Sunday,18 November, 2018
Current issue | Issue 1409, (13-19 September 2018)
Sunday,18 November, 2018
Issue 1409, (13-19 September 2018)

Ahram Weekly

Supporting renewables

Ghada Raafat sounds out leading scientist Hani Al-Nokrashy about the best renewable energy solutions for Egypt

Al-Nokrashy
Al-Nokrashy

Hani Al-Nokrashy is an international energy expert and member of the scientific advisory council to the president of Egypt. In 2009 he was co-founder of the DESERTEC Foundation in Germany, which aims at creating a global renewable energy strategy based on harnessing sustainable power from sites where renewable sources of energy are abundant and transferring it through high-voltage direct current transmission to consumption centres. 

In the same year, the Egyptian government asked Al-Nokrashy to produce a study on the future of electricity production in Egypt, which recommended a gradual but definitive shift to renewable energy. He has also participated in work carried out by the DLR German AeroSpace Centre on renewable energy in the Mediterranean. 

Al-Nokrashy graduated in mechanical engineering from Cairo University’s Faculty of Engineering and obtained his PhD from the Technical University of Darmstadt in Germany. He spoke to Al-Ahram Weekly about the best renewable energy strategy for Egypt.

 

How do you evaluate Egypt’s energy strategy, which targets the diversification of supply?

Any electricity planning must take as its highest priority the security of supply. The diversification of fuel suppliers is the original meaning of diversification in this context, with a view to guaranteeing the security of supply. The strategy adopted now is to diversify electricity production methods, including gas, oil, coal, nuclear and renewables. 

This strategy increases the risk of blackouts because a lack in the supply of one of the fuels, whether gas, oil, coal or nuclear, would cause a gap in the electricity supply as fuel cannot be shifted from one technology to another except under exceptionally expensive conditions.

The renewables that have been adopted in Egypt up to now are wind energy and photovoltaic cells (PV) that convert sunlight directly into electricity. Both are fluctuating sources of energy as they supply electricity only when atmospheric conditions allow. Wind is completely random, and PV operates only during daylight hours. 

From the point of view of electricity supply security, this means that when these sources are unable to supply energy the electrical grid must be able to compensate through traditional energy production methods, which means additional costs. This also means that wind and PV cannot be considered as reliable when planning electricity supply for the future. Only firm capacity can be considered, which comes from the four fossil-fuel sources mentioned.

Another renewable and controllable capacity for supply is the electricity produced by concentrating solar power (CSP), on condition that this provides heat storage for at least 14 hours of full-load production to bridge the darkness during the night. Moreover, there should be hybridisation with another type of fuel to bridge any two or three days of cloudy weather or sand storms (taking place during about one per cent of the year). This already working and proven technology is especially favourable in Upper Egypt, where the sun’s rays are mostly direct all the year round, enabling them to be concentrated by means of mirrors. CSP technology with adequate storage, however, was not considered within the electricity mix adopted in Egypt.

Hydropower, although renewable and controllable, is not available all the year round, and it represents only about six per cent of installed capacity.

 

What is your opinion of clean-coal technology?

Considering coal as a means to secure the electricity supply is quite inadequate, because coal is imported, and it is the most polluting fuel that can be used for electricity production. All countries using coal for electricity production are planning to stop doing so and to replace it with gas and renewables as gas produces half as much carbon dioxide (CO2) as coal. 

Egypt supports the Paris Agreement (COP21) to reduce CO2 emissions, and therefore it is counter-productive to build coal power stations. Egypt’s commitment presented by President Abdel-Fattah Al-Sisi at the COP21 Paris Conference stated that Egypt would promote the “use of advanced, locally-appropriate and more-efficient fossil-fuel technologies, which are less-emitting of CO2”. This has been achieved by contracting three giant gas-combined-cycle power stations, with a net efficiency of over 61 per cent and a total capacity of 14.4 GW.

These points show that the simple diversification of electricity production technologies is not the optimal solution. Instead, this is using renewables as much as they are available — mainly CSP with adequate heat storage — and locally available natural gas.

What is called “clean-coal technology” is a variety of technology used to prevent dust pollution and to remove some poisonous gases emitted from burning coal. The most important technology in this group is “carbon capture and storage” (CCS), which means the CO2 emitted in large quantities from burning coal and causing global warming is captured prior to leaving the chimney and stored in earth cavities, mainly those emptied from oil or gas exploration. This technology has been tested in several pilot projects, however, and it has proved to be inadequate because the storage capacity is limited to 25 to 30 years, meaning it is not sustainable. It has not been used commercially.

Another technology to slightly reduce CO2 emissions involves raising the efficiency of burning coal from about 42 per cent to 47 per cent and increasing electricity output by about 12 per cent at higher cost, thus reducing the emissions of CO2 per kWh produced. Finally, coal is not only polluting but also financially risky as its price varies according to market fluctuations and it must be paid for in foreign currency.

 

Egypt has a lot of sun radiation all year round. What form of solar energy technology might best be implemented in Egypt?

The crowded Nile Valley surrounded by deserts invites the establishment of solar electricity production facilities in the vast deserts east and west of the valley to supply the inhabitants of the cities and villages in it. However, the supply of electricity must be secure. It must be ready at any time on demand and sold at a price affordable to both the rural and urban population and industry. The only technology that fulfils all these conditions is concentrating solar power (CSP).

This is the same technology used in a thermal power station burning fuel to produce heat that is converted to electricity. The difference is that the heat is produced by concentrating the sun’s rays to a temperature of about 550 degrees Centigrade instead of burning fossil fuel. The heat is stored in a mixture of molten salts, a liquid that can be stored in an insulated tank to be used on demand for steam generation that drives a conventional turbine-generator unit. This technology has been successfully used in Spain since 2011.

It is the only technology that uses 99 to 100 per cent natural resources and features a secure and reliable supply of electricity at affordable cost. Water usage is minimised by using air-cooled dry condensers and advanced mirror-cleaning equipment.

Standardising this technology by limiting nominal unit sizes to 20 and 50 MW would enable the mass production of the components of the power stations, thus reducing production costs rapidly. Since these power stations use nearly no fuel, the saved fuel costs can be used to build new power stations according to a carefully designed plan. Small units of 20 or 50 MW could be commissioned in parallel, thus reducing the building time dramatically and making use of electricity produced by each unit when readily commissioned.

Arranging standardised power stations of the same size in groups of five in a local grid parallel to the Nile Valley would give additional advantages. Since in winter electricity demand in Egypt is about one fifth less than in summer, a local grid of five similar power stations could perform annual maintenance lasting one or two weeks in the winter months by closing one power station at a time. The four other power stations would be able to shoulder the reduced winter load. The full load required in the following summer would then be available with freshly maintained power stations.

Adopting such a strategy would relieve the Egyptian grid of increased transmission loads, since each local (five-fold PS) grid would be self-contained — that is, it could work continuously 24/7 and 365 days per year. The choice of suitable locations for the single power stations is also very easy since no fuel pipeline and no water supply is needed.

 

Why has CSP technology not been widely adopted in Egypt? 

The government designed a feed-in tariff for renewable energy by considering only two types — wind and PV — of possible renewables in Egypt. It ignored many other possible energy production technologies, such as biogas from rice straw and electricity from the tides and waves. However, the most important neglected means of electricity production, which is nevertheless especially suitable for Egypt, was CSP technology with adequate heat storage. 

Converting rice straw to biogas protects the environment from in-field burning causing black clouds and converting tide and wave forces to electricity protects the coasts from erosion. CSP enables seawater desalination using waste heat, making it the cheapest available desalination technology. Adopting the strategy described of five connected CSP power stations in a local grid would save transmission-line costs and losses of transmission as well as securing supply even if the main grid is disconnected. Considering all these benefits, CSP is the cheapest means of electricity production in Egypt.

Egypt benefits from a clear sky nearly all the year round, enabling direct sunrays to reach the surface of the earth. These rays can be reflected by means of mirrors and focused to produce high temperatures of above 500 degrees Centigrade. This important local advantage has not been used effectively up to now.

Like for any new technology, the initial costs are high, and private investors may hesitate to start up a project. This can be overcome if a group of investors builds an industrial complex and within the complex the first pure CSP power station with storage to securely supply electricity to the complex is built. Since industry needs electricity mainly during the day time, the CSP power station could then feed surplus electricity out to the grid around sunset in summer, which is the peak hour for domestic consumption, at an agreed price. This would benefit both parties, especially as CSP electricity costs are less than conventional unsubsidised electricity costs in Egypt.

 

What is your assessment of the PV projects in the Upper Egyptian governorate of Aswan, which should generate 1,665 MW of electricity in a year’s time? 

The main advantage of PV is that it can be installed nearly anywhere and connected to the grid. It would have been much more advantageous to distribute the panels throughout the governorates of Upper Egypt, however, so that each governorate could benefit from the electricity injected into the grid and the jobs created.

Concentrating the panels in one spot in the governorate of Aswan brings disadvantages such as a complicated one-spot connection to the grid, including overloading the grid at noon (the peak production of PV), increasing the heat production in the panel field leading to reduced electricity production, and the risk of flames.

Higher ambient temperatures cause a reduction of electricity production in PV panels and probably the quick deterioration of the cells. Therefore, the choice of the hottest governorate in Egypt to install such a large PV field was not necessarily favourable to investors. However, the feed-in tariff is high enough to enable them to cover their costs and to make a profit as well.

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