Co/trigeneration: who, what and why?
Cummins explains who should be considering trigeneration, what questions should be asked pre-installation and why trigeneration may be the right solution for your facility’s energy needs.
The reason why facilities install cogeneration or trigeneration (co/trigeneration) systems depends on the end user. Co/trigeneration systems are generally installed in commercial buildings to maximise the building’s Green Star or NABERS rating. A system may be installed in a data centre because there is an environmental policy or green roadmap to reduce the facility’s emissions.
Industrial customers may consider co/trigeneration because their facility has a need for more energy than the existing infrastructure can supply/support and it has an even balance between electrical and thermal demands. Hospitals install co/trigeneration systems to save costs. These healthcare facilities even consider using gas-fired plant – either as a primary critical back-up or for use in conjunction with traditional diesel standby systems. In all cases, when compared to business as usual, a more efficient energy solution is achieved, with the main goal being to save money.
In general, the facilities mentioned above are the kinds of facilities that install these types of systems, but any energy user that has an electrical and thermal demand can consider co/trigeneration. In addition, co/trigeneration should be considered where there is a need to limit or reduce a facility’s carbon footprint. No other technology currently exists that can reduce carbon dioxide contributions as significantly and cost-effectively.
Each project has a slightly different payback period and co/trigeneration is not cost-effective for all facilities. Some co/trigeneration projects don’t get off the ground because the main board or the company has a policy stating that any investment has to have a maximum payback of two years. With the current market conditions, co/trigeneration in Australia will never achieve this. Projects we’ve delivered to date have had paybacks between six and seven years.
INSTALLATION AND MAINTENANCE ADVICE
Pre-installation, it needs to be decided how the plant will be packaged. Co/trigeneration systems are complicated and gas gensets have very particular installation requirements. Contracting the plant as a package to a single source supplier is recommended. In other words, the genset, chiller, controllers, switch gear and ventilation, among other items, should be managed and delivered by one organisation on a turnkey supply. This also helps when exploring operation and maintenance agreements, as the company that undertook the installation also takes responsibility for the reliability and output of the plant. This reduces the end user that invested in the plant’s risk in the long-term.
In addition, it is advisable to engage early on with the genset suppliers/packagers to ensure that enough space is allowed for in plant rooms. From the very beginning, a lot of focus also needs to be placed on how the plant will be maintained. The more space that can be made available, the better. Easy access for maintenance is vital and it is important to consider an operation and maintenance agreement. The level of maintenance required for this type of equipment is often misunderstood. For instance, if the plant operates 24/7, then the gensets need rebuilding after between seven and eight years of operation.