Energy independence
/ back-up electricity

Have you ever considered what you would do if the grid electricity supply disappeared? Although a worrying thought and still unlikely, the likelihood is increasing with the political instability and climate change pressures the world is facing. What if you could take control of where your electricity comes from and gain some independence from the national grid?

When it comes to a reliable supply of electricity, we can help. Designing a reliable off-grid electricity supply system is complicated because you not only have to balance the demand from electrical loads with the supply from generation sources, but you also have to install and operate those generation sources. On top of that, the system must provide electricity with the correct voltage and frequency that modern appliances need. With modern technology this can be done, and interestingly it can be designed to work now with grid-supplied electricity as a back-up and helping-hand when needed, but also with the capability of operating in a complete ‘standalone’ mode if the grid were to disappear. This will of course mean you could seamlessly carry on supplying your own electricity during a power cut or blackout as well.

Energy Independence System – explained

So, how does a typical system work? The diagram below shows the key items of equipment and the direction of energy flows. The heart of the system is the inverter-charger; this is the central point that the electricity supplies connect to (grid, generator (if used), solar PV, wind turbine and hydro turbines (if either are used) and battery storage. The electrical supplies to the property are also supplied from the inverter – normally via two outlets; one for ‘essential loads’ (lighting, computers and communications equipment, and essential laundry and cooking equipment), and a second outlet for non-essential loads which would only be supplied if the grid was energised or the battery storage system was fully charged. The inverter-charger is available in a range of sizes from single-phase 3 kW to 180 kW three-phase, and any size in between. This would be more than adequate for even the largest properties.

Off-grid electricity supply / green energy

Solar PV
The most common source of generation is solar PV, which can be installed almost anywhere and the annual performance can be reasonably accurately predicted. It can be installed on the roofs of buildings or in ground-mounted arrays. Being of a modular nature, the number of solar PV panels used can be adjusted to suit the area available and / or the expected energy consumption. There are many high-quality solar PV panels available, and many offering performance warranties of 20 or even 25 years, which shows the level of confidence the manufacturers have in their products.

Wind Turbines
Wind turbines are available in a range of sizes from a few hundred watts to multi-megawatt outputs. The megawatt-scale wind turbines are normally too large for private residencies and are reserved for industrial users and wind farms, but some smaller wind turbines are suitable for use at larger properties. If installed in a suitably windy location, wind turbines are highly effective and generate most of their energy during the windier winter months, when solar PV is not as productive.

Hydropower
Hydropower is one of the best sources of energy, but is dependent upon access to a river or stream with a suitable change in water levels. The ideal situation is a mountain stream with tens or hundreds of metres of head (head being the difference in water levels between the intake and discharge), but this is only possible in upland and mountainous areas. Lowland areas might have a large stream or river, but often only with a few metres of head. Energy generation is possible from both, but more head is always better because it means more energy from a physically smaller system, which generally costs less. Many sites will simply have no hydro potential – you either have it or you don’t.

Generators
Generators have been around for many years providing reliable back-up electricity, and modern versions can operate quietly and reliably. The downside is that they need fuel, normally diesel or petrol, which could be difficult to obtain in the future. They are still a good back-up option, though, assuming diesel and petrol are readily available.

Batteries
Batteries are both a source of energy by discharging them, and a consumer of energy when charging them. They are the other key element after the inverter-charger and have come a long way in recent years with Lithium Iron Phosphate (LiFePO4) batteries becoming readily available. A few years ago, lead acid batteries would be used, but these have been superseded by LiFePO4 batteries in good quality systems due to the latter’s significantly better performance, improved efficiency and longer lifetime.

Quality Equipment – for best service
On the selection of equipment, Renewables First works to some key principles. The first is that we don’t want to be and are not the cheapest supplier because our clients are not driven by minimum cost. Our clients are paying us to specify the most efficient and best-performing equipment from manufacturers with a reputation for quality, long-term reliability and long-term product support. This inevitably means that we specify more expensive equipment, but it will be better performing and more reliable. An example would be for the inverter / charger and associated control equipment; we only specify Victron Energy equipment because it is the recognised leader in off-grid capable equipment, and they have a track record extending back decades, originally starting out by selling off-grid electrical systems to expensive yachts. On solar PV panels we only specify manufacturers with ‘Silicon Module Super League (SMSL)’ status, and will also only specify panels with a minimum efficiency of 21 %, and will raise this bar higher as more efficient solar PV panels become available. We only specify and supply premium equipment.

Why choose Renewables first?

So, why should you trust Renewables First to design and build your off-grid green energy capable electrical system? We are an engineering-based business with an in-house team of experienced engineers that actually build stuff. We take projects from initial feasibility, through the consenting and design stages, then build and commission them, then help the owners operate and maintain them. We’ve been doing this since 2009 and have a long list of successful projects and happy clients. Our key differentiator is that we build systems, and only by building systems and sorting out all the teething issues can you truly develop the deep understanding needed to design reliable energy generation systems.