device stores energy when more is produced than delivered, and discharges energy when more is delivered than is produced.

Abstract: A solar energy system includes a photovoltaic (PV) assembly and a drive system. The PV assembly comprises a support subassembly and an array of PV panels pivotable therewith about a longitudinal axis of the PV assembly. The drive system comprises a motor assembly comprising an electric motor and a gearing arrangement, and a pivot wheel comprising a hoop-portion and joined to the PV assembly. The hoop portion includes an outer circumferential channel, and two opposing catches defining a maximum pivot range. A chain resides partly within the circumferential channel, is engaged with the two opposing catches, and is also in geared communication with the motor assembly such that the motor is operable to rotate the pivot wheel. In some embodiments, the opposing catches define a maximum pivot range through an arc of more than ? radians and less than 2? radians.

Abstract: A solar energy system includes a photovoltaic (PV) assembly and a drive system. The PV assembly comprises a support subassembly and an array of PV panels pivotable therewith about a longitudinal axis of the PV assembly. The drive system comprises a motor assembly comprising an electric motor and a gearing arrangement, and a pivot wheel comprising a hoop-portion and joined to the PV assembly. The hoop portion includes an outer circumferential channel, and two opposing catches defining a maximum pivot range. A chain resides partly within the circumferential channel, is engaged with the two opposing catches, and is also in geared communication with the motor assembly such that the motor is operable to rotate the pivot wheel. In some embodiments, the opposing catches define a maximum pivot range through an arc of more than ? radians and less than 2? radians.

Abstract: A control system for a solar energy system causes motor assemblies to pivot the photovoltaic (PV) arrays of the solar energy system about respective longitudinal axes, e.g., to track the sun across the sky. The solar energy system also has an inverter with a known inverter rating, e.g., for a given output level and ambient temperature. The control system is programmed, inter alia, to determine when a calculated electrical output of the PV arrays, e.g., a future electrical output during an imminent future time period, exceeds the inverter rating. The control system then causes some or all of the PV arrays to pivot out of regular solar tracking mode into a position that introduces higher cosine losses, so as to reduce real-time electrical output from at least the direct normal component of real-time solar irradiance incident on the PV arrays involved in order not to exceed the inverter rating, or to exceed it less.

Abstract: A solar energy system comprising a photovoltaic array, an inverter, and an energy storage device is operated according to the following steps: (a) accessing irradiance data for a past time period; (b) acquiring an irradiance forecast for a future time period having a length of not more than 15 minutes and having a cumulative irradiance forecast of between 20% and 80% of clear-sky irradiance; (c) calculating a smoothed energy target-value for an imminent time step within the future time period, using the irradiance data for the past time period and the forecasted irradiance for the future time period; and (d) during the time step, delivering a quantity of energy to the inverter based on the calculated smoothed energy target-value. The energy storage device stores energy when more is produced than delivered, and discharges energy when more is delivered than is produced.

Abstract: Steam can be generated using insolation by a solar collection system. A thermal storage system can store enthalpy in insolation-generated steam at times and can generate steam from stored enthalpy at other times. During some operating periods, a gas-fired superheater can further heat the generated steam to provide superheated steam to generate electricity. Steam at a substantially uniform electricity generating temperature may be produced selectively and at different operating periods from insolation only, from insolation and gas firing, from transfer of enthalpy from a thermal storage system and gas firing, or from a combination of insolation, stored enthalpy transfer, and gas firing. Operating periods can be characterized by at least one of an insolation level, a time of day, or a stage in the operation process. The generated steam can be used in the production of electricity.

Abstract: The disclosed subject matter relates to methods and systems for operating a solar steam system in response to a detected or predicted reduced insolation condition (for example, sunset or a cloud condition). In some embodiments, for a period of time, enthalpy stored within a solid material of a conduit via which steam travels en route to a steam turbine is used to heat the steam to drive the turbine. In some embodiments, a net migration of heliostats away from the steam superheater is carried out in response to the detected or predicted reduced insolation condition.

Abstract: Systems and methods for directly monitoring energy flux of a solar receiver in a solar energy-based power generation system include measuring infrared radiation emanating from the solar receiver. Such measurement can be achieved using one or more infrared thermography detectors, such as an IR camera. Resulting thermal data obtained by the imaging can be used to determine energy flux distribution on the receiver. A user or a system controller can use the determined flux distribution to adjust heliostat aiming to achieve a desired operation condition. For example, heliostats can be adjusted to achieve a uniform energy flux distribution across the external surface of the receiver and/or to maximize heat transfer to a fluid flowing through the receiver within system operating limits.

Abstract: Steam can be generated using insolation by a solar collection system. A thermal storage system can store enthalpy in insolation-generated steam at times and can generate steam from stored enthalpy at other times. During some operating periods, a gas-fired superheater can further heat the generated steam to provide superheated steam to generate electricity. Steam at a substantially uniform electricity generating temperature may be produced selectively and at different operating periods from insolation only, from insolation and gas firing, from transfer of enthalpy from a thermal storage system and gas firing, or from a combination of insolation, stored enthalpy transfer, and gas firing. Operating periods can be characterized by at least one of an insolation level, a time of day, or a stage in the operation process. The generated steam can be used in the production of electricity.

Abstract: Methods, apparatus and systems for operating a solar steam system in response to a detected or predicted reduced or impending reduced insolation event are disclosed herein. Examples of transient reduced insolation events include but are not limited to cloud-induced reduction in insolation, dust-induced reduction in insolation, and insolation events caused by solar eclipses. In some embodiments, in response to the detecting or predicting, steam flow is regulated within the solar steam system to reduce a flow rate into a steam turbine. Alternatively or additionally, one or more heliostats may be responsively redirected onto a steam superheater or steam re-heater.

Abstract: Methods, apparatus and systems for operating a solar steam system in response to a detected or predicted reduced or impending reduced insolation event are disclosed herein. Examples of transient reduced insolation events include but are not limited to cloud-induced reduction in insolation, dust-induced reduction in insolation, and insolation events caused by solar eclipses. In some embodiments, in response to the detecting or predicting, steam flow is regulated within the solar steam system to reduce a flow rate into a steam turbine. Alternatively or additionally, one or more heliostats may be responsively redirected onto a steam superheater or steam re-heater.

Abstract: A method for generating steam for a turbine electric power plant uses solar radiation. Solar radiation is directed onto a solar receiver. The solar receiver includes a first section, which receives feedwater input and is arranged to heat the feedwater input to generate steam using the directed solar radiation. Feedwater flows through a feedwater vessel to serve as feedwater input to an inlet of the first section of the receiver. Water is separated from the steam in steam separation vessel, which is in fluid communication with an outlet of the first section of the receiver. The feedwater input may be selectively preheated by a source of preheat other than solar energy in response to system operating conditions, predicted insolation schedule, or an electrical energy tariff schedule.

Abstract: A solar energy conversion system may include a receiver with a first heat transfer fluid channel having at least two opposite sides. Each side may present an external surface facing in a direction opposite to that of the external surface of the other opposite side. Each side may be configured to contact a heat transfer fluid carried in the first heat transfer fluid channel. A heliostat field may be configured to direct solar energy to each of the at least two opposite sides during the course of a day such that a thermal stress tending to bend the channel remains below a specified level.

Abstract: A solar energy collection system includes a primary solar receiver and a secondary solar receiver. The secondary solar receiver generates steam using energy from solar radiation incident thereon. The primary solar receiver receives the generated steam from the secondary solar receiver and superheats the steam using energy from solar radiation incident thereon. A plurality of heliostat-mounted mirrors reflects incident solar radiation onto one of the primary and secondary solar receivers. A controller aims a portion of the heliostat-mounted mirrors at the primary solar receiver such that a predetermined thermal profile is provided on a surface of the primary solar receiver.

Abstract: A solar energy collection system includes a primary solar receiver and a secondary solar receiver. The secondary solar receiver generates steam using energy from solar radiation incident thereon. The primary solar receiver receives the generated steam from the secondary solar receiver and superheats the steam using energy from solar radiation incident thereon. A plurality of heliostat-mounted mirrors reflects incident solar radiation onto one of the primary and secondary solar receivers. A controller aims a portion of the heliostat-mounted mirrors at the primary solar receiver such that a predetermined thermal profile is provided on a surface of the primary solar receiver.

Abstract: The disclosed subject matter relates to methods and systems for operating a solar steam system in response to a detected or predicted reduced insolation condition (for example, sunset or a cloud condition). In some embodiments, for a period of time, enthalpy stored within a solid material of a conduit via which steam travels en route to a steam turbine is used to heat the steam to drive the turbine. In some embodiments, a net migration of heliostats away from the steam superheater is carried out in response to the detected or predicted reduced insolation condition.

Abstract: A solar energy collection system includes a primary solar receiver and a secondary solar receiver. The secondary solar receiver generates steam using energy from solar radiation incident thereon. The primary solar receiver receives the generated steam from the secondary solar receiver and superheats the steam using energy from solar radiation incident thereon. A plurality of heliostat-mounted mirrors reflects incident solar radiation onto one of the primary and secondary solar receivers. A controller aims a portion of the heliostat-mounted mirrors at the primary solar receiver such that a predetermined thermal profile is provided on a surface of the primary solar receiver.

Abstract: A solar heliostat and system are described with various characteristics particularly suitable for concentrating systems with a relatively large number of small heliostats. Other features contribute to high performance, low cost, high durability, and high temperature operation, such as desired for high efficiency thermal power generation.

Abstract: A multi-mode solar power generation system can include a first energy conversion system that generates electricity from a working fluid heated by a portion of solar radiation focused by a plurality of heliostats. The multi-mode solar power generation system can also include a second energy conversion system that generates electricity from an unused portion of the focused solar radiation using a different energy conversion mode than that of the first energy conversion system. The second energy conversion system can include one or more photovoltaic converters, which directly convert solar radiation to electricity. The unused radiation from the first energy conversion system can include radiation spillage or dumped radiation from a thermal receiver of the first energy conversion system.