The actual estimation of people who do not have access to the main power network in developing countries is estimated to be in the billions.

In such cases, photovoltaïcs, diesel/alternators, co-generation are solutions used to provide local electrical energy, in addition with batteries.

Per Watt AC power from an inverter is generally more expensive than a generator. So why would one add an inverter to an AC generator system?

Apart from the obvious advantages of "silent ac-power", there are major considerations why it is attractive to add an inverter/charger and an additional solar charger to a system with an AC generator:

 

• Fuel Savings due to lower fuel consumption

A typical 7.5kW generator will consume about 1.5l/h diesel at low loads and 2.3l at 75% load. So the "generator only" configuration requires high consumption of diesel per day, whereas the "generator with an off-grid inverter & PV power" configuration requires a lot less diesel to provide the same AC power.

• Cost and time savings as a result of reduced maintenance / Extended generator life

Generators based on a fixed speed diesel engine will last longer when they are run under load compared to being run at no or low loads. Some manufacturers recommend operation at a minimum of 30% load to prevent premature failure. By adding an inverter/charger, the load on the generator can go up and will offer a considerable longer life, than may be expected running purely on the load required. This method of activating the generator in an optimised method will reduce the maintenance due to a lower running time.

• Environmental Impact

The result of reduction of running hours will reduce the harmful exhaust and oil waste from the AC generators significantly.

Using intelligent bi-directional inverters, which makes use of a power demand control function, can improve the efficiency of a hybrid system by under dimensioning of the generator size. Under dimensioning of a generator compared to the peak load required and operating it at a more constant power allows gain in efficiency. Choosing a smaller generator will of course reduce noise, size, weight, fuel consumption and initial investment.

• Smaller Battery Size

The battery size needed is smaller than what may be expected due to the fact that the energy is supplemented by alternative energy elements active in the system.