Power-to-Gas: Rethinking Energy Storage Options

Power to gas could become a new intertie between wholesale electricity systems and wholesale natural gas systems.

Power to gas could become a new intertie between wholesale electricity systems and wholesale natural gas systems.

In a society keen on reducing its levels of greenhouse gas and air pollutant emissions, the use of renewable energy is growing in popularity and demand. Wind power, solar energy and renewable natural gas (RNG) all play a part in the world’s energy evolution, but a big question remains: how can we store power made from intermittent sources such as wind, sun, and water?

The use of electrolysis, also known as power-to-gas, uses surplus renewable electricity to ‘split’ water molecules to produce hydrogen and oxygen. The hydrogen is then injected into natural gas distribution infrastructure and blended with natural gas and used when it is needed, for heating or electricity.  All this to say, we need to start viewing the natural gas distribution system as an energy storage system.

Power to gas could become a new intertie between wholesale electricity systems and wholesale natural gas systems, and is a cost-effective and decarbonizing way to take surplus off-peak electricity and deliver it as green gas to consumers, says David Teichroeb, head of Business Development, Low-Carbon Energy Strategies  at Enbridge Gas Distribution.  Enbridge has partnered with Hydrogenics Corporation on a 2-megawatt power-to-gas project in Markham, Ontario, which will be North America’s first and largest, utility-scale power-to-gas plant.

The use of electrolysis, also known as power-to-gas, uses surplus renewable electricity to ‘split’ water molecules to produce hydrogen and oxygen.

For a power grid like Ontario’s, with a peak demand of approximately 25,000 MW, there is a potential for 1,000-2,000 MW of energy  storage, experts say, and power-to-gas can play a significant role. The Enbridge/Hydrogenics project is expected to be in service in the second quarter of 2017 and is seen as an opportunity for Enbridge to showcase leadership in its renewable energy business and to show how the natural gas pipeline system can support storage of renewable gaseous energy Teichroeb says.

“By researching the various energy storage technologies, we now understand the economic and technical benefits that are related to power-to-gas and that we can harness the connection of the natural gas pipeline system to 3.5 million Ontario customers.  As well, the gas pipeline industry can bring storage solutions to the electric grid, which is taking more and more intermittent wind and solar generation.”

“Storage facilities on the grid are a real game changer,” adds Bruce Campbell, President and CEO of the Ontario Independent Electric System Operator.  “Our electricity system was built on the concept that you can’t store large amounts of electricity – currently we produce electricity at the same time that we consume it.  Energy storage projects will provide more flexibility and offer more options to manage the system efficiently.”

The gas pipeline industry can bring storage solutions to the electric grid, which is taking more and more intermittent wind and solar generation.

The gas pipeline industry can bring storage solutions to the electric grid, which is taking more and more intermittent wind and solar generation.

While there are more than 30 power-to-gas projects already in service in Europe, energy-rich North America is a relative new comer to the technology. To further the technology, the Canadian Gas Association (CGA) has created a Canada-U.S. P2Gas Task Force examining guidelines for blending of hydrogen into the gas distribution network. The idea is to create a set of North American guidelines for power-to-gas, rather than reinvent the wheel on both sides of the border, pooling resources to develop guidelines that would work for the industry in Canada, the U.S. and Mexico.

“Our industry is looking at all ways it can support emissions reductions, drive efficiency, and cooperate on innovation and also ways to make use of other things,” says Jim Tweedie, Director of Operation, Safety and Integrity Management for CGA.  “So the purpose of this task force is to establish industry guidance on how we make use of electricity during off peak times. We need to address a number of issues, such as how do you inject hydrogen into a gas stream, to what percentage, what is the best way to do it, how do we make use of it and what are the limitations.”

“Power-to-gas is another option in that portfolio of alternative energy sources that we should be looking at.”

Part of the Task Force’s goal is to share information, he says. The group may find others have done some of the work already.  For instance, in the case of power-to-gas there is some work that has been done south of the border that Tweedie was not aware of until he presented to the American Gas Association. “That group was brought into the committee to share their findings,” he says. “It will save time, resources, and will also, I hope, help us address issues quicker.”

The guiding principal of the Canada-US P2G group is to have guidelines about everything from health and safety to how much and what percentage hydrogen to use, available before people need them, says Tweedie about the working group.

“Power-to-gas is another option in that portfolio of alternative energy sources that we should be looking at. The environmental targets that Canada has committed to aren’t going to be met by any one thing, whether you are oil, gas or electricity, they are going to be met by a number of things that are done in aggregate so it’s important we pursue them with equal levels of enthusiasm and emphasis because they all can make meaningful contributions,” he says.

Dina O’Meara is former business writer with the Calgary Herald and is now a communications consultant.