Discover the questions that need to be asked when looking into the feasibility of a Combined Heat and Power (also called cogeneration) installation.
In order to determine whether a Combined Heat and Power system is technically and financially viable for your site, you need to carry out an initial scoping study. Here are 8 points which the Carbon Trust suggests you consider prior to carrying out a more detailed cogeneration feasibility study.
1. Have I evaluated other energy efficiency measures?
Before looking into cogeneration, it’s important to have carried out an energy audit. By making sure that any energy saving measures have already been implemented, you will be able to calculate the size of the potential CHP unit accurately according to the baseload consumption.
Implementing energy saving measures after installing Combined Heat and Power could result in an oversized unit, compromising the benefits of the installation.
2. Is there sufficient basic infrastructure in place?
Fuel supply: You’ll need to make sure you can get a secure and steady supply of your chosen fuel which is adequate to produce your site’s heat requirements.
Gas pipework: For gas CHP you’ll need to check your pipework is the right size and has enough pressure for the increased rate of gas the unit will require. A lack of pressure may cause need for a compressor, which will cost more in terms of capital outlay and running costs.
Electrical infrastructure: If the CHP is connected to the grid, you’ll need to check with the electricity supplier that the network can support the connection. The control system must also meet legal requirements, such as the safe disconnection of the CHP unit in the event of a power cut.
3. Is the site physically suitable?
Cogeneration requires additional equipment and pipework to be installed. You’ll need to ensure that the existing boiler house is spacious enough for these requirements. It’s also worth assessing whether or not any areas of the site which aren’t connected to the current boiler house would need to be connected up to the new system.
4. Is the boiler plant scheduled for replacement?
Combined Heat and Power could be considered as a partial replacement, which would offset some of the capital costs of the installation.
5. Will there be changes to site size or production levels?
If there are any planned changes such as site expansion or an increase or decrease in production levels, the site’s energy demand will be affected. As a result, your CHP project will need to take these changes into account in order to be future-proofed.
6. What energy contracts are currently in place?
If you are currently committed to long-term energy supply contracts for gas and electricity, you need to understand the impact of cogeneration on these contracts, as when CHP enters operation you will be buying more gas but consuming much less electricity.
7. What building management or control systems exist?
There may be an opportunity to upgrade the system in order to integrate CHP into the existing plant control system. You should assess the feasibility of integrating the cogeneration system with your existing controls. Modern CHP systems can include enough energy management capacity to look after additional plant and building operation. So if you don’t currently have a BEMS system, CHP could solve two problems at once.
8. Is there sufficient demand for Combined Heat and Power?
Combined Heat and Power only makes savings while running, meaning there must be a constant outlet for heat. According to the Carbon Trust, a rule of thumb is that for CHP to be viable here must be a heat load for at least 4,500 hours a year, which equates to an average heat demand of about 17 hours a day for five days a week. However, cogeneration may still be viable for sites with a lower heat demand.
Before carrying out a detailed feasibility study, ask yourself:
- Have I evaluated other energy efficiency measures?
- Is there sufficient basic infrastructure in place?
- Is the site physically suitable?
- Is the boiler scheduled for replacement?
- Will there be changes to site size or production levels?
- What energy contracts are currently in place?
- What building management or control systems exist?
- Is there sufficient demand for Combined Heat and Power?
Find out more about understanding cogeneration cost. Get your free eGuide now: Calculating CHP: A guide to capital costs
Topics: Energy Management