Ground-source heat pumps and underground thermal energy storage: energy for the future

We need energy for space heating—but in most cases not where or when energy sources are available. Energy storage, which helps match energy supply and demand, has been practised for centuries, also in Norway. Energy storage systems will increase the potential of utilising renewable energy sources such as geothermal energy, solar heat and waste heat. The most frequently-used storage technology for heat and ‘coolth’ is Underground Thermal Energy Storage (UTES). The ground has proved to be an ideal medium for storing heat and cold in large quantities and over several seasons or years. UTES systems in the Nordic countries are mostly used in combination with Ground-Source Heat Pumps (GSHP). Several different UTES systems have been developed and tested. Two types of system, Aquifer (ATES) and borehole (BTES) storage, have had a general commercial breakthrough in the last decades in the Nordic countries. Today, about 15,000 GSHP systems exist in Norway extracting about 1.5 TWh heat from the ground. About 280 of the Norwegian GSHP installations are medium- to large-scale systems (> 50 kW) for commercial/public buildings and for multi-family dwellings. The two largest closed-loop GSHP systems in Europe, using boreholes as ground heat exchangers, are located in Norway

Geothermal-Electric plant offshore using the ELI concept

The technical and economical aspects of the ELI concept for the reutilization of existent oil/gas wells and installations in the North Sea is evaluated. The concept exploits geothermal energy by circulating a fluid in a closed loop thermally connected to a power plant on a platform to generate electricity. The main production costs of the electrical power generated is associated to the drilling of the connecting section between the two existing wells. The ELI concept in the North Sea might only be found economically attractive provided that drilling costs can be reduced by, at least, a factor of 10 compared to present cost level.Norges Forskningsrå

Hydrochemical distribution patterns in stream waters, Trøndelag, central Norway

A regional geochemical sampling program of stream waters has been carried out in the Nord-Trøndelag region of central Norway. This area has hitherto been little affected by regional anthropogenic sources of pollution. Hydrochemical trends appear to be dominated by interplay of two main factors: (i) input of sea salts via marine aerosols in precipitation: and (ii) geological sources (mineral weathering). Factor (i) results in a predominance of Na-Cl waters near the coast, and may also be partially responsible (via proton displacement from soil ion-exchange sites by marine cations) for lower pH values in near-coastal waters. Further inland, the importance of marine salts decreases and waters become dominantly Ca-(Na)-HCO3. Sub-regional anomalies in geochemical maps for, e.g. nitrate and copper may indicate anthropogenic sources for these parameters from agriculture or mining activities

Revised lithostratigraphy of the Mesozoic-Cenozoic succession of the onshore Rovuma Basin, northern coastal Mozambique

A revised formal lithostratigraphy for the Mesozoic-Cenozoic succession of the onshore portion of the Rovuma Basin in northern Mozambique replaces a previous mixture of informal lithostratigraphical and biostratigraphical names. The new lithostratigraphy is based on fieldwork carried out in 2005 by mapping teams from the Geological Survey of Norway (NGU), British Geological Survey (BGS) and the Mozambique Direcção National de Geologia (DNG) , combined with information taken from published papers and maps, and unpublished reports at the DNG made available to the project. The following formations are formally described: Rio Mecole Formation (Jurassic? age), N'Gapa Formation (Jurassic? age), Pemba Formation (late Jurassic and early Cretaceous age), Macomia Formation (Aptian-Albian age), Mifume Formation (Albian (offshore)/Campanian (onshore)-Maastrichtian age), Alto Jingone Formation (Paleocene-Eocene age), Quissanga Formation (middle Eocene to Oligocene age), Chinda Formation (Neogene age) and Mikindani Formation (Neogene age). The thickest accumulation of sediments occurred during the Cretaceous concomitant with intense erosion of the uplifted African interior. The Basin’s geology records the temporal development of the coastline of northern Mozambique and southern Tanzania over the last 200 or so million years. Throughout this period, intermittent, mostly extensional faulting parallel to the approximately N-S to NNW-SSE coastline strongly influenced sedimentation, and the faults remain active along this ‘passive’ continental margin. These faults cut across the ENE-WSW structural grain of the underlying Precambrian crystalline rocks of the East African Orogen. However, transfer faults identified in the offshore part of the Rovuma Basin are parallel to the Precambrian structural grain, and may well represent reactivated major ductile shear zones, e.g. in the area between Pemba and Quissanga

The influence of geology and land-use on inorganic stream water quality in the Oslo region, Norway

Thirty-nine stream and river water samples were collected along a 120 km long transect through the Oslo Rift and the city of Oslo. All samples were analysed for 59 elements (Ca, Fe, K, Mg, Na, Si, Al, As, B, Be, Bi, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Gd, Ge, Hf, Ho, La, Li, Lu, Mn, Mo, Nb, Nd, Ni, P, Pb, Pr, Rb, Sb, Se, Sm, Sn, Sr, Tb, Th, Tl, Tm, U, V, W, Y, Yb, Zr, the anions , ), and the additional parameters pH, alkalinity, colour, turbidity and electrical conductivity. The transect crosses four different lithologies, ranging from Precambrian gneisses, Cambro-Silurian sedimentary rocks (including black shales and limestones) to Permian syenites and granites. Parts of the transect are covered by glacial Drift or marine clays (especially in the south), others are Drift-free. Although varying forms of land-use occur throughout the transect, forestry is predominant in higher elevation, Drift-sparse areas, while agriculture and urban development are more characteristic of low lying areas with clayey Drift. Differences in stream water chemistry are likely to arise from the interrelationship between lithology, Drift cover, landscape, land-use and climate-related factors (different evaporation rates). It is possible to tentatively identify the impacts of marine influence, water–rock interaction, pH-related solubility and lithological influence (e.g. black shales). Even a city of the size of Oslo, which is a major diffuse source of contaminants in southern Norway, and intense agriculture have a limited influence on inorganic stream water quality. Nitrate, however, does appear to indicate human impacts, occurring in some streams in concentrations higher than can be explained by rainfall chemistry. Overall, “natural” element sources and processes dominate surface water chemistry at a short distance from any point source of contamination

Distribution, salinity and pH dependence of elements in surface waters of the catchment areas of the Salars of Coipasa and Uyuni, Bolivian Altiplano

The variation in concentrations of a wide variety of hydrochemical parameters in surface watercourses of the Bolivian Altiplano is statistically characterised. A variation of four to five orders of magnitude is characteristic for several parameters (Al, As, B, Cd, Cl−, Cu, Fe, Li, Mn, Na, S, and SO42−), reflecting (i) evapoconcentration between mountainous watersheds and saline desert evaporative sinks, and (ii) geologically varied sources such as volcanic/thermal springs, fumarolic sulphur deposits and widespread sulphide mineralization. A tendency to increasing salinity from catchment headwaters to the salars is observed. pH values are generally rather high (median 8.3), and exhibit a similar, but weaker increasing trend. Arsenic concentrations are high (median=34 μg/l) and are probably largely derived from volcanogenic sources (fumarolic native sulphur deposits and thermal springs) on the Andean Cordillera Occidental. Arsenic exhibits positive correlations with pH and salinity, indicating its mobility as an oxy-anion under the generally high pH conditions and its susceptibility to evapoconcentration. Arsenic appears to be only weakly attenuated relative to chloride, probably by adsorption onto iron hydroxide precipitates or flocs

The effect of filtration on analyses of surface water samples. A study from the Salars of Coipasa and Uyuni, Bolivian Altiplano

Analyses by inductively coupled plasma atomic emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS) and cold vapour atomic absorption (for Hg, CVAA) of a wide range of elements in some 300 surface water samples from the Salar de Uyuni and Salar de Coipasa catchments of the Bolivian Altiplano have been undertaken. Comparison of analyses of acidified aliquots of unfiltered sample water with water filtered at 0.45 μm reveals that the following elements are not affected significantly by filtration in this high-pH environment: B, Ca, Li, Mg, K, Si, Na, Sr, S. The following elements appear to experience significantly elevated concentrations in unfiltered samples, relative to filtered: Al, (As to a minor extent), Ba, Be, Cd, Cr, Co, Cu, Fe, Pb, Mn, Hg, Ni, P, Ag, Tl, Ti, V. The effect appears to be related to the presence, and subsequent dissolution in acid preservative, of Fe-, Al-or Mn-oxyhydroxide flocs (or coatings on silicate particles) in unfiltered samples, and their retention or precipitation on filters