Solar, wind, and other renewable energy production systems have proven to be viable systems. Electricity from solar energy has almost reached parity with the cost of electricity from coal power plants. The problem which remains is that these renewable energy systems are dependent on the weather or on the sun. For solar energy, there is no power generated during the night or very cloudy skies. For wind farms, there is a minimum wind speed, and a maximum wind speed. In a way, this is also the same problem for hydroelectric power plants. When the water level goes critical, electricity production is also limited.
The benefits of power-to-gas include: the ability to transfer electricity to other sectors on demand, flexibility for the electricity system and support integration of other renewable energy, and the use of existing technology and infrastructure.
The solution needs a bold move: install batteries to store the excess energy produced, and then release this when there is no energy production. Solar energy plants can produce more during the day, and distribute electricity at night. For hydroelectric power plants, batteries may not be the solution. Long term energy storage does not yet exist in its pure form. However, there are other ways to store excess energy besides batteries.
A long term energy solution is now being tested in Europe and in Colorado. Known as “power-to-gas” it uses electricity to collect hydrogen from water and then combined with carbon dioxide. Microbes convert the mixture and produce methane. With a power-to-gas plant, solar and wind energy plants can store hydrogen or methane for future energy production.
U.S. Energy Storage Projects
In the U.S., the National Renewable Energy Laboratory (NREL) in collaboration with Southern California Gas Company (SoCalGas) and Burns & McDonnell is studying power-to-gas project using microbes, clean electricity, and hydrogen.
Another project is ongoing at University of California, Irvine (UC-Irvine) with support from SoCalGas. Their project makes use of an electrolyzer to make hydrogen from electricity and water which feeds into the natural gas infrastructure. The stored hydrogen is capable of very fast ramp ups, similar to when thick clouds dampen solar energy production.
Compared to batteries, storing hydrogen can be cheaper and have more uses. It allows for long term storage, ready for use at any given time. It can either be transported to another utility company or for any other use besides power generation. Hydrogen is also used for transportation purposes via fuel cells. This bold innovation is a step up from batteries, which could not keep energy for long-term storage; transporting large batteries is also not possible.
Financial Impact of Energy Storage
Storing excess energy has big financial impact on producers. Energy markets have been set up for trading electricity between utility companies. Excess supply is sold on the spot market; when one electric utility has a shortage, they buy the slack supply from the market. If an electric company has long-term energy storage, they can use it when they have a shortage instead of buying from the spot market.
The benefits of power-to-gas include: the ability to transfer electricity to other sectors on demand, flexibility for the electricity system and support integration of other renewable energy, and the use of existing technology and infrastructure. Experts believe it is the future source of energy storage capability. More importantly, it is a mature technology and is now ready for use.