To begin, we need to define power-to-gas (PtG) in its simplest form as the conversion of electrical power into gas that can be later distributed on an as-needed basis. The objective of PtG technology is to enable the balance of supply and demand for power in electricity networks with renewable energy. Importantly, as the use of renewable energy continues to grow there will be an ever-increasing need to support ramping and smoothing of renewables and to enable storage of the over-production via transfer of PtG on an as-needed basis.
Specific advantages for the continued use and growth of PtG include:
- PtG allows the conversion of volatile electricity into renewable, synthetic gases (H₂ or SNG) with an unmatched low carbon footprint which can be stored, transported and commercialized for mobility (green, renewable synthetic fuels) and industrial markets (green chemistry);
- PtG decarbonizes the gas grid by replacing fossil natural gas;
- PtG adds flexibility to energy systems and therefore enables efficient integration of high shares of volatile renewables into energy markets;
- PtG facilitates this by:
- Creating a connection between the power grid and the gas grid with its ample storage and transport capacity;
- Recharging the gas grid without timing/technical restrictions and thus allowing utilities to generate electricity and store it for use in the form of synthetic fuel at a later time and place.
Global trends within the renewable energy space continue to be positive for the growing importance and expansion of PtG. Key amongst these are the required reductions in CO2 emissions to meet increasingly aggressive decarbonization requirements, the exiting of both fossil fuels and, in some countries, nuclear power generation and the increasing dependence and growth of renewables (wind and solar). On the negative side, historic factors inhibiting growth have been high capital investment combined with regulatory and infrastructure challenges.
There is no getting away from the fact that there is an urgent need and growing demand to reduce the CO2 levels globally. It is alarming to note that even with the increasing global focus on reducing CO2, there is still significant use of fossil fuels causing an increase of CO2 in the atmosphere. In fact, the United Nations in October 2017 warned that “the concentration of carbon dioxide in the atmosphere increased at record speed last year (2016) to hit a level not seen for more than three million years.” A frightening statement by any measure. Figure 1 shows the impact of continued use of fossil fuels and CO2 levels related to global warming.
Source: Global Carbon Project 2017
Having demonstrated the urgency to continue to pursue non-fossil fuel alternatives there are some examples of by-country activity on the PtG front and specifically on the intended use of gas as a key part of several countries’ renewable energy strategy. The summary also highlights the fact that global development, while promising, has been selective and limited to date. But as proactive government policies continue and costs decline, there is increasing potential for the use of the technology well beyond these early adapters. Below are some examples of countries going beyond CO2 emission requirements:
- BFE: Energy Strategy 2050 (voter approval in May 2017 —reduced dependency on fossil fuels).
- Swiss Gas Association: 30 percent renewable gas by 2030
- Retirement of nuclear power plants by 2022
- California 50 percent renewable by 2030. (AB 2514/2868 are mandates for energy storage)
- Proposal SB 100 to become 100 percent renewable in California by 2045
- California has invested heavily in solar power with the impact of over production of electricity which they’re sometimes forced to pay other states to take
- CGA’s renewable gas targets are 5 percent by 2025 and 10 percent by 2030
- PtG becomes increasingly important as decarbonization intensity grows
- New government announced complete exit of coal power generation by 2023
- Gas from renewable sources to be 10 percent by 2030
While PtG technology has been around for some time it is still considered a “new” and disruptive technology. Below are just two examples on the use of PtG that provide strong validation for its expanded use:
- In June 2013, Audi announced its opening of a 6-MW PtG facility in Germany making it the first automaker to develop a chain of sustainable energy carriers. According to the press release, “the plant uses green electricity, water and carbon dioxide to create hydrogen and a synthetic methane known as Audi e-gas which it distributes to compressed natural gas (CNG) filling stations. The Audi e-gas project demonstrates how large amounts of green electricity can be stored efficiently and independent of location by transforming it into methane gas and storing it in the natural gas network, the largest public energy storage system in Germany.”
- Construction of Japan’s first PtG plant was initiated in July 2017 as a key part of its efforts to reduce CO2 emissions. The press release states: “Instead of being [released into the atmosphere], the CO2 of an existing coal-fired thermal power station will be captured and effectively used for the production of synthetic natural gas (SNG). It is the objective of this test facility to prove the feasibility of large scale PtG plants.”
Navigant Research indicates that a key inflection point for PtG is anticipated beginning around 2020 “as costs reach parity in more areas.”
Source: Navigant Research
In summary, it is clear that the growing increase in renewable energy will create a significant need for storage and energy delivery solutions. The use of a gas infrastructure can fill this need. As renewables continue to become an increasingly key part of a global decarbonization strategy it certainly paints a very bright future for PtG.
Lead image credit: CC0 Creative Commons | Pixabay