International standards for the appraisal of wave energy converters

Many countries have enacted laws requiring the increased use of and research into renewable energy sources. The push to increase the use of renewable energy is directly related to the push to decrease the amount of greenhouse gases being released into the atmosphere. Further, there is a desire to increase the amount of renewable energy and rely less on imported energy, such oil and gas. Wave energy has been identified as a potential source for this renewable energy. The development of wave energy converters (WEC) is still in its infancy. There are over 60 concepts that are in different stages of development. These range from concepts to full-size prototype devices and early commercial units. Each WEC has a different method of operation, resulting in different amounts of power production in different wave patterns. The establishment of standards is important to industry development. Different sectors of the industry need a uniform method to evaluate both a WEC and the location for installation. Investors are interested in the power capabilities, power utilities need to look at the grid connection and interface, and insurance companies have to evaluate safe operation. To address these needs, the wave energy industry approached the International Electrotechnical Commission (IEC) to develop a uniform set of standards for marine energy converters. Wave and tidal converters standards are currently being written, although other forms of renewable energy, such as ocean thermal energy conversion (OTEC), could be included within these standards. The standards under development are for the appraisal of converters, resource evaluation, and design. The first standard¹ under development is the Appraisal of Wave Energy Converters. The Project Team 62600-100 is chaired by the United Kingdom and has ten member-countries supporting the development of the standard. Each country has several experts as part of the working group. The standard has been divided into sections, wi- th each country responsible for a section. The United States is supported through the American National Standards Institute (ANSI). Multiple companies, government agencies, and academic partners are voluntarily assisting with their time and expert knowledge in the development of this standard for the United States. The process of developing the first standard is well underway and the issue of this initial standard is anticipated in 2011. The purpose of the standard is to provide a standard methodology of appraising a post-prototype WEC with the creating of a power matrix. The power matrix will be based on wave height and period at the test site. These parameters are critical since electrical power from the WEC is measured in terms of each wave height and period. The standard will be written to support testing at various locations. This requires the definitions of "test sites" and "measurement systems." Critical information for testing a WEC, such as wave patterns, wave height, wave period, bottom features, and bathyme?trie data, will be clearly defined within the standard so comparisons can be readily made across the wide range of devices. The uniform understanding of the wave pattern, including the wave front direction, height, and period, are needed to predict the available wave power and the subsequent development of an accurate power matrix. This paper looks at the development of a methodology for appraising a WEC using the IEC standard. To date, the WEC standard has gone through several revisions for both methodology and prescriptive changes. Each change requires the experts to understand and agree to the change. This process of standard development and other considerations are discussed.