Equality can be difficult to define and inequality isn't always immediately obvious.

But sometimes it is.

Equality isn't 61 per cent of the top 100 UK-headquartered energy companies having no females on their board; it's not women holding just 5 per cent of executive seats; it's not women in the energy sector earning on average 30 per cent less than their male counterparts. Take a moment to remember women make up 51 per cent of the UK's working population. That's inequality.

Unfortunately, those statistics are the findings of new research by PwC on behalf of POWERful Women, an organisation established by Baroness Verma and MP Laura Sandys in 2014 to advance the professional growth and leadership development of women across the UK's energy sectors.

The PwC research was published this week in a report called Igniting Change: Building the Pipeline of Female Leaders in Energy. I was honoured to be asked to contribute to the report alongside some extraordinary women, including Raghdaa Hasan, a Senior Vice President at Statoil; Tess Sundelin, the Managing Director of Green Hedge Group, and Jane Bowie, Superintending Inspector at the Office for Nuclear Regulation.

Importantly, POWERful Women's supporters are not just females. As with the hugely successful UN He for She campaign, there is an understanding that gender inequality is an issue that not only affects us all, but that requires action by all. The initiative has seen support from male colleagues including Alastair Phillips-Davies, CEO of SSE, and Lord Davies, author of the 2011 Davies Report on Women in Boards.

The Davies report showed there is a strong business case for having more women at board level, and set a target for FTSE 100 boards to have a minimum of 25 per cent female representation by 2015: a target we're well on the way to achieving.

However, as the PwC statistics show, the energy industry lags embarrassingly far behind. Lord Davies' message to CEOs at the launch of the report pulled no punches: "If you don't accept the need for women on boards you are asleep at the wheel and you aren't fit to be in your jobs".

The renewables industry is often seen as a much more progressive sector. Scottish Renewables research has shown there is a higher percentage of women working in renewables than in oil and gas or nuclear, and this is also reflected in the PwC research, which showed renewable energy companies had slightly better gender diversity on their boards than other energy sectors.

However with just 26 per cent of Scotland's renewable energy workforce being female, we've still got a long way to go. That's why I'm incredibly proud to be vice-chair of Women in Renewable Energy Scotland, an organisation boasting more than 500 members.

The good news is that the report finds we are looking at an entirely fixable problem.

It proposes actions for CEOs, HR departments, senior management and women themselves. Targets are one tool, and POWERful Women has pledged to ensure that by 2030 40 per cent of energy company middle management positions and 30 per cent of executive energy company board members are female. But broader cultural shifts are equally important to achieve these numbers. The research found the most important action a CEO can take is to simply lead by example, create a diverse team and challenge bias.

At the Igniting Change launch in London earlier this month, we were all asked to pledge to support women in the energy sector. So what is my personal pledge? Through my work with Scottish Renewables I pledge to ensure at least 30 per cent of our offshore renewables conference speakers are female. It may seem like a small measure, but as I remember Angela Constance, Cabinet Secretary for Education and Lifelong Learning, once saying: "You can't be what you can't see".

By showcasing the enormous female talent that exists across the renewables industry I hope we can inspire and encourage a whole new generation of POWERful Women and ignite the change.

* Lindsay Leask is vice-chairwoman of Women in Renewable Energy Scotland and Senior Policy Manager, Offshore Renewables, at Scottish Renewables.