When agriculture is "grafted" onto photovoltaics, what fruit does it bear?
What is the relationship among light, electricity and agriculture? Photosynthesis and the photoelectric effect, a pair of basic concepts from biology and physics respectively, have undergone a novel collision and combination at the industrial level derived mainly from their principles - photovoltaic agriculture, that is, simultaneously achieving solar power generation and efficient protected agricultural production on a single piece of land.
Why and how did photovoltaic power generation come together with agriculture? After "agriculture + photovoltaics," what will agriculture look like, and where will photovoltaic power generation head? For some time, reporters have continuously followed the development of photovoltaic agriculture and conducted visits and surveys of the Zhongli Wannong "smart photovoltaics + technology agriculture" project of Zhongli Talesun Solar Co., Ltd., among others, in an attempt to find answers to these questions.
Whether at the theoretical level or in current practical exploration, the "grafting" of photovoltaics and agriculture has already been demonstrated and confirmed to be an industrial integration with broad prospects -
A new generation of agrivoltaic complementarity: one exploration cracks two bottlenecks
In Shajiabang Town by Yangcheng Lake, rivers and creeks crisscross and reeds grow thickly, and abundant aquatic resources have created a developed fishery here. In the core area of the Jiangsu Changshu Modern Fishery Industrial Park in Shajiabang, 240 mu of "glittering" fish ponds stand out: rows of aluminum alloy supports rise in the ponds, holding more than 40,000 polycrystalline silicon solar photovoltaic panels above the water surface; in the ponds shaded by the photovoltaic panels, special aquatic products such as Chinese mitten crabs, crayfish, Chinese softshell turtles and snakehead fish all show good growth.
Power generation above water and aquaculture below water, comprehensively utilizing land and solar energy resources - this was China's first "fishery-photovoltaic complementarity" photovoltaic agriculture project developed by Zhongli Talesun in 2011. In the southern Jiangsu region, where fish ponds and reed marsh flats are numerous, such exploration is highly valuable.
Fishery-photovoltaic complementarity, forestry-photovoltaic complementarity, and agricultural greenhouse photovoltaic projects are collectively referred to in the photovoltaic industry as "photovoltaic agriculture." Whether at the theoretical level or in current practical exploration, this kind of "grafting" of photovoltaics and agriculture has already been demonstrated and confirmed to be an industrial integration with broad prospects.
Not far from this stretch of fish ponds, Zhongli Talesun conducted another bolder and more revolutionary experiment in a new generation of "agrivoltaic complementarity": on a piece of improved wasteland, the photovoltaic supports were raised overall and the spacing between support piles was widened, reaching more than 4 m and 10 m respectively, while a unique single photovoltaic panel installation process was adopted, which can both fully enable mechanized operations and satisfy the need for more than 75% sunlight exposure for crops. On October 15, the yield measurement results by agricultural science and technology experts from Jiangsu Province on Zhongli Wannong's 26 mu photovoltaic rice field showed that this plot produced an average of 583.2 kg of rice per mu, comparable to conventional rice yields.
"The success of this experiment has moved photovoltaic agriculture forward by a big step, and many difficulties currently facing the photovoltaic industry and modern agriculture will be readily solved." Wang Boxing, chairman of Zhongli Science and Technology Group Co., Ltd., named this experiment the Zhongli Wannong "smart photovoltaics + technology agriculture" project, and the difficulties he referred to are a series of problems including the land bottleneck for building distributed photovoltaic power stations in the east and the large investment required for modern agricultural facilities.
For traditional photovoltaic power stations that occupy a relatively large area, the barren desertified land in the west with strong sunlight is undoubtedly a "fertile soil." But the western region is far from power load centers, and the cost of power transmission is high, so the resulting problem of curtailment of photovoltaic power and limited power generation has never been well solved. Building photovoltaic power stations in the eastern region can solve the problem of power consumption, but the scarcity of wasteland resources has become a bottleneck restricting the development of the photovoltaic industry. If no breakthrough can be found, the photovoltaic industry will fall into a "dilemma between east and west."
For agricultural modernization, the integration of technologies such as biological control, integrated water and fertilizer management, and full-process mechanization has already taken relatively mature shape, but in terms of investment in efficient agricultural facilities, fiscal strength alone is still insufficient, and investment of social capital is also needed. Over the past few years, considering the compatibility and complementarity of photovoltaic power generation and agricultural production in land use, the photovoltaic industry has been continuously looking for the point where the two can combine.
"In the long run, developing photovoltaic agriculture is of great significance to China's agricultural transformation; in the short run, photovoltaic agriculture is to a certain extent an effective measure for solving the current predicament of the photovoltaic industry," believes Shi Dinghuan, chairman of the China Renewable Energy Society.
At present, models such as fishery-photovoltaic complementarity, forestry-photovoltaic complementarity, and photovoltaic agricultural greenhouses that "grow vegetables inside the greenhouse and generate power on the roof" have already been put into application in many places. And among all explorations of photovoltaic agriculture models, the "agrivoltaic complementarity" model is expected to deliver the most.
"By scientifically and reasonably raising photovoltaic supports or adopting flexible photovoltaic supports, agricultural planting and photovoltaic power generation are combined together." The "agrivoltaic complementarity" defined by Hong Wei, a researcher at the China Energy Economics Research Institute, is exactly what the Zhongli Wannong "smart photovoltaics + technology agriculture" project is doing. Different from other models, the breakthrough of this new-generation agrivoltaic complementarity technology can provide the broadest possible space for photovoltaic agriculture.
"At present, in the eastern region, we mainly build Wannong ecological photovoltaic projects by improving wasteland and barren flats and planting rice and wheat crops. In fact, by raising the photovoltaic panels and reasonably installing single-panel modules, it is entirely possible to at least avoid affecting crop growth and not hinder field operations of general agricultural machinery." Wang Boxing is very confident in Zhongli Wannong Company's patented project.
Of course, constrained by the basic farmland protection policy, Zhongli Wannong still cannot fully free its hands to carry out the new-generation "agrivoltaic complementarity" experiment. Electricity and the final harvest of crops have already been preliminarily verified, but the effectiveness of large-scale application still requires policy relaxation. Only by building a certain number of pilot projects of photovoltaics + large-scale agriculture on eastern farmland can a clear answer be given. Judging from current exploration and practice, Zhongli's practice may blaze a new path for modern agriculture and find a new outlet for the photovoltaic industry.
Photovoltaic agriculture realizes two incomes on one piece of land, and social capital investment builds modern agriculture -
Agriculture + photovoltaics: increasing land value, raising farmers' incomes and supporting poverty alleviation
Industrial integration may fortunately produce a "1+1>2" result, but there is likewise the possibility of "1+1<2," or even "1+1<1." When agriculture is "grafted" onto photovoltaics, what kind of fruit will it bear?
Agriculture is the foundation of the nation. Any exploration related to agriculture, especially to the interests of farmland and farmers, should be evaluated with the utmost caution. When visiting and investigating photovoltaic agriculture projects, the question reporters cared about most was: will photovoltaic power generation compete with agriculture for land and with farmers for profit?
"After occupying our farmland, what if only a photovoltaic power station is built and the land is no longer farmed?" Regarding "agrivoltaic complementarity" photovoltaic agriculture, some farmers interviewed by reporters generally worried that their land would be left fallow in a disguised form.
When photovoltaic enterprises operate photovoltaic agriculture as the main entity, whether they lean more toward photovoltaics or place more emphasis on agriculture depends on the comparison of returns from the two. In the view of Zhang Yong, chairman of the China Photovoltaic Agriculture Working Committee, the returns from modern agricultural operations are not necessarily lower than those from photovoltaic power generation. "The returns from photovoltaic power generation depend on the area of solar photovoltaic panels laid out and are relatively stable; the returns from agricultural production depend on the level of operation and management. If products suitable for photovoltaic agriculture are chosen and facility agriculture and efficient agriculture are introduced, then agricultural returns will be greater than photovoltaic returns."
Ni Zhichun, vice president of Zhongli Talesun Solar Co., Ltd., referring to the industry average, calculated an income account for reporters: a photovoltaic power station with an installed capacity of 100 MW requires about 3,000 mu of land, with an annual profit of about 40 million yuan, and an average photovoltaic power generation profit of 13,000 yuan per mu, equivalent to the average profit per mu of vegetable cultivation; if flowers, Chinese herbal medicines and the like are planted, agricultural returns will be even higher. Obviously, photovoltaic agriculture will not move toward "de-agriculturalization" by forgoing money that can be earned.
At Zhongli Wannong's experimental base, reporters saw what agriculture looked like after being "grafted" onto photovoltaics: on the photovoltaic top supports were placed solar insect-killing lamps, automatic sprinkling, sprayers, biological insect-killing boards and other green and efficient agricultural facilities; the solar water-lifting irrigation system and electrified agricultural machinery and equipment could obtain sufficient electrical energy on site, and agricultural electricity use achieved "self-sufficiency"...