Direct Drive for Economically Sustainable Wind Energy
a report by Andrew Tan
Head of UK Corporate Development, Zenergy Power
In early 2009, the European Wind Energy Association (EWEA) produced one of the most valuable tools for mapping out what are likely to be the dominant commercial trends in the global wind industry over the coming years. In its 156-page report ‘The Economics of Wind Energy’, the EWEA set out to build a holistic financial framework within which the economic factors governing the commercial success of wind energy projects can be identified. Furthermore, the research ranks individual economic factors in terms of their marginal impact on the overall cost of producing wind energy over the lifetime of any wind project. In doing so, the EWEA analysis spells out the most important considerations that wind project developers face and the factors most strongly impacting their commercial decisions. In identifying where returns can most effectively be improved it also maps out the medium- to long-term trends for innovation and technology investment within the industry’s entire supply chain.
Considerations Impacting Commercial Decisions Full Load Hours
Foremost on the EWEA list is the total number of full load hours (FLHs) accumulated by installed wind turbines over the lifetime of a project. A 90% increase in FLHs results in an approximate halving of energy production costs. Second to this is the cost of financing. Wind projects (advocates of replacing the UK’s market-driven Renewable Obligations Certificate system with fixed feed-in tariffs take a well-deserved bow).
At its most basic, the FLH issue boils down to the simple fact that the more hours a turbine runs at its maximum rated power level, the more electricity it will produce each year and the lower the per unit cost of production becomes. Unlike thermal power, the marginal cost of energy production for wind turbines is zero. Borrowing a phrase from real estate agents, the crucial thing about achieving maximum load hours is ‘location, location, location’. On average, onshore sites achieve around 2,000– 2,500 FLHs each year compared with an average 4,000 FLHs for offshore sites. The attraction of a potential doubling of FLHs should not be underestimated and already this is leading to a growing determination to deploy wind turbines in offshore environments – despite the increased challenges in engineering and operations. In fact, the EWEA forecasts that the percentage of turbine investment in offshore sites will rise from 25%
Andrew Tan is Head of UK Corporate Development for Zenergy Power plc. His professional career began in banking at Goldman Sachs where he worked for two years before turning his attention to the funding and development of small innovative technology companies. Mr Tan has worked with a number of clean technology companies and joined Zenergy Power in 2008.
E:
Andrew.Tan@zenergypower.com
in 2015 to about 60% by 2030. The impact of this trend on innovation and technology investment is already visible within the industry.
Economies of Scale
A further factor driving innovation and technology investment is the economic benefit of installing larger rated turbines. For example, the average cost of electricity production at a coastal site has decreased from approximately €0.09/kWh for a 95kW rated turbine to approximately €0.05/kWh for a 2Mw turbine. Put simply, the larger the rating of your electricity generator, the proportionally smaller your infrastructure costs become per installed Mw. Look no further than the release by REPower and Multibrid of 5Mw turbines or Clipper Wind’s development of a 10Mw turbine or the growing development of large-scale blade technology to see the trend set in motion by this economic reality.
Reliability
Inevitably the success of producing the most cost-effective wind turbines for the offshore industry will have a direct impact on the future shape of the wind industry as a whole. As windpower developers seek higher rates of return from their offshore locations by deploying ever-higher rated turbines, the one factor that becomes ever more critical is reliability. Reliability in the offshore market is of critical importance to developers, as the time to repair turbines can be greatly extended by harsh weather conditions that restrict accessibility for maintenance work. Extended repair times lead to increased downtime during periods of strong winds, typically associated with the best power generation conditions and so a substantial loss of FLHs. Overall, reliability of wind turbines comes from a huge range of factors, such as:
• operations and maintenance procedures; • monitoring equipment; • use of new materials; • better control systems; and •
experience (the learning rate within the industry currently sees a 9–17% reduction in cost for every doubling of installed capacity).
These factors are driving a multitude of innovations. To date, extraordinary progress is being made in many areas of wind turbine components. However, one issue that continues to afflict the industry is the reliability of the drive train. Put simply, one of the major challenges in producing wind energy is taking power captured by slow spinning turbine blades (rotating at between 15–24rpm) and turning it into usable electricity using high- speed generators (rotating at between 1,500 and 3,000rpm).
The Effect of Innovation and Technology Development The Mechanical Approach
To date, the industry has relied on a traditional mechanical engineering approach to the problem of bridging the gap between
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