Did you know… there is a place where the bath water never gets cold?

Did you know... there is a place where the bath water never gets cold?

Something you might not know about Bath, England is that it was named for the thermal hot springs used as Roman baths. The natural springs were first discovered by Prince Bladud and his pigs around 863 BC. It is said he was cured from a skin disease (leprosy) after bathing in the healing waters. Subsequently, the baths were used by the Celts, Saxons, Georgians, and, of course, the Romans.

In the 17th and 18th century fashionable society found it very popular to bathe in the hot springs because of the perceived health benefits.

In the heart of the city, there are three natural springs. The biggest and most notable one is the King’s Spring, which is located in the Roman Baths Museum. The other, smaller springs, Hetling Spring and Cross Bath Spring are about 150 m west of the King’s Spring.

The thermal waters contain dissolved salts from over 40 different minerals, leading to elevated concentrations of calcium, sulphate, and chloride. The deep mineral-rich water has a constant temperature of at least 45˚C (113˚F) and the flow is approximately one million liters per day, supplying the four baths at the Thermae Bath Spa.

The bath water comes from rainfall that percolates through the soil into the underground limestone aquifers between 2,700 and 4,300 meters (8,900 and 14,100 feet) deep. Once heated, the water becomes buoyant and it flows upwards through fissures and faults to reach the surface and the baths. The hydrothermal system that provides hot water to the baths resembles an Enhanced Geothermal System (EGS), wherein hot rocks transfer energy to cold water to create geothermal power.





Word of the Week – Rhyolite


Light colored fined grained volcanic rock composed of glass, quartz, K-feldspar and plagioclase, with relatively high silica (69-77 wt %). The composition reflects partial melting of continental crust. Rhyolitic volcanism is a feature of both Yellowstone (USA) and the Taupo Volcanic Zone (New Zealand) where geothermal activity is widespread.  The intrusive coarsely crystalline igneous rock equivalent is called granite.

Word of the Week – Basalt


Dark grey fine grained volcanic rock composed of plagioclase, pyroxene and olivine, with relatively low silica (45-52 wt %). The composition reflects an upper mantle origin. Basalt is the most common type of volcanic rock on Earth, and it erupts from mid-ocean spreading ridges and hot spots (e.g., Hawaii and Iceland). The intrusive coarsely crystalline igneous rock equivalent is called gabbro.

Did you know… three of the largest geothermal power plants in the world are found in Indonesia?

Did you know… three of the largest geothermal power plants in the world are found in Indonesia?

Indonesia is home to beautiful tropical islands, a rich and vibrant culture, and geothermal power plants! The first exploration geothermal wells were drilled in the 1920s, but the first power production did not start until 1978 at Kamojang. Today, there are over 17 producing fields, including three of the world’s largest.

The biggest is called Gunung Salak, which is located 70 km from Jakarta, the Indonesian capital, on the island of Java with an installed capacity of 377 MW. The field was drilled and put into production by Unocal in 1994 and later acquired by Chevron in 2005. In December of 2016, the field was taken over by Star Energy. Electricity is generated and sold by the state-owned company, PLN.

The second biggest field is Sarulla. It generates 330 MW of electricity and is based in the Tapanuli Utara district of the North Sumatra Province. The project is owned by the Sarulla Operations Limited consortium and electricity is generated  by three units of 110 MW each. The first unit was commissioned in March of 2017 and the second in October of the same year. The third unit was commissioned in May of 2018. Geothermal power supplies electricity to approximately 2.1 million homes.

The third largest geothermal project is Darajat which is located 270 km southeast of Jakarata near Garut in the Parirwangi District of West Java. The installed capacity is 271 MW and the resource was initially developed by Amoseas, later acquired by Chevron and since 2016 it has been run by Star Energy. The first power generation commenced in 1994, with the commissioning of a 55 MW unit. A 95 MW unit was commissioned in 2000 and a third unit capable of generating 121 MW was commissioned in 2007.

It is no wonder Indonesia is the second largest producer of geothermal energy in the world, with huge potential for additional growth.





Word of the Week – Packers and Plugs

Packers and Plugs

Downhole devices emplaced into a well to seal zones and intervals so they can be pressurized by pumping fluid from the surface in order to stimulate fractures at a specified location. They are designed for temporary and permanent deployments, depending on operational requirements, and they are commonly used for zonal isolation.

Did you know… Italy is home to the oldest geothermal plant in the world?

Did you know… Italy is home to the oldest geothermal plant in the world?

The first geothermal plant in the world is located in Tuscany, Italy.

The Larderello geothermal plant was constructed in the early twentieth century thanks to Prince Piero Ginori Conti of Trevignano. Through his work in the processing of boric acid, Conti found his way into the world of geothermal energy and, in 1904, created the first geothermal energy generator.

Stationed in the Larderello dry steam field, his generator could produce up to 10 kW of energy. It also powered five light bulbs.

From there, Larderello’s geothermal potential expanded. In 1911, in an area called Devil’s Valley, construction of a geothermal plant was begun. The plant was completed in 1913.

That first plant, Larderello 1, had a capacity of 250 kW and could produce 2750 kW of electricity. That electricity powered the Italian railway system as well as the nearby villages of Volterra and Larderello.

The original plant has been gradually expanded over the years and now consists of 34 plants, which are operated by the Italian company Enel Green Power, or EGP. The site has a capacity of 800MW, which has resulted in Italy becoming the sixth-largest geothermal energy producer in the world.