Solar power? We’d better be careful

Dear Editor,

I see quite a bit of attention being given to solar power in our news media specifically to our rural areas as possible sources of primary power for hinterland villages such as Mabaruma. I would like to advance a few thoughts before I rush in to praise these initiatives, since I believe that this approach may be fraught with some danger. For example, this appears in the weather for Guyana website: “In the north-west (see Mabaruma), there is no real dry season, but only a relative decrease in precipitation: here even September and October are quite rainy, with around 200 millimetres (8 inches) per month…” All of this rainfall must be accompanied with very overcast skies. So Mabaruma would actually be the worst part of Guyana to build a solar farm for the community.

There is no doubt that in Guyana with electricity so expensive and unreliable that some people benefit from solar power as a “stand by” or backup power source, rather than a prime source, opting instead for diesel-powered generators, for example, Banks, DDL, the seafoods guys, etc.

This matter first came up when we had international consultants here to advise us on the possibilities of aquaculture in this country. They advised us that based on their experience in Venezuela, where they were doing a major aquaculture project, and which has a very similar weather pattern to ours, that we should seek to grow our fish and shrimp here in a semi intensive/extensive manner, since to grow our aquafarms in an intensive culture [more fish per cubic ft of water] would require significant stirring of the ponds with big paddle wheel implements, to keep the Dissolved Oxygen [DO] at a good level throughout the depth of the pond, requiring a substantial electrical supply at the ponds. They also identified power generation for pumping water into the ponds and maintaining them at the necessary level, as problematic economically in view of our high cost of electricity from GPL. When I looked at solar power, I ruled it out as probably unreliable since overcast conditions and high rainfall expectations in Guyana are a reality, and I agreed with the consultant that we should work with semi extensive cultures. But I was at all times seeking to see if solar power was feasible here as prime power in our fish cultivation and discovered that the majority of sources agreed with the consultant, that as a standby source of power it can work, but not as a reliable primary source of power, since we can never count on two sometimes even three sunny days in a row during any of our two rainy seasons, which can be as much as 5-6 months a year.

On 15th June 2018 I took this passage off the internet, “Solar panels generate the most electricity on clear days with abundant sunshine (not surprisingly). But, do solar panels work in cloudy weather? Yes… just not quite as well on a cloudy day, typical solar panels can produce 10-25% of their rated capacity. The exact amount will vary depending on the density of the clouds and may also vary by the type of solar panel; some kinds of panels are better at receiving diffuse light. SunPower solar cells, for example, have been designed to capture a broader range of the solar spectrum. By capturing more red and blue wavelengths, their solar panels can generate more electricity even when it’s overcast”. Are we aware of all of this?

Clearly if one is depending on solar power for a field of tilapia stocked with 20,000 fish per acre instead of the 10,000 fish as in semi extensive stocking cultures, and the rain falls three days in sequence and cannot provide power for the nights to keep the ponds aerated, all the fish will die. I don’t know what our Guyana Energy Agency is doing or has done on this matter as legitimate research, and if they have conducted proper trials to determine what will happen with the solar farms around the country which can in fact be nonfunctional for numerous hours per day and more at night during many months of the year.

But the situation in time will not be fatal since there are steps being taken to rectify the dilemma in other ways such as  “Ultraviolet light also reaches the earth’s surface in abundance during cloudy days (if you’ve ever been at the beach when it’s cloudy and gotten a sunburn, you’ve experienced this firsthand). Some solar cells are in development that can capture UV rays, although these are not out on the market yet”. They are also developing panels which work in rainfall i.e. “Rain means clouds and clouds mean less sunlight. That’s bad news for most solar cells, but a new design can actually make use of rain drops that fall on its surface, allowing it to generate electricity even when the weather’s bad.”

Yours faithfully,

Tony Vieira

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