Value for money of wind farm project

Reference is made to the letter of Marco Cremona (January 8). The "amiss" lies in drawing conclusions based on the US wind farm figures without understanding the underlying assumptions.

The Cape Wind project in the US will consist of 130 turbines, each rated at 3.6 megawatts, resulting in a total wind farm capacity of 468 megawatts. Mr Cremona's assumption that the 400,000 US homes will be consuming 31 units per day of electricity from the project is definitely wrong as it means that the wind farm would generate 4526 gigawatt hours of energy per year. This implies a wind farm capacity factor of 110 per cent! Theoretically no energy plant can perform with a capacity factor of more than 100 per cent.

Existing wind farms in the North Sea, which are known to benefit from very good wind conditions, operate with capacity factors of 35 - 48 per cent. Although the US Cape Wind Project will have a total installed capacity of 468 megawatts, it is expected to generate an average of 170 megawatts, which implies a capacity factor of 36 per cent. This is a realistic figure and is equivalent to 1490 gigawatt hours every year. Therefore if one assumes Mr Cremona's quoted figure of 31 units per day for US homes, wind farm will actually generate electricity for 132,000 homes and not 400,000 homes.

On the other hand, the estimate of 21,000 households for Sikka l-Bajda is based on a household electricity consumption of 13 units per day. If this is translated to 10 units per day, the Maltese wind farm, which is much smaller than the US counterpart, will supply enough energy for 27,000 households.

The US wind farm is being quoted to cost €711 million which is equivalent to around €1,500 per kilowatt of installed capacity. This was the price of offshore wind farms five years ago and does not reflect the current market scenario. Unfortunately, the capital costs of wind farms, onshore and offshore, have increased significantly over the past three years as a result of the large demand for wind turbines, lack of availability of transport and installation equipment and the increased costs of raw materials. For this reason, it is very much likely that the US wind farm will in fact turn out to be significantly more expensive than originally quoted.

So taking the above into consideration, concluding "that the Maltese wind farm will be 10 times less cost-effective than its American counterpart" is absurd. Despite being expensive, an offshore wind farm at Is-Sikka l-Bajda is expected to generate energy at a lower cost that small-scale renewables. The project, contrary to what Mr Cremona stated, will not be financed through public funds but by third-party investors and the government will purchase the generated electricity at an agreed tariff.

Is-Sikka l-Bajda is the only shallow water site available around the Maltese islands that offers two important advantages compared to the other sites: (1) the site is large enough to house a reasonably sized wind farm that can contribute significantly to the 10 per cent target. Developing other sites implies smaller projects which are more expensive in terms of euro/ kilowatt. This results from various factors that affect the economies of scale; (2) the site is the furthest one away from the shore and populated areas.

As with other wind farm projects, the Sikka l-Bajda proposal will have to be evaluated in further depth for its economic feasibility and to ensure that any possible impacts are environmentally sustainable. The government will soon be launching a project intended to collect high quality wind data in the area. Through sophisticated computer modelling, it will be possible to correlate the collected data over a short period of time with climate data for the region to derive the long-term wind resource at Sikka l-Bajda.

Contrary to what has been commented by Mr Cremona, the government is not concentrating solely on investigating the offshore site at Sikka l-Bajda and excluding the possibilities of land-based projects. The government affirms its position that onshore sites also need to be assessed for their potential for harvesting wind energy.