Electricity from Biomass: More than you Think?


Fuel of the Future or of the Past?

To be honest, I’m a bit of a sceptic when it comes to bioenergy in some of its guises (though not all). I have concerns over its sustainability and fuel economics under certain scenarios, particularly at very large scale – which I’ll cover in another article.

Perhaps I’m not the only one? For sure, the generation of electricity from various “bio” sources (here I’ll call it all “biopower”) is a topic that receives comparatively little coverage within energy-focused news outlets, twitter conversations, industry get-togethers and the like. Sometimes the coverage it does get is negative (sustainability issues in particular). It’s swamped by the buzz around solar and wind in particular.

That isn’t too surprising. After all, the latter two are faster growth sectors, in terms of investment dollars and newly installed MWs of capacity. Perhaps biopower should be regarded as an electricity source consigned to the past rather than one for the future?

The latter view has some historical logic to it. After all, the trend is that biomass as a fuel has been shrinking in terms of its share as a world energy source, as neatly summarised on the chart below. Coal was first to eat into its dominance in the 19th century (during the industrial revolution), then oil and gas ate away further market share during the last hundred years.

 

Figure 1. Share of Fuels in the Global Energy Mix Across Modern History

fuels in history

Source of chart: World Economic Forum

 

That last chart covers all energy though, not just electricity. Much of the biomass usage it covers was for heating, cooking and lighting. In recent years, oil-replacing liquid biofuels are included in the total too.

 

A Significant Energy Mix Share

So let’s look closer to the present day and focus in on electricity. Below is the mix of sources as of the end of 2014, on a global basis and in three other example markets. The chart is based on electricity actually generated (GWh), rather than installed capacity (GW).

 

Figure 2. Electricity Generation Mix (end 2014)

energy mixes

Data sources: REN21, US EIA, www.destatis.de, UK DECC

 

Of course, unlike wind or solar, biopower can include a wide range of different feedstocks and sources. By way of example, here’s available data for two of the above examples – worldwide and the UK – to show how generated biopower subdivides by source:

 

Figure 3. Biopower by Source

biopower sources

(MSW = municipal solid waste)

 

Looking back to the first chart, conventional thermal generation plus hydro and nuclear still account for the majority of electricity generation – even in renewable-progressive Germany. In each case wind is the biggest of the non-hydro renewables. Notably though, given the profound difference in their relative levels of news coverage, biopower accounts for a greater share of the mix than solar in every case. This is true even in Germany, with its world-leading base (but low capacity factor) of installed solar PV.

Here’s another chart for Germany, taken from the excellent www.energy-charts.de site provided by Fraunhofer ISE. It shows energy generation for a sunny, summer week in July 2015.

 

Figure 4. A Week of Power Generation in Germany

German week

 

Solar energy, with its huge installed capacity, arrives in regular yellow chunks each day. Biomass, the green stripe near the bottom, might never reach the giddy power heights of solar but instead generates steadily and consistently, day and night. Is the area in green as big as the areas in yellow over the week (area being power x time = energy)? I haven’t worked it out, but it probably isn’t far off. In winter, when those yellow areas are smaller, biomass certainly out-generates solar.

The US and Germany are in fact the two largest biopower markets in the world. China, Brazil and Japan make up the rest of the top five. In each of these other three markets too, biopower provided more GWh in 2014 than did solar. (Note that Germany, China, Japan and the US are also all in the top 5 solar PV markets by installed capacity).

It’s also worth noting that biopower has certainly not been a no-growth or declining market.

According to REN21’s “First decade: 2004 – 2014” review, global biopower capacity grew by 49GW from 2004 to the end of 2013. Solar PV grew by almost three times as much (by 136GW). However given the difference in capacity factors between the two sources, it’s possible – likely I’d say – that the growth in generated electricity (i.e. GWh rather than GW) was at least equivalent. [I haven’t found data on that, but let’s assume a generous 20% capacity factor for all that new PV; certainly too high in reality, given that much was in Germany. Then 60% capacity factor for new biopower would be enough to ensure that the GWh electricity generation of the two would be equivalent.]

 

If not Biopower, then lots of something else…

It’s important to stress that my objective in writing this article is certainly not to underplay the phenomenal growth that solar is enjoying! Or to promote biopower (which I have various criticisms of). Solar will certainly eclipse biopower generation sooner (e.g. Worldwide, US, Germany) or later (UK). When end-2015 figures are in, it’ll be interesting to see the German situation in particular. In other rapidly growing solar markets, biopower isn’t even a player.

However, I believe it is useful to highlight the fact that significant quantities of electricity are being generated from bio-derived sources, a fact which receives less attention than one might expect. And in markets where biopower exists it has been growing, not declining.

So perhaps it isn’t an electricity source whose best days are behind it?

The answer will be significant from an energy mix point of view. I’ve read lots of discussion recently about replacing coal or other fossil sources with energy generated from solar or wind power, perhaps aided by big investments in energy storage to provide the kind of reliability of output that we need. I’ve seen less support for the case that biopower might have a role to play (despite the fact that it is inherently “dispatchable”). Indeed some commentators, including proponents of other renewable power sources, question the sense of including biopower in the mix at all.

If the latter is your view then, at least in the markets highlighted above, removing biopower from the current electricity-generation mix means a very substantial capacity of wind and/or solar (or substantial efficiency savings) is needed to replace the energy it generates, along with a solution to the “on demand” ability that biopower provides.

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