M i s c a n t h u s B r e e d i n g
Energy crops - frequently asked questions...and answers
1. I don’t believe human use of fossil fuels has any impact on climate change; can you show me quantitative evidence for climate changes in terms of climate anomalies?
Atmospheric CO2 concentrations have increased from 270 to 400 parts per million (ppm) over the last 200 years and from 340 to 400 ppm in the last 20 years. Global temperatures have increased by ~1.0°C since 1900 due to CO2 rises. Increases of 0.5°C over oceans, and 1 - 3°C over land. In the Arctic about half the sea ice that used to be there is gone. There is a strong evidence for increased floods, but data on droughts is not good enough to establish a clear trend. Eight out of the last ten years have been the warmest on record. Sea level rises combined with storms are set to inundate many large low altitude cities leading to environmental refugees and global upheaval. The sharpest increase in temperatures in the last period only fits with the increasing CO2. [p125 in Global Warming, The Complete Briefing]
2. What can be done about climate change?
We need to de-carbonise our energy systems as fast as possible by developing renewable alternatives appropriate to different regions of the world. A whole range of technologies will be required – in particular improving efficiency, as well as generation from less carbon intensive sources such as nuclear, wind, wave, hydro, solar, tidal and biomass.
3. What unique features does biomass possess?
Biomass is a storable form of renewable energy (most other renewable energies are not storable) that can be used as a direct replacement for fossil fuels in many applications. Biomass is the only renewable energy source capable of replacing products such as platform chemicals, plastics and aviation fuel, all currently derived from fossil fuels.
4. With the population increasing until 2050, and the prospect of additional storms, droughts and floods caused by climate change, is it wise to use land for non-food energy crops?
Global agriculture produces approximately three times the ‘basic’ consumption needed to support the 2013 population of 7 billion people. Between 30 and 50% of food is wasted in advanced economies. There are large areas of less productive (marginal) land in the USA, Eastern Europe, Brazil, India and Africa that have been abandoned due to low fertility, which could be used for energy crops such as sorghum, miscanthus and switchgrass. There is also the prospect of using non-land requiring biomass such as algae.
5. Can you quantify the potential in Britain for growing non-food crops for bioenergy?
There is general consensus that Britain has a theoretical potential 1 million hectares (ha) of land available for bioenergy production, with a realistically achievable figure of approximately 350,000 ha in use by 2020. In the short term this includes lower grade arable lands, but the focus needs to shift to non-arable grade lands.
6. Is it right to grow energy crops in the UK, and shouldn’t we be concentrating on food production and ensuring Britain can feed its growing population?
Right now in the UK we need 0.6 ha of land to feed one person. With a diet that reduces greenhouse gas emissions by 25% the land requirement could be reduced to 0.4 ha per person.
7. How might (our) consumer diet influence the land areas needed to support the population nutritionally and energetically?
Britain cannot feed itself unless diets change and the population doesn’t grow. It has been calculated that a nutritionally balanced diet could be produced on 0.16 ha of land per person. Under this scenario meat consumption would be small. It could be more favourable to grow high value, easily transportable crops (such as food) elsewhere, and bulky energy (biomass) crops locally.
8. Is it right to depend on other countries for our food in order to allow us to produce fuel? What are the greenhouse gas (GHG) benefits and costs of local food or local biomass fuel production?
We already depend heavily on overseas food. In most years the UK exports 1.5 million tonnes of wheat. Additionally our diet includes many items we cannot grow in the UK. Greenhouse gas benefits and costs may not be improved by growing certain foods locally if the land or climate is better suited elsewhere.
9. How much energy can Britain produce from biomass?
Britain can generate 3% of the energy demand from 10% of current agricultural land. This is excluding protected areas, peat soils and national parks. This figure is for current (2013) conditions.
10. Have the soil organic carbon losses on conversion from grassland to energy crops been quantified, and do these negate any fossil fuel carbon savings?
Yes, the figures have been quantified and no, the fossil fuel carbon savings are not negated. Conversion of 10% of agricultural land to miscanthus is estimated to mitigate 3.2 million tonnes of CO2 per year. When grassland is replaced with miscanthus short term changes in soil organic carbon can be 10% of the total stock in the first two years, but after six years it has been shown that there is no net carbon loss because new carbon replaces older carbon. The displacement of livestock farming (with heavy greenhouse gas emissions in terms of CH4 and N2O) is likely to be a further GHG benefit.
11. Where in Britain is a biomass industry likely to develop?
The most productive areas of Britain for growing miscanthus are in the south-west. The highest demand is in the east. Fuel formatting (bales, chips or pellets) will be crucial in determining the logistics of supply and demand. Ultimately the location will depend on government policy.
12. Can’t I do more with improvements in efficiency rather than investment in an alternative fuel source such as biomass?
It’s not an either / or solution, it’s important to implement both. Yes we should improve fuel efficiency, but we will always consume energy and therefore need to do so sustainably.
13. Fossil fuels are still affordable and convenient, when should I change over and where can I buy a bioenergy system to heat my home?
There are a number of biomass boiler and biomass fuel suppliers available who can provide useful information regarding what savings can be made and what fuel supply will be most appropriate for you.
14. Is the bioenergy supply chain mature?
Not yet, but it is maturing rapidly. Increased uptake will help ensure its maturity.
15. Can you show some cost-benefit scenarios and what would be the payback time compared with the projected costs of heating with fossil fuels?
Biomass is the best solution for heating ‘off grid’ houses in rural areas such as Mid-Wales.
16. Will energy crops be grown in large blocks that will ruin the view?
This very much depends on the areas planted. It may be preferable to plant in machinable widths interspersed with other land use types. Modern miscanthus hybrids are less than 3 metres tall, as opposed to traditional varieties, which were typically over 4 metres.
17. Will large machinery, and lorries transporting biomass, damage rural roads?
No. Biomass harvesting and transportation requires less machinery than wheat and some other crops. Energy crops such as miscanthus are perennial, which do not require annual planting and also require low to zero maintenance once established.
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