Critical weather situations for renewable energies – Part B: Low stratus risk for #solar power

Accurately predicting the formation, development and dissipation of fog and low stratus (LS) still poses a challenge for numerical weather prediction (NWP) models. Errors in the low cloud cover NWP forecasts directly impact the quality of photovoltaic (PV) power prediction. On days with LS, day-ahead forecast errors of Germany-wide PV power frequently lie within the magnitude of the balance energy and thus pose a challenge for maintaining grid stability. An indication in advance about the possible occurrence of a critical weather situation such as LS would represent a helpful tool for transmission system operators (TSOs) in their day-to-day business. In the following, a detection algorithm for low stratus risk (LSR) is developed and applied as post-processing to the NWP model forecasts of the regional non-hydrostatic model COSMO-DE, operational at the German Weather Service. The aim of the LSR product is to supply day-ahead warnings and to support the decision making process of the TSOs. The quality of the LSR is assessed by comparing the computed regions of LSR occurrence with a satellite based cloud classification product from the Nowcasting Satellite Facility (NWCSAF). The results show that the LSR provides additional information that should in particular be useful for risk adverse users.

Quick and Dirty Solar Energy Estimating Tool >

When someone considers purchasing a photovoltaic (PV) system to offset their electric bill, one of the first steps they take is to contact a vendor and pay for a site assessment. The assessor performs many steps, including an electric load evaluation, a visual property inspection, a shading analysis, and a financial assessment. This process helps to determine the size of the array, the optimal location for solar panels and “balance of system” equipment, the payback period, and the return on investment. While detailed assessments are crucial to a well-designed and cost-effective system, a ballpark estimate can determine whether it’s worth doing the complete site assessment. Engineers frequently do “back of the envelope” calculations to determine overall feasibility; if the ballpark figures look reasonable, then the detailed analysis will follow. If not, the idea is scrubbed and no time is wasted doing a thorough assessment.

UTILITIES: Ala. goes back to basics as solar flourishes in neighboring states — Thursday, June 19, 2014 —

A new solar research institute is opening in a Southeastern state where coal still wants to be king and solar is barely there: Alabama.

The state’s largest utility, Alabama Power, wants to work with the new Southeastern Solar Research Center (SSRC) in Birmingham (EnergyWire, June 12). The utility wants to evaluate how different solar photovoltaic systems operate and perform under the region’s hot and humid conditions, according to information the SSRC released last week.

via UTILITIES: Ala. goes back to basics as solar flourishes in neighboring states — Thursday, June 19, 2014 —

L.A. councilman wants to put ground-based solar arrays on pause – Los Angeles Times

Councilman Felipe Fuentes argued that before any more such projects are approved, the city should work out a “city planning review process” that would allow community reaction. In a letter to the board, he asked for officials to take action before the utility’s next round of solar applications this summer.

via L.A. councilman wants to put ground-based solar arrays on pause – Los Angeles Times.

Where is free electricity produced by solar going? Letters | 6-17-14 | West Hawaii Today

About a month ago, West Hawaii Today featured an article about how the poor are paying more for their electricity rate because the wealthy upper class have installed photovoltaic panels and that they are not paying their fair share of the cost to produce electricity, so claims Hawaii Electric Light Co. – See more at:

via Letters | 6-17-14 | West Hawaii Today.

#Solar Bridge in London Completed and Operational

Blackfriar’s Bridge, which is the largest solar bridge in the world and part of London’s Blackfriar’s railway station, is finally finished. Work on the structure started in 2009 as part of the worldwide energy conservation efforts. The bridge crosses the river Thames and the solar panels that now cover it were installed by the firm Solarcentury.

Switchable material could harness the power of the sun—even when it’s not shining

“It could change the game, since it makes the sun’s energy, in the form of heat, storable and distributable,” says Jeffrey Grossman, the Carl Richard Soderberg Associate Professor of Power Engineering at MIT, who is a co-author of a paper describing the new process in the journal Nature Chemistry. Timothy Kucharski, a postdoc at MIT and Harvard, is the paper’s lead author.

Read more at: