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Wind Revolution

Mohammed Atif, area manager Middle East, DNV GL Energy, on the potential for wind power in the Middle East

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DNV GL Energy, Middle east, ANALYSIS

The process of identifying potential wind farm sites is time consuming, risky and expensive. To help project developers and planners, wind maps can be used to provide a preliminary prediction of the wind speed potential over a large area.

Derived from state-of-the-art meso-scale modelling techniques, these predictions can be delivered before any measurement equipment has been installed at a site or even before it has been visited. Recently, DNV GL has issued wind maps of Oman and the UAE and hopes to continue this throughout the MENA region to facilitate a better understanding of the wind potential in the region.

A recently published report, by the Abu Dhabi-based International Renewable Energy Agency (IRENA) and the League of Arab States also states that the region’s wind resource, though concentrated within certain geographical pockets, still shows promise.

In particular, the Atlantic and Red Sea coasts show potential for large-scale wind farms, as the wind speed in these areas frequently exceeds the 6.9 meters per second (m/s). The Gulf of Suez area in Egypt, probably the most wind prolific region, enjoys annual average wind speeds of between 7 m/s and 10 m/s, well above the 6.9 m/s economic threshold.

Morocco and Oman have also demonstrated significant wind potential, with speeds that meet the threshold and full-load wind hours of 2,708 and 2,463, respectively, which is similar to a capacity factor of around 30%.

Advances in Technology
The wind turbine market is continually evolving, with a general trend towards machines with larger sizes and rated capacities.

The main design drivers in the selection of machines to be used at a site include: site access and civil engineering issues; cost and proximity of grid connection; local exposure of the wind farm site; relative cost of wind turbines per MW installed; track record of wind turbines under consideration; and planning acceptability.

There is currently a strong drive towards larger machines from the offshore market where there are substantial benefits to be gained from the use of large rotor diameter machines with turbines of up to 7 MW in prototype testing.

The largest machines cannot yet be considered to be proven technology. There are, however, a number of machines around the 2.5MW size with rotor diameters in the range of 90m to 130m that are beyond the prototype testing stage and are in commercial operation.

The large rotor diameter machines enable greater wind capture, which in turn produces more energy at a reduced cost. The result is exceptional profitability in areas with low wind, and new frontier for wind energy development.

A range of turbine hub heights, the distance between the ground and the rotor, are available for machines in the 2 MW to 3 MW range. The hub height is generally cost-optimised for each specific site taking account three things: The increase of mean wind speeds with height and therefore energy production of the turbine with higher towers; Increased cost of higher towers and consequential increase in foundation costs; External constraints, e.g. planning restrictions.

In some regions, it is possible to deploy low wind speed technology such as the conceptual work undertaken for Sir Bani Yas Island in the Emirate of Abu Dhabi.

In this area there are relatively low wind speeds (4-5 m/s) but advances in turbine and blade technology are allowing relatively larger full-load hours to be produced from low wind speed regions. There has been a technical and economic feasibility study completed for a 30MW wind farm on the island.

Major turbine manufacturers, such as Vestas, Enercon and Siemens have, among others, developed new wind turbines with large rotor diameter that can harness energy from low average wind speed sites. Wind energy development in countries such as, Switzerland, Germany and some areas of Western Europe has been further enhanced with these technological developments.

DNV GL’s Head of Renewables in the Middle East, Khaled Klabi states that the “Levelised cost of energy (in a mature market) with a capacity factor of 30% can reach $80/MWh, which is increasingly competitive with other forms of conventional power generation and renewable energy options.”

Morocco, Egypt, Jordan, and the Kingdom of Saudi Arabia have announced wind power generation targets amounting to thousands of MW of installed capacity over the coming years.

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System Integration
System integration becomes an increasingly important issue when power generation from intermittent resources approaches 10% of total system generation.

One of the challenges is to maintain stability in a power system with increased wind power and maintain an economic, reliable and secure power supply.

Countries would need to adopt new guidelines and tools for optimal scheduling of all power stations, control and monitor wind generation and forecasts by defining the most suitable system for wind power forecasting, and design a real-time system for monitoring and control of integrated generation technologies with the SCADA/EMS to facilitate future market operation.

In any power system considering the uptake of increasing levels of energy generated by wind turbines, the following elements need to be considered: Assessment of power system, grid code, wind integration impacts; Guidelines and procedures for improved operational dispatch techniques; Set of minimum technical requirements for new wind farms; and Conceptual design of real-time system for monitoring and control of wind generation, providing the minimum specifications for accuracy, resolution, interfacing with upgraded SCADA/EMS.

In terms of the grid, power systems have to supply both active power and reactive power in order to establish a balanced and secure supply. With increasing levels of wind generation on the system, conventional plants are reduced.

This means that in order to compensate, further regulating technology such as static VAr compensators (SVCs) and static synchronous compensators (Statcoms) are needed. These technologies help provide fast acting reactive power for high voltage electricity transmission networks.

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Innovative use in Enhanced Oil Recovery (EOR)
As wind power technology matures, research and development is looking to harness the technology for other applications that are valuable for the region. This could be relevant for mature oil fields in the Middle East where associated gas is currently being used for EOR.

Water injection (WI) is extensively used for enhanced oil recovery. It is one of the main consumers of electrical energy on an oil installation. In most cases, dependent on reservoir properties, water injection can operate with some degree of intermittent power supply. This makes it an interesting candidate for renewable energy sources such as solar and wind (see Box 1).

There are numerous areas where focus is required in order to ensure the successful integration of wind into the region’s power system. This includes adoption of the technically best option, system operation alignment; grid integration, stability and innovative solutions.

It is also clear, as with solar power that the installed unit cost of wind power has progressively decreased to make it more competitive with conventional power generation and other renewable energy technologies.

Enhanced oil recovery (EOR)
Wind-powered water injection could be a cost efficient and clean means to maximise production rates.

- Cost reduction: when the distance from the reserves to the water injection template is large, stand-alone systems could provide a cost effective alternative, considering cable costs and power demand on host platform.
In cases where power is needed and space on the platform is not available, this solution can save the need for costly retrofitting

- Flexibility: stand-alone systems could more easily be located at the sites where boosting has the most effect. For offshore applications, floating wind turbines are flexible with respect to water depth and distance from platform.

- Technology development: wind-powered water injection can serve as a stepping stone, both for commercialization of floating wind technology, and as the first step towards an autonomous offshore power system that can be used for a larger number of applications

- Reduced need for alternative power: wind-powered water injection reduces the need for associated gas in relation to the power demanding WI activities, hence extending the lifetime of the existing solution. It can also reduce the need for power from shore in electrification cases

- Cleaner power generation: WI is a power consuming activity. By less dependence on gas turbines on the platform, oil recovery can be achieved without increased emissions

DNV GL invites the industry to jointly evaluate the technical and economic feasibility of wind powered water injection systems.

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