Renewable energy systems
To make effective use of any electricity generation source, be it wind, solar, or even diesel, the generation source must be part of a system to manage transmission, storage and consumption.
For example, generation peaks from wind or solar typically don’t coincide with when you want to use the energy. Also, the electricity in a renewable energy system is generated at various voltages so must be temporarily stored (in batteries for example) then configured for your household loads using other system components. There are two types of renewable energy system to consider depending on the application:
Remote Area Power Supply
A Remote Area Power Supply (RAPS) comprises the means to generate electricity, store it, present it in the right configuration for use, and provide control, monitoring and protection systems.
This type of system is useful if you are in an area where there is no network power available (on an island, for example) and you need power. A RAPS, or micro-grid, provides you the means to generate electricity yourself.
In some cases there may be a network available to provide you with energy, which would mean running a cable from the road to your meter box. This could also include the erection of power poles on your property and/or new poles on the road - depending on the circumstances this can be costly.
Generation options include wind, solar photovoltaic panels (PV), micro-hydro, diesel gen-set and possibly even biomass (fossil fuel). There are a host of different reasons why you should go for one generation source over another, but usually there will be at least two of these in a RAPS.
Network connected/Distributed generation
Distributed Generation (DG) is an option for those that are already connected to the network but are seeking alternative energy sources. A DG system gives you the ability to deliver your renewable energy to the national grid via a network.
The benefits of network connected systems include:
- Environmentally friendly
- The ability to reduce your power bill
- Flexibility to use the network when generation doesn’t meet demand
- Ensures continuity of supply during network outages
DG systems typically use wind turbines and/or solar PV panels but no (or very few) batteries. The generating source is connected to a network-connect inverter which feeds energy either into the house or into the network, depending on how much energy you are generating and how much you are consuming. If you are generating more than you are consuming at any given time then the excess is consumed by someone else, while you get a credit for it from your power company measured through your own meter.
New Zealand has very good renewable energy resources so it makes sense that wind turbines are used to generate electricity on a home scale with the excess fed back into the grid.