Posts tagged ‘geothermal energy’

January 15, 2013

Heated pavements – wasted heat or saving resources?

When talking about heated pavements, the first thought that would come to one’s mind would be – what a waste of energy and heat! However many existing schemes in Northern cities could show that these heated ‘roads’ could be beneficial and may even save resources.

A recent pilot project in the Netherlands for example is investigating the possibility to collect and store summer heat underground and release it in the winter months to keep the bicycle lanes ice-free. The benefits could mean less salt used and probably more cyclists on the roads.

In Northern countries, like Norway or Iceland, heated pavements are already well-established – in the latter one mainly fuelled by geothermal energy.

The company ICAX has developed its unique  ‘Solar Road Systems’, which collect the heat in the summer for road heating and de-icing in the winter. Their technology utilises the fact that black tarmac used on the road surfaces can heat up significantly in the sunshine, and by storing this heat – it can be used in colder months – for free. Their first successful trial in the UK took place under an access road to the M1 motorway at Toddington, Bedfordshire. Furthermore, the firm also claims to provide a solution for de-icing runways and parking stands at airports, potentially lowering disruption at busy terminals in snowy conditions.

Another company, Solar Roadways from Idaho, USA [4] has tested specially designed glass panels, with multiple features. These contain LED lights – which could display for instance road signs – , while the heating elements can help melt snow and ice, improving winter driving conditions.
This system is currently quite expensive due to the materials used, but there are also some cheaper alternative methods being investigated. One of these is using photovoltaic panels and cells on the roads, with embedded pipes for storing energy until colder times.

For a small town in Michigan, USA, this idea is nothing new. Here, waste heat from the local power station has been used in the underground pipes to melt the ice on the pavements since the installation of this system in 1988.

Also, there are already many commercially available personal under-driveway and under-pavement melting systems and mats, but these are costly and may not be very environmentally-friendly.

Hence, if cold winters continue to be harsh, heated pavements could be seriously considered as one of the long-term solutions for easing winter problems.
Written for the Energy Saving Warehouse

 

March 4, 2012

Enhanced Geothermal Systems

Heat from the earth has been tapped for a long time. However while conventional geothermal systems utilise the energy from underground only at locations with ideal geological features – where hot water and thus steam already exists -, now also less favourable places can enjoy the benefits of geothermal energy – thanks to Enhanced or Engineered Geothermal Systems (EGS).

These systems use the potential of the “hot dry rocks” under our feet for generating heat and electricity. In the case of the conventional geothermal energy, known as hydrothermal, hot water is in situ, while the new technology artificially fractures hot dry rocks, and then circulates cold water, which eventually turns into steam and so drives turbines on the surface. Later the water is re-injected and the loop is started again.

According to a study by the MIT Enhanced Geothermal Systems have the potential to provide 100 GWe generating capacity just for the US in the next fifty years. This technology is scalable and can provide a continuous base load, but further investigations, including field tests, are needed to determine the real benefits.

Potential challenges include that it may cause minor tremors, and it requires a rather large initial investment, which may hinder companies and countries who are willing to finance such projects.

Australia is already leading the way in testing this technology, while there are further trials in Germany, as well as France and the US. In the UK the Eden Project is one of the latest examples.

According to the forecasts of the European Commission EGS systems can offer cost-effective electricity virtually anywhere, with an estimated potential of 1 GW and a maximum potential of 6 GW for the EU countries by 2020 – about one per cent of gross electricity consumption. For heating purposes the potential is even higher. The EU has supported about ten projects since 2002, including the key pilot project in Soultz, France.

Enhanced or Engineered Geothermal Systems thus offer great potential both for heat and electricity generation and hopefully with more investment it can be developed into a promising new energy source.

Written for the Energy Saving Warehouse 

November 18, 2011

A New Momentum for Geothermal Energy in the UK?

When we talk about renewable energy in the UK we tend to think about on- and offshore wind energy, solar power or the recently emerging new tidal and wave developments. And while geothermal energy is often forgotten about it seems that they may receive more attention in the future thanks to renewed interest from developers.

When is geothermal energy efficient?

Geothermal energy is essentially using the heat of the Earth, ‘generated’ by the radioactive decay underneath us. The most ideal places for harnessing this heat depends on the geothermal gradient of the area, the temperature difference between the surface and the core of the Earth. This is on average 25-30C degrees per kilometer increasing with depth, but can be significantly higher in areas near tectonic plate boundaries or in places where the crust is thinner than usual.

Geothermal energy can be used in two ways: the hot water and the hot dry rock found below are used for heating (directly or indirectly) as well as for electricity generation.

In the UK

Despite the lack of popularity of geothermal energy projects there are already some successful developments in the UK.

One of the earliest developments exists in Southampton, where a Combined Heat and Power (CHP) station operates, providing district heating, not only used in houses but also in shopping malls and hotels in the city – since 1986.

Also, last year the Department of Energy and Climate Change (DECC) announced the ‘Deep Geothermal Challenge Fund’, which awarded significant funding to three projects in Newcastle and Southampton.

In the Gardens of Eden

The latest large-scale project is probably the planned geothermal power plant of 5MW at the Eden Project in Cornwall. This part of the UK is one of the most suitable places for geothermal energy development thanks to its geology, featuring granite bedrock.

The drilling to the hot dry rocks underneath is expected to start next year after all permissions have been granted, and should reach a depth of 4-5 kilometres. Besides the Eden development it is anticipated to also provide power for 3-4000 homes in the area.

The project seems to be rather promising, which could mean that the whole geothermal energy segment might gain momentum in the UK in the near future.

Reasons could include that geothermal energy is available 24 hours a day; it’s clean, sustainable, but not greatly supported by the government – yet.

 

Written for the Energy Saving Warehouse

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