ENERGY AND ELECTRICAL AUDIT
Energy and Electrical Audit (EEA) comprises of 2 parts which can be performed separately or together: a) Energy Analysis and b) Electrical Installation Condition Testing
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DURATION OF AUTONOMY
"Autonomy" refers to your ability to produce or store energy which will be useable whenever or wherever the utility grid is not available. Only you can determine how many hours or days of autonomy you want to invest in.
Battery choice matters (see below). With some types of batteries, the battery size may need to be doubled if you want 2 days of autonomy. Other batteries types may suffice with a slight increase in size.
SELECTION OF ONSITE ENERGY SOLUTION
There are broadly 3 categories to choose from: grid-tied, off-grid, and hybrid.
Grid-tied solar systems and hybrid solutions are viable alternatives in geographies that have a reliable utility grid. The grid is effectively used as a backup battery.
Some off-grid systems are capable of grid-connections. Off-grid solutions must rely on solar PV or other renewable energy sources, or on fossil-fuel generators to produce electricity. All off-grid systems need batteries to function.
Hybrid solutions are able to interconnect with the grid when utility power is available, and are able to operate in off-grid mode during grid absenses. For majority of situations, the only sustainably viable onsite alternative to PHCN's bad grid is an hybrid solution including a core of (a.) energy system and (b.) battery storage, with (c.) solar pv system where applicable, and (d.) addition of diesel-generator as backup.
SELECTION OF BATTERY ENERGY STORAGE SYSTEM (BES)
The quantum of electricity loads calculated above has to be supplied through the battery storage. The solar developer needs to consider many different battery technologies, capacities, life-cycles, and maintenance issues.
Particular attention is required to establish the long-term costs per kilowatt-hour (kWh, the unit of energy measurement). For example, lead-acid chemistry batteries to have lower purchase costs than lithium chemistry batteries, but may not last as long.
SELECTION OF BATTERY-BASED INVERTER-CHARGER (BBIC)
Choice of battery inverter is strongly related to the usage patterns of the particular family or business. Premium-grade inverters are well worth the additional investment.
SELECTION OF SOLAR PHOTOVOLTAIC (PV) SYSTEM
Choice of the solar PV system is strongly related to the installation site and methodology, choices of onsite solution, battery-inverter and battery bank; the energy usage and power demand of the loads, and time of use.
Solar PV are generally marketed by their STC rating. However, priority attention must be given to the PTC ratings, because there can be up to 20% difference between PTC performance of premium-grade panels compared with loweer-cost panels, even when both have the same STC rating.
As may be inferred so far, there is a great variety of components and engineering solutions to choose from. The developer should be concerned with As well as site suitability and procurement issues, system integration, installation, maintainability or replacement issues, durability, and reliability.
Unlike building architectural designs, in which the number and purposes of rooms are largely determined by life-stages of potential occupants, the designs of energy systems are less affected by the individual persons, and more by how and when and where the various appliances present their loads to the system. This is the reason for the primacy of the Electrical and Energy Audit (see above).
Don't be tempted to copy an energy system design that was custom-made for another user. A reputable solar developer will likely offer deductions on the design fee, when an order for the energy system is completed, so you effectively get free design consultation.
Deliverables of the design and quote session include:
- design consultation
- design drawings / installation schematic
- quotation for costs of the components in the design
Your overall energy use will likely increase because 24/7 electricity from sustainable sources has profound and positive life-changing impacts. Here is an outline of the iterative decisions involved in the design and quote process.
- Energy & Electrical Audit
- Duration of Autonomy
- Selection of Onsite Energy Solution
- Selection of Battery System (BES)
- Selection of Battery-Inverter-Charger
- Sizing of solar PV system
- Design Drawings