The ageing STEM workforce - 340,000 specialists approaching retirement

The energy transition is usually discussed in gigawatts, grid connections, planning reform and investment.

But there is another constraint sitting underneath all of them: people.

Across engineering, energy and infrastructure, a significant proportion of the workforce is moving towards retirement at the same time as demand for experienced technical specialists is increasing. The precise number depends heavily on how the STEM workforce is defined, so the headline figure of 340,000 specialists approaching retirement should be treated as an industry estimate rather than a verified UK-wide statistic.

What the evidence does show clearly is that the demographic challenge is substantial.

The UK Government's assessment of the clean energy skills challenge reports that one in three UK workers is over 50. In engineering construction, that rises to 38% of the workforce.

For renewable energy employers, this is not simply a recruitment problem for the future.

It is a knowledge problem happening now.

Retirement is colliding with rapid growth

There are approximately 6.3 million people working in engineering and technology roles in the UK, representing around 19% of the workforce.

That is a substantial talent pool. The problem is the direction of travel.

The clean energy sector needs to expand while experienced engineers, technicians, project leaders and technical specialists leave the labour market.

The Government's Clean Energy Jobs Plan forecasts 400,000 additional clean energy jobs by 2030, while Energy UK says the power sector alone could require 156,900 new roles, with normal attrition taking annual recruitment requirements to approximately 22,400 people.

There is already evidence that supply is struggling to keep up.

Engineering roles account for roughly one in five UK jobs, but one in four job adverts. EngineeringUK has also previously highlighted a STEM shortfall of more than 173,000 workers.

This creates a difficult equation.

Renewable energy needs more people. The wider infrastructure market needs more people. Data centres, grid reinforcement, electrification and advanced manufacturing are competing for many of the same electrical, civil, mechanical and project skills.

And some of the people with the deepest experience are approaching the end of their careers.

The real loss isn't headcount. It's experience.

Imagine a senior electrical engineer who has spent 30 years working around transmission infrastructure.

They know the standards, of course.

But they also know which problems tend to appear during commissioning. They know how designs behave when they meet the reality of a site. They know which questions to ask contractors before an apparently minor issue becomes an expensive delay.

Then they retire.

The company can replace the position.

Replacing the judgement is considerably harder.

This is where the ageing STEM workforce becomes more complicated than a vacancy forecast.

Renewable energy depends heavily on knowledge accumulated through projects. A professional who has delivered multiple wind farms, substations, solar portfolios or battery projects carries lessons that rarely exist neatly in a procedure manual.

When that person leaves, organisations can lose relationships, technical judgement, project memory and mentoring capacity simultaneously.

That makes succession planning a commercial issue rather than simply an HR exercise.

Employers are already competing for the same people

The shortage becomes particularly visible when projects move from development into delivery.

A developer might need electrical engineers. An EPC needs them too. So does a transmission business, a battery storage company and an expanding data centre platform.

The same pattern applies to project directors, commissioning specialists, grid experts, protection and control engineers, construction managers and other technically experienced professionals.

EngineeringUK data shows demand for green capability moving quickly. Job adverts mentioning "green skills" have increased by 48%, while adverts for "green engineering jobs" increased by 55%.

The result is not simply a shortage of candidates.

It is a shortage of candidates with the right depth of experience at the point they are needed.

For employers, waiting until somebody hands in their notice or announces their retirement is increasingly risky.

Succession needs to start earlier

There is a tendency to think about succession as identifying the next person for a senior job.

Renewable energy businesses need to go further.

Which employees hold knowledge that would be difficult to replace externally?

Which roles would materially delay projects if they became vacant?

Where is technical knowledge concentrated in one or two individuals?

And which specialists could realistically be developed into those positions over the next three to five years?

Those conversations need to happen before a vacancy exists.

National Grid provides an indication of what longer-term thinking can look like. Its plans include recruiting 2,300 apprentices and graduates over five years, alongside STEM outreach, upskilling and workforce planning for emerging and safety-critical skills.

Graduate and apprenticeship recruitment matters, but it cannot solve the immediate experience gap alone.

A graduate recruited in 2026 cannot instantly replace an engineer retiring with three decades of project experience.

That gap has to be managed deliberately.

Expert Thoughts

Garry Rogerson, Director of Permanent Recruitment at Hunter Philips, believes the ageing STEM workforce presents a deeper challenge for renewable energy than simply replacing people as they retire. The real risk is losing decades of technical knowledge at the same time as demand for experienced specialists continues to grow.

"The challenge isn't just the number of people approaching retirement, it's the experience that leaves the industry with them. Renewable energy businesses can recruit more graduates and bring new people into the sector, but you can't replace 20 or 30 years of engineering and project experience overnight. We're already seeing strong competition for senior technical specialists across grid, wind, solar and battery storage, and that becomes more difficult when the same talent pool is also being targeted by infrastructure, utilities and data centres. Employers need to be thinking about this much earlier. That means identifying the people and skills that would be genuinely difficult to replace, developing the next generation around them and making sure knowledge is transferred before somebody walks out of the door for the final time. The businesses that approach succession planning as a long-term workforce issue, rather than waiting for a retirement date or resignation, will be in a much stronger position to deliver their future project pipelines."

The overlooked opportunity: keep experience in the industry for longer

Not every experienced professional wants to move directly from full-time employment to complete retirement.

That creates another option for employers.

Part-time advisory positions, consultancy, mentoring, project-based contracts and flexible assignments can allow businesses to retain access to experienced professionals while creating space for the next generation to develop.

Energy & Utility Skills is already exploring ways to retain talent through retiree engagement as part of its 2025-2030 Skills Strategy.

There is also a wider talent pool worth considering.

Government analysis estimated approximately 58,100 STEM returners in the UK in 2023 - people who previously worked in STEM occupations, had become economically inactive due to caring responsibilities and indicated that they would like to work now or in the future.

For an industry facing simultaneous growth and retirement pressures, overlooking experienced returners makes little sense.

The workforce question behind the energy transition

Renewable energy has an engineering challenge, but increasingly it also has a demographic one.

New entrants need to be attracted into the industry. Existing professionals need clearer routes to develop. Experienced people need reasons and opportunities to stay involved for longer. Employers also need a more realistic understanding of where their most serious succession risks sit.

Because projects cannot be delivered by capacity targets alone.

Solar farms, wind projects, batteries and transmission infrastructure still depend on people who know how to design, build, connect, commission and operate them.

The energy transition is accelerating.

The transfer of knowledge between the generation that built today's infrastructure and the generation that will build tomorrow's cannot be allowed to fall behind.