Energy sustainable greenhouse crop cultivation using photovoltaic technologies

This study evaluates potential aggregate effects of net-zero energy building (NZEB) implementations on the electrical grid in simulation-based analysis. Many studies have been conducted on how effective NZEB designs can be achieved, however the potential impact of NZEBs have not been explored sufficiently. As significant penetration of NZEBs occurs, the aggregated electricity demand profile of the buildings on the electrical grid would experience dramatic changes. To estimate the impact of NZEBs on the electrical grid, a simulation-based study of an office building with a grid-tied PV power generation system is conducted. This study assumes that net-metering is available for NZEBs such that the excess on-site PV generation can be fed to the electrical grid. The impact of electrical energy storage (EES) within NZEBs on the electrical grid is also considered in this study. Finally, construction weighting factors of the office building type in U.S. climate zones are used to estimate the number of national office buildings. In order to consider the adoption of NZEBs in the future, this study examines scenarios with 20%, 50%, and 100% of the U.S. office building stock are composed of NZEBs. Results show that annual electricity consumption of simulated office buildings in U.S. climate locations includes the range of around 85 kWh/m2-year to 118 kWh/m2-year. Each simulated office building employs around 242 kWp to 387 kWp of maximum power outputs in the installation of on-site PV power systems to enable NZEB balances. On a national scale, the daily on-site PV power generation within NZEBs can cover around 50% to 110% of total daily electricity used in office buildings depending on weather conditions. The peak difference of U.S. electricity demand typically occurs when solar radiation is at its highest. The peak differences from the actual U.S. electricity demand on the representative summer day show 9.8%, 4.9%, and 2.0% at 12 p.m. for 100%, 50%, and 20% of the U.S. NZEB stocks, respectively. Using EES within NZEBs, the peak differences are reduced and shifted from noon to the beginning of the day, including 7.7%, 3.9%, and 1.5% for each percentage U.S. NZEB stock. NZEBs tend to create the significant curtailment of the U.S. electricity demand profile, typically during the middle of the winter day. The percentage differences at a peak point (12 p.m.) are 8.3%, 4.2%, and 1.7% for 100%, 50%, and 20% of the U.S. NZEB stocks, respectively. However, using EES on the representative winter day can flatten curtailed electricity demand curves by shifting the peak difference point to the beginning and the late afternoon of the day. The shifted peak differences show 7.4%, 3.7%, and 1.5% at 9 a.m. for three U.S. NZEB stock scenarios, respectively.

There is “breakneck” growth in the global photovoltaics market, with the global market of photovoltaic cells growing by about 47% in 2009, 72% in 2010, and 74% in 2011. Global installed capacity in 2011 was three times more than 2009. Italy and Germany are leading with a 57% share of the global market. Costs are dropping rapidly and photovoltaic (PV) power generation is an attractive option for investors. Increasing support of European Union (EU) for renewable energy in general and PV aims to diversify sources of energy and reduce reliance on fossil fuels, on nuclear and on imported energy. Energy security is an important dimension for the EU. Almost all experts agree that there is no single technology that will provide a sustainable global supply of cleaner energy. However, the scale, the cost of the change needed and supporting policy and legislation are often subject to debate. High costs could be counterbalanced by economic yields from new businesses, the creation of new jobs, and economic growth from clean energy investments. The current situation in which Germany and Italy account for almost 2/3 of global PV market growth and, also, the strong reliance on supporting policies is unstable. If PV power generation is to continue growing, the balance of development will have to shift to new markets – both inside and outside of Europe. Fixed price policy is a game to be played with caution. This article highlights examples of Spain, Italy, and Germany that illustrate that without robust policy the system can be easily misbalanced. When – or even if – photovoltaic power does become cheap enough to compete without subsidies against more established energy sources, depends upon a number of uncertainties, including the continuing political will to provide financial support, and how readily developing nations such as China and India embrace renewable energies.

Distribution grid electrical performance and emission analysis of combined cooling, heating and power (CCHP)-photovoltaic (PV)-based data center and residential customers

Potential of carbon emission reduction and financial feasibility of urban rooftop photovoltaic power generation in Beijing

China's dual-carbon program is underway, and although photovoltaic (PV) power generation is not currently able to compete with traditional thermal power generation, it is expected to play a key role in a number of areas, and PV technology has the potential to be an important part of the energy future. The aim of this paper is to explore whether PV power technology has the potential to continue to develop as a large-scale clean energy source by comparing the carbon emissions of PV and thermal power generation in 2021. The importance of this study is that it fills a research gap in terms of carbon emissions from the entire process of PV power generation. By studying and analyzing data on China's energy consumption in 2021, this paper compares PV power generation and thermal power generation in terms of carbon emissions and footprint in 2021. The results show that at the development stage of PV power generation, it produces much lower carbon emissions than thermal power generation, so society can feel at ease with the large-scale construction of more PV power plants for testing and research. However, the calculation method used in this paper is relatively simple and does not take into account all the details in the processes of production, transportation and commerce. As a result, the data are not precise enough. Future research can be devoted to building more accurate mathematical models to simulate the carbon emissions produced by PV power generation and thermal power generation for comparison.

Semi-transparent organic photovoltaics for agrivoltaic applications

SummaryFloating photovoltaic (FPV) plants present several benefits in comparison with ground-mounted photovoltaics (PVs) and could have major positive environmental and technical impacts globally. FPVs do not occupy habitable and productive areas and can be deployed in degraded environments and reduce land-use conflicts. Saving water through mitigating evaporation and improving water security in arid regions combined with the flexibility for deployment on different water bodies including drinking water reservoirs are other advantages of FPVs. They also have higher efficiency than ground-mounted PV solar and are compatible with the existing hydropower infrastructures, which supports diversifying the energy supply and its resilience. Despite the notable growth of FPVs on an international scale, lack of supporting policies and development roadmaps by the governments could hinder FPVs’ sustainable growth. Long-term reliability of the floating structures is also one of the existing concerns that if not answered could limit the expansion of this emerging technology.

Optimizing data center energy consumption via energy complementarity scheduling

Photovoltaic (PV) power generation has become an important clean energy generation source. In the context of transportation development and its very large energy demand, scholars have begun to use PV power generation technology on roads and their surrounding road spaces. Current research on PV power generation in road spaces has mostly focused on its feasibility and technical potential, but there have been few studies on its economic potential. For this reason, this paper used the Zhengding County of Hebei Province, China, to study the evaluation method of the technical and economic potential of PV power generation in road spaces and to analyze the development potential of PV power generation in road spaces. The results show that Zhengding County has a very high amount of road space available for PV power generation, with an effective PV installation area of 20.98 km2 and an annual theoretical power generation capacity of 1.5 billion kWh. If the PV road space project is fully operational in 2021, it could be profitable by 2026, and the net profit (NP) could reach $705 million in 2030. The application of photovoltaic power generation in road spaces is a very promising method of sustainable energy supply.

To improve the constancy of hydropower, wind energy and photovoltaic hybrid power generation systems for power furnish to the grid, the joint optimal allocation of hydropower, wind, and photovoltaic is studied. Firstly, the goal of the highest load-matching degree of hydropower, wind energy, and photovoltaic power is put forward. Considering the constraints such as the maximum total power generation ability of hydropower, wind energy, and photovoltaic power generation and the water balance of the reservoir, a joint optimal allocation model of hydropower, wind energy, and photovoltaic power generation in the basin is created, and solved by a progressive optimization algorithm. An example is given to illustrate the influence of source load matching degree on optimal allocation, and the validity of this approach is verified. The simulation results indicate that during grid-connected operation, hydropower, wind energy and photovoltaic complementary power generation can ensure high electricity furnish reliability and deliver more stable power to the grid.

Potential assessment of photovoltaic power generation in China

As a clean and renewable form of energy, photovoltaic (PV) power generation converts solar energy into electrical energy, reducing the consumption of fossil fuels and significantly lowering greenhouse gas emissions. China, with its vast territory and wide distribution of solar resources, naturally possesses an advantage in developing the PV industry. The technical potential of land centralized PV power in China is about 41.88×109 kW, and its spatial pattern is basically consistent with the spatial pattern of solar energy resource endowment. The “Three North” regions (Northeast, Northwest, and North China) account for 90.95% of the country’s total, while the central and southeastern regions (Central China, East China, and South China) account for only 9.05%. For specific provinces, Xinjiang has the largest potential of centralized PV power, higher than 20×109 kW. The technical potential of distributed PV power in China is about 3.73×109 kW, with the “Three North” regions accounting for 51.34% of the national total, and the central and southeastern regions accounting for 48.66%. In terms of specific provinces, Shandong has the largest technical potential of distributed PV power, close to 400×106 kW. According to the National Energy Administration, in 2023, China’s newly added grid-connected PV power capacity was 216.3×106 kW, including 120.014×106 kW for centralized PV power stations and 96.286×106 kW for distributed PV power, among which the installed capacity of residential distributed PV reached 43.483×106 kW. By the end of 2023, the accumulated grid-connected capacity reached a total of 608.92×106 kW, with centralized at 354.48×106 kW and distributed at 254.44×106 kW. According to data from the National Bureau of Statistics, in 2023, PV power generation for industrial enterprises above a designated size (with a main business income of more than 2×107 yuan) totaled 294×109 kWh, making a year-on-year increase of 17.2%. Overall, the PV power generation in 2023 was 583.3×109 kWh, up by 36.4% compared to the previous year. Currently, China has established a complete PV industry chain that ranges from silicon material preparation to module production. China is also actively exploring the integrated development of PV with other industries, forming a diversified development model of “PV +”, which greatly promotes the diverse application and sustainable development of PV technology. China is actively engaged in the construction and planning of numerous large-scale wind and PV power bases. Forecasts indicate that by 2030, the nation’s cumulative installed PV capacity could range from 840×106 kW to 1260×106 kW, with a further anticipated expansion to 2996×106 kW to 3845×106 kW by 2060. Concurrently, the total electricity generation from PV power is projected to be between 1.47×1012 kWh and 2.28×1012 kWh by 2030, potentially surging to a range of 3.11×1012 kWh to 6.00×1012 kWh by the year 2060. Capitalizing on the surging global demand for clean energy, China’s PV sector is positioning itself as a cornerstone in the pivot towards a sustainable energy future.

This study describes the estimation of solar radiation from photovoltaic (PV) power generation in smart streetlights (SSL) with a heat transfer model. The distribution of solar radiation is important for managing PV power generation. In particular, the demand for electricity for air conditioners and lighting in urban areas is large, so it is a major target for reducing greenhouse gases by introducing PV power. Solar radiation data that includes information on building shadows and reflections can be obtained by high‐density sampling in urban areas using SSL. These data, which include the three‐dimensional effects of urban structures such as buildings, can help urban planning to incorporate PV power generation. Diverse monitoring data in addition to urban canopy top solar radiation data will accelerate the introduction of PV power. The thermal state of the PV panel is an uncertain factor that links solar radiation and PV power generation. Here, we investigate an hourly constant model, a steady‐state model, and two nonsteady state models with daily and monthly intervals for predicting solar radiation from PV power generation at two locations over one winter month. Solar radiation is estimated by evaluating solar cell temperature, except for the hourly constant model. For the nonsteady‐state model, two types of heat transfer model, which consider only wind speed or both wind speed and direction for convection, are used. The model that includes wind speed and direction calculated by a Joukowski transform is effective, and the highest model accuracy is a mean absolute percentage error of less than 6.3% for the monthly average.

Haze has a significant impact on photovoltaic (PV) power generation. When the fine particulate matter reaches a certain concentration, it becomes the main factor affecting solar irradiance and seriously reduces PV power generation, but few quantitative studies on the effect caused by haze to PV power generation. This study proposes the use of the improved method of the degree of grey slope incidence to analyze the weight factors of the effects of haze on irradiance. The exponential-linear model is used to describe the impact of haze on the amount of irradiance. Furthermore, the PV system model is used to focus on the quantitative loss of PV power under the influence of haze. By modeling and analyzing the data samples of PV power generation in Hangzhou, China, it can be concluded that the losses caused by haze on PV power generation in 2017 and 2018 were 5.25 ± 1.19 % and 6 ± 1.16 % of the original PV power generation, respectively. We extended this analysis to other cities to analyze the PV data in Tianjin, China. From December 2018 to December 2019, the loss of PV power generation caused by haze in Tianjin was 8.77 ± 0.9 % . The quantitative analysis of haze on PV power can provide an effective basis for the economic evaluation of new PV systems and also plays an important role in the prediction and scheduling of PV power generation.

With less than a decade remaining until 2030, global investment in clean energy access falls short of the anticipated levels required to achieve the sustainable development goals. Notably, nations with the greatest gaps in electricity access, particularly those in Sub-Saharan Africa, have been largely excluded from energy access funding. Interestingly, the energy sector policy documents of these countries have neglected to incorporate financing strategies or plans for photovoltaic (PV) power generation. This discrepancy in the literature underscores the need to assess the economic impact of finance and investment policies that align with long-term PV power generation targets. To address this gap, our study employs a dynamic Computable General Equilibrium model to evaluate the macroeconomic consequences of achieving Cameroon’s Nationally Determined Contributions for PV power generation through optimized PV investment and finance. The model examines three policy scenarios: the Business-as-Usual, SC1 scenario involving a stable 100% increase in PV investment, and SC2 scenario featuring a stepwise 5%–100% increase in PV investment. By simulating these scenarios, we aim to shed light on their effects. The results reveal that SC1 and SC2 exhibit a 50% higher final demand for PV investment compared to the BAU scenario. Optimizing PV finance and investment in both scenarios leads to a slowdown in Cameroon’s economic growth, with SC1 showing a more pronounced impact. Additionally, SC2 encourages rapid decarbonization in energy-intensive sectors such as crude oil production and electricity generation industries. However, the SC1 policy scenario results in a rapid reduction in total investment expenditure for PV power generation. By 2035, PV power generation is projected to be three times higher in both SC1 and SC2 compared to the BAU scenario. The SC2 policy scenario also predicts relatively high levels of consumption among rural affluent and urban impoverished households. In conclusion, our study highlights the pressing need for enhanced investment and finance strategies to propel PV power generation, particularly in underserved regions. By leveraging the findings of this research, policymakers can make informed decisions and implement policies that promote sustainable and inclusive energy access, driving progress towards the fulfillment of SDGs.