Polaris solar PV net news: Germany is PV installed capacity in the world’s largest country, in promoting photovoltaic development policies, management and technology experience for many countries in the world to follow suit. PV industry development is never plain sailing, Germany also in photovoltaic development process of a grid operating high pressure continues to increase, new energy subsidies leads to problems such as electricity prices rise too fast. Analyze Germany problems in large scale PV development and solution, summarizing related revelation, PV provides a useful reference for China.
Germany PV development update
In 2014, Germany have photovoltaic power generation for the first country in the world for 9 years in a row. By the end of 2014, Germany the photovoltaic power generation capacity of about 38.2 million-kilowatt at that time when the PV reaches 32.8 billion-kilowatt, total generating capacity of about 6.3%.
PV has become Germany’s largest power supply. By the end of 2014, Germany photovoltaic generating capacity accounted for Germany total electricity installed capacity of 21.5%, the highest proportion. Renewable power generation, PV installed capacity accounts for most, 43.5% per cent of installed capacity of renewable energy. In addition, on June 9, 2014, Germany PV instantaneous output over load 50%.
Germany PV market has entered a stable period of adjustment, PV development growth slowed markedly. Germany photovoltaic market developments experienced startup and rapid development, rapid expansion of the market and a smooth adjustment of four stages.
Germany August 1, 2014 the new edition of the renewable energy law requiring Germany future PV annual count size limit of 240~260 million kW. In 2014, Germany PV installed capacity is about 1.8 million-kilowatt, slightly lower than the policy objectives, new installed capacity size decreased significantly, PV growth rate slowed markedly.
Caused by technical problems and solutions
The effects of large scale PV is no longer confined to the distribution network, the system security and stability concerns. Germany PV grid shows three characteristics, large-scale distributed photovoltaic integration will not only have an impact on distribution networks, but also had an important impact on power system safe and stable operation.
Distribution network and device overloading problems caused by grid-connected photovoltaic voltage increase is more prominent. Voltage rise is one of the main impacts of solar access distribution networks. In the conventional power transmission mode, the direction of the current is the single, from the generation of electricity to users, and voltage decrease with distance and power level. After a large number of distributed PV grid connected, especially in fragile or distant power due to distributed PV offset user load to line even at light loads the trend reverse, higher voltage will become a prominent problem.
In addition, with the increased access for distributed power levels, reverse power occurs more frequently. Reverse power may be higher than the capacity of the transformer or a line, caused by transformers or circuit overload.
For bulk power system safe and stable operation, PV balance of influence manifested in the active pressure. PV has a typical daily variation characteristic of large scale PV will significantly change the system power load curve, increase operating pressure. In addition, PV output of large forecast errors, will also increase system security risks.
In addition is the system frequency increased security risks. In cases where no special requirements, distributed PV devices generally do not have a similar unit of frequency characteristics, power grid disturbance situations, photovoltaic equipment available to the grid frequency is less able to support. In 2011, Germany PV “50.2 Hz” problem is the photovoltaic effect on the safe and stable operation of grid frequency of typical examples.
In this regard, Germany presented two main solutions.
First, grid extension. According to Germany on the demand for energy has launched the expansion of the distribution network by 2030, Germany requires extension of 161,000-kilometer line, additional installed capacity of 69.001 million VA transformer. Judging from the grid expansion needs of different voltage levels, medium-voltage and low-voltage need to change the extension line length is the longest, but the highest proportion of high voltage requires extension of line and extension of high voltage transmission line costs high. According to Germany the Energy Department findings, Germany needs to 32% high voltage power grid expansion, expansion of medium-voltage power grid 15%, LV network only requires a 5% extension.
Second, improving system flexibility. On one hand, improved conventional power plant operation flexibility. Germany TenneT company controlled area, for example, the controlled area in July 2013 almost daily lunch-time wind turbine and photovoltaic power generation is greater than the zone loads, climb steep drop and has obvious features. Therefore, require conventional power plants increased operational flexibility, can very quickly start and stop the group. Moreover, enhanced interconnection and grid resources optimization role into full play, and mobilizing resources to improve operational flexibility.
Germany pumped the flexible adjustment of the domestic power supply is low. Now to improve operational flexibility, Germany intends to strengthen the Nordic power systems interconnection, making full use of Norway and other countries of the hydropower to promote Germany’s renewable energies to dissolve. At EU level, strengthen the power grid interconnection, building European single electricity market and promote integration of regional power grids, are important developments in the European power grid construction.
Based on the 2012 European grid operators Union, ten-year plan, within the European Union need to change the extension line length is 52,300-kilometer, of which about 90% extension demand comes from the need to promote renewable energy to dissolve.
Result in economic problems and solutions
Increases with increasing PV development scale and price subsidies, Germany power consumer price pressures continue to increase (see the figure on the right).
Large-scale development of renewable electricity wholesale market prices fell sharply, normal power at a low profit or even a loss, lower the willingness of future investment. According to statistics, Germany at peak load electricity price has been lowered from 80 EUR/MWh of 2008 to 2013 year 38 €/MWh. Because Germany electricity market into a single electricity market, market price reduce profitability have much negative impact on traditional power supply. Germany’s large power plants to operate traditional power such as coal, nuclear, natural gas power generation projects. In 2013, the Germany energy giant RWE a loss of 2.8 billion euros. At present, many traditional power plants to Germany the Federal Network Agency application shut down.
In this regard, Germany also gives two solutions.
Is the adjustment of photovoltaic electricity price subsidy mechanism. Based on its capacity for fixed price descending. To limit solar subsidies cost, Germany the 2009 Edition of the renewable energy law according to its capacity of target and actual capacity, descending a fixed feed-in tariff every year. Zhī hòu, fixed price descending further diminishing frequency adjustment decrease from previous year to half a year, and then adjusted monthly decline. Introducing renewable energy subsidy mechanism based on the market premium, vigorously promote the renewable energy market. And then to exempt renewable energy subsidies before levy is imposed by the spontaneous use of PV power users of renewable energy subsidies.
Secondly, exploring the introduction of capacity price, ensuring the profitability of conventional power plants. Taking into account the volatility of renewable energy such as wind power, photovoltaic, conventional power plants and to ensure power system safety plays an important role in the future. How to guarantee the profitability of conventional power plants, continuous power supply safety plays an important role in the future is Germany faces a critical issue. At present, Germany is exploring modifications electricity market design, capacity price mechanisms introduced to ensure the profitability of traditional power.
Enlightenment and suggestion
First of all, to adjust subsidies. Germany PV high subsidies have caused the rapid development in Germany led to a heated discussion. Recommended countries Germany PV subsidies are too high, electricity prices rose too quickly learned, learn from Germany in flexible photovoltaic development total control and subsidy mechanisms of adjustment, such as the experience and new ideas to encourage innovation and lower costs as the goal, dynamic adjustment of subsidy policies and coordinate the PV development speed and scale to achieve sustainable development of photovoltaic.
Secondly, we must strengthen the power grid construction. Large scale photovoltaic not only have an impact on distribution networks, when access to a certain extent will also have an important impact in the transmission network. Need to strengthen the construction of distribution and transmission networks, promoting photovoltaic and transmission and distribution systems as well as power grid development, give full play to local absorptive and coordinated interaction between networks to ensure large scale PV to dissolve.
Once again, perfect the relevant technical regulations for grid-connected. Germany has the stability of large scale grid-connected PV systems security concern. Proposals to enhance photovoltaic output forecast, based on distributed PV development scale and system health, reference Germany lessons as soon as possible to amend the relevant technical standards, strengthening of distributed PV system voltage, frequency, and other support, he stressed.
Finally, the strengthened power grid interconnection, perfecting the incentive mechanism of conventional power peak. On one hand, flexibility of large-scale photovoltaic grid-connected power demands continue to increase. Strengthening the grid interconnection and grid resource allocation function into full play, use of different regional power grid and regulate supply and demand, is an important way to enhance grid operation flexibility. The other hand, large-scale grid-connected PV requires unit providing support services. Administrative measures on proposals to improve the existing support services to fully tap the potential for peaking of conventional power. Define the responsibilities of various types of power-assisted service and paid compensation for service standards.
(Author: State grid Energy Research Institute)
Original title: Germany PV development