Gas and electricity cannot be seen but they can be metered and supply can be turned off, which makes it possible to trade them like other commodities. Furthermore, there are physical markets that require delivery and off-take of gas and electricity, and financial markets that exchange derivatives linked to the physical market.48 Trading energy derivatives brings in additional funds from investors for operations and long-term investment in the energy sector. More recently, carbon emission has been commoditized so it is becoming a policy instrument for lowering greenhouse gas emissions, and when large investors participate in carbon emission trade, there will be new capital for implementing zero-carbon energy capacity. Once liquefied, trucks or ships with cryogenic or insulated tanks can transport it to places not connected by pipelines.