Estimating the total energy savings potential of adopting a systems approach to energy efficiency is a complex exercise for many reasons.
- The savings can be situated at different levels in the energy stream (e.g. in the power cable feeding a motor, in the motor driven pump system, or in the space heating system with which the pump is integrated), making it hard to avoid double counting;
- The savings can be dependent on the load (e.g. power cable sizing) or lead to load reduction (e.g. heating or lighting control systems), making every case unique;
- The savings can also be the result of a technology switch (e.g. from a natural gas boiler to a heat pump), in which case, to assess the savings potential, the potential share of the market that could make such a shift should be estimated;
- Part of the potential of a systems approach lies in facilitating the implementation of energy savings already subject to regulation. Such a role is difficult to quantify.
Despite these difficulties in making an exact and reliable assessment, a rough back-of-the-envelope calculation can quickly reveal the order of magnitude. Most of the savings potential from a systems approach can be assumed to fit into one of the following three categories:
- Optimisation of pump and fan systems, pneumatic systems, machine tools and non-residential power cables. Together they have a final annual energy consumption of 830 TWh in the EU [WSE 2016, p.5]. A very rough estimation would be that a systems approach could reduce consumption by a third, or 277 TWh per year.
- Building automation and control systems (BACS), improving the energy efficiency of HVAC and lighting systems, among other optimisations. The total energy savings potential of BACS in the EU is estimated at 580 TWh per year [WSE 2014, p.43].
- A technology switch from natural gas to electrically driven heat pumps for space heating and sanitary hot water. According to the Heat Pump Association, the share of this market covered by heat pumps could rise from the current 19.6% to 44% [EHPA 2019, p.7 and 10], and the efficiency gain of such a switch would be around 75%. Knowing that this market has an annual energy consumption of 13225 PJ or 3644 TWh [WSE 2016, p.5], the energy savings potential of a technology switch to heat pumps can be estimated to be around 675 TWh per year.
Aggregating these three main categories, the total energy savings potential of adopting a systems approach to energy efficiency in the EU would be around 1500 TWh per year. This figure is close to 11% of the total annual final energy consumption in the EU and corresponds to 2285 TWh of primary energy and 360 Mt of CO2 emissions each year. Even though it cannot be regarded as anything other than a rough estimate, the figure is high enough to demonstrate the significance of the concept.
The total energy savings potential for a systems approach to energy efficiency in the EU would be around 1500 TWh per year or close to 11% of total annual energy consumption.