Enex

Geothermal Power Plant

Enex' owners Geysir Green Energy, also hold a majority stake in HS Orka that owns and operates direct steam power plants for power production. Their first plant went into operation in 1978. These power plants use steam from geothermal reservoirs that yield up to 320 °C.

Benefits

• Sustainable energy production for urban or rural areas
• Boosts rural economies
• Minimal impact on the environment
• Money spent at home that provides earnings for over 30 years
• Baseload electricity generation, high reliability and availability
• Ecological energy production, minimizing CO₂ release and improved air quality
• Design, engineering, efficiency analysis, construction and training can all be performed by Enex 
• Aesthetic design, minimal and reversible impact on the landscape

Results

• Areas become less dependent on polluting and increasingly expensive imported oil & fossil fuels, which are replaced with a renewable alternative as well as stable energy prices
• Less reliance on imported oil & fossil fuels, hence, more money invested in local manufacturing and knowledge for domestic companies in the area
• Clean, efficient, cost-effective, renewable energy that can benefit from government-supported programmes and CO₂ savings. The respective CO₂ emmissions savings can then be used for emissions quota trading
• Utilizing existing geothermal heat to produce electricity up to 50 MWe pr. unit and energy prices remain stable 
• Possibility of incorporating district heating for communities (CHP)
• Minimal visual impact 
• 38 years of experience ensures proven solutions 

What conditions are necessary for an Enex Geothermal Power Plant?

• A steady source of heat, such as from geothermal fluids, anywhere from 180 °C and higher 
• Supply of make up water or adequite ambient conditions to support dry cooling

Process

The geothermal fluid reaches the surface normally as a two-phase mixture of steam and water. The steam is separated from the liquid brine and enters the turbine while the liquid (unflashed) brine is piped from the plant for re-injection. If applicable, the liquid brine can be used to generate power (e.g. in a binary power plant) or for heating (e.g. for district heating) before being re-injected into the geothermal reservoir.

Figure 1: Simplified schematic for a single-flash power plant

The water fraction of the mixture must be removed before the fluid is sent to the turbine, both to increase the gaseous flow and to avoid damage to the turbine. During this separation of the steam and liquid, the enthalpy remains constant.

The gaseous flow is then directed to the turbine where electricity is generated. A double flash cycle can be applicable if the brine temperature and pressure are adequate; the medium pressure steam from the second flash chamber is injected to the turbine at an intermediate stage.

The steam exits the turbine as a saturated mixture and enters the condenser. The liquid brine exits the condenser and can be injected back to the ground or used for heating where it applies.

Different cooling systems are available in geothermal flash power plants, such as:

• Wet cooling tower
•  Air cooled condenser
•  Direct water cooling.

Selection of cooling system depends on the availability and the nature of cooling media at the proposed plant site.

Enex Approach

The Enex approach achieves high customer satisfaction while emphasizing environmental solutions. As geothermal and hydropower experts, Enex looks at several ways to structure its approach to each project, for example:

Lead Investor
Design, build and operate geothermal/hydropower plants or district heating systems. Enex may sell or transfer the plant at a predetermined date. These contracts can be BOOT (Build-Own-Operate-Transfer), BLT (Build-Lease-Transfer), BOT (Build-Operate-Transfer) or BOO (Build-Own-Operate).

Solution Provider
Engineering, procurement and construction of geothermal/hydropower plants on turnkey basis. Enex provides the equipment, expert technology and geothermal experience while teaming up with strong domestic contractors to build and install power plants or district heating systems. 

Joint Venture
Team up with strong local partners such as developers or contractors. Form a joint operation company with our joint venture partner based on interest, ability and areas of strength.

Enex Geothermal Power Plant Proposal

To receive Enex Geothermal Power Plant Proposal all necessary info has to be available. Such as: 

• Information on source. Temperature, pressure, mass flow and chemistry 
• Ambient Data 
• Availability of cooling water

If your site is on development stage and therefore not all information available then you can contact Enex Project Development.

After receipt of tender, including all necessary data, Enex will deliver the complete proposal within two months time. Presented in the Enex Geothermal Power Plant Proposal are the power production potential (gross and net), efficiency, sizing of main components and binding financial offer as well as detailed description of boundaries and contract proposal.

Design

Design builds on engineers collectively sitting on decades of experience as well as gained experience from Icelandic geothermal power plants, such as Nesjavellir, Krafla and Svartsengi geothermal power plants.
Enex emphasizes flexibility, taking careful consideration to environmental factors such as chemical, visual and noise pollution.