Press | Published on 30th Jun 2016

The future is Green

UK Government has recognised the potential contribution of “green gas” in helping the UK meets its renewable energy targets. As a consequence considerable resources are being spent on ensuring better and more efficient delivery of gas, particularly in the R&D of biogas.

There is no definition of what “green gas” is; indeed this is part of the attraction in that there is no winner or silver bullet but instead a range of green gases. Perhaps “low carbon” gas is a better description. 

Biomethane

This is the gas captured from waste processing, typically anaerobic digestion. The technology is proven, it has worked for years. Companies like Severn Trent clean up the Biomethane from their Minworth sewerage works and inject the “green” gas into the grid.

Bio-SNG

A “green” gas that achieves its status because it uses waste materials, usually sent to landfill or incineration, to create the gas. Ofgem have recently awarded National Grid funding to develop a commercial scale plant in Swindon, having seen the success of smaller trials of the technology. The Swindon plant envisages supplying gas for HGVs but there is nothing to stop it being fed into the gas grid for everyday use once it is blended to reach the gas quality standards required.

Hydrogen

Currently produced from natural gas using Steam Methane Reforming, where the carbon can then be captured. It is possible, within existing gas quality guidelines, to mix up to 2 per cent of hydrogen into the blend that flows through the gas grid. Some studies suggest that up to 20 per cent might be feasible – remember this makes the overall mix of gas “greener”. However, Northern Gas Networks are conducting a feasibility study into 100 per cent hydrogen through the gas grid. Their Leeds 21 study is arousing considerable interest on the basis that it envisages using the existing gas grid, conventional heating systems such as central heating in the home but in a completely carbon-free way.

Bio-propane

For the off-grid sector we have biopropane. EUA’s paper on Biopropane demonstrated that this technology could reduce carbon at approximately 40% of the cost to Government of the current RHI.

At a tariff of 1.85p/kWh of delivered renewable heat, biopropane would require less support per unit of heat than any of the existing options without necessitating any change

in behaviour or upfront expenditure by the householder. Moreover, it would provide much-needed support for the deployment of low carbon heat in a sector that has seen limited uptake to existing schemes.

Green gas, whatever the source, offers a viable way forward using our existing gas infrastructure. Estimates by National Grid in their paper “Renewable Gas — Vision for a Sustainable Gas Network” show that around 50% energy demand for heat could be met by biogases by 2050. This in effect could provide renewable heat to all homes on the gas grid.