In Australia, the salt spray that is part of life for coastal solar systems has a way of diminishing output and hastening corrosion in everything from panels and inverters to batteries and the hardware they are mounted on, not to mention shortening their working life. While proximity to the beach makes for the greatest risk, there is no escaping it; with enough wind or a storm, or simply humid conditions, the salty air will make its way inland.
That said, a coastal system can be made to perform without fail if one goes about specifying, installing and maintaining it with marine conditions in mind. One has to understand that the sea grime is not just an unsightly film. Residues of salt have chloride ions in them which will hold moisture to metal, open up conductive paths and get at the rust or galvanic corrosion. It is a slow and insidious form of damage, rather like a mozzie that bides its time until you are at ease before you notice it.
My name is Nicholas Fairchild. I have had my fill of the damp weather on the coast of Tasmania to know that being “weather-resistant” is not the same as being content beside the sea. You might think a roof is in fine order from the ground but the fasteners, inverter vents and cable clips are having a quiet time of it. I put together this guide to tell you what to look out for, how to go about getting better equipment and what a coastal owner should do to head off a costly replacement down the track.
A Coastal Reality Check
The damage done by salt air is more of a gradual affair than anything dramatic. Corrosion can set in around the inverter housing, mounting rails, the frame or any roof penetrations and the system will still be putting out electricity. It is a reminder that debris effects on output are not always immediately obvious.
You cannot say with any certainty that a system within so many kilometres of the ocean is going to need the same sort of upkeep or be doomed to failure. A place behind some dunes is not subject to the same salt load as one facing the prevailing winds or right next to the surf. Humidity, rainfall, the height of the roof and vegetation all come into play.
When making a site assessment, look at the roof as a map of sorts. Note the slope towards the ocean, where the inverter and battery are sited, the gutters and downpipes, trees and any shade. One can have a well protected array of panels and yet put the inverter in a corner where the salt is thick, akin to donning a raincoat and standing in a puddle in your socks.
How Salt Damages Solar Equipment
It starts with the humidity or small droplets of salt spray. Evaporation puts down a residue that is conductive on the electrical components, frames and glass. Rain will take some of it away but in a sheltered spot it can linger for weeks or months.
Then there are the chloride ions which are a nuisance, able to undermine the oxide layer on aluminium and other metals. With enough moisture there will be pitting and staining. If water finds its way to junction boxes or seals that are not up to the task, the saltwater can do its work.
From Residue To Corrosion
Usually the edges, joints and brackets of a panel are where the trouble begins. The glass is not as susceptible as the rest of the hardware but a cracked backsheet or a seal in poor shape needs to be dealt with.
Put dissimilar metals in contact with salt and moisture and you have galvanic corrosion. Incompatible rails or fasteners will form an electrochemical cell of a kind. You will see it in the red-brown rust, powdery deposits or white oxidation on the aluminium.
This weakens the connection and lets water in where it does not belong and raises electrical resistance. There is no guarantee of a power failure from it though, so a once a year look from the driveway will not do in lieu of an inspection.
Does Salt Air Cut Output?
Sea grime in the form of a film over the glass will rob a panel of some of its power. By way of uneven shading it keeps the light from the photovoltaic cells. How much efficiency is lost is a matter of how thick the residue is and how often it is cleaned, among other things.
Do not put it all down to the salt. Add in some dust, pollen, bird droppings, smoke or debris from a construction site and you have a coating that is hard to shift. Performance can be compromised by a thin, uneven film even when the panel is of a presentable appearance. Do not put stock in what you see to make an assessment; the system’s monitoring data will tell you more. Put current production side by side with that from a day with like weather and sun. Should there be an abrupt decline, it could well be an inverter on the fritz, a string that has failed, shading, a tripped protection device or a bad connector, not merely salt.
What The Numbers Mean
One cannot apply a blanket percentage loss to all coastal installations. An array that is clean and properly angled after a good rain may have no discernible salt effect, yet one in a sheltered spot subject to wind-driven spray will wear down quicker between washings. Your baseline is the only figure of consequence: how does your kilowatt-hour output for the day or week stack up against earlier times in similar conditions?
Do not be put off by a cloud or two. But if for weeks on end the output is below par, particularly when the neighbours or historical records show plenty of sun, then have a professional come and have a look. Under no circumstances should one go up on the roof for an inspection. In daylight the solar system is live and a wet roof is treacherous enough without the wind making things worse.
Most Vulnerable System Parts
While the panel surface is where eyes are drawn, the real coastal risk is often in the unglamorous parts. Corrosion of the inverter, the mounting or cable connections will get ahead of any visible failure in the photovoltaic cells and cause issues of safety and reliability.
| Component | Typical Coastal Risk | What To Check |
|---|---|---|
| Metal frames | Surface oxidation, pitting, staining | Edges and clamps for damage or corrosion |
| Mounting structures | Rust, galvanic corrosion, fastener failure | Rails, brackets, dissimilar metals and roof attachments |
| Cables and connectors | Conductive residue, moisture, brittle insulation | Any cracks, sagging or loose plugs, exposed conductors |
| Inverters | Blocked fan grilles and heat sinks, corroded terminals | Unusual noise, overheating, warning codes and salt deposits |
| Solar batteries | Moisture exposure, housing and ventilation problems | Seals, vents, clearances and fault messages from the manufacturer |
Inverters in particular warrant a closer eye given their sensitive electronics and tendency to be sited low on an outside wall. Salt around the ventilation can impede cooling. Be sure to have a licensed professional inspect the unit if you notice any of the telltale signs such as repeated shutdowns, warning lights or corrosion about the enclosure.
The same care is needed with solar batteries. They must be sited with due regard for the maker’s stipulations on temperature, clearance and the elements. A sealed housing is not proof against the humidity of the coast so do not cover the vents or hose it down.
How Far Salt Spray Travels
It is a matter of the coastline, the elevation, the wind and storm and how much the ocean is kept from the roof. You will have a different set of risks with direct surf than at an inland site or estuary where salty winds are a thing of the occasional.
Even a few kilometres out from the beach, airborne salt and coastal humidity can be found, on an exposed ridgeline for instance. Then again, a house some way off with an open ocean view may take more of a beating from the spray than one near the water but behind solid buildings or vegetation.
Leave it to the installer to judge the exposure, a postcode is not a reliable guide. He should be able to give you the particulars on distance to open water, roof orientation, prevailing winds and if the inverter is under cover. An installer of experience will also let you know which products have the salt mist rating and what sort of maintenance the site calls for.
Choosing Coastal-Ready Hardware
A product is only as good as its selection. “Suitable for coastal areas” is marketing talk and nothing more. Get it in writing as to material compatibility, installation limits, warranty exclusions for salt and the like.
IEC 61701 is the standard most often cited for testing photovoltaic salt mist resistance. It is a good benchmark for a buyer to use in comparing panels and inquiring as to how they were tested, but it is no substitute for a proper job and does not ensure uniform performance by the sea.
Materials And Installation Details
Where called for, use marine-grade hardware, aluminium with the right kind of coating and stainless steel fasteners. But the combination is what counts; without the necessary controls stainless and aluminium can still be prone to galvanic corrosion. Make certain the mounting is up to the wind and roof type, that penetrations are soundly sealed and that the cables are managed so as not to pool water. All the strength in a panel is for naught if a bracket rusts out or a cable is chafed on a rail.
Inquiries are made by some owners as to the merits of Solis or other inverter brands. But the brand is not what one should be fixated on. The pertinent questions concern the inverter’s placement, whether its cooling and enclosure are a fit for the site, the warranty provisions for coastal exposure and who is to see to it if there is corrosion.
Coastal Cleaning And Maintenance
Maintenance of a coastal solar system calls for a gentle, preventive and well-documented approach. An overly vigorous cleaning will put seals at risk, leave scratches or force water into electrical components. Left to itself over the years an array can develop a tenacious layer from a film that was once innocuous.
A contractor with the requisite knowledge of roof access and electrical safety is the surest option for most households. One should enquire as to the method of cleaning prior to any work being done and have nothing to do with pressure washers, abrasive pads, harsh chemicals or treading on the panels.
- It is wise to review monitoring data from time to time for any aberrations in power output.
- Have a professional come round for an electrical and visual inspection; the frequency will be dictated by the degree of exposure, and for those living off the open surf more often than not.
- Make sure the gutters, roof valleys and trees in the vicinity are in order so the array is not beset with wet debris.
- Look in the inverter area for any sign of salt, rust, water intrusion or warning lights, as well as obstructed vents.
- Put down on record the dates of cleanings, faults, hardware changes and take photos.
Do not let a calendar dictate your cleaning schedule, conditions should. A roof in the suburbs under cover will not require the same attention as one to the ocean with its winds and salt-laden vegetation. Should a storm pass and you find the inverter has given up, or cables are hanging, or fasteners and panels have been dislodged, then an inspection is in order.
Safe Access And Timing
There are simple but vital logistics to attend to. Ensure the contractor has an unimpeded way to the inverter wall, the side of the roof and the driveway and put any impediments near switchboards or ladders out of the way. Wet or hot weather and wind can make for a longer job; a slippery roof or threatening weather means a coastal inspection is best put off.
Where time is of the essence and there is a matter to put right, put the inverter display, storm damage, any corrosion you can see and the monitoring data first. There is no point in using the morning to give a panel a good scrub when an inverter is at fault or a cable is loose. This is no weekend bushwalk and getting to the ridge is not a contest.
When Corrosion Needs Action
One should not write off corrosion without getting to the bottom of it even if minor staining does not invariably call for a replacement. A professional will tell you if you are looking at a cosmetic matter, a warranty claim or something that has weakened the structure or its electrical protection.
Red rust about the fasteners, pitting, a frame that is cracked, clamps that have come loose, insulation on a cable in bad shape, water in the connectors, an inverter that will not stay on or a protracted drop in output are all cause for a prompt assessment. Equipment is to be turned off only on the say so of a licensed electrician or the manufacturer, given the hazardous energy a battery or solar system can hold.
Whether it is a case of replacing a connector or fastener, part of the mounting, an inverter or the whole array is a function of how much damage there is, the system’s age and what parts are to hand, and if fixing one thing would mean leaving other corroded pieces in place.
Salt And Debris Losses Compared
Both will have an effect on power but in different ways, be it ordinary dirt or salt spray. One will find that debris tends to block the light or put a shade on the surface. Salt is another matter; it leaves a residue that holds moisture and is conductive, hastening corrosion of any metal or electrical components.
Such distinctions are important in making sense of monitoring data. An after-rain upturn in performance could be indicative of surface contamination. But where there is a progressive decline, corrosion marks or faults that keep coming back, one should look for an equipment problem of a more fundamental nature. Debris can be put right with some safe cleaning and the output will be fine; salt damage is another story and may call for the testing and replacing of parts.
The reality is straightforward: you can wash the grime off a panel but not undo pitting, mend a corroded inverter terminal or make good a seal that has failed. Should a cleaning session fail to make any difference, do not persist with it, get the system looked at instead.
For what the Australian Government has to say on household solar and battery matters, refer to their information on solar photovoltaic and battery storage.
Frequently Asked Coastal Questions
What Is The 33% Rule For Solar Panels?
Under the applicable scheme and connection conditions, the 33% rule as it is talked about in Australian rooftop solar circles means the panel capacity can be taken to 133% of what the inverter is rated for. Do not take this as carte blanche for any network or property. There are still product rules, installation standards, distributor and inverter requirements to be met as well as export limits, so the installer needs to give the design his confirmation.
Why Is My Electricity Bill So High With Solar?
A low bill is no sure thing with solar. One can attribute a high bill to a host of things: the household using more power, little daytime use, changes in the tariff, an inverter that is not up to scratch, seasonal variations in the sun, a battery not doing its job or poor output from the system due to shading. Export limits are a factor too. Coastal grime is a possibility but hardly an automatic answer.
What Did Elon Musk Say About Solar Energy?
Musk has been vocal in his support of renewables, batteries and solar in public. Yet individual remarks can be put out of context and they are no substitute for the advice of a licensed installer or for Australian technical and electricity-network standards. When it comes to a coastal system the questions are practical ones of performance, safe installation and resistance to corrosion.
What Is The 20% Rule For Solar?
Without further context it would be unwise to speak of “the 20% rule” as if it were some universal precept for Australian households. It may be an installer’s way of putting it when referring to a design margin, a network condition or a battery setting. Put it to the installer to tell you what the 20% is in reference to and under whose authority.
Do Solar Panels Near The Beach Need Special Cleaning?
More often than not they will warrant a professional clean and inspection compared to those in an inland spot that is sheltered, especially if the humid air is constant or they are in the path of the wind and surf. A non-abrasive method is to be used, never pressure-wash the electricals. Let the monitoring data dictate the interval rather than some generic timetable.
Then again, a coastal solar setup is not a bad investment per se. Provided there is sensible placement, compatible hardware and an honest choice of product along with maintenance to head off trouble, it will serve well. Regard the salt spray as a risk to the whole system and not just a smudge on the glass and the inverter, battery and panels have a far better prospect of being reliable over time.
