Prof. Chandre Dharmawardana

A floating solar array system installed recently in France.

According to an Islan d news report (http://www.island.lk/index.php?page_cat=article-details&page=article-details&code_title=216282), His Eminence Cardinal Malcolm Ranjith says no to coal, and environment-friendly power projects which utilize renewable energy sources such as wind and solar power must be prioritized.
The Cardinal is said to have made this remark when Minister of Transport Service Management and Minister of Power & Energy Mahinda Amaraweera called on him on 23rd December.  

So, while there is an increasing understanding of the imminent threat of global warming, as well as the  need to move away from Coal, Liquefied natural Gas and other fossil fuels, the so-called hard-lipped CEB engineers and others, as well as many politicians continue to favour fossil fuels. The previous Minster of Power, Mr. Ravi Kaunanayake is said to have even contracted  power suppliers stationed on ships, and  at great cost to the public purse to bridge the power gap”. Mr. Karunanayake is not a person very concerned about costs as he did not even know the rent paid for his own pent-house lodgings and how it was paid by an aptly named perpetual treasury”. But, even more than the cost, the long and short-term health costs and environmental costs have to considered. They are irreparable, irreversible.  People contract diseases and die from the fumes of fossil fuels, their sub-micron sized particular dust that  compound with the already critical levels of  toxins coming  from the congested traffic and  farm equipment that  burn fossil fuel.

The CEM engineers support fossil fuels claiming that solar and biomass energy sources are not adequate to meet the peak-to-trough power  fluctuations and also bridge the currently existing  power gap. We show  below that the use of floating solar arrays coupled to hydro-electric power, together with bio-mass energy provides the needed firm power and gird stabilization within an inexpensive rapidly installable off-the-shelf technology.

Furthermore, there is NO REASON WHAT SO EVER to go to fossil fuels, when we look at recent reports from the CEB itself. A news report in the Island (http://www.island.lk/index.php?page_cat=article-details&page=article-details&code_title=215912) says that the recent rains have shown that when the reservoirs (Tanks) are filled to capacity, Hydro can produce 70% of the total power”

During the dry period, they produced about 15-20% of the total power. Thus on the average they can produce about 40.% of the total power. However, most of the tanks have not been de-silted according to schedule. If such de-silting is done and full capacities are addressed in other ways too, this AVERAGE can be topped up to 50 or 60%.

In addition, we can increase the capacity of power generation very rapidly, i.e., within two years by using the now virtually turn-key setting up of floating solar arrays. I proposed these for Sri Lanka in 2008-2009 (at a meeting held at  the Presidential secretariat) when the technology was not even patented.. Patents came in by 2010 and now China is the world leader. The great advantage of floating solar panels is that we can set them up on the water surface of existing reservoirs. If you take a reservoir like Randenigala as an example, if we cover 50%-75% of the reservoir surface with floating solar panels, even if the panels did NOT operate, we increase the out put of the turbines because evaporation of water is reduced by 30%. That is, the annual capacity of 500 Gwh is increased  to 650 GWh. Furthermore, the solar panels are capable of producing energy at least at an average of 6 hours per day right through out the year. The energy is produced during the day time. Then, during that time that energy is used for supply to the grid while  an equivalent amount of water is saved in the reservoir for night use. That is, the solar energy is SAVED WITHOUT BATTERIES. And has become, in effect, firm power available at all times as stored water.

This power alone is more than the power that will be produced by the proposed coal pwer plant which will come into action only several years down the road, while solar arrays can e set up within two years and after that there is no need to have annual imports of coal and fossil fuels.

In effect, it is easy to significantly increase  the capacity of each of the reservoirs very simply and cheaply by  introducing floating solar arrays in every one of the hydro-electric reservoirs of the country. This gives us more than enough firm power to meet the peak-to-tough energy demand fluctuations and stabilize the grid.

France has just installed the largest floating solar reservoir last October. But China still has the world’s largest floating solar array. The technology is simple. It merely requires putting the solar panels on floater pontoons and connecting them up to the national grid.

The floating solar arrays give us more capacity for generating power than any other method available WITHOUT cutting into natural habitat, or mobilizing the roof tops of private citizens and having to deal with re-strengthening roof structures, and legal issues of  many net suppliers. By cutting down the sunlight reaching the water in reservoirs, great environmental advantages are obtained  by reducing the growth of algae aand other biomass in the reservoir and also by reducing silting. Of course, only a part of the water surface is covered.  Studies have also shown that the fish and other aquatic creatures are much better off as the reduced asphyxiating  bio-mass (like Salvinia”) leaves behind more oxygen for aquatic creatures like fish, frogs and other biota.

In addition to floating solar arrays coupled to hydro-power installations, we also need bio-mass (Dendro)  energy as a standby for extreme droughts. If we set up 75 new Dendro plants within the next three  years, each with a capacity of 10 MW, we have an energy capacity of 750MW, which is more than enough to cover the current energy gap and  peak  demand. There are many bio-mass sectors like castor, cinnamon, coconut husk etc., that are not exploited for bio-energy so far. Rubber seeds rot in the ground in most rubber plantations although they are a great source of energy. Castor grows rapidly like a weed, , and the seeds, stems  and tree can all be burnt to produce electricity using standard technology.

Unlike coal, LNG and other fossil fuels, sunlight and biomass need not be imported annually. They are inexpensive, negligibly polluting and available as well tested off-the-shelf technologies.  

So the Minister must please take note of these while the new broom sweeps clean – and clean out the  Aegean stables of the CEB and get Sri Lanka’s energy policy on the correct path.

 Prof. Chandre Dharmawardana