Cellulosic Electricity: The Most Efficient Biomass

One of the easiest ways to utilise biomass to produce energy, is to partially substitute biomass for coal in a traditionally coal-fired power plant. Yorkshire based Drax power plant intends to do exactly that, making Drax the largest biomass producer of electricity in the UK.

Executives from Yorkshire-based Drax signed a deal with Alstom to build a processing plant that could prepare 1.5m tonnes per year of biomass for use in the power station. Under the plans, biomass would be ground into a fine powder and injected directly into the power station's coal-fired furnaces. Building work for the processing plant will start later in 2008 and the first part of the facility is expected to be completed by the end of 2009.

...Neil Crumpton, energy campaigner at Friends of the Earth, said that using biomass in power stations or combined heat and power schemes is a better use of the resource than, for example, turning it into liquid biofuels for use by diesel-engine vehicles. "Co-firing with biomass is a reasonable way forward - it's a logical extension of what Drax is already doing and I've got no qualms with it on that score. If it helps build the sustainable biomass market in the UK, then all well and good."

...To test whether co-firing would work, Drax has used a 2-3% mix of biomass in some of its coal-fired furnaces for several months already. In their current experiments, the biomass fuel is mixed directly into the coal as it burns but this technique would not work for larger quantities of biomass.

"When you burn just a few per cent of biomass, you can afford to use exactly the same lines as coal," said Patrick Fragman, managing director of Alstom, the company that will build the biomass processing plant at Drax. But, for a higher percentage, he said, dedicated infrastructure is needed.

Peter Emery, production director at Drax, said that the new processing plant was a crucial part of the power station's attempt to scale up their biomass usage. He also added that it would be able to handle a wide variety of biomass fuels.

Different biomass materials burn in different ways, so the processing plant needs to be able to handle the materials accordingly. The resulting fuels then need to be inserted into the coal-fired boilers at different positions to ensure they burn properly. Engineers at Drax estimate that it will take 1.5m tonnes of biomass to replace the energy that comes from 1m tonnes of coal. __Guardian

Biomass CHP or cellulosic electricity, is clearly the most efficient way of producing energy from cellulosic biomass. The only reason for taking the less efficient route of producing liquid fuels (BTL) from biomass is that most of the transportation infrastructure cannot run without liquid fuels, at this time. It will likely require 20 years or more to achieve significant conversion of transportation from liquid fuels to electric drives running on stored electricity. Even fuel cells will probably need to run largely on liquid fuels such as methanol, for the next 10 to 20 years minimum.

Previously published at Al Fin Energy

Cellulosic Fuels to Come Online 2008-2017

We are just now entering the era of cellulosic fuels, according to a new report from Research and Markets.

1. - The US biofuel industry especially ethanol production is expected to lead the global production during the forecasted period of 2008-2017.

2. - Corn is anticipated to dominate the [Ed: near] future ethanol production in the US, however, cellulosic ethanol requirements are expected to boom during the period 2008-2017.

3. - US biodiesel sector need strong support from the government as well as from technology point of view to sustain growth in future.

4. - Biodiesel prices in the US are expected to see a declining trend to push up commercial usage during 2008-2015.

5. - Supply of raw material (corn and soybean oil) will be a major concern for the US biofuel industry in coming years. Source_via_BusinessWire

Here again, we see a mixture of valid conclusion and popular misconception. Biocellulosic alcohols will lead one charge away from "food as feedstock." Biomass to liquids (BTL) will lead another--ultimately much larger--charge away from foods for feedstocks. Biodiesel from algae and non-edible oilseeds such as jatropha, is yet one more important leap from "foods as feedstocks" to foods and food-prices as a non-issue. Cellulosic electricity--substituting biomass for coal in co-generation plants--is yet another way that bioenergy will help to reduce oil costs--and thus reduce food costs.

Zeachem, Coskata, and a number of other small to medium bio-fuel plants will bring cellulosic biofuel product to market starting within the next year. In Europe, Choren is ready to bring BTL biodiesel to market, and looking to expand within North America in the next year.

Biomass, farm waste, agricultural waste, forestry waste, municipal waste, and industrial waste, are all available for making important contributions to the energy supply. It is a matter of making the necessary technological and managerial adjustments that will allow more industries and regions to take advantages of these resources which are currently going to waste.

Why Not Cellulosic Electricity? Bio-EtOH vs. EVs

The ongoing debate between promoters of cellulosic ethanol (or butanol) and electric vehicles (EVs) is heating up. Can you get more energy from biomass by converting to ethanol (or butanol) and burning it in flex-fuel vehicles, or by burning the biomass with (or in place of) coal in power generators--and run the vehicle (EVs) on the generated electricity?

According to the NREL report referenced above, converting biomass into cellulosic ethanol can be done at about a 45% efficiency (i.e. 45% of the energy of the biomass makes it into the fuel.) In contrast, biomass can be converted at 33-37% efficiency [pdf] when cofired. Combining this with the 5x improvement of drivetrain efficiency that comes with electric propulsion, and the same amount of biomass converted to what I'll call "cellulosic electricity" will take a vehicle 3.8x as far as it would in the form of cellulosic ethanol. In a more recent article on Biomass, Vinod Khosla states "we consider [Energy Return on Investment] a less important variable than carbon emissions per mile driven." If carbon emissions per mile driven are the most important variable, a 3.8x increase in miles driven on the same energy source will lead to a less than 27% of the carbon emissions per mile driven.

While cellulosic electricity is still not sufficient to displace all of our current petroleum use, it comes much closer than cellulosic ethanol. Biomass cofiring with coal also tends to reduce SOx and NOx emissions.

Biomass is a distributed resource, seldom available in large quantities in any one place. This will be a problem for the cellulosic ethanol and cellulosic electricity industries. Only a fraction of the available biomass will be close enough to existing coal plants that it will be practical to transport for cofiring. Cellulosic visionaries see a system of distributed ethanol plants, yet that still leaves the problem of getting the fuel to market, since the current pipeline system for petroleum products has difficulty accommodating ethanol.

On the other hand, while distributed direct- fired biomass generation of electricity is probably twice as expensive as cofiring with coal, distributed generation leads to opportunities for Combined Heat and Power (CHP), or cogeneration. CHP can displace heating fuels such as natural gas, propane, or electricity, and often have combined efficiency from 50% to 80%. In addition to the potential of displacing additional fossil heating fuel, cellulosic electricity is identical to the fossil fuel derived kind. Therefore, unlike cellulosic ethanol, cellulosic electricity is completely compatible with the existing electric grid, leading to far fewer difficulties in transport.

Source

The calculations are still in flux. But it is important to include "cellulosic electricity" in the total planning, when looking at biomass power. More here and here