Medium Combustion Plant Permit UK (MCP) – Applications & Testing

Medium Combustion Plant Permit Applications and MCPD Compliance for 1-50 MWth Plant

A medium combustion plant permit is required for any combustion unit with rated thermal input between 1 and 50 MWth under the Medium Combustion Plant Directive (MCPD), implemented in England via the Environmental Permitting Regulations. We prepare and submit MCP permit applications to the Environment Agency, including aggregation assessments, ELV demonstration, monitoring proposals and any Specified Generator additional controls. Existing plant deadlines have largely passed (1 January 2024 for 5-50 MWth, 1 January 2029 for less than 5 MWth) so the focus now is new plant, replacements, Tranche A/B Specified Generators and compliance variations.

Scope and Aggregation

• Boilers, engines, gas turbines and generators between 1 and 50 MWth net rated thermal input
• Aggregation rules where multiple units discharge via a common stack or could technically do so
• Specified Generator classification (Tranche A vs Tranche B, capacity market, less than 50 hrs/yr derogations)
• Standalone permit vs variation of an existing EPR Part A or Part B permit

Emission Limit Values and Monitoring

ELVs vary by fuel type, plant size and whether the unit is new or existing. New gas-fired plant must meet NOx 100 mg/Nm3 (boilers) or 95 mg/Nm3 (engines, gas), with diesel engines and dual-fuel units subject to tighter NOx, SO2 and dust limits. Monitoring requirements scale with plant size: periodic MCERTS testing every three years for less than 20 MWth, annual for 20-50 MWth, plus continuous monitoring where required by the permit. Specified Generators in NOx-sensitive areas may face site-specific tighter limits.

Application Content

• Plant inventory, fuel data, operating regime and aggregation assessment
• ELV compliance demonstration with manufacturer data and any required derogations
• Monitoring plan aligned to MCERTS and the appropriate frequency band
• H1 stack height assessment where new or modified discharge points are proposed
• Management system summary covering maintenance, fuel records and emissions reporting

Ongoing Compliance

Once permitted, operators must keep fuel and operating-hour records, undertake MCERTS periodic testing at the required frequency, report results to the EA, and notify the regulator of any breach or significant change. We provide MCERTS testing under separate scope and can manage the annual EA reporting cycle as part of an ongoing compliance arrangement.

Who Needs MCP Permit Support

• Operators of combustion plant between 1 MWth and 50 MWth (single or aggregated)
• Boiler houses, process heat plant and steam-raising plant
• Standby and prime-power generators, including diesel and dual-fuel sets
• CHP engines, gas turbines and combined heat and power schemes
• Manufacturing, food and drink and pharmaceutical sites
• Hospitals, universities and other public-sector estates with onsite generation
• Data centres and commercial estates with resilience generation
• Specified Generators participating in capacity or balancing markets

Typical MCP Compliance Questions We Answer

• Does this boiler, engine or generator need an MCP permit?
• Which Emission Limit Values apply to my fuel, plant type and age?
• What monitoring evidence is needed — periodic MCERTS, CEMS or both?
• When is stack emissions testing required and at what frequency?
• How are multiple units on one site aggregated under MCPD rules?
• What information do you need to scope and quote the permit work?
• Can existing EPR permits be varied rather than re-applied for?

MCP permit cost drivers

Medium Combustion Plant permit cost varies by site rather than following a fixed price. The main drivers are the number of combustion units involved, whether the application is a new permit or a variation of an existing EPR permit, whether air dispersion modelling or an H1 stack height assessment is required, whether MCERTS stack emissions testing is needed to demonstrate compliance, fuel type and operating profile, site complexity (urban / receptor-sensitive vs rural), regulatory deadline pressure, and any Specified Generator additional controls. We confirm a fixed-fee scope for the permitting workstream within one working day of receiving the site information.

• Number of combustion units and aggregation complexity
• Whether the application is a new permit or a variation
• Dispersion modelling or H1 stack height assessment requirements
• Whether MCERTS stack emissions testing is required to demonstrate compliance
• Fuel type, operating hours and Specified Generator status
• Site complexity, sensitive receptors and AQMA context
• Deadline pressure (standard vs accelerated turnaround)

1 MW boilers, generators and standby plant

Operators frequently ask whether a 1 MW boiler, a standby generator or a CHP engine needs a Medium Combustion Plant permit. Applicability depends on the net rated thermal input of each unit, how units aggregate where they share or could share a stack, the operating profile (continuous, peaking, or genuine emergency-only), the fuel type, and any Specified Generator obligations. Boilers, generators and CHP engines at or above 1 MWth and below 50 MWth typically fall within MCPD scope, but exemptions and derogations apply — for example, genuine emergency standby units running for limited hours per year. Operators should confirm applicability for each unit based on plant rating, aggregation, operating profile and the regulatory context before assuming a unit is or is not in scope. Alkali confirms applicability in writing as part of the scoping step before any permit fee is committed.

Emissions monitoring and stack testing for MCP compliance

Most Medium Combustion Plant permits require periodic emissions monitoring to demonstrate ongoing compliance with the permitted Emission Limit Values. Monitoring is delivered through MCERTS stack emissions testing (typically every three years for plant below 20 MWth and annually for 20-50 MWth), and the results feed into routine Environment Agency reporting. Operators with continuous monitoring obligations also draw on QAL2 and AST CEMS calibration to EN 14181. Alkali delivers MCP permit applications and the supporting MCERTS monitoring under one accredited framework.

What we need to quote MCP permit support

• Plant schedule (boilers, engines, generators, CHP)
• Net rated thermal input for each unit and aggregation context
• Fuel type(s) and any dual-fuel or back-up arrangements
• Operating hours and profile (continuous, peaking, emergency standby)
• Site location, layout and stack details
• Existing environmental permit, Specified Generator registration or correspondence
• Any Environment Agency correspondence or deadline
• Sensitive receptors, AQMA designation or planning context

Related MCP compliance services

MCP permit applications are typically delivered with an H1 stack height assessment, air dispersion modelling where required, and CEMS hire for parallel monitoring during commissioning. Ongoing duties are covered by Environment Agency reporting, broader environmental permit application support and permit-driven evidence through our MCERTS stack emissions testing for MCP. To scope your application, request a fixed-fee quote or discuss your permit requirements with a senior consultant.