woensdag 16 november 2016

GEOTHERMAL ENERGY! (the Dutch situation)


(the Dutch situation)


Wednesday 26-6 I attended a hearing / roundtable conference (Read REPORT)  on geothermal energy (or aardwarmte in Dutch), organized for members of the Dutch Lower House (2e kamer) Specialists from "the field" came to share experiences, insights and techniques and there was a shared &  very positive outlook on the future
Although you might be tempted to equate geothermal energy mainly with countries such as Iceland, Philippines, Kenya etc. with much volcanic activity, in Netherlands - surprisingly – there is ahigh potential for geothermal energy. In theory &  in the long term the total Dutch energy needs might be covered! Whether that is practical and affordable, remains to be seen. 

Geothermal energy: for starters one must immediately distinguish between (relatively) low caloric (or temperature) heat and high caloric heat. The latter is primarily utilized for generation of electricity. There is - in the Netherlands - no experience with that as yet because it requires very deep and therefore very costly drilling. (TransMark does have one concession ("Friesland", including tip Noordoostpolder) for ultra-deep geothermal well exploration. During this session that was not specifically addressed.)
The literature indicates that for electricity (present-day technology!) that wells be drilled into "Hot Dry Rock" and that under favourable conditions where > 220 ° C temperature steam is obtained, pumps would not be necessary and electricity with good efficiency is generated. But in the Netherlands you may have to drill 6 or 7 KM deep for that. Exorbitantly expensive, now ... 

As the name suggests, HDR, this is dry strata in which the transmission of heat is directly from stone on transmission fluid. That is an important difference with geothermal low caloric energy.  Then one specifically drills into porous strata which are hydrous, and are located less deep plus – advantageous for wide public acceptance - they are porous layers so no "Fracking" is needed! HDR may require "fracking" but in many cases only high pressure water injection is sufficient. 

Just a note: Because the drilling for geothermal aims for  water bearing strata (or  HDR) there is little or no chance for leakage of Methane, unlike with  drilling for shale gas. Since Methane in the first 20 years as much as 75 to 100 times more potent greenhouse gas as CO ² that is hugely important! 

Another important aspect that was mentioned: the Netherlands has  a lead over other countries... since the 60s, in the Netherlands (for about 50 billion (guilders probably?)) drilling and seismic testing has yielded an almost complete and very detailed image of the subsurface top 2 KM ... AND that information is public domain, allowing everyone to use it improve one’s chances for success, without any need for costly tests. A national heritage, so to speak. Drill much deeper than that however and the "image" is less detailed, increasing the risk of a "Miss", so right now the deeper you drill the bigger the cost, uncertainty and risk.
The speakers were quite unanimous: we can (and should) use "low-caloric" geothermal energy. Low caloric – less than 100°C - geothermal energy is perfect for heating, sometimes for business - think of drying things for example - and in terms of energy about 40% of the total primary energy use for the Netherlands is heat! Some 55% of that heat demand is low caloric. By 2020 50% of that heat demand could be geothermal energy. Best start sustainable heating at malls, large office buildings, (tropical-) swimming pools, greenhouses, factories, hospitals and retirement homes ... In short, the biggest heat "consumers”. 

Are water bearing Unlike natural gas, oil, shale gas, coal gas, etc. layers with a suitable temperature below the Netherlands for, see this map with temperatures on 2 KM depth! A geothermal resource well drilling is much cheaper than shale gas: different techniques! 

(map) Temperature at 2000 meters depth © TNO NITG

In the recent past there was speculation among politicians in Holland on the possible combining shale gas wells with geothermal as a bonus once the field are empty. Looking at the major differences in technique as well as the targeted strata in both cases, that’s obviously not viable!
In my view this also means that the idea to exploit a failed shale gas well drilling for geothermal energy instead will not work most of the time because of technical problems. So "pot luck" shale gas drilling thinking it will otherwise be used for geothermal company is NOT a good idea.
Technically it is possible to use geothermal energy from about 60 ° (!) C already to generate electricity  in so-called Binary Cycle power plants. However, they have a low efficiency: about 15% or so and generate 1 MW or less it seems. Good for “individual “ use, buildings etc, but not for the national power grid.

The efficiency for electricity generation from (ultra-)deep wells is currently between 20% and 25% (of the thermal power of the well), because in most every case one has to pump water in and out of the well.
New developments in drilling & well casings will be game changers for geothermal electricity so they need constant monitoring on the status of developments. 

Geothermal energy is, once the well is drilled and the technical installation is in situ there are virtually no operating costs! Depending on usage, a thermal well might eventually be exhausted but if it is economical to pause production, the well will "regenerate".

The near future?!!
This all is still based on drilling techniques that have essentially been in use since the mid 1800’s! But there are revolutionary innovations being developed, they right around the as it were, that will make deep or ultra-deep drilling much cheaper and in double-quick time! Actually; we’re going to need new definitions what deep or ultra-deep is… J
Technically: * laser drilling * and “composite” pipe & casing. Boreholes from 75,000 to 100 THOUSAND foot are already being talked about .. 

This will be HUGELY significant! Most thermal power plants generate electricity by burning fossil fuel, often coal! It will be relatively easy and very cost-effective to replace the boiler part and use geothermal steam instead! Existing plants, already hooked up to the power grid must be quickly made emission-free, starting with the coal-fired ones!

Drilling tunnels will be MUCH faster, cheaper, could be longer… storing nuclear waste at 60 thousand feet or deeper… much will change.


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