The Solar Lifecycle

2023, Aug 20    

With the uptake of solar power and the ease of spotting fields covered in panels as you drive along many of the UK roads, I started questioning the lifecycle of these and what the desired end-state may be. As a topic covered in many apocalyptic games (i.e., the end of the world yet power stations have continued to run unmanaged) I figure the evolution of the usage of solar panels has to be along the same lines (even if there are significant challenges).

Speaking of challenges, let's start with the biggest: longevity. Most solar panels available for purchase today have an expected maximum age (from an efficiency perspective) of around 10 years. Due to the solar panel chemistry as the cells within the panels age their efficiency drops (similar to that of the battery of your phone after many recharge cycles). To remove the maintenance overhead the panels need to have an unimpeded efficiency-over-time, whereby the age of the panel doesn't matter providing it is kept in good condition. As battery chemistry is improving each year towards the same goal, solar panel chemistry will likely go the same way (while also increasing their power output).

At the point where we have highly efficient solar panels that don't deteriorate over time, what is the next inhibitor? Well, realistically that is dust / dirt / grime. Depending on the climate / area, solar panels need to be cleaned to ensure they make the most of the available sunlight. With a few panels on a rooftop this is relatively easy (a jet wash with a long-reach pole), but for thousands of panels per field, not so much. Following with the theme of being automated, a possible solution would be to attach cleaning jets to each panel, allowing high-pressure water to be sprayed at/onto the panel to rinse off any dust/dirt/residue. This, when combined with the equivalent of a ceramic coating (to ensure the glass is as slippery/non-stick as possible) could make it viable (without the need for moving brushes etc).

While the above sorts the end-stage of the cleaning, the water is still required to make this work. Standard tap water won't cut it (as the impurities / limescale would block the nozzles over time), and an underground water supply might not be viable either (depending on the area). To design around this a potential solution is to extract moisture from the air (similar to a dehumidifier) and filter/purify it. This process does use some electricity, and the filter arrangement would need to be significant (to remove the need for replacing them periodically), but would provide purified water that can be used to spray the panels to keep them clean. This water also helps prevent the blockages in the pipes over time, and helps keep the pumps happy.

So now there are panels that will last indefinitely and a cleaning solution that follows the same principal, what else is missing? Well, the ground that the panels sit on. Most solar panel installations are on grass-covered fields which realistically will continue to grow. While concrete (or similar) is an option, it brings its own problems and realistically isn't practical. Moving the grass can be performed via automated lawnmowers (these have been around for some time), however we then have the issue of blade sharpness over time / motor longevity / battery longevity / unexpected obstacles. While blades can be made of more expensive materials that won't blunt for extended periods of time and motors can be made brushless with the best bearings available, batteries would need to evolve so they can be recharged indefinitely without deterioration. Even with this there are still challenges around the disposal of the grass (as mulching it will only get you so far, and isn't practical come the start of Spring). Maybe an artificial surface is the way to go.

There are numerous technology enhancements / evolutions that are required before the above can be achieved, but with renewable energy being big business (not to mention good for the environment) it's realistic to assume the big players will be working on this to lower their maintenance overheads. For me at least, it will be interesting to see what is developed over time.