While energy crops alone won’t secure a fossil fuel-free planet, they do represent an enormous opportunity to curb our dependence on harmful fuels. Experts predict these crops will contribute significantly to the world’s renewables portfolio in the not-too-distant future, but obstacles currently blocking market penetration make growing or using energy crops a risky endeavor.
Daring though it may be, the potential is hard to ignore. Using imaging assessment models, research has indicated that in the year 2050, energy crops worldwide could supply about 400 exajoules of energy per year. For those not familiar with that enormous quantity, an exajoule represents 1018 joules. In a newer analysis, more conservative estimates peg the realistically achievable potential for energy crops by 2025 at between 2 and 22 exajoules per year.
These and other research figures have been compiled in one study to evaluate the current status of energy crops and their conversion technologies, assess their potential to contribute to global energy demand and climate mitigation over the next few decades, and examine their potential for the future. The study, “Energy crops: current status and future prospects,” suggests that realizing the massive potential of energy crops will require optimizing—not maximizing—dry matter and energy yield per area of land through the latest biotechnological routes.
“The idea of putting this study together was to pull together all the information on what we know so far; what potential we might get, and how much energy we can generate in this sector,” says Pete Smith, one of the five study authors and professor of soils and global change at the University of Aberdeen’s School of Biological Sciences in Scotland. “Biomass and bioenergy won’t fulfill all energy needs, but will be part of the portfolio.”
In this energy-dependent world, as developing countries get richer, their demand for energy will grow. “We can’t possibly supply all of their energy with fossil fuels,” Smith says. “So we’re going to need to rely on renewables and there is no one renewable technology at the moment that can meet our energy needs.”
Globally, biomass currently provides about 46 exajoules of energy in the form of combustible biomass and wastes, liquid biofuels, renewable municipal solid waste, solid biomass, and gaseous fuels, the study says. Increasing current biomass potential will require changes to agricultural and forestry production, and the active growth of dedicated energy crops. “We’re starting to plant energy crops now, but if you look at where we are globally, the proportion of energy that’s generated from dedicated energy crops in most countries that have a large biomass supply, that tends to be quite small,” Smith points out. It’s likely that bioenergy cropping systems of the future will have primary, secondary and even tertiary uses, propelling bioenergy systems into mainstream markets, according to the study.
In addition, dedicated energy crops have not undergone the centuries of improvement that characterized major food crops, so there’s still plenty of room to grow. “Many of the energy crops we’re starting to use, like miscanthus and switchgrass, we’ve only really started to use them,” Smith says. “We haven’t had many years of selective breeding or even genetic modification with these crops. So I think there’s a great potential to increase yield in the future as we find better genotypes and better ways of managing the crops.” In the U.S., the study’s authors cite, long-term breeding of switchgrass is beginning to produce large yield gains that will continue to improve. And hopefully other energy crop improvements won’t be far behind.
But the U.S. isn’t in the region that tops the list of technical energy crop potential in 2050. Instead, South America takes a powerful lead with an estimated 189 exajoules per year, followed distantly by central Africa with 86, according to the study. The regional breakdown of the potential of about 400 exajoules is based on an imaging assessment model that estimates the technical potential of industrialized countries, which includes the U.S. and Europe, at 30 exajoules. Latin America’s estimated potential for 2050, divided into two regions, is 200 exajoules; Africa’s is 145 and divided into five regions; and China, divided into four regions, has a technical potential of 21 exajoules.
South America also comes out on top in estimated area available for biomass production in 2050, at 0.63 gigahectares, or 630 million hectares (1.6 billion acres). Again and not surprisingly, central Africa comes in second with 280 million hectares, according to the model, and industrialized nations will have an estimated 100 million hectares.
The study also takes into account future technologies that will enable extraction of other useful products from energy crops. In fact, the ability to extract high-value products first with the lower-value residues being used for energy production would most likely make energy crops more economic, it says.
But the main driving force behind energy cropping uptake will be social and environmental benefits such as carbon sequestration opportunities, job creation, support for rural communities, pride and independence, improved social cohesion, and of course reduced dependency on imported oil, the study concludes. Future opportunities for energy crops include development of biorefineries, atmospheric carbon scrubbing, and the growing trend toward small-scale distributed energy systems, it predicts.
But as tremendous potential sits on the horizon, barriers to energy crop market penetration loom, including practical difficulties to biomass projects such as: the public’s perception of the technology as dirty; the challenge to secure biomass fuel supplies; high demand for water and nutrients by some energy crops; and difficulties for conversion plants in achieving economies of scale. Besides that, though, other obstacles such as competition for land also stand in the way, along with the current power generation and distribution infrastructure. And there’s the ever-present policy and incentives issue.
“I think policy would be a barrier,” Smith says. “In many areas, there’s no market penetration because it’s just not economical for growers to invest in energy crops.” Smith speculates that might be because of risk, the fact that energy crops don’t fall under their expertise, or maybe because energy crops are less flexible then annual crops. Whatever the reason, relatively small areas of energy crops are being grown. “Policy could certainly play a part in that, either by providing guaranteed pricing for the products, or it could provide guaranteed markets in conjunction with the energy users.” Subsidies, tax breaks and other economic measures could be a strong force behind an expansion of the global energy crop sector. “I think that would make the difference between relatively small market penetration and a really quite substantial uptake,” Smith says.
Uplift for Uptake’s Sake
To encourage energy crop uptake in the U.K., the Department of Energy and Climate Change announced in March 2010 an increase of half a Renewables Obligation Certificate (ROC) for dedicated energy crop technologies. The U.K.’s Renewables Obligation is banded by technology type and provides incentives in the form of ROCs per megawatt hour to a multitude of renewable technologies. Dedicated energy crops now receive two ROCs, while cofired energy crops still receive one. “The DECC decided it wanted to support energy crops and was looking to stimulate the energy crop sector,” says Tricia Wiley, spokesperson for the U.K.’s Renewable Energy Association. Other biomass technologies receive between 1.5 and 2 ROCs.
Strangely, though, the DECC left energy crops out of the technologies considered eligible for grandfathering into the Renewables Obligation banding, which is reviewed every four years, sometimes amending ROC levels. They sit outside the category with cofiring, bioliquids, and combined heat and power. “Unlike contracts for regular biomass, we did not receive any evidence that long-term 15- to 20-year contracts for energy crops could be delivered,” the DECC explains. Energy crop prices are still variable and the DECC fears grandfathering could mean over- or under-compensating, Wiley says.
Some members of the REA, however, argue that grandfathering energy crops would be beneficial for investment purposes. “There are still quite a lot of capital costs and things like that that go into arranging a contract and setting up to grow energy crops,” Wiley says. “So they felt that grandfathering was needed to ensure investment in that. I think they were quite disappointed it wasn’t grandfathered.”
Many energy crop farmers agree. “That’s one of the reasons why the power stations have not gotten financial closure and have not started procuring that stock,” says Jonathan Scurlock, chief advisor of Renewable Energy and Climate Change for the U.K.’s National Farmers’ Union. “Until those plants break ground, they won’t send anyone out to secure contracts with farmers.”
The U.K. has about 10,000 hectares planted with energy crops, miscanthus being the most common, and also incentivizes them through its Energy Crop Scheme, part of the Rural Development Programme in England. The scheme issues establishment grants for approved energy crops, designed to cover a percentage of the set-up costs, including ground preparation, fencing, purchase of planting stock, planting, weed control and first-year cutback. The program only lasts until 2013, however, and Wiley says there is no talk yet of extending it.
“We’re almost moving away now nationally from a situation of planting grants because they don’t seem to have worked very well,” Scurlock says. Between 2002 and 2006, the program issued flat grants of £1,000 ($1,500) per hectare, roughly half of the total planting cost. But after coming back in 2007, it now works off a formula to determine grant amounts. Farmers also have to prove the amount they’ve spent in order to be reimbursed. “It’s an administrative nightmare,” Scurlock says, adding that the government has been underwhelmed by the amount of interest the scheme has attracted. “Establishment grants were a good first step, but it’s not the ultimate solution to building this supply chain.”
Now, the DECC has proposed a new program to support renewables as well as low-carbon technologies. Electricity Market Reform will work in parallel to the RO through a feed-in tariff beginning in 2013 or 2014, according to Wiley. The government has proposed, however, that all new technologies fall under Electricity Market Reform instead of the RO by the year 2017. Therefore, the DECC must decide by then whether to grandfather the remaining technologies, including energy crops, into the RO banding.
In the U.S., the USDA’s Biomass Crop Assistance Program is designed to drive investment and interest in energy crops, but has hit some walls. Still, many agree that with the proper amendments, the program’s matching payments to farmers for biomass material could be an effective driver to spur development.
Whatever programs do the job, it seems governments all over the world need to step up incentives for energy crops if we’re ever going to realize the 400 exajoule-per-year potential. While that’s not the only change needed, it could be one of the most important.
But Smith doesn’t like to compare progress across oceans and explains that Europe and the U.S. have different anomalies to bear. “There are different challenges and probably both the U.S. and European Union have a long way to go to get in policies that encourage sustainable use of bioenergy and biofuels,” he says. “There’s significant progress to be made on both sides of the Atlantic.”
Author: Lisa Gibson
Associate Editor, Biomass Power & Thermal