Powering a greener future with gas-battery hybrids

While the energy landscape seemed frozen in time for several decades from the 1950s until 2000, we have certainly come out of the ice age and are now headed, perhaps a little too quickly, to much warmer times.

Awareness of the impact of global warming has led to faster change in the energy sector. This has been compared to the changes seen in the great industrial revolution of the 18th and 19th centuries.

And with this, the advent of intermittent renewables has ushered in a brand-new set of challenges never faced by stakeholders before. Technologies and sources of energy celebrated one day fall out of grace the next day. Gas power is one of those but, as I will argue in this article, there’s a way we can bring it back into favor: through the intelligent use of battery storage.

A much cleaner fuel than coal or liquid fossil fuels, gas quickly rose to the top of the energy mix in many countries with the arrival of the new millennium. Combined-cycle gas turbines (CCGT) became the most popular form of centralized electricity generation, driven by the low cost of gas and their high efficiency. This is borne out of figures from Bloomberg New Energy Finance (BNEF), which show that between 2008 and 2015, 250 GW of new gas capacity was installed across about 2,000 sites worldwide.

However, as the need for flexible generation increased due to the rising volume of solar and wind power installations, CCGT got into trouble; although efficient, they’re not able to move fast enough to compensate for the variations in supply associated with renewables. So the sector responded with more gas technology: fast-acting open cycle gas turbines (OCGT) came back into fashion.

This presented new challenges when it came to the integration of renewables. Firstly, the marginal cost of renewables production is effectively zero, leading renewables to compete strongly with CCGT on wholesale electricity markets, and displacing the cleanest thermal generation of the system. Secondly, the increase in renewables led to an increased demand for fast-responding OCGTs, which could keep up with the associated intermittency but were also less efficient than CCGTs.

In short, the most efficient form of gas generation was being displaced by renewables combined with much less efficient OCGT gas turbines.

Surely we can do better?

The answer comes in the form of energy storage. The price of batteries has dropped considerably in the past 10 years – according to BNEF the price of battery cell packs has dropped from almost US $1,200 in 2010 to less than $200 in 2018. Batteries are now a more competitive (and cleaner) alternative to OCGT – a fact that is now being recognized in legislation. For example, California’s two landmark energy storage bills require California’s Investor-Owned Utilities (IOUs) to procure and install nearly 2 GW of storage by 2024. The assessment carried out by the State Government of the cost vs benefits of batteries compared with gas turbines has found batteries to be more economical.

Centralized electricity generation seems to have also found its stride. We now have higher levels of renewables than ever before, made possible by grid-scale energy storage and efficient thermal generation thanks to the use of gas as a controllable baseload power.

At Aggreko, we believe the lessons learned from centralized power generation can be applied to distributed generation to supply our customers, wherever they are, with the best balance of clean, cheap and reliable power. Our ‘CCGT’ is our fleet of highly efficient gas engines, our storage technology is our new Y.Cube – a fully containerized 1MW battery – and the grid operator is our smart YQ energy management system.

There’s a range of examples where we have seen this work across the world.

For example, the Gold Fields Granny Smith gold mine in Western Australia is set to install one of the world’s largest renewable energy microgrids. It will be powered by a combination of gas generators and 20,000 solar panels and supported by Aggreko’s new mobile and specially designed. The use of battery storage will enable the mine operators to use more solar power while also running gas engines more economically.

Gold Fields is just the beginning. In many off-grid locations, the right combination of gas, batteries and solar power is already the most economically attractive technology mix. Gas-battery hybrids have an even wider application than remote off-grid projects. Access to reliable power can also be an issue in countries with a reliable electricity system. Data centers, for example, are often built faster than the grid can keep up with; on top of that the computers in each center are also extremely sensitive to power quality and can require very sudden spikes in demand.

We’ve been able to help our customers who run data centers to meet this challenge. We supplied one such center in Ireland with gas generators and a battery, guaranteeing both a stable energy supply and the highest possible power quality. This also provides an easy-to-implement and reliable way to keep the business running.

Huge strides have been made in the past few years to establish greener power as a source of energy. However, the energy transition is far from complete. New technologies keep emerging, and there’s still little known about what the end point will look like and how long it will take to reach it.

But despite all the uncertainty there are some things we do know. One is that combining batteries with gas will go a long way to making cheaper, cleaner and more reliable power more accessible.