HERALD WEEKLY ISSUE 587: 10 November 2011

Renewable Energy - Solar Panels. Are they “Set and Forget”?
All around the island we are seeing solar panels on roofs, generating electricity for the occupants. With no moving parts, they look as if they’ll need no attention for years.
It’s true that they are the most simple and robust renewable energy system available to us.
But maintenance for solar panels is still a good idea, for a number of reasons.
As much as we want to reduce greenhouse gas emissions, most of us who decide to invest in renewable energy do so to reduce our energy costs. So it makes a lot of sense to ensure that our investment is actually producing the maximum possible energy - bang for buck.
So what’s needed? The obvious thing is to clean the panels. We clean windows regularly to ensure a clear view, and the solar panels need a clear view of the sun too, to work at their best. While rooftop panels get washed by rain, dust and grime can still build up, and a regular wash with soapy water will make a difference to the amount of energy that can be generated. And we might as well wash the solar hot water panel while we’re up on the roof, for the same reason.
Leaves and other debris can get blown onto the panels, shading some cells and dramatically reducing energy output. Breadfruit leaves, or even kikau, are a major problem, being so large.
There can be other, more subtle things, that can reduce the panel output. Even the tiniest shadow in one part of one panel can dramatically reduce the output of the entire array, due to the ‘series connection’ of the solar string that is used in most cases.
TV aerials and satellite dishes are sometimes mistakenly installed where they will cast a shadow over the panels.
Overhead wires, power poles and flagpoles can cast shadows across panels. This might only happen at certain times of day, or during winter months when the sun is lower, but is worth checking.
Building alterations can cause changes to shadow lines - new guttering, or a roof extension for instance. It is useful to check the roof at different times of day, summer and winter, to see where the shadows encroach.
Over-enthusiastic painters can drip paint on the panels, massively reducing the solar efficiency.
And then there is the obvious issue of encroaching trees. While the trees might have been clear of the house when the panels were installed, over time they may have grown and spread so that they are casting a costly shadow.
Having taken care of the panel output, the other important thing to check with the cyclone season approaching, is the security of the panel attachments. All the fasteners need to be tightly secured to their mounting rails, and the rails in turn need to be firmly secured to the roof. The installer should have ensured that the fasteners are spaced and sized properly for cyclone conditions, so a professional installation should weather a cyclone as long as everything is tight.
So what else needs checking? The whole system can be checked for performance by the homeowner, by keeping regular records of the PV solar system’s output. Some systems will have their own meter, which records the output of panels. Others will have a readout on the inverter, that will show the ‘units’ or kilowatt-hours, that have been generated. By regularly monitoring these readings, it is possible to keep track of the output, and discover early if there is a problem.
A breadfruit leaf or other obstruction on a PV Solar panel would be evident very quickly without even climbing on the roof. The solar output would be well down on what it should be. If regular readings are made and recorded, then action can be taken to clear the obstruction and get the system back to full capacity as early as possible. A downward trend in output when there has been consistently good sunlight, would indicate a problem that needed checking.
Solar panels are still a major investment, and that investment needs to be earning the maximum return. Like with most things, a little bit of maintenance can pay back enormously - saving money while saving the environment.

Herald Issue 554 09 March
- Norm exposes Trio of Doom
- Briefs from PM’s media conference Tuesday
- Tourism Industry ponders $5 million draft strategy
- Norman George resigns from Cook Islands Party
- Letter of Resignation from CIP
- Norman selfish says Prime Minister

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