Sea, sun and earth

Standardization and certification for renewable sources

By Morand Fachot

As energy demand keeps rising countries seek to cut their reliance on fossil fuels for economic and environmental reasons. REs (renewable energies) are set to play a role in this shift. Along traditional RE sources, such as hydropower, wind energy and PV (photovoltaic) energy conversion, marine energy and solar thermal are now playing a growing role in energy generation, whilst long-established geothermal energy is also expanding. All rely on IEC standardization work.

Atlantis AK 1000 tidal turbine waiting to be lowered onto the seabed (Photo: Atlantis Resources Ltd) Exploiting the oceans’ power
Atlantis AK 1000 tidal turbine waiting to be lowered onto the seabed (Photo: Atlantis Resources Ltd)

Exploiting the oceans’ power

Marine energy potential is huge, but harnessing it presents particular challenges, which explains why investment in this sector has been relatively modest so far compared to efforts in other renewables. As oceans represent a huge source of power that can be partly converted into electrical power, the drive to develop existing or new technologies led to the creation of IEC TC (Technical Committee) 114 in 2007.

Its title: Marine energy – Wave, tidal and other water current converters, gives a clear indication of its scope. TC 114 is also open to "other conversion methods, systems and products" and as such exploring the potential of exploiting river currents.

The TC’s remit is to prepare International Standards that allow technologies to evolve beyond the early stage of development, where they have remained for some 30 years, to reach full commercial deployment.

To achieve this objective, TC 114 has adopted a structure that brings together, as of October 2014, nearly 120 experts from 14 Participating countries and 10 Observer countries into 10 PTs (Project Teams) and 3 AHG (ad hoc Groups).

The TC prepares International Standards that aim to address essential aspects of marine energy conversion, that include, among others: design requirements, performance measurement of wave, tidal and water current energy converters, resource assessment requirements, design and survivability, safety requirements, power quality, manufacturing and factory testing, evaluation and mitigation of environmental impacts.

OES (Ocean Energy Systems) forecasts that "by 2050 ocean energy will have grown to 337 GW of installed wave and tidal energy capacity", from well under 1 GW today. This expansion will be made possible in no small part by the pioneering standardization work carried out by TC 114.

Tapping the sun’s energy

CSP (Concentrating solar thermal power) has long been viewed favourably by the wholesale energy sector. It comprises a range of technologies that are used to collect and concentrate sunlight, turning it into medium to high temperature heat. This heat may then be used to generate electricity in a conventional way using a steam turbine or a Stirling engine, or used in other applications, for example supplying process heat.

With the exception of dish-Stirling systems in CSP power plants, the solar energy is typically absorbed by a heat transfer fluid, such as oil or molten salts, which is then passed through a heat exchanger and its associated steam circuit. To prepare International Standards for CSP, the IEC created IEC TC 117: Solar thermal electric plants, in 2011.

One of the most significant advantages CSP has over other solar energy technologies is its ability to partially decouple plant output from solar insolation using energy storage. Unlike electrical energy, thermal energy is relatively easy to store. Associated with thermal storage solutions, new CSP projects can provide electricity 24 hours a day, seven days a week. CSP is in the relatively early stages of global development and International Standards help provide a foundation upon which to develop new technologies and enhance existing practices.

Elisa Prieto, director of strategy of Abengoa Solar and an Expert with TC 117, stresses the advantages of developing a comprehensive system of International Standards for CSP, saying: “In a very global world, where tenders are international, those people who are organising tenders ― they’re usually governments ― need to be sure that the requirements they are asking for are met and the only way they can do that is through Standards”.

Heat from deep inside the earth

Geothermal energy, heat from the Earth, is an abundant form of renewable energy that has been used in different civilizations and regions since ancient times to heat buildings and water. Its exploitation in small and large scale applications that include power generation is expanding rapidly throughout the world, proving particularly attractive for countries without easy or affordable access to other forms of energy.

A number of IEC TCs prepare International Standards for components or systems central to its development. Indirect use of geothermal energy for heating and cooling of buildings is widespread. It doesn’t necessarily require hot sources but often relies on constant temperatures found close to the surface, where heat from the ground is absorbed by fluids circulating in underground pipes and extracted using heat pumps during the cold season. The process can be reversed in the summer to transfer heat back into the ground, using it as a heat sink, to help with cooling.

International Standards for heat pumps are prepared by IEC SC (Subcommittee) 61D: Appliances for air-conditioning for household and similar purposes. The application of geothermal energy in power generation is relatively recent. It is now expanding rapidly throughout the world.

To produce electricity from geothermal resources, wells are drilled into geothermal reservoirs to bring steam or hot water to the surface, where the heat is converted into electricity at a geothermal power plant using steam turbines. Steam turbines, which use heat to drive generators, were first introduced in the 1890s. Most of the electricity produced in the world today is generated by them. The development of power generation from of CSP and geothermal sources would not have been possible without steam turbines.

Steam turbine technology is mature and International Standards prepared by IEC TC 5: Steam turbines, have contributed to the expansion of the sector. These Standards concern specifications, as well as acceptance tests related to the accuracy of various types and sizes of turbines and of speed control systems.

IEC standardization work and certification system central to RE expansion

Expanding electricity generation from ocean, solar or geothermal sources to meet current and future energy needs, depends to a great extent on standardization work from a number of long-established and newly-created IEC TCs and SCs.

The IEC recently introduced IECRE (IEC System for Certification to Standards Relating to Equipment for Use in Renewable Energy Applications). As commonalities can be found in the technologies used for generating energy from the sun, the wind or the oceans, IECRE currently covers solar PV energy, wind and marine energy with the possibility of including other technologies such as CSP, fuel cells and geothermal energy in the future. IECRE was created because renewable energies require an approach that covers the entire lifecycle of equipment in RE sectors.

Atlantis AK 1000 tidal turbine waiting to be lowered onto the seabed (Photo: Atlantis Resources Ltd) Exploiting the oceans’ power Atlantis AK 1000 tidal turbine waiting to be lowered onto the seabed (Photo: Atlantis Resources Ltd)
Ivanpah solar electric generating station - a tower receiving system (Photo: NREL) Ivanpah solar electric generating station - a tower receiving system (Photo: NREL)
Bjarnarflag geothermal power plant, Iceland (Photo: Landsvirkjun) Bjarnarflag geothermal power plant, Iceland (Photo: Landsvirkjun)