Thailand touts master plan to float 2.7 GW of solar on reservoirs

It seems that when it comes to renewables, Thailand is not so shabby at thinking outside the box – it has come up with a plan to cover its dams and reservoirs with floating solar panel farms, getting two types of renewable energy in the physical space that would normally be reserved purely for hydro. The 16 solar farms, across 9 dams to be built by 2037, will collectively be the largest floating renewable energy platform ever built – although as more countries catch on – it may well be surpassed quite rapidly.

The State-run Electricity Generating Authority of Thailand (EGAT) said this week it would run its first auction in two months’ time, for an “exemplar” installation for a 45MW floating solar plant on the Sirindhorn dam in the northeast. The full 16 projects are likely to produce as much as 2.7 GW for the country eventually.

There are a lot of positives to be had from floating solar on a lake, not a sea. First off that Lake usually is a source of freshwater, and the solar sitting on top will reduce evaporation – and funnily enough the solar works better, because it is cooled by the water, and pushed into a more productive temperature, or at least it is in hot countries. Running cooler makes the panels last longer, creating a more effective economic project life – which makes the investment easier to pay back. On the other hand, if you over cover a reservoir too aggressively, you risk killing all the wildlife in the lake from lack of sun.

Quite a few places in South East Asia have escalating land costs, due to more intense agriculture and exploding populations, and the local electric companies already own the dams – and the surface of the water. They also have in place a connection to the grid from running hydro power – so lower infrastructure costs.

Interestingly as climate change melts the glaciers in mountain ranges, water will flow more rapidly to the sea, which in Asia means instead of monsoon waters lasting 9 months of the year, existing as slowly melting snow, that water can be back in the sea in as little as three days if not collected in some way. A strategy involving the use of far more dams to hang onto the precious water for both drinking and irrigation, will have the double whammy of creating the opportunity for more floating solar farms as well.

Other candidates for the largest floating solar platforms include the Singapore development from the Sunseap Group, in the Strait of Johor, but there it is in the constantly moving sea, and the cost of building it is less clear and likely to be considerable higher as it needs to be more robust and exposed to greater corrosion. This was announced back in November 2018 and when complete will generate 6.4 GWh of electricity a year although Sunseap has never mentioned its peak output, and it is likely far less than the Thailand adventure.

Wind is on the verge of shifting to floating platforms rather than those embedded in the sea’s bed, and over the coming 5 years will increasingly be placed just out of view slightly more than 20 kilometers from shore. This will lead to more expensive Wind power compared to onshore, in terms of how difficult it is to conduct maintenance and also to create cabling to bring the electricity back to shore. Onshore wind is generally understood to be the most cost effective form of renewable energy right now, and offshore is about to take that step closer to the economics of onshore as major research projects come to a head.

But even offshore wind has long lead times, as lengthy consultations have to be undergone to establish the threat to fishing and shipping and planning to avoid conflict.

Thailand feels that the inherent advantages of reservoir floating solar , including slightly more efficient operation and reduced property costs, and reduced costs of connecting to the grid, and these counter the extra cost of building them on water – and that may make them cost effective as of right now. We shall see.

China is thought to have around 1.1 GW of floating solar capacity but the largest individual installation is around 150 MW, about three times the size of the trial installation which Thailand is looking to build now. India earlier this week announced a push to install 100 GW of new solar capacity by 2022, and is researching the feasibility of getting 10 GW of that from floating solar. But currently its largest installation is a 500 KW plant at Banasura Sagar reservoir in Kerala, so just how it is going to get to that mark is tough to see. Let’s see if Thailand forges ahead.

The bidding for the first floating solar project will begin in two months and will be open to international companies, with a budget of the local currency equivalent of $63 million.