The solar energy industry keeps growing. Even in a global recession, the largest PV manufacturers are still implementing expansion plans. Longi, for example, has recently presented an innovative new panel based on TOPCon n-type technology.
This panel boasts better efficiency (2-3% improvement over PERC) and promising long-term yields (estimated power output of 87.40% after 30 years). On the other hand, companies such as Tongwei are trying to improve efficiency and reduce costs. Tongwei is mainly focused on HJTexpansion plans for the near future.
We can?t predict exactly which of these technologies will prevail. For now, we can see that manufacturers are trying to move towards n-type solar cells. Yet, the overall market tendency of building larger wafers and the higher performance levels seem to be inclining the balance towards p-type PERC. Moreover, and despite the many attempts from the n-type adepts, the PERC technology is still more cost-effective.
But solar panels are not only developed for industrial uses. Residential solar technology is also on-demand as people are seeking new ways to generate sustainable energy and reduce costs.
In this context, it becomes essential to consider the residents? needs and safety as well as other factors like government conditions, etc. Next, we present the latest technologies one can use to efficiently power a house with solar energy.
Inverters for optimization and safety
Safety is a very important part of an electric system. This is why the US National Electric Code (article 690) requires solar panel inverters to have a ?rapid shut down? function. Thanks to this, the panels will stop exporting electricity if the system has been shut down.
Inverters have two main functions:
- Generate electricity: They are responsible for turning direct current into alternating current, thus allowing an electricity flow to power the household?s devices.
- Safety: The inverter must cut the energy supply when the system has been shut down for any reason. The US established this as a mandatory security measure, boosting companies such as Enphase and SolarEdge. These corporations now dominate the residential solar market partly thanks to the ?rapid shut-down? implementation.
Nonetheless. Modern inverters come with new features that can help to optimize the energy flow. Inverters can optimize the panels’ performance and maximize electricity generation. The two largest inverter manufacturers have taken different approaches when it comes to functionality.
Optimizing energy with an inverter
Microinverters: Like all inverters, the microinverters? main function is to optimize the energy production even in those panels receiving fewer amounts of light. This can be due to the panel?s angle on the rooftop, the season, shade position, etc. Thus, microinverters are small inverters placed behind each panel and converting DC to AC directly on the roof.
Optimizers: In the same way that Enphase works with microinverters, its main competitor offers ?optimizers?. Solar Edge uses smart modules to connect the panels with a central inverter. These optimizers monitor the panel?s performance and adjust the power points for better yields. Instead of converting the current to AC, optimizers maintain a consistent DC voltage while current varies.
Both these options are designed to optimize the powering process by monitoring or working with panels individually. In a solar electric system, each panel?s efficiency depends on the performance of the previous one. Thanks to inverters, the system can keep working even if one panel fails.
But this is not the only innovative approach taken by Solar Edge. The company has implemented car charging devices into their new inverters. Apparently, this company sees the future of residential solar as a comprehensive service. It?s striving to create a product that can cover all needs of an average citizen or family.
They believe in this future to such an extent that they bought an electric car company and a battery company.
Solar Edge?s inverters are specifically designed to charge electric cars. This innovative tool is called ?Excess PV? and works on a simple principle.
During the day, the inverter prioritizes solar energy to power the house. The energy that remains available (or ?in excess?, hence its name ?Excess PV?) is directed to the car. Most importantly, at this moment the car is not charged with the power grid.
The amount of available energy will depend on the household?s electricity consumption. While the inverter is designed for maximum optimization, it may be necessary to charge the car with fossil-based fuel at times.
Users should also consider the type of charger they will need. Many companies offer different car-powering products and customers need to understand what they are buying.
There are two main types of chargers: level 1 and level 2. The difference lies mainly in the level of efficiency one gets with a charge.
Vehicles charged with level 1 devices can output approximately from 3 to 5 driving miles per hour. Level 2, on the other hand, can push 12 to 60 miles of driving range per charging hour.
Also, while level 1 chargers are simple devices (with standard wall and car plugs on both ends), level 2 are more complex. They look like a dryer machine or an induction stove and usually require special permits for permanent use.
This technology is so promising that many of the major players are starting to consider it. Tesla, for example, announced its intentions to integrate different tools and create a residential solar ecosystem.
It won?t be surprising if, in the future, Tesla offers a solar power project with the full package: a car, a charger, and a car battery. However, these are mere ideas for now, although residential solar structures can currently be connected to any Tesla car charger. It makes no difference if the solar project was manufactured by Tesla or not.
Using your car as a backup generator with V2H technology
There is a promising device called V2H (?Vehicle to house?). Its main purpose will be to power a whole house with the car?s battery. This can be useful during an emergency or a power cut, in which people will be able to use their cars as backup generators.
Two major companies have partnered to make this project come to life. These are Ford and Sunrun who worked together to present the electric F-150 Lightning.
This vehicle will come with an 80-amp charger and be designed to power a whole house only on its battery. The battery system will boast over 100kWh, which is more than enough to run a home for several days.
Energy Storage options
Energy storage and batteries are matters that concern many solar panel users.
While solar energy is reliable and cost-effective, it?s not always stable as it depends on seasonal and climatic conditions. Hence, homeowners need a reliable storage system that helps them prepare for contingencies.
The main problem is that energy companies don?t offer enough financial support when it comes to storing energy in residential properties. This makes battery storage quite expensive.
If we consider that an average house uses nearly 10,000 kWh a year (27 kWh a day), then a solar energy system is supposed to generate this much as well. A solar structure should generate this amount despite the seasonal variations.
However, power backups are usually used for emergencies, hence the stored energy is not supposed to keep the house running for an entire year. Nowadays, most storage systems available can power up a full house for at least a few hours.
Yet, homeowners may not need the whole home powered during an emergency. This opens an opportunity for storage and energy optimization. When it comes to the battery?s storage size, we can consider the following aspects:
- What areas of the house will be powered during the emergency, e.g., refrigerator, emergency light bulbs (energy-efficient), etc.
- How much time do you want the devices to be powered? This can be a few minutes or days, depending on the needs and conditions.
- How much of the solar power system will be charging the backup? In this case, relative size should be considered.
Providing a deeper description of the battery options is beyond this article?s intentions. Nonetheless, these are the basic principles to consider when establishing battery storage.
Smart panels for better optimization
To complete the solar ecosystem, it?s possible to use special smart panels. This is the cherry on the cake that, in combination with other resources, can streamline a household?s power supply for maximum optimization.
These panels are usually installed between the solar energy system, the storing batteries, and the house?s electrical appliances.
Span has recently released a unique product. This is a smart panel that provides a circuit which can be controlled from a smartphone.
With this technology, homeowners can optimize their electricity usage with programmed tools. When an electricity event hits, these tools will automatically shut down the circuit.
Sonnen offers state-of-the-art storage batteries with smart solutions. They help assure that the house?s power system runs smoothly. Their ?eco? version can run an entire house with its batteries and analyse weather conditions, assess the price of the energy, and optimize electricity consumption. It automatizes many processes like turning the lights off when you leave the room.
Today?s technology already allows for the creation of a solar power ecosystem to power a residential property.
By combining an efficient solar system, the right storage batteries, a car charger, and a smart circuit to optimize the processes, people can enjoy the advantages of solar energy.
This points to a more sustainable future where humans can derive electricity from renewable sources at affordable prices without compromising comfort.
John Fitzgerald Weaver, June 24, https://pv-magazine-usa.com/2021/06/24/solar-101-the-brains-behind-the-beauty-of-your-solar-power-system/
John Fitzgerald Weaver, July 12, 2021, https://www.pv-magazine.com/2021/07/12/solar-101-accessorize-your-rooftop-pv-with-batteries-panels-and-ev-chargers/