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Denmark's sustainable energy future

Thinking about energy for some considerable time could leave one in a depressed and pessimistic mood. It may then happened that one reads an article by J. Amos with the title given above and this puts a silver-lining on problems relating to energy. Here is a country that is proposing (a) to reduce its total energy use and (b) is cutting back considerably on its dependence on oil.

In the introduction of this article it is explained that in the early 1970's Denmark had a 90% dependency on oil imports for its energy needs. The oil crisis of 1973 therefore came as a shock and government action was taken immediately to make the country less reliant on oil. Subsequent National Energy Policies have been very effective at developing renewable energy sources, cutting down waste through District Heating initiatives and getting people to use less energy.

Table 1 gives comparison data between Denmark and the UK for the year 2003

                                                         TABLE   1

Item                                                            Denmark                                     UK

Area of country (square kilometers)                43,000                                      243,000

Population (millions)                                           5.3                                            59.1 

GDP per capita (dollars)                                33,000                                        24,000

Primary Energy Use (million toe)                       19.5                                            220

                                      (Peta Joules)                           819                                          9,240

Energy use per capita (toe)                                 3.6                                              3.9

Annual average temperature (degreeC)                   8                                               9

The figures show that the annual average temperature is virtually the same in each country but that the energy use per capita is over 10% higher in the UK. District heating in Denmark ensures that power station low grade heat is not wasted and this will, in part, contribute to a lower energy use per capita. Better home insulation in Denmark may also reduce energy use and, perhaps, the citizens of Denmark are more fugal in their use of energy.

The poposed future energy mix is given below:

The chart shows that oil consumption ,which was at record highs approaching 800 PJ per annum in the early 1970's, has been reduced to 300 PJ per annum and is likely to fall to about 200 PJ per annum in 2030. Renewable energy, on the other hand will increase to over 200 PJ by the year 2030. The forecast for the total energy consumption gives a reduction to about 700 PJ per annum and hence the Danish government has greatly increased the security of supply and made savings to its energy bill. 

Note - on page 207,  SE-HA, we see  that Denmark has very good policies regarding waste, the incineration to landfill ratio is very high indeed - about 1.1 whereas it is much less than 1 in the UK.

Reference  J Amos  - Denmark's  sustainable energy future, see https://sth-se.diino.com/f.thompson/migrated_data/EandH         Engineering Sustainability Volume 156, p 34 - 40, March 2003

Table 1 and the above chart has been adapted from this article.

As Copenhagen hosts the Climate Change conference this year ( 7th to 18 December 2009) the Danish people can be rightfully proud of their achievments -

Given in the "Danish Example" -- since 1980, the Danish economy has grown by 78%, energy consumption has remained constant and CO₂ emissions have been reduced.

Additional Numerical Information

It is necessary to deal with big numbers when talking about energy and practitioners of science or engineering use prefixes to make these numbers look more compact:-

mega(M)  x10⁶,  giga (G)  x10⁹,  tera (T)  x10¹², peta (P)  x10¹⁵, exa (E) x10¹⁸

American literature can be confusing as the billion or quadrillion can mean different conversion multipliers - a billion can be a million million or a thousand million.It is customary in UK to take a billion as one thousand million and a quadrillion (sometimes called a Quad) as a thousand million million.

Other conversions are necessary for energy units as the Americans often adopt the British unit (BTU or British thermal unit)  instead of the usual unit, namely, the Joule. Also, since we rely so much on oil these days an oil equivalent of energy is often used.

We see that 1 million tonnes oil equivalent (Mtoe) is equal to 42 Peta Joules (PJ) or 3.97 x 10¹³ BTUs. Now since a Quad is 10¹⁵ BTU then 1Mtoe is 0.0397 Quad.

Note also that 1 kiloWatt hour (kWh) is 3.6 MJ and  1BTU is 1.055 kJ.