What is trigeneration?
It is the process by which methane fuel is consumed to simultaneously produce electricity, heat and cold.
Where is it applicable?
Such plant is feasible with at least 6,000 hours per year of demand for electricity combined with either simultaneous heat or refrigeration.
When is it economically appropriate?
Where you have a baseline electrical and thermal (hot or cold) energy requirement that coincides with the following parameters:
thermal power > = 90% electrical baseline
cooling power < = 70% electrical baseline
What are the risks?
The risks are related to:
– uncertainty about the application of system charges to
– consumption variations over extended time periods (3/5 years).
What total implementation costs should be considered?
Firstly you should consider the machinery costs such as the cogenerator, the absorber, absorber cooling systems and the parallel control panel.
Other significant costs include:
– construction works;
– electrical connections;
– plumbing [hydraulic] connections.
Can the cogenerator replace
It would be like asking if you can tow a Caravan with a Ferrari – you could, but not for more than a few kilometres!
The cogenerator is a very sophisticated machine designed to work in parallel with the grid and it is very sensitive to load variations.
What are the management costs?
In addition to the cost of methane fuel, other significant costs include:
– lubricating oil;
– routine maintenance;
– large-scale maintenance after 50/60 thousand hours of operation.
A number of vendors have approached me with the proposal that they would set up the trigeneration plant at their expense and sell me discounted thermal and electrical energy for 10 years.
Are they to be trusted?
Beware of such initiatives! Establish clearly who will bear the costs for the future variations in the tariff component related to system charges; these are currently quite low but they likely to increase in future. Also be careful that there are no “Take or Pay” clauses.
What is a Take or Pay clause?
You must either consume energy corresponding to a given amount or pay a charge in lieu. So the consumption variability risk falls on yourself: if you reduce your consumption below the contract value you will still be obliged to pay as if you had consumed it.