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Global Grid-Storage Capacities

Also known as cogeneration, CHP is a technology which is used to gain more efficiency from a power station. As the name suggests, both electrical power and useful heat is generated by the burning of fuel.

Also known as cogeneration, CHP is a technology which is used to gain more efficiency from a power station. As the name suggests, both electrical power and useful heat is generated by the burning of fuel.

CountryTotal generation /TWhper capita /MWhFossil share /%Renewables share /%Nuclear share /%

Data source: IEA Energy Atlas

Coal supplied 1520 Mtoe (46%) of the 3292 Mtoe of additional global primary energy supply from 2000 to 2012 [IEA]

Electricity Production by percentage

SourceWorld (2015)OECD (2016)
Natural Gas22.9%28%
Total fossils66.3%58%
Other renewables2.2%
Total non-hydro renewables11.4%11%

Data source: IEA Electricity Summary IEA

World electricity generation = 24,345 TWh (final consumption 20,200 TWh) in 2015. Annual increase 3.4% since 1974. Worldwide in 2016, hydro and non-hydro accounted for 2,588 TWh (24% of total electricity). [IEA]

OECD electricity generation = 10,964 TWh (final consumption 9,397 TWh in 2015) in 2016. Non-OECD electricity production overtook OECD production in 2011 [IEA]

In OECD Europe, non-hydro RE (17%) overtook hydro (16%) in 2015 and 2016, and RE in Europe = 33% of electricity generation.

OECD electricity consumption by sector: Commercial and public services = 31.9%; Industry = 31.6%; Residential= 31.1%; Transport = 1.1%; Others (incl. agriculture) = 31.6%.

Non-OECD electricity consumption by sector: Commercial and public services = 14%; Industry = 51%; Residential= 23%; Transport = 3%; Others (incl. agriculture) = 9%. Non-OECD countries have a rate of transmission and distribution losses of 9.6% (2015), compared to 6.3% in OECD countries.

Energy Intensity

The ratio TFC (total final consumption) to GDP has more than halved in the OECD from 1971 - 2015, seeing energy consumption increasing at a much lower rate than GDP growth. This indicates a gradual decoupling of energy consumption from economic growth.

Power Purchase Agreement PPA

Corporate Renewable Power Purchase Agreements (PPAs) allow corporates to purchase renewable energy directly from an energy generator.

Corporate Renewable PPAs are rapidly emerging as a business model in Europe because these PPAs allow corporates to reduce their carbon footprint and manage volatile energy costs, all while maintaining a fixed price per/kW of energy over a period of years.

Corporate Renewable Power Purchase Agreements are changing the market terrain for renewables – the volume of these PPAs almost tripled in Europe in 2016 compared to the year before, with over 1 GW of capacity contracted. In the US, they accounted for almost half of the installed renewable energy capacity in 2016.

Why are big corporates investing in renewables?

Corporates are playing a catalytic role for the deployment of renewables worldwide. More and more companies are procuring or aiming to procure 100% renewable energy. Corporate PPAs in Europe had a dramatic increase in 2016 to 1.6 GW of capacity, almost triple when compared to 2015. By choosing renewable energy as a commercial and strategic priority, corporates are showing a leadership and huge commitment in the global sustainability agenda.

(Source: http://resource-event.eu/new-to-ppas/)


Also known as cogeneration, CHP is a technology which is used to gain more efficiency from a power station. As the name suggests, both electrical power and useful heat is generated by the burning of fuel.

Combined cooling, heat and power (CCHP), also known as trigeneration, is a system which obtains electrical power, useful heat and cooling from an energy source. The source can be the burning of a fuel or solar heat collector. Some of the heat is used for cooling, such as in an absorption refrigerator. CCHP have higher efficiency rates than CHP plants.

In CHP, what would otherwise be waste heat in the power generation cycle is utilised, often for district heating (CHPDH combined heat and power district heating). For example, a CHP plant in Metz, France, has a 45MW boiler which burns waste wood biomass. The electricity and heat it generates is sufficient for the needs of a town of 30,000 residences.

Achievable efficiency is 45% electricity, 40% heat and cooling, of the 100% energy from burning fuel. It is therefore a technology which can help reduce greenhouse gases, as well as being economically viable, and adaptable to micro-generation.

EU CHP Directive: European Union’s Cogeneration Directive 2004/08/EC. 11% of EU electricity is cogenerated. Northern countries have more utility of heat as a secondary product of power generation, so they are more advanced in its implementation. Denmark, Holland and Finland (81.8% in 2012) have the greatest proportion of cogeneration plants.

German law for the maintenance, modernisation and development of cogeneration plant: KWKG Kraft-Wärme-Kopplungsgesetz (German)

Combined heat and power involves locating an industrial scale gas turbine generator near a thermal host, and recovering the high temperature exhaust in a heat recovery steam generator. Advantages: transmission and distribution losses (avg 7% in USA) are eliminated; CO2 emissions fall 45% c.p. gas without heat recovery; reliability increases on local griid and or industrial host; low-cost, highly dispatchable power is generated. Waste heat can be sold as steam (e.g. to neighbouring industry for competitive prices.

Combined cycle

In electricity generation, combined cycle usually refers to the exploitation of the waste heat from the primary steam turbine cycle, either for further electric power generation, or for district heating, or other direct use of the heat.

In the Carnot Engine, the greater the temperature differential between the input and output of a process, the greater the energy conversion possible.

Fuel is burnt in a boiler, which is enveloped in tubes containing water. This water converts to steam, and under pressure of gas expansion can provide kinetic energy to drive a turbine. This turbine has a shaft which rotates, allowing electricity to be generated by the magnetic flux through coils of wire in the electrical generator. The amount of electricity generated depends on the energy provided by the steam to the turbine, since the mass of magnets or wire coils (either may rotate, while the other is static) must push against the electromagnetic resistance.

In a traditional single-cycle steam turbine, the steam returns to the water state, through cooling. This results in the loss of the residual heat in the water.

A combined cycle plant would incorporate a second cycle to exploit this latent heat, and can raise the efficiency of the overall electricity generation from 40 to 60%.