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.

Economic and technical assessment of solar tracking system for solar panels via EnergyBiz

“One hour of solar energy is enough to meet the energy demand of entire Earth’s population for one year.

When the solar radiation reaches earth’s top atmosphere it is relatively constant everywhere but the radiation near earth’s surface may vary considerably due to following reasons:

  • – Atmospheric effects, such as absorption and scattering.
  • – local variations in the atmosphere, such as water vapour, clouds, and pollution;
  • – latitude of the location; and
  • – the season of the year and the time of day.”

By Emma White at

Also interesting: Clouds, Pollution and Solar Radiation

Solar Company Complications « Greening The Apple

There is always some small “insignificant” detail, in every industry, that sits in the back of your mind when you’re selling a product. Just ask the automobile dealers at Toyota and General Motors. In the Residential Solar Market it would be the quality of the roof you’re proposing to place a solar array on. This is a good article that highlights that issue. While we certainly aren’t concerned about new construction or houses that have been built in the last decade or two, a great deal of new homes has been placed in the housing stock, we should worry about older stock. We’ve been inundated with wet and icy weather, leading to a more rapid decay of facades and roofs, buildings are literally falling apart in some areas. The condition of roofs plays into the process, from proposal to contract, to commissioning. That is why we see roofing contractors entering the market as installers, or solar companies partnering. As the industry expands, and consumer look to the Jones, roof condition and quality will become more important, and maybe impact the final decision to have an installation.

When Should You Worry About Snow on Solar Panels? | Solar Builder Magazine

“Let it snow, let it snow, let it snow.”

Interested in adjustable roof racking? Active Solar Power enthusiast, those individuals who tinker with their system may chose to install adjustable racking. During the winter months an adjustable rack would allow you to take advantage of the suns winter positioning.

via When Should You Worry About Snow on Solar Panels? | Solar Builder Magazine.

A tale of solar panels, snow, and roof rakes – CNET Mobile

But if you’re so inclined…

“On Wednesday morning, I was prepared. A week earlier, I had bought a snow rake. (These are hot items this year given all the snow and problems with ice dams.) A snow rake–the one I bought was about $75–is just a flat aluminum plate with a long handle. Run it down your roof and the snow comes off.”

via A tale of solar panels, snow, and roof rakes – CNET Mobile.

What happens when you get snow on solar panels? – Home Energy Pros

“In heavy snowfall, the solar panels still give off heat, allowing the snow to begin melting above them. Houses with solar panels will avoid roof cave ins because of the dispersion of the snow due to the heat of the panels.
Snow falling off panels simultaneously cleans them and therefore boosts their power output.
On days when snow covers your solar panels, there is no need to worry about your output because your total energy is calculated throughout the entire year, meaning that variations in output during winter months are made up at other parts of the year.”

via What happens when you get snow on solar panels? – Home Energy Pros.

I wouldn’t advise using a rake to clean your panels, but I’d seriously think about some Rain-X.

Most people are especially concern about their electricity generation during storms because a utility’s outage usually means your solar power system may power down IF it has not been UPGRADED to, or DESIGNED as a BIMODAL or ISLAND-capable system. Contact your Solar Power Consultant, Contractor, or Installer and inquire about Bimodal and Island-capable Solar Power Systems.