"Complementary fisheries and light" opens up a new way for the sustainable development of aquaculture

"Fishery and solar complementarity" can not only achieve efficient utilization of water surface and increase clean energy production capacity, but also improve the quality and efficiency of aquatic products, promote the development of ecological agriculture and increase farmers' income
。 In recent years, China's "fishery-solar complementarity" industry has developed rapidly, but due to the constraints of few aquaculture species and weak technology for the construction of aquaculture facilities, the basic research of "fishery-solar complementarity" is still in a blank state, and it is necessary to carry out systematic research from the perspective of industrial ecology, fully consider the synergy, matching and complementarity of fishery production and photovoltaic power generation, establish a breeding technology system according to the requirements of green aquaculture, and at the same time strengthen relevant policy guidance and planning layout, and simultaneously explore the "fishery-solar complementarity" mode of ponds and sea.
Contribute to the realization of the "Two Carbon Goals
".

"Fishery and light complementarity" is in full bloom

"Fishery and solar complementarity" refers to the combination of fishery aquaculture and photovoltaic power generation, photovoltaic panel arrays are set up above the water surface of the fish pond, fish and shrimp aquaculture can be carried out in the waters below the photovoltaic panels, and photovoltaic arrays can also provide good shielding for fish farming, forming a new power generation model
of "upper power generation, lower can raise fish".

In 2012, the country's first "fishery-solar complementary" photovoltaic power station was built in Jiangsu Province and connected to the grid, mainly built on the breeding pond, the first phase of the project capacity is 20MW, the annual power generation capacity is 21 million kWh; The "fishery-solar complementarity" project of Zhouxiang Reservoir and Changhe Reservoir in Cixi City, Zhejiang Province, put into operation in 2017, is the largest "fishery-solar complementary" power generation project that has been put into operation in China, with a total investment of 1.
8 billion yuan, a total water area of 299.
47 hectares, a total installed capacity of 200MW, and an estimated average annual power generation of 220 million kWh
。 In the southwest region, the "fishery-solar complementary" photovoltaic power generation project in Laibin City, Guangxi Zhuang Autonomous Region, located in Lianhuatang Reservoir and Tiexiang Reservoir, covers an area of 400 hectares, invested by Laibin City Binhui Integrated Energy Service Co.
, Ltd.
with an investment of 1.
5 billion yuan, with a total installed capacity of 300MW, and the project has entered the land planning stage
in 2020.

In recent years, China's photovoltaic industry has developed rapidly, and the installed capacity of photovoltaic power generation has grown
by leaps and bounds.
However, due to the large land area occupied by ground photovoltaic power plants, as the installed capacity of photovoltaic power generation continues to rise, the development of ground photovoltaic power plants will be limited
by land resources.
China's inland water area is relatively wide, of which the lake area is about 9.
1 million hectares, the reservoir area is about 2.
5 million hectares, the inland pond area is 2 million hectares, if you consider the full paving, you can build about 15,000GW of photovoltaics, only consider the use of 20% of the water area to build photovoltaic power plants, the installed capacity can reach 3000GW.

Therefore, the use of inland waters such as lakes, reservoirs, ponds and other areas to build water photovoltaic power plants, not only does not occupy the land area, but also increases the installed capacity of photovoltaic power generation, is a new form of efficient photovoltaic power generation
.

Transboundary integration of clean energy and aquaculture

Some experts said that "fishery and solar complementarity" can not only realize the cross-border integration of clean energy and aquaculture in China, but also greatly increase the value output of the land area, truly realize the three harvests of "fishery, electricity and environmental protection", and provide a new path
for the sustainable growth and green development of China's economy.

From the perspective of energy utilization, the "fishery-solar complementarity" model adopts green and clean energy - solar energy, which is a typical modern renewable energy with clean and ecological characteristics and rich
reserves.
The "fishery-solar complementary" photovoltaic power station directly converts solar energy into electricity, reduces the dependence on mineral resources such as oil and coal, meets the requirements of national ecological civilization construction, and conforms to the strategy
of sustainable development.

From the perspective of practical application, first of all, through the "fishery-solar complementarity" mode, solar generators are built on ponds, lakes and reservoirs, so that pond fish farming and solar power generation are spatially combined and make full use of space resources
.
Secondly, in the production process, the installation of photovoltaic modules can reduce the water surface temperature to a certain extent, especially in South China, which can prevent the loss of aquaculture caused by high water temperature, which is conducive to improving the growth and feeding
of fish.
Traditional aquaculture only obtains aquaculture products and has a single
source of income.
Through the three-dimensional comprehensive development of large-scale ponds, the efficiency of resource utilization is improved and the comprehensive income
of farmers is increased.

By the end of 2020, China's cumulative installed capacity of renewable energy has reached 934 million kW, accounting for 1/3 of the total installed capacity of global renewable energy, especially wind power and photovoltaic, with about 120 million kW of new installed capacity in 2019, accounting for more than
half of the new installed capacity of global wind power and photovoltaics.
The large-scale development of renewable energy in China has also strongly promoted the development of new energy technologies represented by wind power and photovoltaics, making global renewable energy, especially wind power and photovoltaics, become the new main energy sources
.

Compared with traditional aquaculture and traditional land construction photovoltaics, "fishery and solar complementarity" has unique advantages, which does not affect photovoltaic panel power generation or aquaculture during its operation, which can enable farmers to achieve the goal of
increasing production and income.
In particular, because the photovoltaic panels have a blocking effect on sunlight, it changes the breeding environment and is conducive to the growth
of negative and excellent species, such as green crabs, sand shrimp, turtles, river crabs, yellow jaw fish, sand pond snakeheads, etc.

Industry insiders believe that photovoltaic power generation is an economical way to generate electricity, but traditional photovoltaic is placed on land, occupying a lot of land resources, so that the development speed of the photovoltaic industry is gradually reduced, and the emergence of "fishery and solar complementarity" solves the above problems, which can save land resources and improve social power supply
.

Policies promote the development of "fishery and solar complementarity"

"Fishery-solar complementarity" creates strong synergies, including water conservation, aquatic product production, ecosystem improvement, and economic benefits from power generation
.
However, the basic research of "fishery-solar complementarity" is still in a blank state, and it is necessary to study the industrial characteristics, system structure, environmental response mechanism, material and energy exchange and metabolic process between the industrial system and the natural ecosystem, optimization and regulation methods, and engineering construction models to achieve efficient and harmonious development of the industrial system through the combination of production, education and research
.

"Fishery and solar complementarity" was first built on freshwater aquaculture ponds, and after years of development, a set of feasible complementary models of aquaculture and power generation has been basically formed
.
However, at the same time, the "fishery-solar complementary" facility system has problems such as
irregular construction, low operation efficiency and high construction cost.
For example, solar photovoltaic power loss generally has three main losses, namely inverter loss, transformer loss and photovoltaic array loss, how to effectively reduce the waste of photovoltaic power, need to be solved
by engineering means.
In addition, how to solve the increased biochemical oxygen demand due to the addition of feed and the environmental pollution caused by the addition of feed in the "fishery-light complementary" aquaculture system also needs to be solved
through engineering technology.
At the same time, it is also necessary to develop production mechanization technologies and special equipment
such as feeding, pesticide application, fishing, and photovoltaic cleaning.
Experts suggest that a "fishery-solar complementary" technical system should be established and corresponding national and industry standards and specifications
should be formulated.

China's "fishery and solar complementarity" industry is developing rapidly, but due to the constraints of few aquaculture species and weak technology for the construction of aquaculture facilities, the overall technical level of "fishery and solar complementarity" is low, the aquaculture efficiency is not high, the pollution problem of aquaculture waters in the photovoltaic area still exists, which does not meet the requirements of green development of aquaculture, it is necessary to carry out systematic research from the perspective of industrial ecology, fully consider the synergy, matching and complementarity of fishery production and photovoltaic power generation, and establish a breeding technology system
according to the requirements of green aquaculture 。 In addition, experts suggest that while developing "fishery and solar complementarity", we can focus on popular science education in the photovoltaic industry, increase the popularization of photovoltaic power generation knowledge, advocate low-carbon life, and promote the sharing of scientific and technological resources and the socialization of science popularization
work.

Experts said that as of 2020, the national aquaculture area was 7,036,100 hectares, of which 2,625,400 hectares
were pond culture.
Starting from the difficulty and cost of project construction, it is more appropriate
to build "fishery and solar complementary" facilities on aquaculture ponds.
The eastern coastal area of China is the main area of pond aquaculture, and there is also a situation
of dense population and scarce land resources.
Taking Jiangsu Province as an example, in 2020, the aquaculture area of Jiangsu Province reached 598,500 hectares, ranking third in the country, of which the pond aquaculture area was 316,400 hectares, it is estimated that the electricity cost per hectare of high-density aquaculture ponds in the 80-day breeding period is about 5250 yuan, without changing the nature of the land, if the ponds are transformed into "fishery and light complementary" ponds, it will effectively save electricity costs
。 According to the latest simulation results of the latest spatial distribution of the total annual total radiation of the Wind Energy and Solar Energy Resources Evaluation Center of the National Meteorological Administration, Sichuan and Guizhou provinces are the areas with the least solar energy resources in China, with an annual radiation per square meter below 4200MJ, which belongs to the four types of photovoltaic areas and the difficulty of engineering construction is generally high, which is not suitable as a "fishery-solar complementary" promotion area
.
Southern Guangdong not only belongs to the second category of photovoltaic areas, but also has a vast area of freshwater and marine aquaculture, flat land and developed economy, which can not only develop pond "fishery and light complementarity", but also explore the "fishery and solar complementarity" mode
at sea.

"Fishery and solar complementarity" is the new development direction of the photovoltaic industry and aquaculture industry in the future, and the current global water photovoltaic industry is in a stage of accelerated development
.
Experts suggest that China's relevant departments should actively seize the new opportunity period of industrial cooperation, give full play to technology and cost advantages, deeply participate in global market competition, and demonstrate China's mature project development and construction experience
.
At the same time, the Chinese government can strengthen relevant policy guidance and planning layout, promote the cultivation of key markets through intergovernmental cooperation, create favorable conditions for the development of "fishery and solar complementarity" projects, and contribute to the realization of the "two carbon goals
".

(Wang Jiayi, comprehensive arrangement)

China Food News(2023.
01.
17.
06)

(Responsible editor: Wang Jiayi)