Description
Affordable High-Resolution Irradiance Prediction System
Case ID:
18/0006
Background
Power output from photovoltaics (PV) is directly related to the amount of sunlight, or irradiance, striking the panel. Irradiance is modulated by the solar position and the level of atmospheric attenuation, which is the absorption and scattering of sunlight due to water and ice particles in clouds, fog and haze, as well as other particulates such as dust, ash, and smog. Complex, nonlinear, and dynamic atmospheric processes affect these particles, and create large uncertainty and variability in solar power generation. At high PV penetration levels, the range of variability and uncertainty in power production complicates electric grid operations and can lead to inefficiencies. Solar forecasting systems (SFS) provide information to reduce the uncertainty in solar power generation and enable grid operators and management systems to address the variability, improving operational reliability and economic efficiency.
In the short-term, transient clouds are the primary driver of PV power fluctuations. As a cloud passes between the sun and panel, PV power output can drop by 60-80% within seconds. High resolution (time and space) cloud monitoring is required to predict these large, quickly occurring fluctuations (ramps). Currently, total sky imager (TSI) systems are the best option for high-resolution sky monitoring, however, they typically cost over $20K per instrument. Additionally, to be used as a SFS, the TSI requires additional instrumentation to determine cloud position and attenuation. This limits the TSI as a cost effective option for solar forecasting, particularly for distributed PV, which requires widespread deployment.
Technology Overview
Researchers at the University of Hawaii’s Hawaii Natural Energy Institute have developed a novel ground-based irradiance mapping and prediction instrument for short-term proactive management of solar energy generation. The Affordable High-Resolution Irradiance Prediction System (AHRIPS) monitors sky conditions with an omnidirectional camera and thermopile-based pyranometer and uses stereographic pattern tracking techniques, solar geometry and clear-sky irradiance models, and a cloud advection/diffusion algorithm to forecast future cloud and irradiance conditions.
Features
Low production cost
● Off-the-shelf components
● Open-source hardware
Flexible deployment
● Fully wireless operation
● Self-powered
● Compact weather-proof housing
Autonomous operations in an edge-computing framework
● Standard operational deployment is a cluster 3-5 AHRIPS instruments
● Onboard high-performance, single-board computer processes imagery and generates forecasts at the instrument
● Generates 3D cloud maps and 4D cloud surface trajectories using stereographic tracking methods
● Requires no additional instruments to generate irradiance and power forecasts
● Contains additional environmental sensors necessary for accurate PV power modeling
● AHRIPS instruments directly exchange information: upwind conditions to increase forecasting horizons, irradiance observations for improved estimation of cloud attenuation, and operational communication and status metrics
Self monitoring and calibrating
● A single-board microcontroller monitors the state of the instrument and onboard computer
● Irradiance observations (and PV power output in self-powered version) allow for realtime calibration and validation of forecasts
● External calibration coe.
Potential Benefits
Higher penetration of PV systems
Reduced PV generation uncertainty
Tighter operation reserve management
Gain insight into windflow in the urban environment
Improved management of building thermal loads
Improved management of grid-tied battery storage
IP Status
Utility patent application filed
Seeking
Development partner
Commercial partner
Licensing
University spin out
Investment
Key Words
Cloud monitoring
Distributed PV Systems
Electricity
Energy
Grid Infrastructures
Irradiance
Photovoltaic (PV)