Introdução
O termo peak sunshine hours refers to the amount of solar energy available at a location, expressed as an equivalent number of hours at 1,000 Com m². A daylight incident cannot be exposed to night hours. Entendendo o horas de pico do sol an area receives can give insight into how much energy painéis solares may receive. It’s a good starting point for estimating solar production.
What Are Peak Sunshine Hours?
What does “peak sunshine hours” mean?
Peak sunshine hours e Horas solares de pico are used interchangeably to quantify the solar resource for solar irradiation. It means the sum of the sun-hours of the day’s solar rays is as much in 1000w/m². NREL describes sun-hours as being equal to hours (or some fraction thereof) of peak 1000w/m² sunshine.
5 horas de pico do sol do not mean five hours of sunlight 1,000w/m² for a flat 6-sun; solar irradiance changes with the time of day. It changes cause the sun’s position, some due to the clouds, and some more due to the atmosphere. Agora, peak hours of the sun carry the varying solar energy of the day to one single equivalent value.
According to this system, a place might receive weak, unfavorable sun early in the morning and evening or comparatively stronger sun around midday, but the total energy received equals 5 peak solar hours. Por isso, peak solar hours are a measure of solar energy reception instead of the count of hours of sunshine.
Peak Sunshine Hours vs Daylight Hours
Peak sunshine hours also need to be distinguished from daylight hours. Daylight hours are the number of hours between sunrise and sunset, whereas peak sun hours refer to the number of solar energy hours needed to reach a particular value of irradiance.
| Medição | What it measures | Common unit | Solar-planning relevance |
| Daylight hours | Time between sunrise and sunset | horas | Shows duration of daylight |
| Solar irradiance | Solar power received at a given moment | Com m² | Indicates instantaneous intensity |
| Solar irradiation | Solar energy received over a period | Wh/m² or kWh/m² | Indicates total solar resource |
| Horário de pico do sol | Solar irradiation normalized to 1,000 Com m² | horas | Useful for basic PV energy estimates |
How Are Peak Sunshine Hours Calculated?
Peak Sun Hours Formula
O calculation of peak sunshine hours is when the daily solar irradiation is converted into the equivalent number of hours at 1000 Com m². NREL gives the relationship as total daily sunlight in Wh/m² because Wh/m² is a unit to measure irradiation divided by 1000 Com m².
Peak sun hours = Daily solar irradiation ÷ 1 kW/m²
When the solar resource is expressed in Wh/m²/day, the same calculation can be written as:
Peak sun hours = Daily solar irradiation (Wh/m²/day) ÷ 1,000 Com m²
Units are extremely important. Solar irradiance is measured as power per unit area, such as W/m², whereas solar irradiation is the accumulated energy over time, typically expressed as Wh/m² or kWh/m². Peak sun hours are derived from the Wh/m² instead of a single irradiance reading.
Worked Calculation
Suppose a location receives 5,000 Wh/m²/day of daily solar irradiation.
This implies that the total daylight energy of the day is five hours of radiation at 1,000 Com m². This does not imply that the particular location experienced five constant hours of 1,000 W/m² radiation.
This is an illustrative calculation, not a significant estimate of that area. Real sun-oriented asset information needs to be gathered from an area-specific data set or a sun-based evaluation tool.
Irradiance vs Irradiation
You may note that there is a common error in understanding the concepts of solar irradiance and solar irradiation. Irradiance refers to the solar power that reaches a surface at a particular moment. Por outro lado, irradiation denotes the solar energy that is accumulated over a period. To calculate the peak sun hours, the latter factor is considered.
The irradiance and irradiation differences have been explained by the Solar Atlas. It expresses solar-resource parameters like GHI and DNI as quantities of energy over a defined period; it also provides PV electricity-output estimates. The database of the Solar Atlas distinctly differentiates between solar-resource measurements and modeled PV output.
Solar resource must be distinguished from modeled PV output. A single midday measurement of irradiance cannot fully represent the solar resource during an entire day. A fully daily (or monthly) irradiation value is needed for a proper peak sun hours calculation.
How to Find Peak Sun Hours for Your Location
Why Location-Specific Data Matters
Not every city in a country has the specific value of peak sun hours by location. Due to the difference of geographic features, climate and weather, slope and place, season and surface, every site has different solar energy. A country-specific average never matches every city’s data.
Developers use solar resource maps and specific location solar panel modeling tools for efficient solar planning. Global Solar Atlas has data on solar-resource maps for the entire world. It typically includes the global horizontal irradiation (GHI), direct normal irradiation (DNI), the tilted plane irradiation, and the electricity output from PV. Its solar resource datasets are much more specific in comparison to the country-average energy levels.
Tools for Finding Peak Sun Hours
O Global Solar Atlas is useful when comparing solar resources between different locations or carrying out a detailed site-specific assessment. It is a free map and information resource for solar irradiation and photovoltaic (VP) energy potential.
Além disso, o NREL PVWatts contains a power output for the PV system using specific site estimation. It includes downloadable data or maps of the solar resource information with the minor click.
No entanto, for European projects, the user can consider PVGIS from the European Commission’s Joint Research Centre. It is based on solar radiation and photovoltaic (VP) output information for locations worldwide, excluding the polar regions.
| Dados | What it represents | Main use |
| GHI | Global horizontal irradiation | General solar-resource comparison |
| DNI | Direct normal irradiation | Direct-beam applications |
| POA/GTI | Irradiation on a tilted plane | PV planning |
| PVOUT | Estimated PV electricity output | Production assessment |
To find the peak sun hours in my area, use the location-specific solar resource rather than using a countrywide average, which can serve as a rough estimate of solar gazing.
How Peak Sunshine Hours Affect Solar Panel Output
The relationship between the hours of sunshine and the solar panel output can be used to give a rough estimate of the energy produced. Por exemplo, a simple calculation suggests:
Estimated daily PV energy ≈ System capacity × Peak sun hours × Performance factor
Since each project has its performance factor (which is also the percentage of theoretical energy that the system will create after system and operating losses have been gouged out; e, portanto, multiplying the system size by the peak sun hours should always be looked at as an estimate and never as guaranteed production.
Por exemplo, consider a hypothetical 10 Sistema solar KW:
| Horário de pico do sol | Theoretical daily energy before losses |
| 3 horas | 30 kWh |
| 4 horas | 40 kWh |
| 5 horas | 50 kWh |
| 6 horas | 60 kWh |
Illustrative calculation only. Actual production depends on site and system conditions.
The real produção de energia solar will likely be much lower than what is forecasted. The PVWatts model of the NREL considers loss categories that include soiling, sombreamento, module mismatch, fiação, e mais. The present calculator assumes a modeled system-loss value of 14%. This should not be taken as the universal loss rate, as actual projects differ.
We can measure the soiling effect. According to IEA PVPS, pó, contamination, and biological materials deposited on PV modules are estimated to be, em média, responsible for 4–7% of global PV energy losses. No entanto, it can vary substantially by location and operating conditions.
Então, evidently, solar power output calculation should go beyond the peak sun hours when a project necessitates a more realistic production estimate. Instead of assuming that every available peak-sun hour becomes usable AC electricity, a detailed PV model incorporates location, system configuration, and relevant losses.
What Factors Affect Peak Sunshine Hours?
The number of peak sun hours is affected by the amount of solar energy present at one location and the capacity of a solar panel to produce energy. Several factors affect peak sunshine hours; these are the main reasons for explaining that two locations can have very different solar resources even at the same latitude.
Latitude and seasonal solar geometry influence solar resources
Sunshine hours of a location are affected by the latitudinal position. Latitude affects at what height the sun appears in the sky and the angle at which the solar radiation reaches the surface of the Earth. The sun’s relative position changes throughout the year as the Earth’s position relative to the sun changes.
Besides latitude, there are several other factors that help determine the number of peak sunshine hours. A place that is near the equator does not necessarily have to result in a high solar resource. The entire sky could be covered with clouds, or there could be dust in the atmosphere to reduce the solar radiation.
Weather and atmospheric conditions affect solar irradiation
Solar radiation reaching the surface of the Earth can be reduced due to clouds. The passage of solar radiation through the atmosphere can be further affected by aerosols and moisture present in the atmosphere. Solar-resource models use multiple factors, not solely geographic location, to estimate solar irradiation. The resource assessment in the Global Solar Atlas methodology incorporates satellite observations with atmospheric and meteorological information.
Seasonal and site conditions also matter
An annual average may disguise large differences in availability. The amount of energy available for a Sistema de energia solar can vary with seasonal changes in solar geometry, cloud cover, and weather.
Local context is also important. The irradiation received by a specific PV array can be altered due to buildings, árvores, terreno, array orientation, and tilt. Por esta razão, peak sunshine hours are an indicator of the wider solar resource, but the actual energy received depends on the site and design of the system.
How Peak Sunshine Hours Affect Solar System Sizing
Knowing the peak sunshine hours for a location allows a preliminary estimate of the PV capacity required to meet a target amount of electricity. A simpler relationship is:
Required PV capacity ≈ Daily energy demand ÷ Peak sun hours
If a site is using 30 kWh of electricity per day and receiving an average of 5 horas de pico do sol, then the simple calculation will give:
30 kWh ÷ 5 horas = 6 kW
This figure of 6 kW is merely a theoretical starting point. A useful calculation of dimensionamento do sistema solar needs to take into account the difference between the theoretical solar energy and the electricity received from the PV system. Adicionalmente, the design must take into account the monthly energy requirement of the site and periods of lower solar availability.
A system designed around an annual average may seem to perform well on paper. No entanto, it will generate less energy in months with weaker solar resources. The impact of high energy demand systems is more pronounced in a seasonal consumption scenario.
Exemplo do mundo real: From Solar Resource to Energy Storage
A practical example can illustrate why solar-resource data must be considered together with storage design. A HBOWA forneceu um 100 kW / 500 kWh energy storage system for a project in Bohol, Filipinas. Dois 50 kW Deye hybrid inverters and 500 kWh of battery storage are used in the project. HBOWA recognises that application as island solar self-consumption energy storage.
The project was designed to favor direct solar self-consumption, consume part of the excess daytime solar energy, and deliver electricity at night or during low-solar periods. The system also allows local load supply, where the client wanted more energy self-sufficiency.
Peak Sunshine Hours and Battery Energy Storage Planning
The average sunshine hours determine the solar energy available for charging a battery. No entanto, it does not determine the required capacity of the battery. The battery size depends on the electricity requirement, the timing of that requirement, the required backup duration, the usable battery capacity, a profundidade da descarga, the charging and discharging limits, and the expected PV production.
Por exemplo, A commercial building may produce most of its solar electricity during the day and then use electricity after sunset. A system that stores energy can transfer part of that daytime generation to later periods. The necessary battery size will depend on the amount and time of the evening load rather than just on the peak sun hour.
This difference has implications for the design of ESSs. Um armário de armazenamento de energia ou BESS container can meet various operating requirements, depending on whether it supports self-consumption, backup, peak-demand, or off-grid operation. The IEA PVPS implies that for reliable PV-based battery systems, desempenho, monitoramento, and maintenance should be proper.
How to Use Peak Sunshine Hours Correctly
Utilize the peak sunshine hours for the planning question. GHI, or global horizontal irradiation, describes sunshine from the sun. The use of peak sun hours can aid in a rudimentary PV estimation. Por outro lado, PV modelling provides a clearer indication of most production figures.
Monthly data can help with this seasonal generation assessment. To size a battery, one requires load, PV output, and autonomy. The tariffs and system costs are also necessary. Como tal, peak sunshine hours are a useful input, but not a complete Sistema de energia solar design approach.
| What you want to know | What to use |
| Solar resource | GHI / solar irradiation |
| Basic PV estimate | Horário de pico do sol |
| Expected PV production | PV modeling |
| Seasonal generation | Monthly solar-resource data |
| Tamanho da bateria | Carregar + VP + autonomy |
| Project economics | Produção + tariffs + system costs |
Conclusão
The daily solar radiation can be expressed as a number of hours equivalent to 1,000 Com m² (aquilo é, around the peak sunshine hour). They help you do a quick estimate of solar potential and PV energy. Precise planning necessitates site- and season-specific information as well as the real characteristics of the project system. HBOWA can help you analyze and design the whole energy storage system; feel free to contact us to discuss your detailed requirements.
Perguntas frequentes
Claro. Ao longo do tempo, days with different weather events have specific peak solar times when they maximize their solar energy generation. Solar geo-positioning is the calculation of these time values in relation to a specified location. For the purpose of planning, long-term averages are usually more useful than a single day’s value, while monthly data can indicate important seasonal changes in available solar energy.
Irradiation generally varies quite significantly over the year, which is why monthly data is much more useful for dimensionamento do sistema solar. Over the year, solar irradiation may present shortfall periods. For systems that have seasonal loads, necessidades de backup, or limited grid access, a monthly solar resource may provide a better basis for estimating the expected PV production.
Sim, but only as a preliminary assessment of solar power availability. The battery capacity or charging requirements cannot be determined by peak sunshine hours sozinho. A variety of daytime electrical load factors impact battery charging, including solar panel output and seasonal conditions. These factors must be considered for a complete armazenamento de energia solar assessment.
To analyze a commercial PV project, horas de pico do sol are combined with site solar-resource and production data. GHI can give a general idea of the solar resource, while irradiation on the collection plane and PV modeling can provide more relevant production estimates. Profile loads, tariffs, perdas do sistema, and operating conditions must be accounted for.
