Grid&Storage Market and Policies

Electricity Grid and Storage Market

The transition to a decarbonised energy industry demands the adaptation of new technologies and the development of new infrastructures

The unexpected trend towards electromobility, and its eventual dominance of the vehicle market, has been confirmed by leading oil industry companies themselves, who foresee as a consequence a possible peak in oil demand around the year 2020. Oil company forecasts predict the number of electric cars worldwide could rise from the 1.2 million in 2015 to 100 million by 2035.

Electric vehicle charging networks

Oil producers and distributors, such as BP (SEO Bob Dudley), are seeking cooperation opportunities with electric vehicle manufacturers to find solutions to the issue of charging stations for electric cars at its petrol stations in the future. Discussions between oil companies and electric car manufacturers are exploring options of bundling oil tank station networks with charging demands.

Oil companies and gas station operators see the principal problem being the long charging times, requiring large areas for static vehicles at petrol stations, which make electrical vehicles still uncompetitive with fossil fuel.

Power generation efficiency

The rating of an electricity generating power station, as a percentage of the ratio of effective electrical output over energy input.

An important principle of thermodynamics states that no conversion is perfect – there will always be some loss to another form of energy. The amount of energy available to the animal’s body is much less than the total amount of energy from the sun to make the glucose in the plant. A ball does not bounce back to the same height as before, because some of the energy is ‘lost’ to heat and sound. The total amount of energy is always the same, but not all of the energy can be converted to a single form. The percentage that can be converted is known as efficiency.

η = output/input

This loss of ‘usable’ energy is called degradation of energy.

Efficiency is a technical term for the conversion of one energy from one form to another. Energy is never lost (Second Law of Thermodynamics), so if a fuel is burnt entirely, 100% has been converted to other energy forms. However, much of the new energy may be ‘unusable’, such as sound. If heat is the objective of the conversion, as it is in a boiler and turbine power generator, the efficiency would be a measure of how much electrical power results from the burning of an amount of fuel.

Burning oil in a power plant has the purpose of heating water, which is converted to steam, which drives a turbine, which generates electricity. Burning petrol in a car considers efficiency of conversion to be the kinetic energy of motion, and heat is ‘unusable’, so is lost to the purpose of the conversion.

Energy source Energy type Current range Theoretical max.
Wind kinetic 30-50% 59%
Photovoltaic radiative 15-20% 90%
Hydropower gravitational 80-90% 90%
Fuel cell chemical 70-80% 85%
Gas turbine chemical 30-40% 40%
Combined cycle* chemical and thermal 40-60% 60%
World Total All types 39% gross 33% net

* Two stage production: gas turbine then steam turbine

The irregularity of renewable power generation from wind and solar has led to the need for an efficient way to store the excess energy for later use. Batteries are the traditional technology, but researchers have put forward some intriguing and inventive alternatives.

California passed a law in 2013 requiring energy companies to provide a total of at least 1.3 GW of storage capacity. At 1.75 kW per household (figure for the UK) this would be enough for 750,000 households.

Ice

The Portland General Electric (PGE) company in Oregon (USA) has a pilot programme (TAGES Thermal Approach to Grid Energy Storage), investigating the possible use of state change from water to ice (or slush) to store energy, and using a heat exchanger to extract the energy later when needed. This system could also take advantage of waste heat from a conventional power station. 80% efficiency of recovery is theoretically possible.