The summer months are always a critical time for Saudi Arabia's power sector. Demand soars in line with air-conditioning usage and outages are not uncommon. But this year will be particularly testing for the electricity authorities as peak summer temperatures are set to converge with Ramadan and the start of the new school year.

These events individually are sufficient to cause surges in power demand, but coming all at once they will place the kingdom's electricity networks under even greater pressure.

In the summer of 2008, Saudi electricity consumption peaked at 38,000MW. With total installed capacity in the country at 39,242MW, demand came dangerously close to exceeding supply, leaving a reserve margin of just 3.2 per cent. This compares with the industry norm of at least 10-15 per cent. Reserve margins exist to provide back-up in the event of a breakdown in the system or sudden increases in demand.

Power demand has been growing in Saudi Arabia by about 7 per cent a year and Saudi Electricity Company (SEC), the kingdom's principal electricity provider, is engaged in an uphill struggle to bring new capacity on line quickly. Consumption is forecast to peak at 41,065MW this year and rise to 65,360MW by 2018.

Power shortages

SEC has already had to implement temporary power shutdowns at the industrial zone in south Jeddah due to a temporary shortage of generation capacity. Industries located in the zone are currently being denied power from 1pm to 4pm to avoid longer blackouts.

"Some of the generation units are out of service, but when they restart the situation will improve," says Bander Allaf, senior trans-mission engineer at SEC.

"We have a limited timeframe before reaching the summer so we are trying our best to bring all the units back into service. Some units are down for maintenance, but some are unplanned outages."

To meet future demand requirements and rebuild the reserve margin, 8,542MW of new generation capacity is under construction in the kingdom. Projects to add a further 4,760MW of capacity have been committed to and another 15,715MW is in the planning phase. In total, 29,017MW of new power capacity is due on stream by 2018 at a total cost of SR206bn ($54.9bn).

But of course, insufficient generation is not the only cause of summer power outages in Saudi Arabia. Weaknesses and overloading of transmission and distribution networks also lead to failures in the power system. For example, in May there was a partial blackout in the Mecca area when a 380kV transformer tripped.

Rapid demand growth has put a huge strain on the kingdom's power networks in recent years, and projects to strengthen the system have suffered delays because of the sheer amount of work involved.

"There has been some delay with new substations and this has caused congestion in the transmission networks," says Allaf.

Nonetheless, SEC has several projects it hopes to wrap up in the coming weeks, including upgrading the substation that failed in May, which should bolster the network ahead of the summer peak.

"A third 380kV transformer will be located in the Mecca area in South Aziziah substation," says Allaf. "We are also expecting two new 110/13.8kV substations in Mecca, one in Medina, three in Jeddah and one in Taif, which is supposed to come into service soon."

A new gas turbine is also due to start up at the Rabigh 2 power plant, which will strengthen generation capacity.

The main draw on the power supply during the summer months is for air-conditioning units. "One of the major challenges we have in both the central area and the western region is the need to support the system voltage, especially after major faults, which cause a phenomena called 'motor stalling', resulting from a large amount of air-conditioning load," says Allaf. "After any fault, especially a three-phase fault in the 380kv network, there will be a delay in the voltage recovery due to the motor stalling."

Faults in the transmission system cause the line voltage to dip, and during the high-load season, the voltage recovers to a level that is insufficient to reaccelerate the motors of air-conditioning systems, which then stall and demand high current from the system. The low voltage following the clearance of a fault not only causes outages but can also damage equipment.

To reduce this problem, SEC has installed three large static var compensators (SVCs) since the summer of last year: two in the Jeddah area and one in Medina. SVCs block the motor-stalling phenomenon and facilitate the quick recovery of voltage. "We have seen a lot of improvement in voltage profile after faults, especially after single-phase faults, after installing the new SVCs in Jeddah and Medina," says Allaf.

Outage solutions

SEC is also working on a longer-term project to build a national grid that will connect the electricity networks of the western, central, eastern and southern regions of the kingdom. The internal interconnections are intended to improve the stability and reliability of the networks, and to enable reserve sharing across the country, which will decrease the capital investment needed in each region and reduce the amount of reserve capacity needed to be held overall.

The central and eastern regions are already linked through two 380kV double-circuit lines and one 230kV line. The utility is in the process of studying the interconnection of the western and central regions, and the western with the southern region via 380kV connectors. There are no plans to connect the two isolated networks in the northern area.

"The western and southern regions will be connected through a 380kV connector, but at the moment the highest voltage level in the southern region is 132kV and they still do not have a 380kV substation," says Allaf, explaining the slow progress on the project. "So we have two phases. Phase one will interconnect the southern region itself on a 380kV network, and phase two will connect that with the western region through the Shuaibah-Namera line."

The estimated completion date for the interconnection of the western and central regions is 2011, and 2014 for the western and southern regions.

The western region has the most to gain from a national grid. It is the largest operating area in the kingdom as it includes the major population centres of Jeddah, Rabigh, Yanbu, Medina, Mecca and Shuaibah. It has had the most rapid growth in consumption in recent years and has to contend with the demand surges generated by the millions of Hajj and Umrah pilgrims who visit the kingdom each year.

This year, electricity demand in the western region is expected to peak in mid-August at 11,670MW. This is more than double the lowest consumption period experienced in the second week of January, and 9 per cent higher than the 10,700MW peak recorded in 2008.

With a national grid, the western region would be able to draw on reserves from other areas within the kingdom in an emergency situation, and even from neighbouring countries via the GCC electricity grid.

Phase one of the GCC grid, which connects Kuwait, Saudi Arabia, Bahrain and Qatar, has already been energised and the entire project is scheduled for completion in 2010. Without the completion of the Saudi grid, the use of the GCC interconnection would be limited to central and eastern parts of the kingdom.

"One of the key reasons for the interconnection between the western and central region, which is already connected to the eastern region, is to transfer power to the west," says Allaf. "The interconnection is expected to provide up to 1,400MW of additional power."

The eastern region currently delivers about 2,500MW to the central operating area. An additional double-circuit 380kV line is in the process of being installed, which will increase the interconnection capacity to 3,500MW.

The connector between the western and southern regions is intended to have a capacity of 800MW.

A $2bn project is also under way to build a 1,400-kilometre-long, 500kV electricity interconnection between Saudi Arabia and Egypt.

The 3,000MW link will allow the two countries to trade energy during peak consumption, which in Saudi Arabia falls between 1pm and 4pm, whereas in Egypt it occurs after 8pm.

Canada's SNC Lavalin was awarded the consultancy contract for the scheme in June and the firm will now prepare the requests for proposals for the engineering, procurement and construction parts of the project.

A feasibility study has also been conducted on an interconnection between Saudi Arabia and Yemen.

But these are all long-term projects. For the time being, SEC's attentions are firmly focused on making it through the next three months with as little disruption to services as possible.

In the past, the utility has been threatened with legal action by customers claiming loss of earnings and damage to machinery following sudden outages. It will be hoping to avoid a repetition this summer.