Experience and Enlightenment of the hottest new en

The experience and Enlightenment of new energy consumption in Germany

Abstract: the development of new energy such as wind power and photovoltaic power generation is an important part of China's energy strategy, but the development of new energy is a systematic work that must be participated in by the whole society. The optimization of power supply structure, the improvement of power system flexibility, institutional reform, technological progress and so on are indispensable

on April 30, 2017, Germany set a new record for its use of renewable energy - 85% of electricity consumption on that day came from renewable energy, including wind power, solar power, biomass power and hydropower. Records show that at 12:00 local time on April 30, the output of renewable energy such as solar power generation, wind power, biomass power generation, hydropower and energy storage reached 55.73 million KW, accounting for 95.76% of the electricity load (58.2 million KW) at that time, which is equivalent to that all electricity in Germany is basically provided by renewable energy

Germany's realization of the maximum consumption of new energy mainly depends on the flexible power spot market mechanism, strong power regulation capacity, strong transnational transmission network and advanced new energy dispatching and operation technology

electricity price mechanism in the spot electricity market

Germany has established a market-based consumption mechanism combining bidding in the new energy market and government subsidies. In fact, the power market is a competition of marginal cost. New energy has an absolute advantage in the market competition because of its low marginal cost of power generation. New energy can realize preferential power generation by participating in the market. Since the power of wind power and photovoltaic power generation can only be predicted days ago, that is, the generation curve of the next day can be predicted on the same day, foreign new energy developed countries usually adopt the day before and day after day power spot market to absorb new energy. New energy will participate in the bidding according to the zero electricity price (the insufficient part will be subsidized by the government) to ensure the priority. When the output of new energy is high, the clearing price in the power market decreases, and even negative electricity prices appear. Affected by electricity prices, hydropower, thermal power, oil and gas power generation, etc. reduce output as much as possible; When the output of new energy is low, the clearing price in the power market rises sharply, stimulating all kinds of flexible power sources to generate electricity to the greatest extent

similarly, taking Germany as an example from April 25 to 30, 2017, the electricity price of wind power and photovoltaic power generation decreased during the large generation, and the electricity price of wind power and photovoltaic power generation increased during the low output of the electricity market. The highest clearing price of the day ahead market occurred at 8:00 on April 26, and the electricity price was 0.053 euros (0.41 yuan)/kWh. The lowest electricity price of the day ahead market occurred at 14:00 on April 30, and the electricity price was -0.075 euros (-0.57 yuan)/kWh. Due to the uncertainty of new energy output, the daily real-time electricity price is even as low as -0.111 euros (-0.85 yuan)/kWh, which is equivalent to paying 0.85 yuan to users for every 1 kwh generated by the power plant. Stimulated by the price mechanism of the day ahead and day after day electricity spot market, Germany's conventional power supply is very willing to carry out flexible transformation, so as to minimize output when the electricity price is low and increase output as soon as possible when the electricity price is high

despite the rapid development of new energy, the clearing price in the German power market has declined steadily, but the terminal sales price has continued to rise, which is known as a product that can be painted by yourself. Due to the high comprehensive cost of new energy power generation, the development of tear resistance performance of new energy is bound to bring about an increase in the overall power generation cost, which is finally reflected in the terminal sales price. The renewable energy sharing fee in the sales electricity price in Germany continues to rise. Taking the residential electricity price as an example, the renewable energy sharing fee increased from 0.0051 euros (0.039 yuan)/kwh in 2004 to 0.06354 euros (0.486 yuan)/kwh in 2016, accounting for 21.2% of the residential electricity price, and the residential electricity price increased by 60%

flexible regulation performance of conventional units

the proportion of flexible regulation power supply to new energy in Germany is not very high, but the regulation capacity of conventional coal-fired power is very strong

take April 25-30, 2017 as an example, when the output of solar power and wind power in Germany is large, pumped storage, gas power generation, lignite power generation, hard coal power generation and even nuclear power are involved in regulation. On April 30, the lowest pressure of gas-fired power generation reached 18% of the maximum output of this week, the lowest pressure of lignite power generation reached 34% of the maximum output of this week, the lowest pressure of nuclear power reached 63% of the maximum output of this week, and the lowest pressure of hard coal power generation reached 10% of the maximum output of this week

hard coal power generation, the main part of peak shaving, fell from 15.63 million kW to 5.14 million kW in 18 hours, and then fell to 1.86 million KW one day later. After the reduction of wind power output on May 2, hard coal power generation increased from 3.5 million kW to 9.56 million kW in six hours. From April 28, the output of hard coal was 15.63 million KW, to April 30, the minimum output was 1.76 million KW, and then to May 3, the output returned to 13.61 million KW, the total time was only 5 and a half days

strong power grid

countries with high utilization rate of new energy usually have sufficient electrical connections with adjacent regions. There are nine countries bordering Germany, and the transnational transmission is mainly composed of 380 kV to 400 kV lines; 220 kV to 285 kV transmission lines are used as auxiliary. Among them, there are 28 380 kV to 400 kV lines and 31 220 kV to 285 kV transmission lines

when the output of wind power and photovoltaic power in Germany is large, in addition to relying on domestic conventional power supply for regulation, it also increases the intensity of power export. Similarly, taking April 30 as an example, the export power reached 13.36 million KW, equivalent to 80% of wind power (with an output of 16.75 million KW at that time) or 45% of solar power (with an output of 29.76 million KW at that time) sent abroad. In 2015, Germany imported 33.564 billion kWh and exported 85.348 billion kwh, accounting for 5.2% and 13.2% of the total power generation respectively. At the same time, Germany's wind power generation only accounts for 12.3% of the country's total power generation when the pendulum swings back

advanced new energy generation prediction and dispatching operation technology

the basis of new energy consumption in power system is new energy power prediction. In Germany, new energy power prediction based on weather forecast belongs to the commercial field. Major power companies and power supply and demand parties will purchase forecasting services from professional institutions

the root mean square error of wind power prediction of German 50hertz electric power company in the whole day is acceptable, but it is recommended to reduce the shear as much as possible in the mold design to reach 2% - 4%, and the solar energy can reach 5% - 7%. Large new energy stations, such as offshore wind farms, should also carry out power prediction and participate in market competition according to the predicted power generation capacity

Deutsche power realizes real-time dispatching of wind farms through transmission control centers and hundreds of distribution control centers. The real-time data of the wind farm is directly uploaded to the distribution control center. According to the provisions of the renewable energy law of Germany, all renewable energy power generation equipment with a capacity greater than 100 kW must have the technical conditions of telemetry and remote regulation before it can be connected to the interconnected power. When the transmission lines of transmission operators are blocked, they first issue power limitation instructions to their subordinate distribution dispatching instructions to limit a certain share of power. Then, power distribution may directly limit the renewable energy power connected to the company, or give instructions to its subordinate MV power dispatching center to limit a certain share of power. At present, although the output of new energy in Germany has reached a high proportion, the flexible market and dispatching operation mechanism can still ensure the safety of power operation

the development of new energy such as wind power and photovoltaic power generation is an important part of China's energy strategy, but the development of new energy is a systematic work that must be participated in by the whole society. The optimization of power supply structure, the improvement of power system flexibility, institutional reform and technological progress are indispensable. China should fully learn from the experience and lessons of foreign new energy developed countries, based on the actual situation of its own economy and power development, and find a new way to meet China's actual needs and promote the sustainable development of new energy