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China Special - Offshore: Due diligence vital in move to offshore

For China to maximise its potential for offshore wind power development, it would do well to heed the lessons learned from the European industry and avoid some of the early costly mistakes it incurred.

Over the last decade China's electricity requirement has increased by around 110%, supporting ongoing industrialisation and rising levels of personal wealth. The line that "China is commissioning a new coal-fired power station every week" has become so well used in environmental circles that it has come to represent the futility of taking local action against climate change. Yet, in 2008 China installed more wind power than any other country except the United States - a massive 6246 MW. In this one year China installed almost twice as many megawatts as the UK has installed in total. This year, it is likely to top the table for installed wind capacity.

There is no denying that China has jumped into the wind industry with a real sense of purpose, but so far the focus has been on exploiting the onshore wind resources in areas such as Inner Mongolia. However, the recent installation of turbines for China's first offshore wind farm, Donghai Bridge, near Shanghai (see page 18), marks the start of a burgeoning offshore wind industry.

To discover the potential and challenges for China's offshore wind market, we can look at the history of the industry in Europe. Here the offshore market has already taken off, and lessons that have been learned can be applied to the future industry in China.

European Example

Europe's offshore wind industry dates back to 1991, with the commissioning of the 5 MW Vindeby project, comprising 11 Bonus 450 kW machines, off the coast of Denmark. Eighteen years later, there are still no operational offshore wind farms outside Europe. So why has the rest of the world not yet followed Europe's lead?

There is no doubt that progress in Europe has been driven by strong political will, an excellent wind resource, shallow waters and a mature wind turbine manufacturing industry. This has allowed projects to be developed that, with the right support mechanisms in place, are technically, economically and environmentally attractive.

Combine this with the limitations for new onshore wind farms in the typically small, densely populated countries of Europe with arduous planning systems, and it is perhaps natural that offshore wind is attractive here.

Despite these favourable conditions, Europe's offshore industry development has not had an easy ride. Construction of the projects has often been over budget and behind schedule, with installation vessels that are expensive and hard to get hold of. In operation, a number of high profile technology failures have dogged turbine manufacturers and project owners, resulting in expensive repair bills and significant loss of power generation.

High capital costs and significant risks involved in developing offshore wind projects have limited the main players to the large utilities with their deep pockets and strategic reasons for increasing renewable generation capacity. Only more recently have banks started to be comfortable with lending to offshore wind projects, allowing smaller developers to come into the industry.

On the operational side, there is still very limited capability for offshore operation and maintenance (O&M) in the marketplace, with virtually all O&M being carried out by the original turbine manufacturers. Costs have risen (Windpower Monthly Europe Offshore Special Report, September 2009) and with ambitious installation targets in Europe, an increasing shortage of suitable personnel, equipment and vessels is likely.

While Europe has been on this often painful journey to maturity, countries such as China have focused on developing simpler, cheaper onshore wind projects on their considerably larger land banks. But they've been keeping a weather eye on Europe's offshore progress, and the installation of the 100 MW Donghai Bridge project signals that they are ready to get their feet wet. For a successful transition to offshore it is essential that the Chinese industry learns the lessons from Europe.

To maximise revenue, site selection must be carefully considered - locating wind farms in a favourable wind resource while minimising the construction challenges to keep capital costs down. Ongoing O&M and electrical transmission costs should also be considered at this stage. The difficulty of access and maintenance in the offshore environment means that turbine reliability must be top priority in both design and quality. Condition monitoring should be employed to forecast failures and undertake proactive maintenance. Operation and maintenance strategies must be optimised to maximise the accessibility of the turbines and also ensure that large crane vessels are readily available for major component replacement.

The European offshore wind industry does not, however, hold all the answers for the expansion of the industry in China. There are crucial differences that will require new solutions. Most significantly, the wind regime in China is not the same as in Europe, where the excellent offshore wind resource - typically over 9m/s - enables economically viable projects.

The Chinese coastline tends to experience lower mean wind speeds (see map page 12), but also suffers from typhoons that regularly sweep along the coast in some regions. This is an engineering challenge for manufacturers, calling for a turbine with a large rotor to catch as much energy as possible from moderate resources for most of the year, but that can also withstand very high wind speed gusts during typhoons.

The lower mean wind speeds along the Chinese coast also means that for projects to be economically feasible, the capital outlay will need to be lower than in Europe, making effective site selection critical. Many areas of the Chinese coast are technically and environmentally suitable for offshore wind farms. But, in order to minimise installation costs, the sites should also be suitable for simple single-pile or gravity-base foundations. This means they should be in relatively shallow waters, where tried-and-tested installation using jack-up barges can be used. Grid connection points with adequate capacity also need to be easily accessible.

The use of locally manufactured turbines can also reduce capital costs when compared to European turbines, but the offshore track record of the turbine must be considered to ensure that a saving in capital cost does not result in high maintenance costs and low availability.

Calculating the cost

Underpinning these requirements is the need for a suitable tariff structure for power generated by offshore wind farms. The Donghai Bridge project currently receives a tariff of CNY 0.97/kWh ($0.142/kWh). There is a significant difference to the UK market, where offshore wind gets around CNY 1.58/kWh ($0.23/kWh).

It may be possible to install and operate offshore wind more cheaply in China but, when considering the significantly lower wind resources available, it seems likely that the Chinese authorities will need to increase their tariff to enable the Chinese wind industry to develop financially feasible offshore wind farms.

By invitation Richard Boddington Wind Analysis Manager SgurrEnergy Ltd

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