Renewable methane offers a solution to fuel security and to the problem of waste disposal.
In the search for alternatives to gasoline and diesel for fuelling Europe's vehicles, renewable methane is making a strong challenge with new high performance cars and vans coming to market in Germany in 2008. This article reviews the overall UK energy market and shows the significant developments that are taking place in relation to transportation.
The UK has a very mature gas market, with a network valued at around US$ 50 billion and with more than 90 per cent of all UK consumers having a gas supply. 90 per cent of the UK's heating energy and 50 per cent of its electricity generated comes from natural gas. The third source of demand for energy-transportation - is 99.9 per cent based on petroleum. The total energy from renewables is around 1.5 per cent of the total, with a long way to go for the UK to meet the target of 15 per cent agreed with the European Union (EU) for 2020.
The UK Government supports a high price for carbon to make it 'less economic' to use coal and natural gas for power generation and to support the relaunch of a nuclear electricity generation industry in the UK. This industry has seen a decline in recent years as nuclear generation plants built in the 1960s have been closed down. A high CO2 price with obligations on electricity suppliers to source an increasing proportion of their generation from renewable sources, also supports investment in renewable energy including wind and biomethane.
The key initiatives taken by the UK government to address a major challenge of achieving the 15 per cent renewable target by 2020, are:
Although there are many options for electricity generation and heating homes, the greatest challenge has been running vehicles on something other than gasoline or diesel. During 2004-2007, biodiesel and bioethanol were seen as better alternative fuels.
Unfortunately, a raft of reports in the last three months indicate major difficulties with first generation biofuels made from vegetable oil, sugar cane and wheat. As a result, the UK Government has launched an enquiry into liquid biofuels and the EU has admitted that its policy may be flawed and there are growing concerns related to overall CO2 performance (biofuels may not be very effective and may even increase global warming emissions), sustainability (accelerated rain forest destruction) and impact on world food prices. The EU has recognised that the biofuels target of five per cent by 2010 may be unhelpful for the planet. Against all that background, something transformational is happening with respect to biomethane as a fuel for vehicles. The key of course, is the vehicle.
The first natural gas vehicles developed in the UK in the 1990s were petrol vehicles converted to run on natural gas. The first filling stations were built on the site of British Gas depots located on local 'gasholders' where gas is stored. Unfortunately, the gas was 'wet' and led to problems with both the vehicles and the filling stations. It is only now that the UK NGV industry has been able to get over the poor CNG experiences that it had as a 'first mover' in respect to NGVs.
Taking advantage of developments in Europe, UK is restarting the CNG industry. On March 03, 2008, at the Biomethane for Transport Conference, Mercedes Benz and Volkswagen announced that they would make available the new CNG vans, developed for the German market, in the UK.
The MB Sprinter CNG is being launched in Germany in June 2008 and will be available in the UK (in right hand drive form) by end 2008. Its key characteristics are:
VW's Caddy Ecofuel, a car developed by Volkswagen that runs on CNG, will also be available in right hand drive form in the UK by Q4 2008, with its key characteristics as follows: Runs on CNG but also has a back up petrol capability
In addition, MB announced that the CNG Econic was now available in the UK in right hand drive form, with a number of alternatives:
The rigid is put to trials by a major UK supermarket group, with major advantages due to significantly lower noise which allows it to run into London during the night (when diesel trucks are banned due to noise). This will avoid congestion and save significant time, as well as having EV standard emissions, far cleaner than any diesel vehicle.
There are no plans for the UK to follow the German model, which aims to have 1000 CNG filling stations by 2009 (750 at present), used by around 100,000 cars and vans. Instead, the UK is following a depot-based model, with CNG filling stations built at utility depots and distribution centres. CNG Services has worked with a number of companies to identify that significant benefits can be achieved by replacing existing diesel vans with CNG ones.
In addition, Canadian company FuelMaker is testing Phill, a home refuelling device, and fuel provided by Mouchel plc and CNG Services Ltd., with VW's Caddy Ecofuel. This will potentially offer a CNG option to home based technicians who do not visit a depot.
The UK produces the largest volume of renewable methane (biomethane) in Europe, around one million tonnes of oil equivalent. This arises because the UK disposes of around 40 million tonnes per annum of organic waste by putting it into landfill. There it decays into methane, which is captured and burnt in reciprocating spark ignition engines to make electricity, at an average thermal efficiency of around 30 per cent. Even though efficiency of this form of electricity is poor, it receives a renewable premium of around US$ 90 per MWh. The UK government has recognised that it is not efficient to waste 70 per cent of the energy from the biomethane and is consulting the industry for amendments to legislation that would maintain the financial incentives for biomethane production, but allow the gas to be injected into the gas grid and consumed in higher efficiency applications or used to displace gasoline as a road fuel.
The regulations in UK allow renewable methane to be injected into the gas distribution network and this is seen as a highly efficient way of getting this gas to consumers, whether for vehicle use, for heating or electricity. The renewable gas must meet the quality specification of the distribution network with the following contaminants removed in a clean-up process:
Next, the gas has to meet a minimum calorific value (CV) which is in the range of 38-41MJ/m3. This is likely to require enrichment with small volumes of propane as the renewable methane has a CV of around 36MJ/m3. The gas has to have a characteristic smell added (i.e. an odorant), which is added via a 'wick' system, with a small amount of smell added as gas flows over the wick. All these processes are relatively straightforward and can be carried out by skid-mounted equipment. Once the gas meets the necessary quality standards, it is metered and injected into the gas grid.
The UK currently disposes of 30-40 million tonnes of organic waste to landfill each year. Even if 25 per cent (10 million tonnes) of this is diverted to AD, nearly 400,000 tonnes of renewable methane would be produced. This requires around 200 ADs, each processing 60,000 tonnes of organic waste and making around 2,000 tonnes of renewable methane. Each AD could fuel around 120 Econic tractors doing 80,000km each or around 2600 Caddys each running 15,000km.
It is a compelling vision: Supermarket waste to AD to gas grid to Supermaket Delivery vehicle. In the UK, this is set to transform the waste industry, reducing oil imports, air pollution and noise, with increasing energy security at the same time making a significant contribution to the UK target of producing 15 per cent of energy from renewable sources by 2020.
John Baldwin is the managing director, CNG Services Ltd. He holds C Eng M I Mech E, M I Gas E, MA (Oxon) degrees. John is a former president of the Society of British Gas Industries and is the director of Natural Gas Vehicle Association. Baldwin, a graduate engineer from Oxford University, has worked in various designs, operational and commercial roles in British Gas.
