Energy resources and sustainability

The Master Plan covers those energy resources on which the largest part of the populations' energy generation is based  - i.e. hydroelectric power and geothermal energy. In phase 3 there is an addition of wind power.

When working on the Master Plan it is necessary to take into consideration multiple different interests. The task consists in weighing and evaluating the viewpoints of the interesting parties, whether they are power companies, farmers, tourists, nature itself or someone entirely different. Only after a strict and transparent process of weighing and evaluating the interests involved the decision is made regarding the classification of power plant options into protection category, on hold category, or energy utilisation category.

Article one of the Master Plan Act describes the objectives of the Act and reads as follows:

The objective of this Act is to ensure that the utilisation of geographical areas where there are power plant options, is based on long-term views and a comprehensive assessment of the interests taking into account the conservation value of the nature and the cultural historical relics, the cost effectiveness and profitability of various different utilisation options and other values that affect the national interests, as well as the interests of those who use these same resources having sustainable development as a guide."

Energy consumption in Iceland

Energy consumption per capita in Iceland is the highest in the world and the ratio of renewable energy resources is substantially higher than with other nations. The proportion of domestic energy resources has increased a great deal in recent decades, in particular during the 21. century. More than 85% of all energy consumed here in Iceland is domestic and comes from renewable energy resources (based on the year 2010). Of the domestic energy consumption 19% of the total consumption comes from hydroelectric power and 66% from geothermal energy which makes up the largest part of space heating. The rest, nearly 15%, is primarily imported fossil fuel for the population's fishing fleet and car fleet.

In 2013 the production was 18,000 GWh (gigawatt hours) of electricity in Iceland. Approximately 71% of this electric power was generated from hydropower energy and the other 29 percent from geothermal energy. Electricity production from fossil fuel and wind was therefore well below 1%. Approximately 40% of the power that is generated from geothermal energy is used in electricity production. Another 43% is used for space heating and the rest is used for fish farming, swimming pools, snow melting, greenhouse production and other industries. The overwhelming portion of the electrical power that is generated in Iceland, or approximately 70%, is used for aluminium production and an additional 10% is used for other heavy industry. The remaining 20% is used more or less equally by households, by service industries of different types, utilities or distribution systems and by small scale industries.

Iceland possesses unused energy resources but they are not inexhaustible. An assessment of the capacity of these energy resources is always subject to many uncertainty factors that involve possible utilisation, technical potentialities, cost effectiveness and environmental and sociological aspects. The annual growth of electricity requirements for general use is on average 50 GWh.

Renewable energy resources

Hydroelectric power, geothermal energy and wind power are renewable energy resources. That is not to say however that these resources are at the same time sustainable. The term "renewable" in this context means that the power source will not be depleted, at least not within the time frame that humans are used to refer to (a decade, possibly a century or a millennium).

The sun has shone upon the earth for more than four billion years and it will probably continue to do so for another similar length of time, long after humans have disappeared from the scene. Solar energy is therefore renewable energy seen from a human standpoint. Similarly can be said about the wind, which is precisely one of the manifestations of solar energy.

In the same way hydroelectric power is based on the sun's energy that powers earth's water cycle. Hydropower is thus actually generated from the sun's energy, which is a renewable resource. Hydroelectric power is renewable so long as the rivers flow in the channels where they flowed when the power plants and distribution systems connected with them were constructed.

Geothermal energy is generally classified as a renewable resource because geothermal power is continually being renewed although the rate of renewal varies in different geothermal areas. This energy comes from deep within the earth and is not based on solar power, such as wind and hydroelectric power, but rather on the decay of radioactive materials in the earth's mantle. The lifespan of individual geothermal systems is very short on a geological timescale and that is why these systems cannot be referred to as renewable in the same way as e.g. wind and solar power. Individual geothermal areas may however have a lifespan of one hundred thousand years or so and that is long enough for the system to be classified as renewable on a human scale.

Sustainable energy resources

Sustainable energy resources are those renewable energy resources that can be exploited or utilised at the rate at which these resources renew themselves. In order for an energy resource to be considered sustainable the resource must not be utilised at a rate exceeding its renewal rate. The utilisation must in addition result in economic and societal benefits without damage to nature and the environment.

The terms renewable energy and sustainable energy generation are closely related. Generally speaking the principal energy resources of the Icelanders, geothermal power and hydropower, are classified as renewable (see above). Renewability describes the properties of an energy resource (the energy resource renews itself) but the term sustainable is connected with how its utilisation is managed (taking care that a renewable energy resource is not exploited at a rate exceeding its renewal rate).

Sustainable geothermal energy production

Geothermal energy is maintained through a continuous natural flow of energy. Therefore it is considered more appropriate to classify geothermal power as a renewable energy resource rather than a limited energy source. This classification is however not simple because geothermal energy has by its very nature a twofold aspect, i.e. it is a composite of an energy flow (through convection and thermal conductivity) and stored heat. The renewal of these two aspects is very variable since the energy flow is constant (continuously renewed) but the stored heat is renewed relatively slowly. That portion of the stored heat that is maintained by thermal conductivity is actually renewed at such a slow pace that in the time scale of human activity it should rather be considered finite and limited - than renewable. The balance between these two aspects in geothermal energy generation varies by both geothermal systems and resource utilisation load. In what is referred to as "Hot Dry Rock"-systems the importance of the stored heat dominates, but in the most powerful high-temperature systems in Iceland's volcanic belt the importance of energy flow is large.

In a lecture that was given at the Orkuþing 2001 - Energy convention - there was a proposal for the following definition of the term "sustainable geothermal energy production" at a certain geothermal area:

For every geothermal area and every production method there is a definite maximum processing stage, E0, which is such that by way of a lower processing stage than E0 it is possible to maintain an unaltered level of energy generation from the system over a very long period of time (100-300 years). If the resource utilisation load is more than E0, it is not possible to maintain an unaltered level of energy generation for this long. Geothermal energy generation that is less than or equal to E0 is defined as sustainable energy generation but energy generation in excess of E0 is not sustainable."

This definition does neither touch upon economic issues, environmental issues, nor technical development but it is expected that such factors will fluctuate a great deal over time. The definition covers all the energy that can be generated and the definition is therefore dependent upon the nature of the system that is being discussed but not dependent on load or stress factors or efficiency. It is also dependent on the method of energy generation. 

This simple definition of the term sustainable geothermal energy production is based on the premise that for every geothermal system there is some sort of energy production limit so that it will be possible to keep the production more or less in a state of balance over a long period of time - if the production is kept below this limit. The experience from many geothermal areas in recent decades does support this situation. (Primarily based on the conclusions report of phase 1 of the Master Plan, pgs. 68-69.)

Sustainable production of hydropower

In the production of hydropower the water cycle is used and this cycle is driven by solar power. The original power source is independent of how water is used and thereby the hydropower energy as such is renewable, i.e. sustainable, at least on a foreseeable time-scale. 

In Iceland the annual variation in river flow stands in most instances in an inverse relation to the demand for electricity - the demand is greater over the winter months when the flow is at its lowest. This is solved by storing the water that flows during the summer months and then distribute this water from distribution reservoirs during the winter. The largest rivers in Iceland are glacial rivers and over time the distribution reservoirs get filled with sediments. This fact does not change the nature of flowing water as a renewable resource. On the other hand this situation gradually reduces the capacity of the power plants if no action is taken.

Within the international community there have been a variety of views about how to classify hydropower energy in this respect. It is generally admitted that hydroelectric power plant options should be classified as renewable resources if the sediment deposits and the size of the land area involved are insignificant. But what is insignificant in this respect? One important criterion is without doubt the service life of a power plant but there is also the question what is reasonable in this respect, e.g. in comparison to the useful life of other sources of energy?

The utilisation of hydropower energy options can not be considered sustainable if it entails a very negative impact on human communities or ecological quality, e.g. if people need to be relocated in large numbers and important natural conditions are at stake. If it is possible to reclaim the natural environment of the power plants one may speak with a greater degree of certainty about a sustainable power plant.

To choose sustainability

There is no one single definition as to what is a sustainable and an unsustainable power plant project. On the other hand it is possible by way of comparison to analyse whether a certain power plant project is more sustainable than any other. An open and transparent decision process should bring forth the benefits and the disadvantages of different ideas.