Pump up the volume

We need more pumped storage, but the future lies in multiple smaller facilities, says Dave Holmes

Plans are being laid to build the first new pumped storage facilities in the UK for 30 years. Multiple factors are converging to force a re-evaluation of the role and scale of storage. North Sea gas reserves are declining and we are increasingly buying our gas on the global market, facing inexorable year-on-year rises in cost and potential insecurity in supply. At the same time the clock is ticking against the remaining coal-fired power stations and it could be ten years before a new nuclear site is operational.

In the short to medium term the UK will rely primarily on gas plants for power generation, and on a growing contribution from wind and other renewables. But with renewables the gap between capacity and demand can change, literally, with the weather. More storage will be required to keep the lights on.

In the UK, the first response to outages or short-term demand peaks is provided mainly by diesel generator sets and open cycle gas turbine power stations. They cost the grid more per MW than regular generation and market forces will inevitably make the premium grow even larger. Against this backdrop, pumped storage is set to become increasingly financially viable on a much smaller scale than before.

Does Britain need a second Dinorwig, the huge 1.8GW Welsh pumped storage power plant in Wales? In terms of capacity – yes, that and more. But on a single site? No. Such schemes require a lot of land – and suitable sites are few. They would also tend to be in landscapes highly valued for their beauty.

Smaller pumped storage facilities, perhaps with a tenth the output of a large site like Dinorwig, require far less land each, so many potential sites exist, such as the disused slate quarries at Glyn Rhonwy (see box).

However, the UK regulatory framework needs to change. A report by Imperial College calculated that by 2050, pumped storage could be worth tens of billions of pounds to the UK. National Grid would save on transmission network upgrades, while distribution network operators would pay reduced transmission costs – but neither will share the risk of developing new pumped storage schemes. The report says this something-for-nothing attitude is a clear instance of market failure that will put an unhelpful damper on investment in pumped storage. It needs to be resolved.

Dave Holmes, managing director, Quarry Battery Company

The Glyn Rhonwy project

The Glyn Rhonwy quarries stand on the hillside above Llanberis, north of the Snowdonia National Park. They fell into disuse in the 1930s and are now owned by Gwynedd Council. When operational, the 600MWh pumped storage scheme being developed by the Quarry Battery Company is expected to create 20 to 30 full-time jobs. The company is currently talking to potential partners about the £100 million-plus construction phase of the project and is aiming to be operational within five years.

The Glyn Rhonwy scheme is believed to be the first to use existing brownfield quarries for both upper and lower reservoirs and as such could be a blueprint for other sites around the UK. It will be commercially viable for a number of reasons. Build costs are lower because reusing abandoned quarries is recycling on a grand scale. Less civil works are required because the holes in the ground are already there and the spoil from original excavations is in many cases ideal material with which to construct reservoir dams. And the geology of such sites is already well understood because people have already dug there. This reduces the level of risk.

This article first appeared in Utility Week’s print edition of 5th July 2013.

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