Combined Heat and Power
A plant facilitating the generation of electrical power and recovery of usable heat from a combustion process is termed a Combined Heat and Power (CHP) plant and it is more efficient than conventional power generation that is focused on power generation alone.
Heat is produced as a by-product when generating electricity through the combustion of a fuel. The utilisation of this heat can significantly increase the efficiency of a power plant. By generating heat and power simultaneously, CHP can reduce carbon emissions by up to 30% compared to the separate means of conventional generation via a boiler and power station, making use of the heat which would otherwise be wasted when generating electrical or mechanical power[1].
For many organisations, CHP is the measure that offers the most significant single opportunity to reduce energy costs and to improve environmental performance with existing users of CHP typically saving around 20% of their energy costs[1].
The heat generated during this process is supplied to an appropriately matched heat demand that would otherwise be met by a conventional boiler[1]. The economic benefits are optimum when there is a continuous heat demand, for example, industrial users of heat or district heating systems[2]. The heat produced could also be utilised by an alternative end market, for example to generate cooling through a heat exchange system for refrigeration processes[3]. The transportation of heat can be problematic and is dependent on the proximity and reliability of the heat customer, additionally the total cost of a project can be increased notably by the installation and maintenance of the required insulated pipe network[3].
The consequence of cogenerating heat and electricity is that the electricity generated is reduced. Therefore, a compromise is needed to be made considering the specific heat and electricity demand, the economic value of each, and the incentives in place to support CHP generation when establishing how a CHP plant will operate[2].
Many CHP Energy from Waste EfW plants are built ‘CHP ready’ but without a viable heat customer in close enough proximity and therefore operate in the less efficient mode of producing solely electricity[2].
Below is a table displaying how much heat is exported from the 10 Energy from Waste facilities that are utilising CHP (derived from Tolvik, 2019[4]).
| EfW | Est. Export GWhth | Heat/Steam Offtake | |
|---|---|---|---|
| 2018 | 2017 | ||
| Runcorn | 408 | 405 | Steam supply to Ineos |
| Eastcroft | 332 | 224 | Enviroenergy for electricity generation and hot water |
| Sheffield | 112 | 96 | District heating operated by Veolia |
| Wilton 11 | 100 | - | Adjacent Wilton International site |
| Devonport | 59 | 54 | Adjacent naval dock yard |
| Gremista | 40 (est) | 40 (est) | District heating on the Shetland Islands |
| SELCHP | 38 | 37 | District heating operated by Veolia |
| Coventry | 11 | 5 | District heating operated by Engie |
| Leeds | 8 | - | District heating operated by Vital Energi |
| NewLincs | 3 | 3 | To industry (produced 17GWhth but limited demand) |
| Total | 1112 | 865 | |
References
- ↑ 1.0 1.1 1.2 Department for Business, Energy & Industrial Strategy, 2019. Combined heat and power. GOV.UK. [online] [Accessed 30 Oct. 2019].
- ↑ 2.0 2.1 2.2 Defra, 2014. Energy from waste A guide to the debate February 2014 (revised edition). London.
- ↑ 3.0 3.1 WRAP, 2012. EfW Development Guidance. Waste and Resources Action Programme.
- ↑ Tolvik Consulting, 2019. UK Energy from Waste Statistics – 2018. Gloucestershire.[online]