Ways to Generate Energy

Solar

Solar power is the fastest growing energy technology in the world.  In our town, Totnes, Transition have been educating and facilitating installation of household-scale solar PV for some time.  And we have installed solar on the roofs of two community-scale buildings, Leatside Surgery and Follaton Community Centre.  Where TRESOC can really make a difference in is in relation to scale and the community investment mechanism by which we can scale up from there to thousands of roofs.

TRESOC’s goal is to build a portfolio based on a range of natural resources, but solar certainly offers a fast track.  Our friend, David Saunders at Bristol Power Co-op writes: “Wikipedia (on Photovoltaics) has been comparing and contrasting the government’s forecast that we’ll be generation quite a lot of our energy renewably by 2050, with the geometric growth of solar – and notes that solar is 7 “doublings” away from providing all world energy demand, and that solar has been growing 40% year on year, i.e. doubling every two years.  That would give us 100% solar energy by 2027.  And then … in the last 4 years the cost of solar systems halved twice, and all of a sudden it’s cheaper than grid electricity for 98% of the world’s population.  Hardy surprisingly, the growth rate notched up closer to 60% in 2013, and (for instance) Kenya has decided to have 50% solar energy by 2016.  At that rate my 2022 starts to look not far off the mark, while 2024 would be the best estimate.  There comes a time of course when everything unites behind the solution which has become the no-brainer, hands-down obvious winner.  Solar.”

Basic facts on solar PV from the Renewable Energy Association

Hydro

From the Renewable Energy Association on hydro: “Hydro power is produced when the kinetic energy of flowing water, is converted into electricity by a turbine connected to an electricity generator. Though the UK generates only about 1.3% (5000GKh) of its electricity from hydro electric schemes, hydroelectricity has proven to be an efficient and reliable technology, as most modern plants have energy conversion efficiencies above 90%. Research estimates the remaining hydro potential in the UK ranges from 850-1550MW, which could contribute significantly to the UK’s renewable energy targets.”

The River Dart runs right through our town, bubbling up on Dartmoor and pouring out at Dartmouth.  We are a coastal market town, with a history of water-based trade and mills, so it makes sense that we would explore this way to generate energy.

In a ground-breaking collaboration with Plymouth University’s Department of Marine Engineering, TRESOC created a research project to investigate the potential for power at the Anchor Stone Channel at Dittisham.  Read the whole story here, on our blog.  This led to a much broader research project for a whole team of MSc students to determine the potential for investment in marine renewables in the South West.  Download their excellent presentation here (it’s a large.pptx file, about 60MB): https://dl.dropboxusercontent.com/u/16415034/TRESOC_MRE_4DEC_v2.pptx.

Wind

Wind remains the most cost-effective way to generate electricity renewably.  TRESOC has deep experience in this area, partnering with wind developer Infinergy to position two turbines on the best site for wind in the South Hams.  These two, community-owned turbines would have met the energy demand of 2,500 homes.  Unfortunately, our application was turned down in August 2012.  Read the whole story here, on our blog.

Biomass & Energy from Waste

This is the most complicated area that we pursue because the category breaks down into many sub-categories.  Energy can be recovered from waste by various (very different) technologies. It is important that recyclable material is removed first, and that energy is recovered from what remains, i.e. from the residual waste.  Energy from waste (EfW) technologies include:

  • Combustion in which the residual waste burns at 850°C and the energy recovered as electricity or heat
  • Gasification and pyrolysis, where the fuel is heated with little or no oxygen to produce “syngas” which can be used to generate energy or as a feedstock for producing methane, chemicals, biofuels, or hydrogen (see also landfill gas and sewage gas)
  • Anaerobic digestion, which uses microorganisms to convert organic waste into a methane-rich biogas that can be combusted to generate electricity and heat or converted to biomethane. This technology is most suitable for wet organic wastes or food waste. The other output is a biofertiliser.

We are currently working on a pyrolysis research project that uses biomass, in this case, wood waste, to generate electricity.  The challenge is what to do with the heat it also generates?