Standards Development

Scope

This Technical Report describes the metering challenges and approaches to the measurement of wet gas flows as required by renewable energy applications, e.g.. hydrogen with entrained water flow, gas / liquid carbon dioxide flow, wet biogas flow, and geothermal saturated steam flow.

The energy industry that developed and used wet natural gas flow meters has broadened its interest and activity into renewable energy related wet gas flows, e.g. hydrogen storage, geothermal steam, carbon capture and storage, biogas wet gas flows.

Hydrogen extracted from storage has entrained water, carbon capture flows are often processed close to the phase boundary producing wet gas flow, biogas is often wet, some solar field designs have wet saturated steam flows, and geothermal power plants receive wet saturated steam from the geothermal wells. All applications lie outside of the scope of wet natural gas metering standards documents yet are analogous.

There is dearth of information in the literature on how to approach such wet gas metering. However, some of the wet gas metering technology developed by the hydrocarbon production industry is applicable. This technical report discusses the wet natural gas metering technology applicable to such applications, inclusive of discussing the similarities and differences, and the pros and cons of different methods.

Purpose

The energy companies are increasingly working in renewable energy projects. These projects produce various wet gas flows that must be metered to achieve maximum process efficiency. Presently, there is no guidance on how to approach such renewable process wet gas metering. However, the same energy companies developed and use wet natural gas flow metering technology which is described in ISO TC 193 SC3 WG 2’s TR 12748 (which will soon be converted to a TS).

It is recognised that the same technology could and should be utilized in these renewable energy / environmentally friendly based processes. However, presently the TC 193 SC3 WG2 wet natural gas metering document TR 12748 that contains this technology description is explicitly titled as a natural gas document thereby giving the misleading impression the technology it describes is not applicable. TR 12748 is presently being updated to include the latest information on single phase gas meter response to wet gas flows. This new information is directly transferable to this proposed renewable wet gas meter document. However, the TR 12748 updated text will be wide ranging and has many sections that are not relevant to the renewable wet gas metering issue. Hence, it is proposed that TC 193 SC3 WG2 should produce a separate standalone document that transfers the relevant information and converts the wording such as it is explicitly for these renewable based processes.

The subject was first brought up to TC193 SC3 WG2 by the French delegation, specifically discussing the problems of metering hydrogen storage extraction when it has entrained water. This hydrogen is a natural gas substitute in the form of a power to gas system. It is therefore within the TC 193 scope.

The TC193 SC3 WG2 convenor added that there is an increase in wet bio-gas metering requirements in North America. This is a natural gas mixture and in the TC 193 scope. The convenor further commented on the Carbon Capture and Storage issue if CO2 often being processed close to the phase boundary and wet CO2 flow metering therefore being an industry problem. This CO2 is captured from natural gas combustion, so it is on the border of the TC 193 scope, with the metering technology used taken from wet natural gas metering technology.

Landsvirkjun, the Icelandic power company, has subsequently offered support to the idea of geothermal industry wet steam flow metering technology being included. Whereas this specific topic is not within the TC 193 existing scope, the technology being adopted is that of the natural gas industry. It should be noted that the various uses of wet gas metering in industry are rather eclectic and as such the topic of renewable energy wet gas metering will not fit neatly into any ISO committee. As all wet gas metering is approached with similar methods, there is an obvious advantage of having one renewable energy wet gas metering document. With most of the renewable energy wet gas flow metering applications being associated with the natural gas industry, with the subject matter specialists already involved with and aware of TC 193, and with the TC 193 TR 12748 update going to contain much of the same technology, TC 193 is an excellent choice for this proposed document.