Clean Power

Published on May 8th, 2012 | by Nicholas Brown


L.A. Can Generate 5 GW of Solar Power Using Virtually No Additional Land, Minimal Backup

May 8th, 2012 by  

The city of Los Angeles has more than 12,000 acres (48.5 million square metres, 19 square miles, or 48 square km.) of rooftop space available for an array of solar panels large enough to generate 5.5 GW (5,500 MW or 5.5 billion watts) of electric power, according to a recent announcement from the Los Angeles Business Council.

Simplified Distributed Solar Illustration. The figures are not very realistic, but it gets the point across. Click the image and then click it again on the next page to see a larger version of it.

Benefits of Distributed Rooftop Solar Schemes Like This

Due to the fact that rooftop solar schemes involve only a few or several kilowatts of solar panels per rooftop, rooftop solar panels are spread out (distributed) over a much larger area than they would be if installed in a typical solar power plant.

Typical utility-scale solar power plants contain many solar panels clustered barely a few feet away from each other, and this puts them at risk of the worst reliability issue that solar power plants have — clouds, which I discuss in the “reliability benefits” section below.

The reliability issue also creates a need for a large amount of backup from other non-solar power plants, or from batteries, which are a more expensive alternative.

Reliability and Cost Benefits

At a conventional solar power plant, storm clouds can cover most of the solar panels and significantly reduce their power output.

When this happens, natural gas peaking power plants may be switched on to compensate for this, or modern baseload power plants (natural gas, coal, nuclear, geothermal) may be adjusted, such as GE’s recent combined cycle natural gas (CCNG) plant, which can adjust its power production by 50 MW per minute to compensate for those pesky clouds.

Now, for the good news: Distributed solar schemes have the potential to reduce the need for backup generators and energy so much that only a small fraction of the solar panels would need backup at any given moment. In other words, little energy storage or backup is required, which saves a massive amount of money.

There will be large storms, which are exceptions to this rule but, not most of the time.

Why: Spreading solar panels out over a large area of hundreds or even thousands of miles, across the U.S or large U.S. regions, for example, means that when a few houses are overcast by clouds, less than 20 kW of solar panels are affected, compared to an example 20,000 kW of panels at a utility-scale solar power plant.

This is up to 1,000 times worse!

Another potential cost benefit: Land does not have to be purchased for rooftop solar panels, because they are put on existing rooftops. Most rooftop space is not put to use. Therefore, putting solar panels on them isn’t really a waste of space, because they are generating clean electricity while occupying no additional land.


h/t PR Newswire

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About the Author

writes on CleanTechnica, Gas2, Kleef&Co, and Green Building Elements. He has a keen interest in physics-intensive topics such as electricity generation, refrigeration and air conditioning technology, energy storage, and geography. His website is:

  • david

    If only they would start adding solar panels to the larger roofs today and working there way down to the smaller roofs. In 5-10 years they could be complete and running at 75% renewable energy

  • Ross

    The LADWP website says peak demand is 6.2GW and generating capacity is 7.2GW so 5GW could make a major dent in that and be used for EV charging.

  • rocky john

    Good to know about the Benefits of Distributed Rooftop Solar Schemes

  • Bob_Wallace

    And another benefit. Distributed, rooftop solar will use existing transmission lines. Power made on rooftops will flow to the grid over the same wires that already bring power to the building.

    That is a cost saver.

    • Mattpeffly

      Better yet Bob is that most of the electric from distributed solar is used on site and does not suffer transmission loses. A kW at a power plant 100 miles away is not the same as a kW on your roof.

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