Clinton Noble addresses some frequently asked questions about the MCPD and back-up generators
The medium combustion plant directive (MCPD) is a means of improving air quality. It controls SO2, NOx, CO and particulate emissions from plant equipment, by regulating medium-sized equipment that performs combustion. The MCPD became law in December 2018, but there is still some confusion surrounding it.
The MCPD filled the regulatory gap in between large combustion plants and small appliances, by regulating medium-sized equipment, such as that used in hotels, commercial offices, schools, hospitals and for agricultural and industrial processes. It may therefore apply to power generation equipment, such as generators, boilers and turbines.
Does MCPD apply to me?
Many operators of diesel generators are unsure whether their equipment needs to comply with the emission limits set out by the MCPD. The first thing to understand is that the legislation applies to plants with a combined output of 1 to 50MWth. If your business is planning on expanding into this category, you will need to be mindful of this threshold.
In addition, if the diesel generator will be running for less than 50 hours a year over a three-year average in a new plant, or a five-year rolling average in an existing plant, it will not be covered by the MCPD. The legislation therefore would apply to a diesel generator running 24/7 but may not apply to a back-up generator.
However, standby generators that are not covered by the emissions limits may still be required to be registered via a permit. This applies to existing standby generators in existing plants greater than 5MWth from 2024 and in existing plants between 1 and 5MWth from 2029.
Can I synchronise my equipment to the grid?
Operators of power generation equipment must comply with the legislation if
they are selling energy back into the grid. So, operators considering synchronising their equipment with the grid will have to consider the MCPD regulations and meet emissions requirements. This can be done by adding a selective catalytic reduction (SCR) aftertreatment device. However, you should weigh up the financial gain from selling the energy with the cost of SCR technology.
Are there any local authority restrictions relating to the medium combustion plant directive?
This is one of the biggest questions about the MCPD and, unfortunately, there is no easy answer. The local authority will look at the emissions in the area and assess how your emissions will contribute to the overall amount.
If you are applying in a high NOx area, such as near an airport, you are less likely to get approval. When establishing a new site, you will have to apply for planning permission and act on the guidance given.
Will the MCPD legislation change?
The MCPD came into force for new equipment from 2018 and applies to existing medium combustion plants greater than 5MWth from 2024 and those between 1MTth and 5MWth from 2029. There is some concern that new regulation, which does apply to standby machines, will be introduced in the future.
It is common to run a back-up generator for around 20 years. Understandably, businesses operating power generation equipment that do not currently have to comply with the MCPD are worried about the future of their equipment.
Although no-one can accurately predict the future, working closely with a power generation equipment supplier that can produce custom solutions for your business can give you peace of mind. In most cases, it is preferable to upgrade an existing installation, rather than fit an entirely new model, especially if your current set up is running reliably.
It is possible to future-proof your back-up generator with careful design, for example designing a container that means it is easy to retrofit an SCR if needed. If you are purchasing a new generator, one good option is to choose a smaller generator with good power density – a measure of power output per unit of volume – so that there is more space for retrofitting an SCR if needed.
Clnton Noble is with Finning