Neither CCS nor biofuels offer a path to CO2 management because they can't possibly scale to the size of the problem. By 2035 the EIA forecasts annual US CO2 emissions of 6.32 billion metric tons, 38% of which (2.40 billion) will be from US coal plants alone. There's no space underground to store that much CO2 every year, and trying to do so will endanger the water supply.
CCS (conventionally understood to mean amine scrubbing for CO2 capture and underground storage for sequestration) is fundamentally impractical because of water issues. Energy pundits tend to neglect water issues as beyond their narrowly siloed expertise, but water is a deal-breaker. Amine scrubbing will double the already huge water consumption of coal plants. Sequestration at the scale required, even if practical, will displace salty formation fluids, which might eventually contaminate the groundwater.
Extrapolating EOR experience to justify CCS is an elementary error. The huge Permian Basin oil field’s current annual enhanced oil recovery (EOR) demand is only 7 million tons of CO2, about the annual output of a single 1 GW coal-fired power plant. See this article from POWER magazine at http://www.powermag.com/carbon-control-the-long-road-ahead/. Clearly, EOR in depleted oil and gas reservoirs can't handle the expected 2 BILLION tonne volume of CO2 that must be stored each year just from coal power generation in the US alone. CO2 for EOR is of benefit to the oil companies, but no help for global warming.
Deep saline formations have lots of pore space, i.e. spaces between grains in the rock, but -- unlike depleted reservoirs where EOR has worked -- the pores in the rock are full of very salty brine at high pressure. For example, the FutureGen sequestation will displace 47,500 ppm brine (saltier than seawater) from the Mt. Simon formation under Illinois. No one knows or evidently cares where this brine ends up. There is no plan to handle it.
Moving the brine out and the CO2 in will be impossible at the scale of billions of tonnes each year. No one will insure the risk. We hear a lot about the 25 years of successful experience with EOR, but EOR in depleted reservoirs (empty tanks) is immaterial to the viability of utility-scale CO2 sequestration, which must be in deep saline formations (full tanks).
Once injected into the formation, the CO2 would have to be securely contained. Closure is of the essence. Experience with an open system, like EOR, is inapposite. An open system for secure storage is nonsense. This fundamental point seems to have been overlooked. In 2010, a sobering article appeared in the refereed Journal of Petroleum Science and Engineering (70:123-130), authored by two distinguished full professors of petroleum engineering, Christine Ehlig-Economides and Michael J. Economides. Here's a quote from the abstract:
“Published reports on the potential for sequestration fail to address the necessity of storing CO2 in a closed system. Our calculations suggest that the volume of liquid or supercritical CO2 to be disposed cannot exceed more than about 1% of pore space. This will require from 5 to 20 times more underground reservoir volume than has been envisioned by many, and it renders geologic sequestration of CO2 a profoundly non-feasible option for the management of CO2 emissions.”
Cramming 2 billion tonnes each year into deep saline formations is a vain hope to begin with. The danger of saline intrusion into the groundwater and CO2 plumes erupting and killing people must be weighed against the trivial benefit to global warming, which is the ostensible motivation for FutureGen. If it's expected to be an open system, like EOR, where there is mass flow through system boundaries, then secure containment of the brine and the CO2 will not be possible. Better to save the billion dollars to be wasted on this futile and dangerous experiment.
Solid biofuels require water to grow, and they need to be dried so they can be transported and burned. The energy and water needed to deliver this low-grade fuel need to be taken into account. Liquid biofuels, like corn ethanol, have disappointed, despite confident predictions. Gaseous biofuels from waste-to-energy schemes involving anaerobic digestion (AD) create a water pollution problem in order to solve an air pollution problem, which they might even aggravate. AD sludge (digestate) is heavy to transport and leaches nitrates into the groundwater. The AD product, methane, is a potent greenhouse gas that has so little commercial value (due to the abundance of methane from shale oil production) that it just gets flared so it won't get in the atmosphere. Biofuels might have a small role in niche applications (e.g. sugar ethanol in Brazil).