Smart energy systems

Questions and answers

Why is it so important to be able to store energy?
The aim is to in time completely eliminate the use of non-renewable energy sources such as oil and nuclear power. There is ample renewable energy but it must be made available where it is needed, when it is needed and at competitive prices. It must then be possible to store it and distribute it in a functioning infrastructure. If surplus electricity is transformed into gas, it can both be stored and distributed in the gas grid.

How can Power to Gas contribute to more renewable vehicle fuels?
With Power to Gas the surplus electricity generated by wind power can be used together with carbon dioxide to form methane. This is the same as biogas, which is used for cars, buses and trucks.

In what way is Power to Gas of significance to the expansion of biogas?
When biogas is produced, both methane and carbon dioxide are formed. The carbon dioxide can be used together with electricity in order to break down the water molecules, forming hydrogen and oxygen. Power to Gas increases the yield from the biomass, i.e. more gas is extracted from the same volume of raw material.

What are 'intermittent energy sources'?
They are renewable energy sources that cannot be controlled, governed or stored, e.g. wind power, solar power and wave power, and in effect the energy must be used at more or less the same second it is produced.

How does surplus power arise?
When the proportion of intermittent energy increases, there will be periods when it generates more electricity than can be used. This 'surplus power ' has a very low, sometimes even negative, price on the electricity exchanges. This is already happening in Denmark and Germany, where there has been a substantial expansion in wind power. Power to Gas is a way of utilising this cheap electrical energy.

How can electricity become gas?
The electricity is used to break down water into its components, hydrogen and oxygen, with the aid of an electrolyser. The hydrogen that is formed can be used as fuel in its present form but can also be allowed to react with carbon dioxide and form methane. Methane can be fed into the national gas grid. 

How much biogas can be produced by surplus electricity?
According to calculations, 2-3 TWh of methane can be produced each year once we have 30 TWh of wind power in the system. In 2015, wind power produced 16.6 TWh.

Why is Swedegas investing in Power to Gas?
We want to contribute to switching energy systems, allowing us to make smarter use of available resources. Power to Gas can become part of the long-term solution in Sweden for a smart energy system that becomes more integrated and stable.

What is the European Power-to-Gas Platform?
It is a platform where different bodies with an interest in Power to Gas in Europe have been brought together. Sweden is involved through Swedegas. 

Sources: "Ny vision i energi­debatten: Lagra vindkraft i naturgasnätet" (2012) and "Power to gas. Internationell utblick och potentialen i Sverige" (2013), both from ÅF 
"Framställning av gröna gaser" (2014), Svenskt Gastekniskt Center AB