Decomposing Changes in the Energy Demand of UK Manufacturing

Over the period 1990-2007 the energy demand of UK manufacturing has fallen. A decomposition analysis was conducted to identify the effects of changes in output, structure and energy intensity on the changing energy demand. It was found that a falling energy intensity (indicating improving energy efficiency) was the principle reason for the fall in energy demand. As the UK manufacturing sector is so broad in its uses of energy, it was split into an energy-intensive (EI) and a non-energy-intensive (NEI) sub-sector to better understand the improvement in energy efficiency. The NEI sub-sector made much greater relative reductions in energy intensity in comparison to the EI sub-sector. Previous studies indicate that the EI sector may have made larger improvements in energy intensity in the period between 1973 and 1990 and this may be the reason for the limited improvement seen here. Neither energy price nor production growth appears strongly correlated with the improving efficiency over the period 1990-2007

Heat recovery opportunities in UK manufacturing

A database of the heat demand, heat recovery potential and location of UK industrial sites involved in the EU Emissions Trading System, was used to estimate the potential application of different heat recovery technologies. The options considered for recovering the heat were recovery for use on-site, using heat exchangers; upgrading the heat to a higher temperature, using heat pumps; conversion of the heat energy to fulfill a chilling demand, using absorption chillers; conversion of the heat energy to electrical energy, using Rankine cycles; and transport of the heat to fulfill an off-site heat demand. A broad analysis of this type, which investigates a large number of sites, cannot accurately identify site level opportunities. However the analysis can provide an indicative assessment of the overall potential for different technologies. The greatest potential for reusing this surplus heat was found to be recovery at low temperatures, utilising heat exchangers; and in conversion to electrical power, mostly using organic Rankine cycle technology. Both these technologies exist in commercial applications, but are not well established, support for their development and installation could increase the use. The overall heat recoverable using a combination of these technologies was estimated at 52PJ/yr, saving 2.0MtCO2e/yr in comparison to supplying the energy outputs in a conventional manner. A network and market for trading in heat and the wider use of district heating systems could open considerable potential for exporting heat from industrial sites to other users

Prospects for emissions reduction in the UK cement sector

The UK cement sector was responsible for around 7 Mt of carbon dioxide emissions in 2010. These emissions were due to direct fuel use, the chemical reactions that occur as part of the production process, and electricity use (leading to indirect emissions). Historical trends show that the sector has made considerable reductions in its emissions. This was due to a combination of reduced output, the substitution of emissions-intensive clinker, improved efficiency and fuel switching. The prospects for reductions in the specific energy use and emissions were explored under a range of scenarios out to 2050. Further efficiency improvements were found to be limited. There is potential for additional clinker substitution and fuel switching – although such options are not without their difficulties. The use of carbon capture and storage technology, and alternative (low carbon) cements could lead to larger reductions in specific emissions, but the widescale use of these options is unproven. The approach taken in analysing the cement sector is an example of the bottom-up analysis of the UK industrial sector that has been undertaken in order to produce a database of industrial energy use and improvement potential aimed at meeting the modelling needs of policy makers. </jats:p

Contrasting Thermodynamic, Technical and Economic Potentials:The Example of Organic Rankine Cycle Use within UK Industry

AbstractThe laws of thermodynamics set a theoretical limit on the energy savings that can be realised in a given application. This thermodynamic potential cannot be reached in practice, and a technical potential for energy savings is defined by the performance of available technology. Only applications of the technology that are considered economic will usually be considered for installation. This economic potential will itself not be fully realised, with the actual savings achieved limited by further barriers. A database on surplus heat availability within UK industry was used to estimate the thermodynamic, technical, and economic potentials when converting this surplus heat to electricity using organic Rankine cycles (ORCs). Technical and economic information was based on that reported from existing installations and manufacturers. Various parameters, such as the local price of electricity, are subject to considerable uncertainty, and so a range of possible scenarios were investigated. The results form a basis for discussion on how to close this “gap” between the identified potentials and the savings realised