Geothermal electric power stations are generally located where high temperature geothermal resources are available near the surface, often near areas where there are natural hot springs. Geothermal power stations pull hot water / steam from the ground, use it to run turbines and then return the water back to the original source. The three basic designs for the geothermal power stations are:
• Dry steam – steam goes directly from the ground to the turbine
• Flash steam – hot water is “depressurised” in to steam that then dives the turbine
• Binary cycle – hot water is used to heat secondary liquid, one with the lower boiling point than water. Using secondary liquid allows for production to be varied, can be increased or decreased multiple times each day, so energy produced can match actual demand.
Geothermal energy systems offer a cleaner, more sustainable renewable energy, that can supply regular, continuous power but it can still have negative impact on the environment, people and wildlife. Water, air and land can be affected. Water pumped from underground contains high levels of harmful chemicals like sulfur, so it is important to ensure that used water is not returned in to the environment. The power stations that have a loop air system emit gases from the extraction well, like hydrogen sulfide, known to smell like rotten eggs, into atmosphere.
The problem with hydrogen sulfide (H2S) is that when in contact with the oxygen in the air (O2) changes into sulfur dioxide (SO2). 2H2S + 3O2 «–» 2SO2 + 2H2O
Sulfur dioxide is found to cause heart and a lung disease, acid precipitation, which then damages plants, soils and acidifies water bodies. Pumping large amounts of water from the geothermal reservoir can cause land surface to sink and use of fracking process increases already high risk of earthquakes. The constant monitoring and reporting is imperative when a geothermal power station is located near populated areas.
Firstly, there will be a requirement to monitor the weather in the area using Tier 2 weather station equipment to record the ambient conditions, especially wind speed and direction, so there is good knowledge of the general wind conditions to make sure emissions from the plant are not being carried by the wind to areas of population, such as a local town or city. There may be the need for one Tier 2 to be installed at the plant and at each perimeter fence of the facility to get a good reading for the local area.
Unidata supplies various weather station instruments, either a multifunction ultrasonic weather transmitter, which is very convenient to install, as well as separate discrete weather instruments. For this application, the simpler ultrasonic weather transmitter would most likely be the best choice for the application. To provide telemetry option, a Neon Remote Logger can be connected to each weather station and be set up to read the instruments every minute, store the raw and average readings every 5 minutes, and then transmit the data to a central Neon Server every, say, 15 minutes.
As well as weather station equipment that measures weather conditions such as wind speed, direction, humidity, temperature, solar radiation etc, there would also be a requirement to add additional instruments to measure the presence of noxious gases and seismic activity. There are many manufacturers of gas monitoring equipment. One such manufacturer is Dräger and there are sensors to measure noxious gases such as CO, CO2, NO, H2S, SO2 as well as O2and N. These instruments typically provide a 4-20mA analog output or a Modbus output which can be read by Neon Remote Logger routinely, perhaps every minute and then routinely send the data to the Neon Server every 15 minutes. The system could also be equipped with a ground seismic monitor to take daily readings of seismic activity. This way, so a clear pattern of the base level of seismic activity can be determined, and then used as a reference for monitoring the effects of the geothermal power station activities.
The Neon Remote Logger scheme / program can also be set up to check parameters each minute and raise an alarm and an immediate transmission to the Neon Server in the event of any reading is outside it’s preset limits. The Neon Server can also be set up with alarm actions, to notify staff by email or text, with an escalation process, of any out of limits conditions. As well as the immediate actions to deal with for high / dangerous gas levels, data can be analysed and long term trends can be determined to help minimise environmental impacts and optimise production.
Finally, water quality measurements for any outflows can be important, so a water quality instrument on any outflows would allow outflows to be checked for quality, to maintain environmental compliance. These instruments can also be connected with a Neon Remote Logger to the central Neon Server, either with a radio link, or buy connecting directly into the plant network using an Ethernet cable.
|Options for Application Specific Instruments / Inputs||Unidata Part Number||Description|
|Drager Gas Detection Instruments||Drager MiniWarn||CO2/CO Gas Monitor|
|Vaisala Weather Transmitter WXT536||6501V-H||Vaisala Weather Transmitter measure barometric pressure, humidity, precipitation, |
temperature and wind speed and direction
|Temperature Thermistor Probes||6507E||Red Thermistor Probe 3K@25C with requested cable lengths|
|Linear Temperature Probe||6535A||Temperature Probe LM34 with requested cable lengths|
|Humidity and Temperature Probe||6539B||Humidity and Temperature Probe|
|Rain Gauge||6506C||Rain Gauge/Tipping Bucket|
|Mounting Arrangement for Temperature Probes||6704A||Radiation Gill Screen and Mounting - Full Size|
|Mounting Arrangement for Temperature Probes||6704B||Radiation Gill Screen and Mounting - Half Size|
|Radiation Sensor||7241C-A||Pyranometer Sensor – Solar Energy|
|Mounting Arrangement for Pyranometers||7241M||Pyranometer Sensor Instrument Mounting and Hardware|
|Four Electrode Conductivity Instrument||6536E||4EL Water Conductivity Instrument|
|Four Electrode Water Conductivity Probe||6536P-2-X||4EL Water Conductivity Probe with 10m, 20m, 30m or 50m of cable|
|Options for Neon Telemetry - NRL / NRT / RTU / Field Units||Unidata Part Number||Description|
|Neon Remote Logger 16 Channels||3016A||Options Available: 3G/4G Cellular, Ethernet, Globalstar, Inmarsat, Iridium SBD and LoRa|
|Neon Remote Logger 8 Channels||3008A||Options Available: 3G/4G Cellular, Ethernet, Globalstar, Inmarsat, Iridium SBD and LoRa|
|Neon Remote Logger 4 Channels||3004A||Options Available: 3G/4G Cellular|
|Neon Remote Logger 4 Channels M Series||3004A-M||Options Available: 3G/4G Cellular, Ethernet, Microsatellite, Iridium SBD and LoRa|
|Cellular RTU 3G/4G||2013F-AB03 / 2013F-AB04||Neon Metering Module 3G/4G with Antenna and Li Battery|
|Cellular RTU 3G/4G - Industrial||2016F-AB03 / 2016F-AB04||Neon Remote Terminal 3G/4G with Antenna and Li Battery|
|Ethernet||2017F-0B0-1 or 3||NRT Ethernet with single or triple Ethernet Ports with three Li Batteries|
|Equatorial Orbit Satellite - Inmarsat||2018F-AB0-1 or 3||NRT Ethernet with single or triple Ethernet Ports with three Li Batteries|
|LCD Display||2500E||NRT LCD Display|
|NRT Field Termination Strip||2103F||2015F,2016F,2017F, and 2018F NRT FTS|
|NRT Firmware Option||2303A-8M||8M Extended Memory Option|
|NRT Firmware Option||2303A-8M-CAM||8M Extended Memory & Serial Camera Option|
|NRT Firmware Option||2303A-CAM||Serial Camera Option|
|Options for Neon Application Software - Customer Server||Unidata Part Number||Description|
|Neon Application Software||2302A||Neon Server Software Licence Incl 5 NAL |
|Neon Application Software||2302A-10||Additional 10 NRT Access Licences|
|Neon Application Software||2302A-20||Additional 20 NRT Access Licences|
|Neon Application Software||2302A-50||Additional 50 NRT Access Licences|
|Options for Neon Application Software - Unidata Server||Unidata Part Number||Description|
|Neon Application Software||2301A||Neon Data Initial Subscription Setup Fee|
|Neon Hosting Service||2301A-01||Neon Data Service Fee for 1-50 NRTs|
|Neon Hosting Service||2301A-02||Neon Data Service Fee for 51-100 NRTs|
|Neon Hosting Service||2301A-10||Neon Data Service Fee Metering|
|Options for Conventional Dataloggers / Field Units||Unidata Part Number||Description|
|Neon Remote Logger 16 Analog Channels / Touch Screen Display||3016A-000||16 Ch NRL (Superseded Prologger 7001D)|
|Neon Remote Logger 8 Analog Channels / Touch Screen Display||3008A-000||8 Ch NRL (Superseded Stalogger 6004D)|
|Neon Remote Logger 4 Analog Channels / Touch Screen Display||3004A-000||4 Ch NRL (Superseded Micrologger 8010C)|
|Starlog V4 Management Software||6308A-AUE||Starlog V4 Full Licence Key|