BEST HOURS OF THE DAY TO USE PORTABLE OFF-GRID POWER DEVICES
Portable off-grid power devices can be a great way to power up the devices outdoors in the absence of on-grid electricity. There are many situations where this sort of power would come in handy, such as camping, using electric tools on a job site, or keeping video equipment charged during outdoor shooting.
Most outdoor adventurers will find off-grid power essential to their comfortable, self-sufficient lifestyles. However, it can be challenging to know precisely when the best times are for using off-grid power devices.
This article explores crucial aspects of the use of these types of devices and the best time to use them.
WHY IS TIMING IMPORTANT FOR USING PORTABLE OFF-GRID POWER?
Off-grid power simply refers to sources of energy generation that are not connected to the utility grid. They are mostly in the form of renewable energy – solar, wind, micro-hydro and biomass. Notably, most portable off-grid power devices used by outdoor adventurers are based on solar and wind energy.
A common characteristic of these renewable energy sources is that they have increased downtime for power generation in comparison to their on-grid alternatives. Therefore, knowledge of peak timing for the usage of portable off-grid devices is essential to ensure maximum power generation.
The daily or seasonal periodic change of sunlight availability, as well as the seasonal variation of wind energy, are the two main time-based indicators for the use of portable off-grid power.
Sunlight Availability Changes Throughout the Year
Solar power has been a valuable alternative to fossil fuels in many parts of the world for many years and a viable option for off-grid power. In the outdoors, portable solar panels are the common devices used in harnessing solar power. The amount of solar exposure throughout the year significantly influences the output of solar panels.
To ensure that solar panels produce as much energy as possible, it is important to consider weather patterns and sunlight availability. The amount of sunlight available at different times of the year can vary significantly depending on geographical location. For example, in temperate regions, more energy is generated from solar panels in summer than in winter due to the availability of more sunlight in the summer months.
Wind Generation Can Vary Across Seasons
The types of weather conditions experienced during the year will determine how much wind generation will occur each day, which will affect how much energy can be generated by the off-grid power device.
For instance, the EIA reports that in the US, "Capacity factors for wind power typically rise or are flat from January through April, fall through August or September and then increase from September/ October to December." This shows that changes in wind power output are typically due to seasonal variations at different periods of the year.
BEST TIMES FOR PORTABLE SOLAR POWER
The daytime is best for using off-grid portable solar power devices as solar panels generate energy when the sun shines. Seasonal differences also influence the amount of sun obtained by solar panels, as daylight hours vary according to the seasons. Summer is the best season for solar power generation because it has the longest day lengths.
It is worthy of note that there are specific times in the day in which energy generation by solar devices peaks. These are known as peak sun hours.
Peak Sun Hours for Solar Power Generation
Peak sun hours occur at the point where solar irradiance attains a power density of 1000 watts per square meter. To determine the peak sun hours for harnessing solar power, two factors are important.
First is the sun's rising and setting (motion of the sun), which makes the amount – and direction – of sunlight reaching the panels vary at each period of the day. Also, the climate of an outdoor camp's location plays a large role as it determines temperature and day length.
For example, peak sun hours for solar power generation in the US and Australia are 11 am to 4 pm. In Europe, the time gap is a little wider, and Bloomberg reports that in the recent heat waves, Germany recorded power generation spikes between 12 pm and 1 pm.
It is recommended that solar panels receive, at least, four hours of direct sunlight each day.
Winter Season for Solar Panel Setup
Solar panels generate less energy during the winter season. This is because, during this season, there are shorter day lengths, increased cloudiness and a layered atmosphere, all of which drastically reduce the amount of sunlight available for a solar panel setup to harness.
Nevertheless, the winter season's cold temperature is favourable to photovoltaic cells. These photovoltaic cells are responsible for the conversion of the sun's rays to energy on the solar panel, as it places them in an optimal state of functionality.
This implies that despite the challenges posed by the winter season to a solar panel setup, a considerable amount of energy can still be generated if panel placement and orientation are maximised, as the panel's photovoltaic cells achieve better functionality at this time.
Solar Panel's Placement and Orientation Do Matter
When installing a solar panel, two things are important to consider with respect to the solar panel's positioning – placement and orientation.
As for a panel's orientation, there are three main ways solar panels can be oriented:
- Horizontal: These are the most common style of solar panels. Horizontal panels face directly toward the sun throughout most of the day but then tilt towards the sun at night to maximise their exposure to sunlight.
- Vertical: Vertical panels face the earth for most of the day but then tilt towards the sky at night. Their orientation changes as clouds pass overhead, so they always face direct sunlight during daylight hours.
- Bi-directional: These panels have horizontal and vertical orientations, allowing them to absorb more light during daylight hours than single-directional models.
Regarding panel placement, the direction and angle tilt of a solar panel are of utmost importance. Ideally, solar panels in the northern hemisphere (US, Europe) should face true south while panels in the southern hemisphere (Australia) should face true north.
The angle tilt of a panel for maximum energy output is dependent on the geographical latitude of the panel's location. A rule of thumb is that the farther a panel is from the equator, the more it should be tilted towards it; the more it is closer to the equator, the more it should be tilted upwards.
In temperate climates, low tilt is strongly advised against during the winter season as it can lead to snow accumulation which blocks the sun's rays. A study conducted in Alberta, Canada, concluded that the annual energy loss due to snow accumulation was 5 times higher for solar panels with low tilt (15°) than those with optimal tilt (53°).
BEST TIMES FOR PORTABLE WIND POWER
Aside from solar panels, one of the most common portable off-grid power devices is a portable wind turbine. The conditions favourable to the use of this device are not much different from the conditions that enable wind farms with much bigger turbines to generate energy maximally.
According to the Energy Information Administration (EIA), in the US, “Wind farms perform at their best during the spring and at their worst during the mid-to-late summer.”
The EIA also notes that the performance of a wind power device is highly site-specific, as it is not only influenced by wind speed but also its direction, constancy and variation by height above ground. The wind characteristics listed here are caused by other atmospheric conditions, most especially, temperature differences at different locations.
Best Season: the Spring
Wind power devices generate more energy during windier periods of the year, and one of such periods is the spring season. On March 29, 2022, the EIA reported that, for the first time, wind turbines generated the second highest energy output of all power generation sources, coming only behind natural gas.
The reason for the windy nature of the spring season is the increase in the sun's angle relative to the surface of the earth (at the onset of the season), which allows more direct exposure to the ground, resulting in the rise of warm air. Consequently, more air rushes in to occupy the vacuum left by the rising warm air, causing greater surface winds.
Wind Power During Mid-to-Late Summer
Wind is caused by uneven heating of the earth's surface. By mid-to-late summer, most of the surface of a particular region is evenly heated, thereby reducing the temperature disparity and movement of atmospheric air. This makes this season less windy and less favourable to the use of wind devices for power generation.
However, a siting adjustment can allow an outdoor camper to obtain wind for power generation around this period. It is advised to site one’s camp beside a water body – the disparity in the water temperature and surrounding land temperature results in an increase in the atmospheric wind.
EXPERIENCE CONVENIENCE WHILE SPENDING TIME OUTDOORS
Portable off-grid power devices are a great way to obtain off-grid power on the go. It is intriguing to know that there are certain best hours of the day (and periods of the year) to get the most out of these devices. Of course, this varies depending on your location and what you are trying to accomplish with your device.
A perfect example of a portable off-grid power would be a portable wind turbine like Texenergy's Infinite Air 18.
The Infinite Air 18 also includes a 12V adapter that can charge 12 volts devices, extending the power availability to more appliances and letting you experience the outdoors without running out of power source to charge your devices, whether during the day or night.