Coming from the Greek word for “water”, hydro applies to rivers and oceans. IEC standardization work for the first covers both large-scale and small-scale river projects, while ocean power is new for us as we began considering the subject recently for its potential to require standards (the market for this is still largely in the research and development stage).
Some of the world’s biggest hydroelectric power plants, in terms of both total installed capacity and annual average power generation volume, produce millions of kilowatts and billions of kilowatt hours. At the other end of the scale are small, micro- and pico-hydro stations. For us, “small” means up to 15 MW. Microhydro schemes can be as large as 500 kW and are generally run-of–the-river developments for villages. Pico-hydro systems have a capacity of 50 W to 5 kW and are generally used for individuals or clusters of households.
IEC Technical Committee 4, Hydraulic turbines, set up in 1913, prepares standards and technical reports for designing, manufacturing, commissioning, testing and operating hydraulic machines. Its focus has been, and at present remains, river projects. These include turbines, storage pumps and pump-turbines of all types as well as related equipment such as speed governors and performance evaluation and testing. For now it focuses on river power.
The two main forces driving much of TC 4’s work are, on one hand, new large-scale hydroelectric river projects in Asia, the Russian Federation and South America and, on the other, refurbishment and up-rating of existing plants in North America and Europe. As a result, the work programme focuses on turbine runners and pump impellers, acceptance tests of hydro turbines, control systems testing, and evaluating both cavitation pitting and discharge measurement methods, as well as hydraulic turbine efficiency, vibration, stability, upgrading and rehabilitation. Particle erosion is a potential future topic for TC 4.
Ocean energy devices work with tides or with waves, although ocean currents are another potential source of power. These devices are either floating or fixed and, to generate electrical energy, they tend either to oscillate or to rotate.
Research appears to have started in Japan in the 1940s, the technology for it has been around since the 1970s and functioning units have been deployed in various countries in the 1990s, mostly as prototypes. In 2007 the IEC created TC 114, Marine energy - Wave, tidal and other water current converters, to begin preparing standards for this emerging field of technology.