Challenges in meeting President’s target

Development of renewable energy projects II –

By Dr Janaka Ratnasiri

The comments made by the President at the meeting he had on 15.12.2020 to discuss the development of renewable energy (RE) projects were highlighted in recent media reports, as described in the writer’s earlier write-up which appeared in The Island of 28.12.2020 under the same heading. However, there was no reference in these reports to any feedback that would have been made by officials present. The purpose of this write-up is to discuss likely issues that would have been of concern to institution officials and the challenges they may have to face in meeting the President’s target.

FEARS OF DESTABILIZING THE SYSTEM

The first challenge is to change the mindset of professionals concerned. Energy experts both within the Ceylon Electricity Board (CEB) and outside have been saying for years that connecting too many of RE plants such as wind and solar power systems to the grid will cause its destabilization, not being able to maintain the voltage and the frequency within permitted limits. The output of these RE supplies keep fluctuating momentarily, hourly and diurnally and the problem is how to balance the supply and load under such dynamic conditions. It was also said that excess harmonics generated during conversion of direct current (DC) output from solar systems or from DC wind turbines into alternating current (AC) for feeding into the grid could degrade the quality of the supply.

According to a website on RE systems, “Impacts caused by high penetration levels of intermittent renewable distributed generation can be complex and severe and may include voltage increase, voltage fluctuation, interaction with voltage regulation and control equipment, reverse power flows, temporary overvoltage, power quality and protection concerns, and current and voltage unbalance, among others. The uncertainty and intermittency of wind and solar generation are major complications that must be addressed before the full potential of these renewables can be reached”. These challenges require advanced control strategies to solve the problems effectively.

PROBLEMS ASSOCIATED WITH RENEWABLE ENERGY SYSTEMS

One problem associated with RE systems is that they are not considered dispatchable, which means that their output is not available as and when necessary, unlike in the case of thermal power plants. Wind power output is available only when wind blows which keeps changing in a stochastic manner hourly, diurnally and seasonally. In Sri Lanka, wind is generally strong during the second half of the year than in the first half. In the case of solar panels, their output is available only during the daytime peaking at noon and declining with the increasing solar angle. Even during daytime, the output would drop if there is cloud cover or rainfall. If there is extended periods of bad weather, a consumer has to depend on some back-up power.

According to the CEB Chairman’s Review given in its 2018 Annual Report, “a study on Integration of Renewable Based Generation into Sri Lankan Grid 2020-2030 was conducted during the year (2018) with the objective of investigating the main challenges faced in renewable energy-based generation and determining the optimum level of renewable energy generation”. However, there is no report of this study available in the CEB’s website.

STORAGE SYSTEMS FOR RENEWABLE ENERGY PLANTS

In order to make use of solar energy that is generated during the day, at night time, it is necessary to store the electricity by suitable means. This also applies to wind energy to even out the fluctuating output into a steady output. If the system is connected to the grid, energy generated by solar systems during the day or by wind systems when the wind blows can be fed into the grid and the grid provides the electricity to the consumer during night time or when there is no wind blowing. Hence, there is no need for a separate storage facility with grid-connected systems.

For large scale solar systems, one method of storage is to make use of exiting hydro power reservoirs by saving the water which would have been used for generating an equivalent amount of energy generated by solar panels during the day, and using the water saved during night time. This does not require any additional expenditure on building extra facilities. Another is to build pump-storage facilities comprising two sets of reservoirs at two elevations connected via a penstock with a generator/pump system at the bottom. Already one such system is being planned at Aranayaka.

Any surplus energy generated during the day from solar panels or when wind blows is made use of to pump water from the lower reservoir to the upper reservoir. At night time or when there is no wind, the pumped water is allowed to flow down the penstock driving the pump in the reverse mode to generate electricity. In the West, such pump-storage systems have been used for many decades for peaking purposes. One good example is the system installed at the Niagara Falls.

HYDROGEN SYSTEMS FOR STORAGE

Another method available is to feed the solar panel output to a set of electrolyzers, which are available commercially today, to generate hydrogen by splitting water. Hydrogen generated is stored and fed to a bank of fuel-cells to generate electricity in the form of direct current (DC) and later inverted to AC. After filtering out harmonics, this steady output is fed to the grid as and when necessary, day or night, using the stored hydrogen which makes it dispatchable. Each solar or wind or hybrid energy park that is being planned could be supplemented by such hydrogen storage system accompanied by a bank of fuel cells, enabling the output from these RE parks dispatchable.

There is much interest among developed countries to develop hydrogen energy systems. European Union has set out plans which could require up to € 470 billion (USD 570 billion) of investment in green hydrogen by 2050. Germany alone is targeting 5,000 MW of electrolysis capacity by 2030. Japan, a front-runner along with South Korea, is looking to sharply increase a target to import 300,000 tonnes a year of hydrogen in 2030. U.S. President Joe Biden wants to fund research into technology, including large-scale electrolyzers, to help make green hydrogen costs match conventional hydrogen within a decade. (https://energy.economictimes.indiatimes.com/news/renewable/explainer-why-green-hydrogen-is-finally-getting-its-day-in-the-sun/79672523).

PROPOSAL FOR ROOF-TOP SOLAR INSTALLATIONS

The 2021 Budget Speech states that a capacity of 500 MW will be added to the grid, by providing solar panels each generating 5 kW, to 100,000 houses of low-income families. At the meeting the President had on 15.12.2020 with the two Ministers and Ministry officials, he has said that the Government would bear the cost of LKR. 800,000 per house for installing solar cell panels under this project. This means the expenditure on this project will be about LKR 80 billion. The question arises who will be responsible for implementing this project? The SLSEA Act grants powers to it for “entertainment of applications for carrying on of on-grid and off-grid renewable energy projects”. It also has powers for “the development of guidelines on renewable energy projects and disseminating them among prospective investors”. Hence, the SLSEA may be assigned the task of coordinating the project.

The purchase of 100,000 roof-top panels and getting them installed is a challenge by itself. There is a large number of local companies, numbering about 200, involved in supplying and installing roof-top solar panels. The government should call for expressions of interest (EOI) from these companies to undertake this assignment requesting information on their track record and proof of their ability and competency. Next, bids need to be invited from selected companies after announcing detailed specifications for the panels.

It is important to specify in the bid document itself the limiting values for key parameters with tolerances that need to be met by the panel offered, without just saying that panels offered should conform to international standards, as normally done by the CEB. The evaluation of the bids would be much simpler and faster then. It is best if the supply is distributed among as many vendors as possible, after agreeing on a fixed price, to expedite the implementation of the project and avoid complaints from unsuccessful bidders.

POOR PLANNING FOR RENEWABLE ENERGY PROJECTS

Though the Cabinet of Ministers since 2016 has been taking decisions to introduce RE projects including solar power systems at both domestic level and utility scale, their follow up by the two implementing agencies, viz. SLSEA and the CEB has been rather slow, possibly due to divided responsibility. According to the SLSEA Act, any RE project needs the approval of the SLSEA before commencing any work.

The Electricity Act also requires accepting projects selected only after calling for tenders except those recommended by the SLSEA. The misinterpretation of the Electricity has resulted in projects recommended by the SLSEA getting held up by the CEB for extended periods. The CEB’s draft LTGE Plan for 2020-39 prepared in May 2019, plans to add only 165 MW of mini-hydro systems, 555 MW of wind systems, 880 MW of solar systems and 55 MW of biomass systems up to 2030. Even the SLSEA has failed to come out with a plan to develop RE systems in an optimal manner as highlighted in the Writer’s article in the Island of 28.12.2020.

This is despite the fact that the previous Cabinet decisions had wanted about 2,000 MW of solar power added within a shorter time frame, comprising 1000 MW of roof-top systems and 1000 MW of utility systems. As mentioned in the previous article, even the SLSEA has failed to come up with a plan to develop RE systems though it is a requirement given in its Act. So, another challenge is to get the CEB and SLSEA to enhance their plans for RE generation and fall in line with the Government policy. If they do not comply, the solution is not closing down of the PUCSL as highlighted in writer’s article in The Island of 25.12.2020. (See https://island.lk/cabinet-discussion-on-public-utilities-commission/)

INCOMPATIBILITY OF NEW COAL POWER PLANTS WITH INCREASED RE SHARE

One problem possibly encountered in increasing the RE share is the incorporation of several new coal power plants in the system by 2030. This increases the share of fossil fuel share leaving only a small fraction to be filled by RE systems. For example, the draft Plan for 2020-39 shows the demand in 2030 as 31,740 GWh, out of which 20,640 GWh (65%) will be from fossil fuels and 11,100 GWh (35%) from RE sources. Out of the 20,640 GWh expected from fossil fuel plants, 7,721 GWh (24%) will be from the two new coal power plants to be built at Norochcholai (600 MW) and Trincomalee (300 MW). Another 4,781 GWh (15%) will be from the existing coal power plant at Norochcholai.

This means by 2030, 12,502 GWh (39%) of the demand will be met from coal while another 8,140 GWh (26%) will be from oil or jointly 20,640 GWh (65%) from fossil fuels. If 70% of total demand is to be met from renewables, then only 30% could be generated from fossil fuels. This means that the RE contribution has to be 48,160 GWh if the fossil fuel contribution is to be maintained at 20,640 GWh, making the total supply to be 68,800 GWh, which is more than double the forecasted demand in 2030. In order to make achieving of 70% share from RE sources feasible, it is therefore imperative to limit the fossil fuel contribution to 9,520 GWh in order to maintain the total supply at 31,740 GWh.

The easiest way to achieve this target is to stop building the two new coal power plants at Norochcholai and at Trincomalee, and retire the 20-year-old existing coal plant at Norochcholai. Hence, building new coal power plants is not compatible with President’s target on RE share of 70% in electricity generation. The President should therefore give a clear directive to CEB to discontinue planning of new coal power plants disregarding what its Unions say.

It is reported in the media that a former Army Officer has been appointed as Vice-Chairman of CEB to help CEB “to achieve President Gotabaya Rajapaksa’s of goal promoting renewable energy and providing electricity at a minimal cost” (Island of 22.12.2020). Perhaps the new Vice-Chairman will keep those within CEB who oppose President’s move at bay, including the trade unions.

IMPROVING RESEARCH CAPABILITY OF CEB

According to the CEB Act of 1969, CEB has powers to conduct research into matters affecting the generation, distribution, transmission, supply and use of electricity (Article 12h). However, CEB’s Annual Reports do not refer to any research being done within the CEB. Students in the Physical Science stream having the highest scores at GCE (A level) examination get admitted to engineering courses and those who follow electrical engineering ending up in institutions like CEB.

It is a pity that the CEB management does not make use of this talented graduates to undertake research to seek solutions to such problems such as integrating RE systems into the grid, develop new storage systems and to provide other research and development support for RE systems. In 2019, the CEB has spent about LKR 97 Billion on importing fuel for thermal power plants (SD 2019).

With the introduction of large scale RE systems, part of this expenditure could be saved which could be utilized to set up a Research and Development (R&D) Division in CEB as provided for in its Act.

Perhaps, a senior academic with research experience in RE systems could be invited to set up the R&D Division and provide him with a team of young engineers comprising both electrical and ICT engineers with aptitude for research to undertake studies on how to make the grid smart as described above.

THE WAY FORWARD

If the full potential of the country’s RE resources is exploited, it will be possible to achieve the entire electricity generation from RE sources. It will also save hundreds of Billions of Rupees annually on importing fuel required for operating thermal power plants. However, there are many problems to surmount before this could be achieved. Among these are the following:

a. Change the mindset of senior officials controlling the power sector that changing from fossil fuels to RE sources to meet the base load requirements is technically feasible.

b. Discontinue building new coal power plants and retire the existing coal power plant by 2030 as their presence will exceed the 30% share from fossil fuels.

c. Introduce mechanisms for energy storage at utility scale through utilizing existing hydro power reservoirs or building pump-storage systems or adding large batteries or adding electrolyzer-fuel cell systems which are commercially available now.

d. Set up a R&D Division within CEB to seek solutions for problems associated with integration of utility scale RE systems into the grid.

e. Entertain investors directly for RE projects on build, own, operate and transfer (BOOT) basis by providing efficient, clear and transparent mechanism for accepting proposals and guaranteeing security of their investments.

f. Publish a set of guidelines prepared jointly by SLSEA, CEB and PUCSL for accepting and approving candidate RE projects proposed by investors on BOOT basis.

CONCLUSION

It is important for decision makers to take a wholistic view of the power sector in the country and take evidence-based decisions rather than taking a piecemeal approach. It is not possible to build more coal power plants on one hand and fix targets for increased RE share on the other. While the President wants more renewable energy projects, the Ministry and CEB want more coal power plants. The President should decide on his priorities. If his priority is to have more renewable energy share by 2030, then he should get CEB to give up building more coal power plants. He cannot have both. It is his biggest challenge.