Why pharma manufacturing is ideal for solar
The pharmaceutical manufacturing sector in the UK is estimated to consume approximately 3.5 TWh of electricity per year — roughly equivalent to the annual output of 700 MW of offshore wind capacity. This consumption is concentrated in a relatively small number of large, energy-intensive facilities: the 30 or so largest pharmaceutical manufacturing sites in the UK (including AstraZeneca's Macclesfield campus, GSK's Ware site, Pfizer's Sandwich facility, and dozens of contract development and manufacturing organisations) account for the majority of this total.
Several structural features of pharmaceutical manufacturing make it exceptionally well-suited to solar:
Round-the-clock consumption
Cleanroom environmental control (temperature, humidity, pressure differential, particle counts) must be maintained continuously — 24 hours a day, 365 days a year — regardless of whether production is occurring. This means electricity demand never falls to zero, and solar generation during daylight hours is almost entirely self-consumed rather than exported.
Large roof areas
Pharmaceutical manufacturing buildings are typically large single-storey or low-rise structures — cleanrooms, production halls, packaging areas — with substantial flat or low-pitch roof areas well-suited to solar panel installation. A 50,000 sq ft building can typically accommodate 300–600 kWp of rooftop solar.
High electricity unit rates
Large pharmaceutical facilities are typically on Half-Hourly electricity supply contracts with all-in unit rates of 25–33p/kWh. The high unit rate means each kWh of self-consumed solar generation has high financial value, delivering faster payback periods than sectors with lower electricity costs.
Strong ESG and regulatory drivers
The pharmaceutical sector faces strong ESG pressure from investors (many signatories to CDP and TCFD), from NHS procurement (NHS Net Zero Supply Chain programme), and from parent company sustainability commitments. Solar provides a direct, auditable Scope 2 reduction that satisfies multiple reporting frameworks simultaneously.
The combination of high self-consumption rates (typically 85–95% for a 24/7 pharmaceutical site), high electricity unit rates, large available roof areas, and strong regulatory and ESG drivers makes pharmaceutical manufacturing one of the most compelling sectors for factory solar investment in the UK.
Energy profile: cleanrooms, HVAC, autoclaves, cold chain
Understanding the pharmaceutical manufacturing energy profile is essential for correctly sizing and positioning a solar system. Unlike a simple factory where production equipment dominates energy use, pharmaceutical facilities have a complex multi-layer energy demand driven by facility infrastructure, process utilities, and manufacturing equipment.
HVAC and cleanroom environmental control (50–65% of total electricity)
The dominant electricity load in any pharmaceutical facility. Cleanrooms (Grades A through D under EU GMP Annex 1, or ISO 5 through ISO 8) require constant air handling — supply, filtration (HEPA for Grade B and above), temperature control, humidity control, and differential pressure maintenance. Air change rates in pharmaceutical cleanrooms range from 20 air changes per hour (Grade D) to 600+ air changes per hour (Grade A/ISO 5 unidirectional flow). The resulting fan, cooling coil, and heating coil loads are substantial and continuous. Critically for solar: HVAC loads are heaviest during business hours in summer (when cooling demand and production activity both peak) — well-aligned with solar generation.
Process utilities: WFI, PW, clean steam (10–20% of total electricity)
Water for Injection (WFI) generation (multi-effect distillation or membrane systems), Purified Water (PW) systems, and clean steam generators consume significant electricity and thermal energy. WFI multi-effect stills can consume 20–80 kW of electrical power depending on output capacity. These loads typically operate during production shifts and are therefore well-matched to solar generation hours.
Autoclaves and sterilisation (5–15% of total electricity)
Steam sterilisation autoclaves (for equipment, garments, and product) and dry heat ovens are significant electricity consumers during production. A production autoclave (500–1,000 L capacity) can consume 15–40 kW of electricity during its cycle for jacket heating, vacuum pump, and control systems. Radiation sterilisation (gamma or e-beam) used by some sterile manufacturers is contracted to specialist facilities rather than performed in-house.
Cold chain: refrigeration and controlled temperature storage (8–15% of total electricity)
Pharmaceutical cold chain requirements are particularly demanding. Biologics (vaccines, monoclonal antibodies, cell and gene therapies) require storage at 2–8 degrees C; some products require deep frozen storage at -20 to -80 degrees C. Cold chain refrigeration runs continuously and is highly critical — power interruption, even brief, can destroy product batches worth millions of pounds. The constant compressor load is an excellent match for solar generation, including weekend periods when production may be reduced but cold chain must be maintained.
Manufacturing and packaging equipment (10–20% of total electricity)
Tablet presses, granulators, fluid bed dryers, filling lines, blister packaging, and inspection equipment. Loads vary significantly by product type and batch schedule. Tablet compression typically consumes 30–100 kW; fluid bed drying 50–150 kW; injectables filling lines 20–60 kW. These loads are shift-aligned and therefore well-matched to solar.
Solar Self-Consumption for Pharmaceutical Manufacturing: Key Metrics
Typical self-consumption rate
85–95% (24/7 continuous operation)
Highest of any manufacturing sector
Minimum overnight load
60–80% of peak daytime load
HVAC and cold chain maintain high baseload
Recommended system sizing
Match available roof area, not constrain by load
Self-consumption will absorb most generation
GMP compliance and solar — what you need to know
Good Manufacturing Practice (GMP) regulation governs the manufacture of medicinal products and is enforced in the UK by the Medicines and Healthcare products Regulatory Agency (MHRA). A common concern raised by pharma site energy managers and quality teams is whether installing solar panels affects GMP compliance. The short answer is: no, provided the installation is handled correctly through the site's change control system.
The MHRA's GMP guidelines (Chapter 3, Premises and Equipment) require that pharmaceutical manufacturing facilities are designed, constructed, and maintained in a way that prevents contamination and mix-up. Solar panels are roof-mounted utility equipment — not contact materials, not processing equipment, and not within the manufacturing environment. They do not interact with product, process, or personnel in the classified manufacturing areas.
The following GMP-relevant considerations apply to a pharmaceutical solar installation:
Change control
The decision to install solar must be managed through the site's formal change control process. This is standard for any significant modification to facility infrastructure. The change control record should document: the scope of works, the contractor qualification status, the impact assessment (including electrical systems, HVAC, structural, contamination control), and the post-installation verification activities.
Contractor qualification
Pharmaceutical site GMP requirements typically extend to contractors performing work on or within the facility. The solar installer should be assessed under the site's supplier qualification programme — particularly for contractors working on the roof above classified areas. Key requirements: site induction completion, contamination prevention procedures (footwear covers, waste management, no open food or drink), and safe working at height accreditation.
Electrical system integration
The solar system's connection to the site electrical distribution must be reviewed by the site electrical engineer and the quality team. The inverter and metering equipment will typically be installed in an existing electrical room or a dedicated enclosure. The change control should confirm that the solar electrical supply is correctly integrated as a non-interruptible supply (i.e., cannot affect the UPS-protected circuits serving critical manufacturing and cold chain loads).
HVAC integrity
Any roof penetrations (cable routes, mounting fixings) must be assessed for their impact on the building envelope and the roof-level HVAC equipment. Penetrations through the roof of a cleanroom must be sealed to maintain the differential pressure and contamination barrier function of the building. The solar installer and the site facilities team should survey all roof-level HVAC supply and exhaust locations before design to ensure panels do not obstruct airflow patterns.
With these considerations addressed, there is no fundamental reason why a pharmaceutical manufacturing site cannot install rooftop solar under a managed GMP change control. The MHRA's guidance explicitly encourages pharmaceutical companies to pursue sustainable manufacturing — solar is consistent with this direction.
Backup power and solar: UPS and battery integration
Pharmaceutical manufacturing facilities typically have sophisticated power resilience infrastructure: static UPS systems protecting critical manufacturing and cold chain loads, diesel generator backup for extended outages, and in some cases a dedicated secondary grid connection. How does solar fit with this existing infrastructure?
A standard grid-tied solar inverter (without islanding capability) will cease generating during a grid outage — this is a mandatory safety requirement under G98/G99 to prevent back-feeding the grid during an outage when engineers may be working on the network. This means a standard solar installation provides no benefit during a power cut.
For pharmaceutical sites where backup power has genuine product protection value, there are two approaches to integrating solar with the site's resilience strategy:
Option 1: Solar with battery and islanding inverter
A battery storage system with an islanding-capable inverter can operate as a standalone microgrid during a grid outage, continuing to supply power from stored energy and (if the sun is shining) from solar generation. The battery system is sized to bridge the gap until diesel generator startup (typically 10–30 seconds) or to cover the expected outage duration for the critical load.
This configuration is more complex and expensive than a standard solar installation but provides genuine backup value for cold chain and critical instrument loads. It requires careful design of the automatic transfer switching (ATS) and load management to ensure GMP-critical circuits are prioritised.
Option 2: Solar optimised for energy cost saving; UPS handles resilience independently
For sites with robust existing UPS and generator infrastructure, the most cost-effective approach is to design the solar installation purely for energy cost and carbon reduction — not as a resilience asset. The solar system generates and saves on electricity costs during normal operation; the UPS and generator provide backup during outages as they always have.
This is the correct approach for the majority of UK pharmaceutical manufacturing sites. Attempting to integrate solar into the backup power strategy adds complexity and cost without adding net reliability, since the existing UPS and generator infrastructure is already highly reliable.
The question of whether to add battery storage to a pharmaceutical solar installation should be evaluated on its own financial merits — self-consumption uplift, peak demand reduction, and grid services revenue — rather than primarily as a backup power solution. See our battery storage guide for a detailed analysis.
ESG reporting benefits: Scope 2 emissions and CDP disclosure
The pharmaceutical sector faces some of the most demanding ESG reporting requirements of any UK industry. Large pharma companies (AstraZeneca, GSK, Pfizer, Novartis UK) have public net-zero commitments with specific Scope 2 targets; contract development and manufacturing organisations (CDMOs) face pressure from their pharma customers who are auditing supply chain emissions under Scope 3 reporting.
The key ESG frameworks that require or incentivise Scope 2 emissions disclosure for pharmaceutical manufacturers include:
CDP Climate Disclosure
CDP requires Scope 1 and Scope 2 emissions reporting from all disclosing organisations. The market-based Scope 2 methodology (which counts renewable electricity tariffs and on-site generation as zero-emission) allows solar generation to reduce the reported Scope 2 figure more favourably than the location-based method. A 500 kWp solar system generating 420,000 kWh/year of self-consumed electricity directly reduces the market-based Scope 2 figure by 84 tonnes CO2e/year (at 200 gCO2e/kWh) — or more accurately, to near zero for that portion of consumption since on-site solar generation counts as zero-emission under the market-based method.
NHS Net Zero Supply Chain Programme
The NHS, as the UK's largest buyer of pharmaceutical products, has committed to a net-zero supply chain by 2045 and is actively working with suppliers to reduce Scope 3 emissions. The NHS's Evergreen Sustainability Assessment questionnaire includes Scope 2 electricity questions. Pharmaceutical manufacturers supplying the NHS — which includes virtually every UK manufacturer — are increasingly assessed on their Scope 2 reduction actions, with solar investment directly evidenced through generation meter data and utility bills.
TCFD and CSRD (for EU market exposure)
UK pharmaceutical manufacturers with EU operations or parent companies are subject to the EU Corporate Sustainability Reporting Directive (CSRD), which requires detailed Scope 1, 2, and 3 emissions disclosure from 2025 onwards for large companies. Solar generation data, with verified metering, directly supports the accuracy and auditability of Scope 2 disclosures under CSRD.
For a pharmaceutical CDMO or contract manufacturer, the ESG benefit of solar extends beyond the company's own reporting. Customers conducting Scope 3 audits of their CMO supply chain will see the CMO's solar generation data as evidence of active Scope 2 reduction — a competitive differentiator in tender processes where sustainability criteria are now commonly scored.
CBAM exposure for pharma exporters
Pharmaceutical products are not currently listed in the initial scope of either the UK CBAM (2027) or the EU CBAM (2026). The initial CBAM sectors — steel, aluminium, cement, ceramics, fertilisers, and hydrogen — were selected for their high direct carbon intensity. Pharmaceutical manufacturing is energy-intensive but its products are not classified as carbon-intensive basic materials in the same category.
However, there are two important caveats for pharmaceutical manufacturers:
First, the EU Commission has committed to reviewing the CBAM sector scope in 2026 and is expected to extend coverage progressively. Chemicals — which includes active pharmaceutical ingredients (APIs) and pharmaceutical intermediates — are under active review for CBAM inclusion. UK API manufacturers exporting to the EU should monitor this development. If APIs are brought within CBAM scope, the embedded Scope 2 carbon from electricity-intensive API synthesis could create significant certificate costs.
Second, pharmaceutical manufacturers who use bulk chemicals (solvents, reagents, packaging materials) that are themselves subject to CBAM will face higher input costs from 2027 as their EU CBAM-exposed suppliers pass through certificate costs. This is an indirect CBAM exposure through the supply chain rather than a direct product exposure. For now, the most material near-term CBAM-related action for UK pharmaceutical manufacturers is to reduce Scope 2 through solar to support existing ESG reporting frameworks, while monitoring the CBAM expansion timeline for API inclusion.
Case study: 500 kWp at a UK API manufacturer
The following case study is based on a composite of real projects at UK pharmaceutical manufacturing sites.
Site Overview
Solar System
Financial and Carbon Outcomes
| Capital cost (ex-VAT) | £362,500 (£725/kWp) |
| Full Expensing tax relief (year 1) | -£90,625 (25% of capital) |
| Net capital after tax relief | £271,875 |
| Annual electricity saving (year 1) | £119,700 (420,000 kWh x 28.5p) |
| Annual SEG export revenue | £1,500 (30,000 kWh x 5p) |
| Annual O&M cost | -£3,500 |
| Net annual saving (year 1) | £117,700 |
| Simple payback (post Full Expensing) | 2.3 years |
| Post-tax IRR (25yr, base case) | 24.8% |
| Annual Scope 2 CO2e saving | 84 tonnes CO2e/year |
| 25-year cumulative CO2e saving | ~1,800 tonnes CO2e |
This case study illustrates why pharmaceutical manufacturing is at the compelling end of the factory solar ROI spectrum. The combination of a very high self-consumption rate (93%), a high electricity unit rate (28.5p/kWh), and Full Expensing tax relief produces a post-tax payback of just 2.3 years and a 25-year IRR of 24.8% — returns that would satisfy any pharmaceutical company's capital committee.
The change control process added approximately six weeks to the project timeline — the contractor qualification and impact assessment were completed in parallel with the detailed design phase to minimise programme impact. The installation was carried out in two phases to allow production to continue uninterrupted during the electrical connection works.
Getting started — key checks before commissioning
A pharmaceutical manufacturing site solar project typically takes 6–10 months from initial enquiry to commissioning — longer than a standard industrial installation due to the additional time required for change control, contractor qualification, and roof survey above classified areas. Starting the process early is therefore important.
Obtain half-hourly AMR data
Request 12 months of half-hourly consumption data from your electricity supplier or energy broker. This is the foundation for an accurate self-consumption model and ROI calculation.
Commission a roof structural survey
A structural engineer must confirm available load capacity on the roof, taking into account existing plant. EPDM or PVC roofing membranes should be inspected for condition — a solar installation on a roof that needs replacement within 10 years is a poor investment.
Map roof-level HVAC and extract locations
Identify all air supply and exhaust units on the roof. The solar design must preserve clearances around all HVAC equipment for maintenance access and to avoid airflow disruption. This step is critical and often overlooked by installers without pharma experience.
Initiate DNO connection application early
Your DNO's acceptance testing and connection agreement can add 8–16 weeks to a project in areas with constrained network capacity. Initiating this in parallel with design and change control prevents it from becoming the critical path item.
Open the change control record
Open the site change control record at the feasibility stage — not just before installation. This allows the quality team and facilities team to contribute to the impact assessment during design rather than reviewing a completed design that may require changes.
Select an installer with industrial/GMP experience
Not all MCS-certified commercial solar installers have experience working on GMP-regulated sites. Specify that your installer must have completed at least one pharmaceutical manufacturing installation and can demonstrate familiarity with the change control, contamination control, and contractor qualification requirements.
Frequently Asked Questions
Does rooftop solar affect GMP compliance for pharmaceutical manufacturing?
How much electricity does a typical pharmaceutical manufacturing facility use?
Can pharmaceutical facilities use solar to support backup power requirements?
How does solar support Scope 2 emissions reporting for pharmaceutical ESG disclosure?
What are the key planning and roof checks before commissioning solar on a pharma site?
Trusted Solar Installers Across the UK
We work with a network of MCS-certified regional installers. If you need a recommendation outside our coverage area, these are the firms we trust:
- ALPS Electrical — MCS-certified solar installer — Teesside & North East England
- Midland Solar — Commercial & industrial solar installer — West Midlands
- EC Eco Energy — UK-wide commercial solar & renewables installer
- Sola UK — Solar panels & battery storage specialist — Hertfordshire
- Carbon Legacy — Solar & green energy solutions — East Midlands
- Premier Electrical Renewables — Solar, batteries & EV chargers — South Yorkshire