The installation capacity demand of your gas generators depends on your gridsystem you use. To compare we use as an example the following load curve of a customer:
Gridparallel operation
Within a gridparallel system you feed in a certain amount of electricity independent of your actual demand. Therefore you don’t have to cover your peak demand of 2,100kW with your gas generator capacity.
An average of 723kW means 723kW x 24h/d = 17,352kWh/d.
Based on an agreement with your “mothergrid”, you might just install one gas generator with a capacity of for example 1,200kW.
To generate your own average demand your generator has to produce 17,352kWh/d. This can be achieved by operating it about 15 hours a day (15 x 1,200 = 18,000). So during peak demand time of the mothergrid you support it; when during low demand the mothergrid has enough capacity it supports you. Your gas generator only runs at highest efficiency.
Depending on your agreement with your mothergrid you even might be able to sell any excess power to the grid.
You should consider taking advantage of the CHP possibilities of your gas engine as well.
As your generator is independent of your own demand you don’t need any kind of load stabilizer to protect your own grid as you are still part of the mother grid. The more people participate in this system, the more stable and homogeneous it gets.
You don’t need either a separate process performance unit because your generator operates separately from your actual demand.
Depending on the feed in point an additional transformer for your gas generator might be necessary to raise the voltage from 400V to 11kV.
Standalone operation
The total demanded installation capacity, amount and sizes of the generators depends on your individual and actual demand.
- your peak demand defines the max capacity of your gas generators. To provide an optimized regulation of the generators to match your actual demand you need an capacity overhead of about 15%, i.e. with a peak demand of 2.000 kW you need an installed capacity of about 2.300 kW;
The lower your peak demand the lower your installation demand.
- your minimum demand level defines the capacity of your smallest generator. Most gas generators have to run constantly with at least 50% of their max capacity; i.e. a minimum demand of 80 kW defines the smallest generator capacity at about 160kW.
most generators we work with can be operated at 30% minimum, i.e. a minimum demand of 80kW can define the smallest generator to have a capacity of about 250kW.
The higher your minimum demand the less engines you have to install.
There are many ways in reducing your peak demand:
- reducing your total consumption
- shifting consumption from peak demand into lower demand times
There are many ways as well in raising your minimum demand:
- shifting consumption into low demand times
- selling energy during low demand times to neighbors
The maximum and the minimum demand of your system define the total capacity, the size of your smallest gas generator and the amount of generators you need.
Based on the above shown example you need to install here for example:
- two gas generators of about 250 kW total 500 kW
- two gas generators of about 600 kW total 1,200 kW
- one gas generator of about 800 kW total 800 kW
- total capacity installed 2,500 kW
If you are able to adjust your daily demand in order to lower your peak demand and/or to raise your minimum demand your installation demand changes significantly:
After adjusting your consumption profile you need to install here
- three gas generators of about 600 kW total 1,800 kW
- total capacity installed 1,800 kW
If you are able to even reduce your electricity consumption for example by taking advantage of the CHP characteristics of your gas generators the installation demand gets even lower.
As you can imagine now, the easiest and cheapest way would be if your actual demand would always correspond to your average demand; in that case you only would need one gas generator with no buffer. But this is more a theoretical possibility. Investmentwise this would be comparable with the investment demand for a gridparallel solution.
All generators work within one internal grid together. They are synchronized and can substitute each other as long as the total demand can be matched.
Not all generators operate at the same time. To keep them running at an optimized efficiency of around 80% generators are automatically switched on or off depending on the actual demand.
