I. PV and "agriculture" background
With the improvement of agricultural production conditions, the promotion and application of agricultural technology, and the implementation of agricultural policies, farmers' awareness of planting has greatly improved. In the twenty-first century, agriculture will be a revolution in green agriculture, and the safety of food is becoming more and more of a concern to the government and the people. Eco-agriculture is an agricultural development model that follows the laws of ecology and ecological economics and uses systems engineering methods and modern science and technology to intensify management under the premise of protecting and improving the agricultural ecological environment. Ecological agriculture is an agro-ecological and economic complex system that integrates and unifies the agro-ecological system with the agricultural economic system in order to achieve the greatest overall ecological and economic benefits. It is also a large agriculture that integrates agriculture, forestry, animal husbandry, vice and fishery, and a modern agriculture that integrates agricultural production, processing and marketing and adapts to the development of market economy.
Agro-photovoltaic complementary, also known as photovoltaic agriculture, is the use of solar photovoltaic power generation pollution-free zero emissions characteristics, both with power generation capacity, but also for crops, edible mushrooms and livestock breeding to provide a suitable growth environment.
Second, "agriculture and light complementary" homeopathic development of the reasons
1, to meet the needs of crop growth
Crop growth needs of light and photovoltaic power generation needs of different light waves, photovoltaic solar greenhouse can realize power generation planting both. As the solar cell module will cause a certain amount of shading, each greenhouse can be designed with different installed capacities according to the light needs of different crops, to meet the light needs of plant photosynthesis.
Solar modules can also block some of the ultraviolet rays and reflect the blue and violet light needed for insect reproduction, which can effectively reduce planting crop pests and diseases, reduce the use of pesticides and improve the quality and yield of planting crops, a new model of green ecological agriculture using high technology.
2、Improve land utilisation and reduce the cost of the photovoltaic industry
The traditional way to build photovoltaic power station, generally for industrial land, high cost and does not meet the government's rational use of resources. The use of agricultural "agriculture and light complementary" project, improve the land utilization rate, in line with the national advocacy of green agricultural trends. At present, the state strongly supports the development of supporting infrastructure, loans and other aspects to provide support [photovoltaic is clearly included in the Central Bank "green bond support projects directory"].
3、Solve employment and increase farmers' income
The construction of "agriculture and solar complementary" project, the farmers in addition to get the rent of the transferred land, photovoltaic project company can provide jobs for local farmers, solve the "40, 50, 60" age group of labor force employment problems, so that farmers do not have to go far away from work and have a The company can provide jobs for local farmers and solve the employment problem of the "40, 50 and 60" age group.
4、In line with national industrial policy and guidance
In recent years, the state has frequently promulgated policies related to photovoltaic power generation [Notice on Further Support for the Healthy Development of Facility Agriculture]. With the introduction of various preferential policies, including planning development goals, subsidy standards, subsidy periods, funding sources, a series of policies to support the development of photovoltaic power generation industry system has been basically perfect, to vigorously develop photovoltaic power generation to provide a strong policy guarantee.
Third, the development status of "agriculture and photovoltaic complementary"
Photovoltaic agriculture is a new form of comprehensive land use, is a product of modern agriculture and clean energy close combination, can promote green agricultural production, to achieve science and technology efficient cycle of ecological agriculture. It has the ability to generate electricity and provide a suitable growing environment for crops, edible mushrooms and livestock breeding, thus creating better economic and social benefits.
1, foreign PV agriculture development status
According to statistics, the global centralized photovoltaic power generation projects slightly more than distributed power generation projects, in fact, foreign photovoltaic industry to distributed mainly.
Japan's agriculture, forestry and fishery field in 2013 relaxed the regulations on agricultural photovoltaic power generation: if the shadow of the power generation equipment caused by the proportion of crop reduction within 20%, the pillar of the foundation part will be approved for temporary agricultural land. Australia, the United States and other large agricultural countries with a wide geographic area are more for photovoltaic rooftop power generation, less combined with agriculture. At this stage, Europe and the United States government subsidies down, photovoltaic investors are less motivated, short-term, slow progress in agricultural photovoltaic.
2, the current situation of domestic photovoltaic agriculture development
Compared to foreign PV forms, China's centralized and distributed power plant development imbalance, investment in solar power plants, requires highly intensive capital, and centralized management. This means that usually, investment in large solar power plants need to occupy a large area, this area in the distributed roof is more difficult to obtain. As a result, investing in large plants on wasteland has become the dominant form of application for a while. China has reached the world's number one installed capacity with 10G per year, just a few years ago.
However, investment in solar power stations in the desert areas of the west presented problems of consumption, and in serious areas, where distributed solar power could not be consumed, the grid imposed planned restrictions on the output of solar power for security reasons, resulting in lower returns on investment in solar power stations. As a result, investing in large power stations towards the eastern region became the mainstream application.
In the State Council "on the promotion of the healthy development of photovoltaic industry a number of opinions" and a series of supporting policies to support, the domestic photovoltaic application market ushered in explosive growth, the country according to local conditions, complementary advantages, to agriculture, fishing, scenery and other multi-energy complementary way to build photovoltaic power station, its project has the economy and promotion, help slow crack large-scale renewable energy access to the grid bottleneck, a big The project is economical and scalable, helping to ease the bottleneck of large-scale renewable energy access to the grid, and has the potential to "ignite" the domestic PV application market. This new model of agricultural and photovoltaic complementary, fishery and photovoltaic complementary, combined power point, not only optimizes the quality of photovoltaic power, to avoid "abandoned light", but also improves the regulating capacity of the grid and the utilization rate of the transmission line.
However, the lack of flat wasteland in the east, solar energy and greenhouses are a special solution for solar energy to occupy arable land, so there are many photovoltaic greenhouses "modern agriculture". Many people then set up "photovoltaic sheds" that look like sheds but are in fact solar power plants, in order to be opportunistic.
The National Energy Board, in the recent past, has also issued norms regulating the use of solar energy in combination with agriculture. Solar power stations that are built on buildings with "property rights" can only be considered distributed solar power stations, while temporary buildings or sheds without property rights must be approved by the strict feasibility of large power stations to prevent the inefficient occupation of arable land resources.
Three, "agriculture and light complementary" photovoltaic project correct operation
Zhejiang Tongjing New Energy Group Co., Ltd, as an important representative of agro-photovoltaic projects, has joined hands with Huawei, China Power Investment and other well-known enterprises to apply single-axis and dual-axis tracking system technology to a total of about 200MWp during 2011-2015. The Zhejiang Tongjing project adopts self-developed solar dual-axis tracking and pressurized bracket system to set the height of PV panels for different terrains, and build an agricultural photovoltaic power generation model of "photovoltaic power generation at the top and agricultural planting at the bottom", so that the power generation unit can be tracked in both directions from east to west and from south to north. "The model is a two-way tracking system with large-scale cultivation of crops underneath. Compared with the traditional fixed model, this model can significantly improve the conversion rate of light energy and crop yield, realise multiple uses of one place, and promote farmers' income, enterprises' efficiency, the government's tax increase and environmental gains.
The principle of agricultural and photovoltaic complementarity
According to the geological conditions, the foundation of the tracking system is a cement foundation pressed into the ground, no earth excavation, preventing soil erosion, the land under the components can still be cultivated for crops, the tracking battery module bracket installation process does not damage the land, does not change the nature of the land. At the same time, the structure of the truss louvers of the tracking bracket system blocks about 30% of the sunlight, forming a low-temperature microclimate, reducing pests and diseases, while also effectively extending the growth time of crops and improving their quality.
b Tracking advantages
Tongjing dual-axis tracking system based on solar astronomical coordinates control, PV module subsystem of east-west and north-south rotation in two directions, to achieve a comprehensive, real-time tracking of the sun's operation, to achieve intelligent PV dual-axis tracking control, to ensure that throughout the day, PV modules are always in the best light angle, morning and evening more power generation, can improve the light utilization rate of 20% to 35% (varies by latitude).
Fourth, the development trend of China's agricultural photovoltaic
At this stage, although the development of photovoltaic agriculture is facing a marginal policy environment, no uniform construction standards, runaway horses and other difficulties, but around the photovoltaic agriculture project still received the double importance and support of the field of photovoltaic and agricultural cross-sector. Facing up to these problems and rationalising the idea of continuing the healthy development of PV agriculture, so that PV and agriculture in combination with a win-win situation is the development of PV agriculture is a top priority.
The market for industrial applications is attractive, and the market for PV products in agriculture is difficult to estimate. The combination of PV and agriculture is not only beneficial to the PV industry itself, but is also of great significance to the transformation of agriculture. According to statistics, at present, China's photovoltaic agriculture project total more than 400, if in the country large area, large-scale promotion of photovoltaic agricultural products, its market can reach a hundred billion yuan scale, in 5 years can reach trillion yuan scale.
Taking into account, the area of agricultural greenhouses in China is the first in the world, and the construction area of sunlight greenhouses and plastic greenhouses has reached more than 2 million hectares, but the area that can be utilized is very little. In terms of arable land, China ranks fourth in the world in terms of arable land, far behind the United States, while the population is the first in the world. Even more worrying is the fact that 55% of the available arable land is water-scarce dryland. However, even if only 1% of the 55% of the water-scarce dryland is covered by PV water-raising technology, this could result in an installed market of 400GW. And 1GW of installed solar photovoltaic water lifting equipment can meet the water needs of 5 to 10 million mu of land.
Compared to the traditional water conservancy construction requires a lot of electricity laying, reservoir construction, ditch excavation, the overall investment scale difference between the two is huge, the ecological significance of photovoltaic water conservancy makes it more obvious advantages.
The National Energy Board recently issued the "thirteenth five-year development plan of solar energy use for comment" points out that the focus will be on Shandong, Anhui, Jiangsu, Jiangyang, Guangdong and other eastern coastal provinces and modern agricultural development of the region. Relying on fishery farming, agricultural facilities and other construction of fishery photovoltaic complementary and agricultural photovoltaic complementary power generation concentrated areas, and in large areas of water more areas, to explore low-cost, technically mature water and light complementary construction technology, planning water and light complementary concentrated areas. From the top design to strengthen support for the central support for photovoltaic agriculture can be described as leaving no stone unturned, and even use a large amount of financial funds, a strong reflection of the will of the state. If you follow the national policy of subsidies to calculate, photovoltaic agricultural greenhouse profitable, stable earnings. Data shows that a 10 MW PV agricultural shed project with an investment of 100 million yuan can have an annual return of more than 10%.
From the perspective of environmental protection, haze incidents in many places have sounded the alarm to the government. As a PV agricultural project that combines social, economic and environmental benefits, it responds to the government's call for energy saving and emission reduction, saves land resources and is undoubtedly the darling of energy projects. A 30WM photovoltaic project, for example, can generate 43 million degrees of electricity per year, saving 480,000 tonnes of coal and reducing dust emissions by 30,000 tonnes over a 25-year lifespan.