Salah satu usaha manusia dalam mengurangi pemanasan global atau penggunaan listrik PLN yang berbahan bakar fosil adalah dengan penggunaan sel surya. Pemasangan sel surya ini efektif karena wilayah Indonesia berada di daerah tropis. Penggunaan sel surya di Pondok Pesantren Nurul Iman sangat membantu karena kebutuhan energi listrik di Pondok Pesantren Nurul Iman sangat besar. Hal ini dapat dihitung dari biaya yang dikeluarkan per bulan oleh Pondok Pesantren Nurul Iman, pada bulan Agustus 2015 sebesar Rp. 1.372.100,-. Dengan audit energi dapat dikurangi beban yang digunakan sebesar 1.250 watt. Kalau penggunaan lampu rata-rata 12 jam listrik dapat dihemat sebesar Rp. 436.271,- per bulan. Penghematan lampu dengan surya sel yang dapat dilakukan sebesar Rp. 77.555,- per bulan. Lebih dari sepertiga yang dapat dikurangi biaya listriknya dengan sel surya.

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Mapping geophysics research was conducted by geomagnetic method to know anomaly pattern of magnetic pole and to know distribution location and depth of temple gate composing stone in Losari Temple Site by using magnetic data. Data collection used Proton Precessions Magnetometer (PPM) G-856AX by area width of 88 km x 40 km and measurement space of 3 meter used looping method. Field data was corrected by daily variation and IGRF (International Geomagnetics Reference Field) correction and then reduction to pole. The slice modeling was conducted on local anomaly map on height of 6 meter. The result of the local magnetic field anomalies incision then interpolated to get an idea of the spread and depth of rocks making up the fence Losari temple. Local anomaly map shows that anomaly position lies in southwest, southeast, and northeast from main temple. Based from interpolated distribution of magnetic pole anomaly is dominated in depth of 2 meter to 4 meter.

Landslides occur due to the field of slip. Identification of Soil Landslide Identification Using Geolistrik Method The Wenner configuration has been done in Gayamharjo Village, Prambanan Sub-district, Sleman District. This study aims to determine the structure of subsurface rocks and identify the field of ground slip in the landslide prone areas in the study area. Measurements were made as many as 3 trajectories, the smallest spaced between 20 meters electrode with 300 meters of track length. The tool used is Syscal Jr Switch-48. Data processing uses RES2DINV software that produces 2D subsurface modeling. The results of the interpretation showed that th e location of the study identified the constituent rock consisting of three layers of subsurface rocks (1,36 to 6,86) Ωm, sandstone (15,4 to 34,6) Ωm, and andesite rocks (77, 8 to 393) Ωm. In the three trajectories of the research area, there is a slip field with th e potential for landslide: track 1 at point 40 s.d.80 with a depth of 37 m, track 2 at point 220 s.d. 240 with depth 26 m, path 3 at point 100 s.d. 140 with a depth of 37 m.

Indonesia is an archipelago country so rich with coral reefs that are a major component of the carbonate rock constituents. Where as much as 40% of carbonate rocks in Indonesia is a hydrocarbon reservoir is still rarely done exploration. This is because conventional hydrocarbon exploration technology has not been able to provide detailed information about the physical quantities. Hydrocarbon exploration technologies currently leads on digital technology to know the physical quantities of a reservoir of more detail such as porosity. Porosity which is physical quantities related to the presence of hydrocarbons in the pores of rocks. Digital Rock Physics (DRP) is a digital image-based method as an alternative method to find the physical quantities of rock samples to make it more effective and efficient. This study aims to identify the physical quantity using the method of porosity of the DRP until obtaining porosity of rock core carbonate reservoir by analyzing the binary image of the two rock cores from the same reservoir but has different dimensions to find out the exact core rocks to analyze the value of porosity. Binary image obtained from a scanned image of a projection of rock that has been reconstructed to become the greyscale image and have gone through the process of thresholding. The results of this study showed that the method can identify the physical quantities of DRP porosity and non-damaging rock pore structure (non-destructive). Analysis of the porosity of the rock core with histogram variations performed (by adjustingting the histogram), using the otsu method of thresholding and pixel size of the image has high (5.343750 μm) used to analyze the value of porosity. The porosity values acquired for 18.040 and has precision 96.20%.