ALARP in the energy transition (Part 1) – The gift that keeps on giving

The shift towards clean energy is not just about sustainability – it is also about ensuring that new technologies are as safe as they are effective. As industries transition to wind, solar, hydrogen, and battery energy storage, they face both familiar and novel risks. Reducing these risks to an acceptable level requires a structured approach, and the ALARP (as low as reasonably practicable) principle provides a practical framework to do so. But while ALARP offers flexibility, demonstrating compliance can be complex. Understanding its origins, regulatory expectations, and role in modern risk management is essential for ensuring that safety remains at the forefront of the energy transition.

This article is the first of a three-part series exploring ALARP’s role in the energy transition.

Introduction

In this article we introduce the concept of ALARP and examine its origins, underlying principles, and regulatory expectations for ensuring the safe and sustainable growth of clean energy. This sets the foundation for our second article, which delves into how ALARP can be effectively demonstrated.

While the ALARP principle is the keystone of UK safety law, its influence extends beyond the UK. The principle has been adopted into law in several other countries, including Australia, Norway, and the Netherlands. Additionally, many multinational corporations apply ALARP principles globally to ensure consistent safety decision-making across their operations. By embedding ALARP into their internal risk management processes, these companies create harmonised safety standards that align with both local regulations and international best practices, ensuring a structured and defensible approach to risk reduction worldwide. 

ALARP origins – from coal mines to clean energy

The ALARP principle has deep roots in UK case law, originating from Edwards v. National Coal Board (1949) (Ref. 1). This case arose after the tragic death of a miner, Mr. Edwards, who was killed when an unsupported section of the travelling road in the mine collapsed. The National Coal Board contended that reinforcing every roadway was too costly. However, the crux of the case was not about reinforcing every roadway, but whether it was reasonably practicable to reinforce those presenting a significant risk. Justice Asquith’s landmark ruling established that ensuring safety is not about doing everything possible but about balancing risk reduction against cost, time, and effort in a rational way.

It is somewhat ironic that ALARP – born in the coal mines – is now being applied to the clean energy sectors striving to replace fossil fuels. What was once a legal precedent shaped by industrial-era hazards is today influencing decision-making for offshore wind farms, hydrogen plants, and battery energy storage systems. It is also remarkable that, just four years after World War II, legal frameworks were already prioritising structured risk management to protect workers, highlighting the foresight and societal shift towards safety in post-war Britain.

Before the case, many risk decisions were made based on an unspoken “gentleman’s agreement” in industries like shipping, mining, and rail. It was understood that some level of death was inevitable, and courts tended to side with industry over worker safety. The Edwards case flipped the burden of proof, making companies responsible for proving why a risk reduction measure was not reasonably practicable.

Justice Asquith, renowned for his sharp wit and clarity of thought, delivered a ruling that became a cornerstone of modern UK safety law. His articulation of the ALARP principle was later enshrined in the Health and Safety at Work etc. Act 1974(Ref. 2), embedding the powerful idea that safety is not just a question of feasibility, but of proportionality. The brilliance of ALARP lies in its enduring relevance – it is just as effective for today’s challenges in green hydrogen production and storage, artificial intelligence, and commercial space flight as it was for managing the hazards of coal mining over 70 years ago.

Defining ALARP

The case established a formal definition of ALARP:

“… a computation must be made in which the quantum of risk is placed on one scale and the sacrifice, whether in money, time or trouble, involved in the measures necessary to avert the risk is placed in the other; and that, if it be shown that there is a gross disproportion between them, the risk being insignificant in relation to the sacrifice, the person upon whom the duty is laid discharges the burden of proving that compliance was not reasonably practicable.”, (Ref. 3).

More simply, safety measures are required unless the total cost is grossly disproportionate to the risk reduction gained.

At times it might not feel like it, but ALARP is a legal gift. It is a safeguard for businesses, ensuring that while safety is paramount, they are not burdened with implementing every possible measure regardless of cost.

Regulatory expectations

The UK’s regulatory framework follows a goal-setting approach rather than a purely prescriptive one. This means that rather than providing a rigid set of rules, the law requires companies to assess risks and take reasonable steps to mitigate them. This has advantages in allowing flexibility and innovation but also presents challenges in demonstrating compliance. The regulator expects ALARP to be demonstrated through two primary means (Ref. 4):

• Good practice: Where the risks are well understood, adhering to established standards and recognised industry practices is generally sufficient. This is often acceptable for lower consequence risks. While the UK regulatory regime is goal-based, it nevertheless includes prescriptive legal requirements outlined in Approved Codes of Practice (ACOPs), and these must be complied with.
• First principles: When good practice does not exist, or when dealing with complex or high severity risks, deeper analysis is required. This needs consideration of risk reduction measures based on their effectiveness and sometimes includes cost-benefit analysis. The depth of analysis increases with the level of risk and uncertainty.

The first principles approach involves several critical elements:

• Hierarchy of risk controls: The most effective risk reduction measure – risk elimination – should be considered first before moving to prevention, mitigation and control strategies (an example application in the hydrogen sector is presented in Ref. 5). No effort needs to be applied in managing risks that do not exist. Therefore, as early as possible in a project, an inherently safe approach to risk management should be taken based on factors such as technology selection, and facility and equipment siting.
• Gross disproportion: The “fulcrum diagram” (Figure 1) illustrates that safety measures should be implemented unless their cost is “grossly disproportionate” to the reduction in risk. The subtlety in the diagram is that the fulcrum is deliberately offset by a “proportion factor” to ensure the bias towards risk reduction (benefit). However, the magnitude of gross disproportion is not explicitly defined in regulations or guidance. It is the responsibility of the owner to justify the proportion factor – in general, the higher the level of risk, consequences, or uncertainty, the higher the proportion factor.

Figure 1 – The “risk-cost fulcrum diagram”

• Cost-benefit analysis (CBA): The requirement to decide whether the cost of a risk reduction measure is grossly disproportionate implies the need for a quantitative CBA. In practice, many decisions can be based on qualitative or semi-quantitative analyses. CBA is normally only justified for high levels of risk or consequences. Before engaging in CBA, companies must first comply with any prescriptive ACOPs, and CBA cannot be used to argue against implementing relevant good practice.

Other important considerations include:

• Reject affordability as a defence: Companies cannot rely on lack of budget or high cost as a justification for ignoring valid risk reduction measures. The first consideration is feasibility, not cost. Budget constraints do not override legal duties – companies must allocate sufficient resources to meet safety requirements.
• Start with the safest option: Organisations must guard against “salami slicing” – where a series of small, low cost, incremental decisions are individually justified but collectively lead to a solution that is not ALARP overall. ALARP assessments should begin with a big-picture view, considering the safest option as the starting point. Without this, later improvements may appear unjustifiable simply because earlier decisions locked the solution into a suboptimal direction.
• Take a holistic view: ALARP is not just about balancing costs and benefits; it also requires assessing new risks introduced by risk reduction measures. For example, introducing an automated safety system might reduce operational risk but create cybersecurity vulnerabilities. Alternative process chemicals may reduce flammability risks but introduce new toxicological hazards. Effective ALARP assessment must ensure that the overall risk profile improves rather than merely shifting hazards elsewhere.
• Act without delay: Organisations must not delay ALARP assessments and, once a safety improvement is identified as reasonably practicable, it should not be delayed for financial reasons. It must be implemented within a reasonable timeframe.
• Document every decision: ALARP requires companies to demonstrate a structured, evidence-based approach when assessing risk reduction options. The decision to implement or reject each identified option must be backed by detailed, documented analysis showing whether the expenditure would or would not be grossly disproportionate to the safety benefits.
• Keep ALARP under review: ALARP is not a one-off activity. Companies must regularly review risk factors to ensure ALARP arguments remain valid, considering changes such as increased personnel exposure, the condition and effectiveness of safety measures, newly established good practices, and technological advancements that could further reduce risks.

ALARP in the energy transition

The transition to clean energy sources like wind, solar, battery energy storage and hydrogen, introduces new technologies and can create gaps in our knowledge of the associated risks. Unlike traditional energy sectors, these technologies lack decades of operational experience, making it harder to define industry-wide good practices.

Applying ALARP effectively in the energy transition requires:

• Combining evolving good practice with first-principles risk assessment and management.
• A rigorous approach to safety decision-making in the face of emerging risks.
• Ensuring that new technologies are implemented with clear risk management frameworks.

Conclusion

The ALARP principle remains a cornerstone of UK risk management, ensuring that safety decisions are proportionate, justified, and continually reassessed. It offers a structured yet flexible approach to balancing risk against cost, time, and effort – providing not just a regulatory requirement but a strategic advantage.

ALARP is a legal gift. It protects companies from excessive and impractical safety obligations, empowering them to make sensible, defensible decisions about risk reduction. In doing so, it supports innovation and progress – critical in navigating the complexities of the energy transition.

ALARP is both an obligation and an opportunity. It enables safety and sustainability to advance together. Success depends on early identification of risks, adoption of good practices, and thorough documentation to justify decisions. Importantly, ALARP is not static – it requires regular reassessment in response to technological advancements, regulatory updates, and operational changes.

In the energy transition, where the pace of change is rapid and the technologies evolving, ALARP continues to prove itself as the gift that keeps on giving.

In the next article, we will explore the practicalities of demonstrating ALARP. The third article will present case studies highlighting the application of ALARP to energy transition assets.

References 

1. Edwards v. The National Coal Board (1949) 1 All ER 743 (CA).
2. Health and Safety at Work etc Act 1974.
3. HSE Books, 2001. Reducing risks, protecting people – HSE’s decision-making process,
4. HSE. ALARP “at a glance”.
5. Cairn Risk. Hydrogen Safety by Design – Unpacking the hierarchy of risk controls.