White Papers

At the request of national and international conferences, Green Power Labs has presented on a variety of topics related to its core expertise in predictive analytics for planning, deployment and operation of solar technologies. We have presented peer reviewed papers at EU PVSEC 2014, CIGRE 2014, Eco Asia on Solar Urban Planning, UVIG: Impact of California Marine Layer on Solar Resource; SNEC: Solar Urban Planning, Aarhus Solar Integration Workshop, Solar Power Forecasting Performance, Impact of California Marine Layer on Solar Resource; US Meteorological Conference on Energy and Weather Parameters; Aarhus Solar Integration Workshop, Solar Power Forecasting Performance Towards Industry Standards; 4th Energy Forum on Solar Architecture and Urban Planning, Bressanone, Italy and 7th International Conference on Architecture and Urban Planning, Sun and Sense, Berlin/German. Selected papers are presented here.

Solar Architecture in Atlantic Canada Reshaping the Icons

Authors: Alexandre Pavlovski, Jim Fletcher, Vladimir Kostylev, Green Power Labs Inc., John Crace, WHW Architects
Energy Forum in Bressanone, December 2009

Abstract: The modern built environment has been developed in a context of readily-available, low-cost energy from highly concentrated fossil fuels. Today's global energy landscape has dramatically changed; energy costs have become significant in the operation of buildings, and the sector uses a major portion of the global resources of fossil fuels.
In recent years a major focus of green building development in North America and internationally has been on setting up sustainable energy practices for the built environment. While advancing energy conservation and efficiency measures for buildings, onsite clean energy generation is now positioned as a critical next step in meeting increasing energy demands and enhancing the functionality and comfort of buildings. “Solar Architecture” as a green building concept addresses sustainable energy practices and needs of the three major tiers of the built environment: new construction, existing buildings and community planning.
Solar Architecture for New Construction - Building on the Resource: including solar architecture principles in integrated design for new buildings allows for the most comprehensive approach in utilizing solar energy in a building energy mix. The Joggins Fossil Centre incorporates the key elements of solar architecture, advanced use of solar resource and solar energy generation technologies with conservation and efficiency to reduce energy consumption by 64.5%, compared to the baseline, and provide over 50% of the energy demand by on-site renewable energy generation.
Solar Architecture for Existing Buildings - Reshaping the Icons: revising the functionality and appearance of iconic buildings is an efficient way to create and showcase sustainable energy practices. Maritime Centre Re-invented project describes opportunities for solar applications in combination with re-cladding an existing building. The Maritime Centre is an iconic urban structure built in the 1970's. Re-cladding provides the opportunity to provide a contemporary image and to address building envelope and indoor air quality issues. It also provides the opportunity to reduce energy needs, add more natural ventilation and integrate renewable energy technologies. Detailed knowledge of energy consumption patterns allows for reducing the existing extreme peaks of energy to heat and cool the building by setting the criteria for energy storage, performance of the building envelope and solar heating, cooling and power supply.
Solar Energy for Communities - Advancing the Vision: application of solar architecture principles to community master planning involves quantifying solar energy generation potential of community buildings and open areas. Solar Architecture concept for Dalhousie University Master Plan describes the integration of solar energy into a University Campus Master Plan. The application of solar architecture principles to community master planning involves quantifying solar energy applications. The new Dalhousie University Campus Master Plan utilizes advanced solar energy generation potential mapping and the SolarStar RatingTM system to facilitate the integration of solar technologies in the community energy mix. The advanced mapping also serves as a decision tool in planning the landscaping of the campus by shaping areas of high and low solar gain throughout the year.
To read a full version download as a pdf (2.1Mb)

Download a pdf

Advancing Satellite-based Solar Power Forecasting: Integration of Infrared Channels for Automatic Detection of Coastal Marine Inversion Layer

Authors: Vladimir Kostylev, Andrey Kostylev, Chris Carter, Chad Mahoney, Alexandre Pavlovski, Tony Daye, Green Power Labs Inc.,
Dallas Eugene Cormier, Lena Fotland, San Diego Gas and Electric Co
2nd International Workshop on Integration of Solar Power into Power Systems Lisbon, November 2012
Abstract: The marine atmospheric boundary layer is a layer or cool, moist maritime air with the thickness of a few thousand feet immediately below a temperature inversion. In coastal areas as moist air rises from the ocean surface, it becomes trapped and is often compressed into fog above which a layer of stratus clouds often forms. This phenomenon is common in many parts of the world and poses a particular challenge for satellite-based solar radiation monitoring and forecasting. Hour ahead satellite-based solar radiation forecasts are commonly using visible spectrum satellite images, from which it is difficult to automatically differentiate low stratus clouds and fog from high altitude clouds.
This provides a challenge for cloud motion tracking and cloud cover forecasting. San Diego Gas & Electric® (SDG&E®) Marine Layer Project was undertaken to obtain information for integration with PV forecasts, and to develop a detailed understanding of long-term benefits from forecasting Marine Layer (ML) events and their effects on PV production. In order to establish climatological ML patterns, spatial extent and distribution of marine layer, we analyzed visible and IR spectrum satellite images (GOES WEST) archive for the period of eleven years (2000 - 2010). Historical boundaries of marine layer impact were established based on the cross classification of visible spectrum (VIS) and infrared (IR) images. This approach is successfully used by us and elsewhere for evaluating cloud albedo in common satellite based techniques for solar radiation monitoring and forecasting. The approach allows differentiation of cloud cover and helps distinguish low laying fog which is the main consequence of marine layer formation. ML occurrence probability and maximum extent inland was established for each hour and day of the analyzed period and seasonal patterns were described. SDG&E service area is the most affected region by ML events with highest extent and probability of ML occurrence. Influence of ML was the strongest in coastal areas up to 50 km away from coast.
Extent of ML inland in SDG&E service area was the largest in May and receded towards coast gradually through summer and fall. The ML probability correlated well with accuracy of solar radiation and PV forecasting in the region. Coastal sites appeared the most challenging for accurate forecast while PV forecasts in inland areas were performing consistently well. Improvement of automated cloud classification algorithms through integration of infrared satellite channels as well as better understanding of meteorological drivers of ML events is the key for improvement of satellite-based PV generation forecasting in coastal areas.
To read a full version download as a pdf (640Kb)

Download a pdf

Solar Power Forecasting Performance Towards Industry Standards

Authors: V. Kostylev and A. Pavlovski, Green Power Labs Inc.
Abstract: Due to the rapid increase in deployment and high penetration of solar power generation worldwide, solar power generation forecasting has become critical to variable generation integration planning, and within utility and independent system operator (ISO) operations. Utilities and ISOs require day ahead and hour ahead as well as intra-hour solar power forecasts for core operations - solar power producers and energy traders also require high quality solar power forecasts.
As a result of the erroneously perceived simplicity of solar radiation forecasting, very often non-repeatable, poorly explained or obscure estimates of solar power forecast performance are used. This creates uncertainty with the quality of forecasting service, as well as unrealistic expectations of possible forecast precision. As a result, there is an immediate need for defining a common methodology for evaluating forecast performance, establishing verification procedures, and setting common standards for industry-approved quality of solar forecast performance.
Solar power forecast quality claims can be easily verified when the source of forecast is known. Most often the offered power generation forecasts are based on publically available results of Numerical Weather Prediction (NWP) models and on the use of empirical relationships between solar resource and generated power at a specific plant. The quality of these forecasts is limited by the quality of the NWP models utilized, which is known. Less frequently, solar radiation is estimated based on proprietary models such as satellite-based or total sky image-based cloud cover and radiation forecasts. In such cases, there are also known limits to the accuracy of prediction which can help objectively evaluate claims of the forecast service companies.
This paper is proposing a set of standards for evaluating intra hour, hour ahead, day ahead and week ahead solar power forecast performance. The proposed standards are based on sound methodologies and extensive field practice and offer a solid ground for reliable inter-agency comparisons of forecast performance.
To read a full version download as a pdf (340Kb)

Download a pdf

Distributed PV Power Generation Forecasting for Distribution Management

Authors: C. Carter, J. Fletcher, V. Kostylev, C. Mahoney, M. Palmer, T. Daye, A. Pavlovski, D. Cormier
Abstract: High penetration of distributed PV generation (DG-PV) assets has created a new energy management and control landscape in the power industry as it has substantially changed operating conditions in the distribution grid. In 2013, Green Power Labs (GPL) and San Diego Gas and Electric (SDG&E) developed an approach to integrate distributed PV generation forecasts with SDG&E’s existing distribution management system (DMS) to help account for this growth. The developed technology provides forecasts for the over 20,000 DG-PV assets currently in the SDG&E service area for near real-time forecast horizons at the “electrical resolution” level of service transformers . Enabling distribution management systems with high “electrical” resolution DG-PV forecasting achieves improvement in the performance of existing grid assets and a reduction in the limitations on distributed PV penetration.
To read a full version download as a pdf (78 Kb)

Download a pdf