Tony Lodge: We have the chance to lead world with a new clean fuel

In Yorkshire and the Humber, more than 500 megawatts of wind energy projects are operational, in construction or with planning approval departments and the sector can potentially power 250,000 homes. But there remains a deep underlying problem. What happens when there is no wind?

Renewable power is the only genuinely green energy form. All other forms either release CO2 to the atmosphere or consume fossil fuel reserves. So if we are to maximise an energy system that is built mainly on renewable power, present-day policies must change quickly. Green electricity is arguably the most sustainable form of energy but it cannot always be matched to demands for heat, power and mobility without energy storage, as we have seen in recent winters.

As the penetration of renewables into the grid increases, intermittent wind power will need to be increasingly curtailed to maintain power system stability. At any one time the grid has a block of base-load power in operation, reducing this to accommodate intermittent power risks destabilising power supply and increasing carbon emissions as fossil fuel plant is ramped up and down.

Also, unpredictable wind energy's admission to the grid could exceed consumer demand. This will lead to this green energy being rejected and wasted by the grid. In May, Scottish Power was paid 13,000 by National Grid to de-couple turbines whose high input was unbalancing the grid. In the future this wasted energy should be stored, instead, as a clean fuel to be used later.

There are periods, usually in the coldest months of January and February, when western Europe experiences long spells, occasionally weeks, of very cold and windless days. It is therefore all the more important that when the wind does blow it can be fully utilised through energy storage.

There are a number of ways to store electricity, ranging from the small scale, such as batteries for short periods of time, to large scale pump-storage reservoirs for storing vast amounts of energy for long spells. But topography and demography dictate that the UK doesn't have many available sites to flood in order to create pumped storage reservoirs.

There is, however, another option; energy can be stored as hydrogen, a clean fuel, that can be obtained from wind, marine and solar generated electricity, resources that the UK has in abundance. The process is electrolysis, and the technology can be found in the Sheffield factory of ITM Power. Importantly, the Danish government has given full tax exemption for the production of hydrogen from electrolysis. The UK should now develop its own policy to support green energy storage.

Not only does energy storage, using hydrogen, enable efficient capture of increasing amounts of variable renewable energy, it also has a beneficial impact on how power is generated from existing power stations. It allows those stations that have to be turned on and off, as we wake up or return from work, to be run at a steady load and hence greater efficiency.

Hydrogen can be used as a zero carbon transport fuel, this then burns with zero carbon emissions in a modified petrol engine and can be used to power fuel cell vehicles as well as the zero-carbon home of the future.

In other words the flexibility of hydrogen energy storage more than cleans up the power system. It can also decarbonise the transport system, thereby improving air quality in cities. Unlike batteries, hydrogen is a fuel that can be stored for long periods of time, providing security and independence from diminishing and unreliable oil and gas producers.

The UK has the opportunity to generate a clean fuel from its growing renewables portfolio, benefiting energy security and the quest for clean air, so decarbonising its power, transport, cities and towns. It would have substantial benefits for the economy. How many times has the UK threatened to become the world leader in an evolving sector and missed the boat? This is an opportunity that cannot be missed.

Rescuing Renewables – How Energy Storage Can Save Green Power by Tony Lodge was published this month by the Bow Group think tank.