I have written about a few different floating solar projects recently. These floating platform-based power plants are ideal for countries that don't have much land to spare for large solar farms. They can be built over ponds, lakes and reservoirs and help to prevent water evaporation and algae overgrowth. Floating solar panels seem to be catching on, but there is one place for which they haven't seemed well-suited: the ocean. As with any technology that dares to reside in the rough environment of the sea -- offshore wind turbines, wave power buoys, etc. -- building something that is both tough enough to withstand harsh conditions and light and flexible enough to be effective (and not totally cost-prohibitive) is very tricky. Researchers at the Vienna University of Technology think they have developed just the right combo with their Heliofloat concept. These floating solar platforms meant for any body of water including the ocean, are lightweight and flexible enough to bob with the waves while remaining steady on the surface, even in rough weather. The key to this, the researchers say, is that the bottom is supported with open floatation devices as opposed to closed ones. "Were a platform to be simply mounted onto air-filled, closed containers, the design of the construction would have to be inefficiently heavy and robust in order to be able to withstand heavy waves," said explains Professor Markus Haider, from the Institute for Energy Systems and Thermodynamics. The floats look like upside-down barrels made out of a flexible material. The barrels create a column of air over the water that allows the platform to float and also acts as a shock absorber, while the soft material of the barrels absorb small, horizontal forces. The result of this is that the waves rise and fall beneath the platform while the platform itself stays steady above the water. A closed air floatation device would absorb so much of the wave energy that the platform would ultimately break. The researchers believe that this design would allow floating solar installations the size of football fields to grace the coast of countries that don't have the land to spare for large solar power projects or over lakes where water evaporation is a problem. In addition, the Heliofloats could be used in sea water desalination plants in areas that need more clean water. A very small-scale prototype will be unveiled at the Hannover Messe trade fair and the researchers are in discussions with investors to produce large-scale versions.
Power grids have evolved historically. Large sections of them date back to times when power distribution requirements were very different from today. In future, electricity generation will be further decentralised, with alternative energy providers feeding energy into the power grid. Electricity generation and storage will be integrated, all the way to the level of individual households. There have been various attempts to adapt power grids to these challenges but none of them solves all problems in a sustainable way. Power engineer Albana Ilo, from the Institute for Energy Systems and Electrical Drives at TU Wien, is convinced that we shouldn't be satisfied with merely stopgap solutions. She has completely rethought the basic power grid concept, and is now able to present 'LINK', a new smart-grid paradigm aimed at making our power grid fit for the future. LINK re-organises the management of networks, electricity generation, energy storage facilities and consumers by dividing the whole system into clearly defined units ('links'), each with its own control system and clearly defined interfaces to their adjacent unit. This should result in a better, simpler and more automated electricity industry, whilst providing greater stability and solving data protection issues. There is no doubt that we need new electricity supply solutions. "For years, we have been discussing new concepts such as virtual power plants or 'microgrids'" says Albana Ilo. Virtual power plants combine a large number of small, decentralised power generators. This allows them to compete in the market, but some technical problems remain: They cannot be controlled as easily as a large power plant, and large quantities of data have to be constantly exchanged in order to keep the system working. Microgrids are network parts that can be thought of as quasi-independent units, in which power generation and consumption are kept more or less in balance. However, splitting the whole power grid into manageable, autonomous units is not an option. When we build large offshore wind parks at sea or huge solar power plants in the desert, it is not possible to view the power grid merely at a local level. The electricity market, the management of the networks and the actual physical aspects don't necessarily fit together. Physically, the power grid is divided into a high-, medium- and a low-voltage grid. There are also power stations, storages and consumers to add to the mix. Albana Ilo thinks that the management of the power grids should be divided along precisely these lines. The individual elements in her LINK paradigm fit together like links in a chain that can be combined and connected as requirements dictate. In Ilo's concept, a high-voltage grid – Austria's for example – will be managed separately, based on a physical model. Using clearly defined interfaces, it communicates with neighbouring high-voltage grids and the subordinate medium-voltage grids. This system of linked elements continues right down to household level. Each 'link' receives input from its neighbouring elements and then decides which actions need to be taken. This means it will not be necessary to send large volumes of data to a central coordinating centre. "With regard to data protection, it's a huge advantage", emphasises Albana Ilo. "Nobody would want utility companies to be able to collect data about individual devices being switched on and off in their own house. In our LINK paradigm, this is no longer necessary." Each link shares only a small set of absolutely necessary electrical data with the neighbouring units, the rest of the information is used only locally. The danger of cyber-attacks from outside is thereby reduced drastically. LINK leads to a new kind of power grid operation, which is consistent with physical aspects of the power grid. "Today, electricity can be sold from the North Sea to Italy. Physically, however, the electricity might flow via the Polish grid, which can become overloaded - although the country is not even involved in the deal", explains Ilo. In a LINK system, this would be easy to manage. The individual high-voltage LINKs would automatically adjust all parameters so that such transactions could be carried out smoothly. The risk of major blackouts would be eliminated. Instead of making further small adjustments and implementing emergency solutions, complicating an already outdated power grid system, LINK could be a clean, fresh start across the whole system. After many years of research in industry and academia, Albana Ilo is convinced that this is the only way for the large scale integration of decentralised energy resources into a secure and stable power grid. A resilient, self-regulating operating system would also minimise the need to expand the network: "The European power grids still have capacities", explains Albana Ilo. "We just need to make the most of this." A small-scale pilot project in a test region in Salzburg has already shown that the concept works. A gradual transition from the current system to the LINK paradigm would be possible. "It's not an overnight process, or even something can be achieved in just a couple of years," says Albana Ilo. "However, the transition to a smart power grid is possible, and if we take the move to "Energiewende" seriously, we should start now." Explore further: Energy transition project moves into its second phase
Hentschel J.,Institute for Energy Systems |
Babic U.,Paul Scherrer Institute |
Spliethoff H.,Institute for Energy Systems |
Spliethoff H.,Bavarian Center for Applied Energy Research
Energy Reports | Year: 2016
Conventional generation units encounter a changing role in modern societies' energy supply. With increased need for flexible operation, engineers and project managers have to evaluate the benefits of technical improvements. For this purpose, a valuation tool has been developed, comparing economical cornerstones and technical constraints of generation units to European Energy Exchange prices for PHELIX 2014. It enables the user to relate a change in technical parameters to an economic effect and possible revenues. Four different types of conventional power plants are investigated in scenarios with increasing CO2 and fuel prices to determine the impact of different flexibility options. Results show that an increased ramp rate has not the same magnitude of positive economic impact as reduced minimum operation load, based on an observation on a price signal with resolution of fifteen minutes. © 2016 The Authors. Published by Elsevier Ltd.