VILA-SANA, Spain — In one small town in Catalonia, pigs are being trialed as a way to fuel the future of mobility.

As auto majors across Europe push a vision of battery-powered vehicles, Spanish carmaker Seat sees a niche in the market for cars fueled by an alternative: compressed natural gas (CNG). But instead of making CNG from natural gas extracted from wells, Seat is trying out green gas generated from garbage, industrial waste and, on one farm outside Barcelona, pig feces.

“It works like a human stomach, digesting,” said Andrew Shepherd, a Brit who runs the pig project for Seat at a farm in Lleida, a rural region roughly two hours drive inland from the Catalonian capital. He raised his arm to point at multiple domed storage units carrying tons of waste, which emits biomethane that fuels two gas-powered cars parked in the nearby mud.

The €4.6 million research project — partly funded by the EU — converts manure from 1,600 pigs into vehicle fuel to test whether such an energy generation scheme could work. It’s a personal mission for Seat’s fast-rising boss Luca de Meo.

“There is a little bit of a misunderstanding on the potential that battery technology has,” de Meo told a conference on the sidelines of the COP25 climate summit in Madrid last week. “It’s getting there but, before we get an electric car to perform for the customer in exactly the same fashion as a combustion car will do, it will take some time.”

Neumann said that using either biomethane or “e-gas” generated from renewable energy lowers CNG's carbon footprint even more than using natural gas.

Seat already makes cars running on CNG and sales for this year are above 16,000 — a 42 percent increase compared with 2018. Still, that's tiny compared with the 1.15 million new car registrations in Spain last year.

Seat's parent Volkswagen is one of the Continent's leading CNG producers, making 17 models that use the fuel; Italy is the largest market, followed by Germany, Belgium and Spain.

“It is sufficiently proven, immediately available, efficient and cost-effective. Furthermore, CNG cars are not affected by driving bans in city centers,” Stephen Neumann, the Volkswagen Group's head for CNG mobility, said at an event in Berlin earlier this year.

Seat has put €6 million into expanding its giant Martorell car factory near Barcelona to produce 250 gas cars per day, up from 90 at present.

Clean dream

Neumann said that using either biomethane or “e-gas” generated from renewable energy lowers CNG's carbon footprint even more than using natural gas.

That's what the pig trials are testing in Spain; the test also offers a potential solution for a smelly environmental issue. “In Spain, there are more pigs than people and this is an urgent ecological problem,” Shepherd said as the stench of thousands of pigs wafted over the fields around Lleida.

In a country with a strong line in cured meats, figuring out what to do with the byproduct of industrial breeding from 50 million pigs is an important ecological issue. Capturing the fugitive methane emissions seeping out of agricultural waste and using it to power transport offers an attractive narrative.

The project is also getting going as the new European Commission looks for measures to boost clean car sales as part of its Green Deal program.

Seat insists that CNG makes environmental sense. The industry says CNG vehicles emit 25 percent less carbon dioxide than gasoline cars and 75 percent less nitrogen dioxide than diesels, as well as much less of the fine particulate matter that chokes many European cities; they're also as quick to fill up as conventional cars, unlike battery-powered vehicles.

“Seat is committed to boosting CNG as a sustainable alternative to conventional fossil fuels," de Meo said in August. “And thanks to the technology’s compatibility with renewable biomethane, it makes it an important part of the fuel mix as we move towards low emission mobility.”

But getting economical green gas is a problem. Conventional CNG produced from natural gas is cheaper than gasoline but the gas made from biomethane is three times pricier, said John Chamberlain, another Brit working on the Lleida project for Spanish utility Naturgy.

Feces to fuel

At the Vila-Sana site, some 7,500 tons of pig excrement along with the same weight in other agricultural products and 700 tons of wet industrial rubbish are dumped into the roughly two-story-tall storage domes. That's heated to 35 degrees Celsius and left to ferment in anerobic conditions for around 30 days. The methane gas that seeps out is then refined at the site and turned into CNG.

Shepherd says the mini plant generates 150 cubic meters of gas per hour — enough to power one of the test cars for 2,500 kilometers.

There will be 80 public CNG stations in Spain by the end of this year, hardly an expansive network and far below the thousands of electric charging posts popping up across the country.

However, green groups are wary of CNG. One reason is that they don't see a long-term use for natural gas — a greenhouse gas-emitting fossil fuel — albeit one that's cleaner than diesel or gasoline. The use of biomethane is supposed to allay those fears, but even there environmentalists question if using green gas for transport makes sense.

Carlos Calvo Ambel, from the NGO Transport & Environment, argued that even if all the pig excrement in Spain was collected, it would cover only around 4 percent of Spain’s gas demand. The maximum technical capacity of biomethane production from all sources would meet 8 percent of demand, he said.

"Biomethane should be used by sectors already using natural gas today, like heating or industry," said Ambel. "Stating that biomethane will be available in large amounts in the future is simply a Trojan horse to increase the market share of CNG cars in Spain."

CNG does have other drawbacks. The cars are also more expensive than conventional ones, and there's a lack of refueling stations.

There will be 80 public CNG stations in Spain by the end of this year, hardly an expansive network and far below the thousands of electric charging posts popping up across the country. Italy has the most in the EU, with 1,310 stations, followed by Germany with 843, according to the Natural & bio Gas Vehicle Association.

To kick-start an industry, Seat and utilities need to team up to underwrite demand, said Ramon Damingo Melgos from Ecobiogas, a company that handles the conversion process from the fuel fermenting in the domes at Lleida to the finished gas pumped into cars.

“If the government helped it would be easier,” he said of the need for public support to promote the biomethane for transport industry. “If they don’t do it the electric cars will overload everything."

The EU’s Deployment of Alternative Fuels Infrastructure Directive calls for member countries to make CNG refueling points available at 150-kilometer intervals along main highways by the middle of the next decade, although progress on that target is slow. Strong demand for CNG cars would allow a greater scale for biomethane projects and cut production costs, Shepherd said.

That’s prompted the Spanish government to try to boost sales by offering generous tax and eco-labeling for CNG cars (which allows them to drive into city centers) — but green groups complain that those subsidies are misdirected.

If there’s not enough pig waste to power a transport revolution, another ready energy source could be the millions of tons of household waste Spaniards toss out each year.

“In the absence of these two [taxes and eco-labeling], CNG cars would have no future in Spain,” said T&E's Ambel, arguing that Madrid needs to move to end support for gas cars. “It is not a question of public demand, but of public policy. The next Spanish government needs to fix this public health and environmental problem.”

The biomethane trial will conclude in 2023. Shepherd’s team will then take apart the test cars to see what the effect of biomethane on their components.

If there’s not enough pig waste to power a transport revolution, another ready energy source could be the millions of tons of household waste Spaniards toss out each year. The country sent almost 54 percent of its garbage to landfills in 2017, but EU rules call for that to fall to 10 percent by 2030. With around half a million landfill sites in Europe, the project could offer a new way of handling waste.

Eline Schaart contributed reporting.

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