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Ha Noi Power Corporation (EVNHANOI) is working alongside residents and businesses in the capital to develop self-produced, self-consumed rooftop solar power, aiming to promote the efficient, proactive and safe use of electricity generated on-site.
However, for these systems to deliver their full benefits, the key lies not only in installation but also in selecting the appropriate capacity and operating methods to match actual electricity demand.
From installing solar power to using electricity efficiently
Self-produced, self-consumed rooftop solar power refers to electricity generated by photovoltaic panels installed on the roofs or external surfaces of buildings, with priority given to meeting the electricity needs of the buildings themselves. Under this model, electricity is generated at the point of consumption, helping reduce the amount purchased from the grid and providing greater control over part of the electricity supply for daily activities, production and business operations.
Importantly, the effectiveness of a system does not simply depend on the number of solar panels installed, nor does greater capacity necessarily mean better performance. EVNHANOI recommends that customers begin by reviewing their electricity consumption data over the previous six to 12 months to determine how much electricity they use, particularly at times of peak demand during the day. This provides a basis for calculating an appropriate system capacity, avoiding excessive investment relative to actual needs, while a system with insufficient capacity may fail to make full use of the rooftop’s solar energy potential.
For households, buildings with high daytime electricity consumption are particularly well suited to using solar power directly as it is generated. This advantage is even more apparent at production and business establishments, where electrical equipment often operates continuously during the day. When solar power is generated and consumed directly by equipment in operation, the benefits of the self-production and self-consumption model can be maximised.
The experience of AEON MALL Ha Dong Shopping Centre demonstrates how solar power can provide practical support for electrical equipment in facilities with high electricity demand. Pham Van Tien, a representative of AEON MALL Ha Dong, said the solar power system has made a significant contribution to operating the centre’s electrical equipment, particularly its air-conditioning system.
According to Tien, solar power helps keep the air-conditioning system running continuously while reducing demand for electricity from the grid. With the shopping centre consuming more than 26 million kWh of electricity annually, solar power currently accounts for approximately 7–10% of its total electricity consumption, helping the centre take a more proactive approach to meeting its operational electricity needs.
This also reflects one of the key principles of self-produced, self-consumed rooftop solar power: using electricity directly as it is generated to meet immediate consumption needs. EVNHANOI also emphasises the importance of prioritising on-site electricity consumption. For buildings with substantial evening electricity demand or a significant mismatch between electricity generation and consumption times, customers may consider installing a battery energy storage system (BESS).
Appropriate capacity, actual demand and safe operation
One of the most common concerns among customers investing in rooftop solar power is determining the appropriate system capacity. According to EVNHANOI, rather than starting by asking “How many kWp of solar panels can the roof accommodate?”, customers should first determine how much electricity their building consumes and when most of that electricity is used.
Suggested capacities of 3 kWp or 5 kWp for households, or 10–20 kWp for small production and business establishments, are intended as references only. The optimal capacity should be determined based on actual electricity consumption data, rooftop conditions and the intended use of each building.
In addition to selecting the right capacity, rooftop conditions must be carefully assessed. Roof area, orientation, shading, structural integrity and load-bearing capacity all affect the system’s performance and safety. EVNHANOI’s guidance recommends prioritising roof areas with good sunlight exposure while ensuring that the building’s structure meets requirements for electrical safety and fire and explosion prevention.
For systems connected to the national electricity grid at low voltage, organisations and individuals are required to submit a notification to the commune-level People’s Committee where the system is to be installed, in accordance with regulations. Systems with an inverter capacity of less than 1 kW are exempt from this notification requirement. If no response is received within 10 working days of submitting the notification, organisations and individuals may proceed with installation in accordance with the notified details and relevant legal regulations.
In particular, customers should not focus solely on electricity output or anticipated savings while overlooking safety requirements throughout the system’s lifespan. Priority should be given to selecting equipment with a clear origin, engaging experienced consultants, surveyors and installation contractors, and ensuring adequate protection systems, lightning protection, earthing, roof structural safety and compliance with fire prevention and firefighting requirements.
EVNHANOI stresses that economic efficiency is meaningful only when a system operates safely, reliably and over the long term.
Rooftop solar power, therefore, is about more than simply installing additional panels on a roof. Understanding how solar electricity is generated, accurately assessing consumption needs, prioritising on-site use and complying with technical and safety requirements will enable each building to make more effective use of solar energy while contributing to economical, proactive and sustainable electricity consumption.
LE CHI
Translated by NDO
Amid the risk of energy supply chain disruptions caused by military conflicts in the Middle East, Viet Nam’s oil and gas industry is proactively increasing production to meet domestic demand. In the coming period, businesses will continue expanding trading activities and seeking international sources to ensure stable fuel supplies.
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