A recent survey of energy managers has highlighted the importance of onsite energy generation in enabling organisations to achieve higher levels of energy efficiency and resilience. Nearly half of the respondents said they have installed combined heat and power (CHP) as part of an onsite energy generation strategy.
The benchmarking survey was carried out by edie in association with E.ON and asked energy managers in both small and large organisations about their activities relating to energy efficiency. Encouragingly, 95% described themselves as ‘more efficient’, having moved from just being compliant to being more knowledgeable about improving energy efficiency.
Surprisingly, of the initiatives deployed, only 9% addressed efficiencies in heating, ventilating and air conditioning (HVAC) systems despite the significant contribution these can make to energy consumption. There is clearly more scope here for significant improvements.
Beyond ‘being more efficient’, 73% of energy managers classified themselves as ‘self-sufficient’, having moved into onsite energy generation. Of these, 47% have installed CHP as all or part of their onsite energy generation mix.
Where CHP is contributing to onsite energy generation it’s important to maximise the percentage share of the heat and electrical loads that are met by the CHP plant. Achieving this means using the right type of CHP plant.
For instance, traditional fixed-output CHP imposes a number of constraints by the inability to handle variable demand efficiently. For example, if fixed-output CHP is sized to meet the site’s base electrical load this inevitably limits the contribution that can be made to meeting heat loads.
Similarly, if the CHP is sized to meet the base heat load, the effect is that electrical power output will be determined by the heating requirements of the site, rather than the requirements for electricity.
A more responsive and dynamic approach is to use load tracking CHP units that are able to modulate their output and dynamically track site demand to ensure the power output of the CHP is aligned to changing site requirements. This provides effective management of the most expensive utility – the electrical power – thereby delivering maximum cost savings.
Load tracking CHP, such as SAV’s LoadTracker, also makes it easier to reconfigure the system as the building’s use of heat and power changes to maintain optimum onsite energy generation. This could be the result of improvements to the building’s fabric or changes in staff density.
Further flexibility is afforded by the ability to use dynamic, load-tracking CHP in a modular/cascade configuration – in the same way as the more familiar modular boilers – to accommodate a wide range of applications. For example, five 20kWe/38.7kWth units can be combined to provide outputs up to 100kWe/193.5kWth.
A summary of the edie survey in infographic format can be downloaded here